Patent Application
20200368094
This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2019-094440 filed on May 20, 2019 and Japanese Patent Application No. 2019-094439 filed on May 20, 2019, the contents of which are incorporated herein by reference.
The present disclosure relates to a power assist suit that supports motion of a left thigh and a right thigh with respect to a waist of a wearer.
In recent years, various power assist suits that assist (support) lifting motion and lowering motion of object have been disclosed. These power assist suits are configured to appropriately assist the motion of the wearer of the power assist suit assuming a case where the wearer is holding an object. For example, at a time of a lifting motion of the object, the power assist suit assists an operation of standing up while holding the object from a state in which the wearer lowers the waist and grips the object.
For example, JP2018-061663A discloses a power assist robot apparatus configured to allow the wearer to select one motion mode among walking, loading, half-sitting posture, and damper motion of the wearer. The wearer wearing the power assist robot apparatus can select one motion mode among walking, loading, half-sitting posture, and damper motion from an operation type input unit to obtain a desired assist operation.
Furthermore, in recent years, there have been various power assist suits that reduce a burden of the wearer's waist and the like in various fields such as manufacturing, distribution, construction, agriculture, care, and rehabilitation.
For example, the assist device described in the following JP2018-199186A includes a body wearing tool to be worn on the body of a subject including the periphery of an assist target body part of the wearer, and an actuator unit that is to be worn on the body wearing tool and the assist target body part and that assists a motion of the assist target body part. The actuator unit includes an output link that is rotated around a joint of the assist target body portion to be attached to the assist target body portion, and an actuator including an output shaft that generates an assist torque that assists the rotation of the assist target body portion via the output link.
The output shaft of the actuator is connected to an inner end of a spiral spring. An outer end of the spiral spring is connected to a speed-increasing shaft of a speed reducer that reduces a rotation angle from the output shaft of the actuator via a pulley. A speed-reducing shaft of the speed reducer is connected to the output link. An output link rotation angle detection unit that detects a rotation angle of the output link is provided on the speed-increasing shaft of the speed reducer. Further, a motor rotation angle detection unit that detects a rotation angle of the output shaft of the actuator is provided.
A synthetic torque stored in the spiral spring is obtained from the rotation angle of the output shaft detected by the motor rotation angle detection unit, the rotation angle of the output link detected by the output link rotation angle detection unit, and a spring constant of the spiral spring. Further, a wearer torque is extracted from the obtained synthetic torque, and an assist torque corresponding to the wearer torque is output from the actuator.
In the power assist robot apparatus described in JP2018-061663A, since the wearer needs to select the motion mode from the motion type input unit before starting his/her own motion and operation, this selection operation is troublesome. For example, when the wearer moves by walking from a wearing room of the power assist robot apparatus to a work site, performs loading operation from the half-sitting posture at the work site, and moves by walking from the work site to the wearing room, the motion mode needs to be changed sequentially to walking, half-sitting posture, loading, and walking, which is troublesome. In addition, when the wearer is in a hurry, change of the motion mode may be forgotten, or work efficiency may be reduced.
Furthermore, in the assist device described in JP2018-199186A, when a malfunction occurs in the output link rotation angle detection unit, it is difficult to accurately detect the rotation angle of the output link, and an inappropriate assist torque is output by the actuator, and the wearer may feel uncomfortable. In addition, in the event of an assist torque exceeding an upper limit of a mechanical strength of the spiral spring being output by the actuator, an appropriate assist torque cannot be output suddenly due to deformation of the spiral spring or the like, and when the load is lifted or the like, the wearer may suddenly feel the load and feel uncomfortable when lifting an object or the like.
The present disclosure provides a power assist suit capable of automatically and appropriately switching a motion mode without requiring switching of the motion mode by a wearer.
Furthermore, the present disclosure provides a highly reliable power assist suit that can output an appropriate assist torque with an actuator without causing a sense of discomfort to a wearer.
According to a first illustrative aspect of the present disclosure, a power assist suit includes: a body wearing tool configured to be worn around at least a waist of a wearer; a left actuator unit configured to be attached to the body wearing tool and worn on a left thigh of the wearer, such that the left actuator unit generates an assist torque of assisting a motion of the left thigh with respect to the waist of the wearer; a right actuator unit configured to be attached to the body wearing tool and worn on a right thigh of the wearer, such that the right actuator unit generates an assist torque of assisting a motion of the right thigh with respect to the waist of the wearer; a left-torque-related amount detector configured to detect a left-torque-related amount, which is a torque related to a left wearer torque and a left assist torque, the left wearer torque being a torque input from the left thigh of the wearer to the left actuator unit, the left assist torque being the assist torque generated by the left actuator unit; a right-torque-related amount detector configured to detect a right-torque-related amount, which is a torque related to a right wearer torque and a right assist torque, the right wearer torque being a torque input from the right thigh of the wearer to the right actuator unit, the right assist torque being the assist torque generated by the right actuator unit; and a controller configured to automatically switch a motion mode based on the left-torque-related amount and the right-torque-related amount.
According to a second illustrative aspect of the present disclosure, the motion mode includes three modes whose assist motions are different from one another, the motion mode including: a lifting mode of assisting a lifting operation in which the wearer lifts up an object; a lowering mode of assisting a lowering operation in which the wearer puts down the object; and a walking mode of assisting a walking motion in which the wearer walks. The controller is configured to switch or maintain the motion mode to one of the lifting mode, the lowering mode, and the walking mode, based on the left-torque-related amount and the right-torque-related amount.
According to a third illustrative aspect of the present disclosure, the controller is configured to: switch the motion mode to the lowering mode when the left-torque-related amount and the right-torque-related amount relates to the torques in a direction in which the wearer leans forward and are larger than a first predetermined threshold, and switch the motion mode to the lifting mode when the left-torque-related amount and the right-torque-related amount relates to the torques in a direction opposite to the direction in which the wearer leans forward and are larger than a second predetermined threshold.
According to a fourth illustrative aspect of the present disclosure, the left-torque-related amount detector includes a left thigh angle detector configured to detect a swing angle of the left thigh with respect to the waist of the wearer. The right-torque-related amount detector includes a right thigh angle detector configured to detect a swing angle of the right thigh with respect to the waist of the wearer.
According to a fifth illustrative aspect of the present disclosure, the power assist suit further includes a storage unit in which a learning model is stored. The controller is configured to perform a machine learning with the learning model, such that the controller adjusts values of the first predetermined threshold and the second predetermined threshold, respectively.
According to a sixth illustrative aspect of the present disclosure, a power assist suit includes: a body wearing tool configured to be worn around at least a waist of a wearer; a left actuator unit configured to be attached to the body wearing tool and worn on a left thigh of the wearer, such that the left actuator unit generates an assist torque of assisting a motion of the left thigh with respect to the waist of the wearer; a right actuator unit configured to be attached to the body wearing tool and worn on a right thigh of the wearer, such that the right actuator unit generates an assist torque of assisting a motion of the right thigh with respect to the waist of the wearer; and a controller configured to control the left actuator unit and the right actuator unit. Each of the left actuator unit and the right actuator unit includes: an output link configured to be worn on one of the left thigh and the right thigh of the wearer and to move rotationally around a joint of the one of the left thigh and the right thigh; an actuator including an output shaft configured to generate the assist torque of assisting a rotational movement around the joint of the one of the left thigh and the right thigh via the output link; an elastic member configured to accumulate a synthetic torque obtained by synthesizing the wearer torque input from the output link moved rotationally by a force of the wearer and the assist torque input from the output shaft in the one of the left thigh and the right thigh, one end of the elastic member being connected to the output link, the other end of the elastic member being connected to the output shaft of the actuator; and a deformation state detector configured to detect a deformation state in which the elastic member is deformed. The controller includes: a synthetic torque acquisition unit configured to acquire the synthetic torque accumulated in the elastic member based on the deformation state of the elastic member, the deformation state being detected with the deformation state detector of each of the left actuator unit and the right actuator unit; and a spring failure determination unit configured to determine whether the elastic member of each of the left actuator unit and the right actuator unit is to fail, based on the synthetic torque accumulated in the elastic member acquired via the synthetic torque acquisition unit.
According to a seventh illustrative aspect of the present disclosure, the spring failure determination unit is configured to determine that the elastic member is to fail when the synthetic torque acquired via the synthetic torque acquisition unit is equal to or greater than a predetermined torque threshold.
According to an eighth illustrative aspect of the present disclosure, the power assist suit further includes a power supply unit configured to supply an electric power to the left actuator unit and the right actuator unit. The controller includes a power supply control unit which controls to stop supplying the electric power to the left actuator unit and the right actuator unit when the spring failure determination unit determines that the elastic member is to fail.
According to a ninth illustrative aspect of the present disclosure, the deformation state detector includes: an output shaft rotation angle detection device configured to detect a rotation angle of the output shaft; and an output link rotational movement angle detection device configured to detect a rotational movement angle of the output link. The synthetic torque acquisition unit is configured to acquire each of the synthetic torques based on the rotation angle of the output shaft detected by the output shaft rotation angle detection device and the rotational movement angle of the output link detected by the output link rotational movement angle detection device.
According to a tenth illustrative aspect of the present disclosure, each of the left actuator unit and the right actuator unit includes a speed reducer including a speed-reducing shaft connected to the output link, and including a speed-increasing shaft connected to the output link rotational movement angle detection device.
According to an eleventh illustrative aspect of the present disclosure, A power assist suit includes: a body wearing tool configured to be worn around at least a waist of a wearer; a left actuator unit configured to be attached to the body wearing tool and worn on a left thigh of the wearer, such that the left actuator unit generates an assist torque of assisting a motion of the left thigh with respect to the waist of the wearer; a right actuator unit configured to be attached to the body wearing tool and worn on a right thigh of the wearer, such that the right actuator unit generates an assist torque of assisting a motion of the right thigh with respect to the waist of the wearer; a power supply unit configured to supply an electric power to the left actuator unit and the right actuator unit, and a controller configured to control the left actuator unit and the right actuator unit. Each of the left actuator unit and the right actuator unit includes: an output link configured to be worn on one of the left thigh and the right thigh of the wearer and to move rotationally around a joint of the one of the left thigh and the right thigh; an actuator including an output shaft configured to generate the assist torque of assisting a rotational movement around the joint of the one of the left thigh and the right thigh via the output link; an elastic member configured to accumulate a synthetic torque obtained by synthesizing the wearer torque input from the output link moved rotationally by a force of the wearer and the assist torque input from the output shaft in the one of the left thigh and the right thigh, one end of the elastic member being connected to the output link, the other end of the elastic member being connected to the output shaft of the actuator; and a deformation state detector configured to detect a deformation state in which the elastic member is deformed. The controller is configured to control the left actuator unit and the right actuator unit, and the controller includes: a synthetic torque acquisition unit configured to acquire the synthetic torque accumulated in the elastic member based on the deformation state of the elastic member, the deformation state being detected with the deformation state detector of each of the left actuator unit and the right actuator unit; a first rotational movement torque acquisition unit configured to acquire a first rotational movement torque of moving rotationally the output link of each of the left actuator unit and the right actuator unit, based on the synthetic torque accumulated in the elastic member acquired via the synthetic torque acquisition unit; a current detector configured to detect a current value supplied to each of the left actuator unit and the right actuator unit; a second rotational movement torque acquisition unit configured to acquire a second rotational movement torque of moving rotationally the output link of each of the left actuator unit and the right actuator unit, based on the current value supplied to each of the left actuator unit and the right actuator unit detected with the current detector; and a device failure determination unit configured to determine whether the deformation state detector of each of the left actuator unit and the right actuator unit fails, based on a difference between the first rotation torque and the second rotation torque.
According to a twelfth illustrative aspect of the present disclosure, the device failure determination unit is configured to determine that the deformation state detector fails when the difference between the first rotational movement torque and the second rotational movement torque is equal to or greater than a predetermined error threshold.
According to a thirteenth illustrative aspect of the present disclosure, the controller includes a power supply control unit which controls to stop supplying the electric power to the left actuator unit and the right actuator unit when the device failure determination unit determines that the deformation state detector of the left actuator unit or the right actuator unit fails.
According to a fourteenth illustrative aspect of the present disclosure, the deformation state detector includes: an output shaft rotation angle detection device configured to detect a rotation angle of the output shaft; and an output link rotational movement angle detection device configured to detect a rotational movement angle of the output link. The synthetic torque acquisition unit is configured to acquire each of the synthetic torques based on the rotation angle of the output shaft detected by the output shaft rotation angle detection device and the rotational movement angle of the output link detected by the output link rotational movement angle detection device.
According to a fifteenth illustrative aspect of the present disclosure, the device failure determination unit is configured to determine whether the output link rotational movement angle detection device of each of the left actuator unit and the right actuator unit fails, based on the difference between the first rotation torque and the second rotation torque of each of the left actuator unit and the right actuator unit.
According to a sixteenth illustrative aspect of the present disclosure, each of the left actuator unit and the right actuator unit includes a speed reducer including a speed-reducing shaft connected to the output link, and including a speed-increasing shaft connected to the output link rotational movement angle detection device.
According to a seventeenth illustrative aspect of the present disclosure, the elastic members includes a spiral spring.
According to the first aspect of the present disclosure, the motion of the wearer can be appropriately determined based on the left-torque-related amount and the right-torque-related amount, and the motion mode can be automatically and appropriately switched by using the control device.
According to the second aspect of the present disclosure, since the motion mode includes the lifting mode for assisting the lifting operation, the lowering mode for assisting the lowering operation, and the walking mode for assisting the walking motion (movement of a work place), it is possible to appropriately assist an operation of the wearer that requires a physical strength.
According to the third aspect of the present disclosure, it is possible to appropriately switch between the lowering mode and the lifting mode based on the motion of the wearer.
According to the fourth aspect of the present disclosure, it is possible to appropriately realize the left-torque-related amount detection unit and the right-torque-related amount detection unit.
According to the fifth aspect of the present disclosure, by performing machine learning, it is possible to automatically adjust an optimal value of the first predetermined threshold and an optimal value of the second predetermined threshold for each wearer, which is convenient.
According to the sixth aspect of the present disclosure, the control device acquires the synthetic torque stored in each of the elastic members based on the deformation state of each of the elastic members detected by the deformation state detection device of each of the left actuator unit and the right actuator unit. Further, the control device determines whether the elastic member of each of the left actuator unit and the right actuator unit is to fail (e.g., deform, break, etc.) based on the synthetic torque stored in each of the elastic members.
Accordingly, when the control device determines that the elastic member of the left actuator unit or the right actuator unit is to fail, it is possible to adjust the assist torque by the actuator so as not to exceed an upper limit of a mechanical strength of the elastic member, and it is possible to avoid failure of the elastic member. In this way, it is possible to provide a highly reliable power assist suit that can output an appropriate assist torque with the actuators without causing a sense of discomfort, such has feeling a sudden load, to the wearer.
According to the seventh aspect of the present disclosure, the control device determines that one of the elastic members is to fail (e.g., deforms, breaks, etc.) when the synthetic torque is equal to or greater than the predetermined torque threshold. As a result, by acquiring the “torque threshold” at a time when the elastic member fails in advance via computer aided engineering (CAE) analysis, experiments, or the like, the control device can accurately determine whether the elastic member is to fail (e.g., deform, break, etc.) before the elastic member fails, and can improve the reliability of the power assist suit.
According to the eighth aspect of the present disclosure, the control device stops supply of power to the left actuator unit and the right actuator unit when it is determined that one of the elastic members is to fail based on the synthetic torque. As a result, the assist torque by the actuator is set to “0”, and thus the synthetic torque can be gradually reduced by a spring force of the elastic member. As a result, it is possible to provide a highly reliable power assist suit that does not cause a sense of discomfort, such as feeling a sudden load, to the wearer when assisting the lifting motion and lowering motion of an object.
According to the ninth aspect of the present disclosure, the synthetic torque acquisition unit acquires each of the synthetic torques based on the rotation angle of the output shaft detected by the output shaft rotation angle detection device and the rotation angle of the output link detected by the output link rotation angle detection device. Therefore, each of the synthetic torques can be acquired with a simple configuration including the output shaft rotation angle detection device and the output link rotation angle detection device when assisting the lifting motion and lowering motion of the object.
According to the tenth aspect of the present disclosure, the output link rotation angle detection device is connected to the output link via the speed reducer. Accordingly, since a change in the rotation angle of the output link can be increased and detected by the output link rotation angle detection device, it is possible to improve detection accuracy of the rotation angle of the output link, and to improve detection accuracy of the synthetic torque.
According to the eleventh aspect of the present disclosure, the control device acquires the synthetic torque stored in each of the elastic members based on the deformation state of each of the elastic members detected by the deformation state detection device of each of the left actuator unit and the right actuator unit. Further, the control device acquires the first rotation torque for rotating the output link of each of the left actuator unit and the right actuator unit based on the synthetic torque stored in each of the elastic members.
Moreover, the control device acquires the second rotation torque for rotating each of the output links based on the current value supplied to each of the left actuator unit and the right actuator unit. Further, the control device determines whether the deformation state detection device of each of the left actuator unit and the right actuator unit fails based on the difference between the first rotation torque and the second rotation torque.
Accordingly, when it is determined that the deformation state detection device of the left actuator unit or the right actuator unit fails, the control device can stop output of an inappropriate assist torque by the actuator. In this way, it is possible to provide a highly reliable power assist suit that can output an appropriate assist torque with the actuators without causing a sense of discomfort to the wearer when assisting the lifting motion and lowering motion of the object.
According to the twelfth aspect of the present disclosure, the control device determines that one of the deformation state detection devices fails when the difference between the first rotation torque and the second rotation torque is equal to or greater than the predetermined error threshold. As a result, by acquiring the “error threshold” at a time when one of the deformation state detection devices fails in advance via computer aided engineering (CAE) analysis, experiments, or the like, the control device can accurately determine whether one of the deformation state detection device fails, and can improve the reliability of the power assist suit.
According to the thirteenth aspect of the present disclosure, the control device stops supply of power to the left actuator unit and the right actuator unit when the device failure determination unit determines that the deformation state detection device of the left actuator unit or the right actuator unit fails based on the difference between the first rotation torque and the second rotation torque. As a result, the assist torque by the actuator is set to “0”, and thus the synthetic torque can be gradually reduced by the spring force of the elastic member. As a result, it is possible to provide a highly reliable power assist suit that does not cause a sense of discomfort, such as feeling a sudden load, to the wearer when assisting the lifting motion and lowering motion of the object.
According to the fourteenth aspect of the present disclosure, the synthetic torque acquisition unit acquires each of the synthetic torques based on the rotation angle of the output shaft detected by the output shaft rotation angle detection device and the rotation angle of the output link detected by the output link rotation angle detection device. Therefore, each of the synthetic torques can be acquired with a simple configuration including the output shaft rotation angle detection device and the output link rotation angle detection device when assisting the lifting motion and lowering motion of the object.
According to the fifteenth aspect of the present disclosure, the control device determines whether the output link rotation angle detection device of each of the left actuator unit and the right actuator unit fails based on the difference between the first rotation torque and the second rotation torque of each of the left actuator unit and the right actuator unit.
Accordingly, when a failure of the output link rotation angle detection device of the left actuator unit or the right actuator unit is detected, since the rotation angle of the output link cannot be detected accurately, the control device can stop output of an inappropriate assist torque by the actuator. In this way, it is possible to provide a highly reliable power assist suit that can output an appropriate assist torque with the actuators without causing a sense of discomfort to the wearer when assisting the lifting motion and lowering motion of the object.
According to the sixteenth aspect of the present disclosure, the output link rotation angle detection device of each of the left actuator unit and the right actuator unit is connected to the output link via the speed reducer. Accordingly, since a change in the rotation angle of the output link can be increased and detected by the output link rotation angle detection device, it is possible to improve detection accuracy of the rotation angle of the output link, and to improve accuracy of the first rotation torque.
According to the seventeenth of the present disclosure, by using the spiral spring, as compared to a case where the output torque of the actuator is adjusted via a current, the output torque can be adjusted by simply adjusting an amount of expansion or contraction of the spiral spring (that is, the rotation angle of the output shaft), so that the assist torque can be adjusted easily.
An overall structure of a power assist suit 1 will be described below with reference to
[Overall Structure of Power Assist Suit 1 (
As shown in the exploded perspective view of
The load detection units 71R, 71L are, for example, insoles of shoes, where the load detection unit 71R is disposed in a right shoe of the wearer and under a right foot of the wearer, and the load detection unit 71L is disposed in a left shoe of the wearer and under a left foot of the wearer. The load detection unit 71R is provided with a load detection unit 72R (e.g., a pressure sensor) capable of detecting a load around toes of the right foot of the wearer and a load detection unit 73R (e.g., a pressure sensor) capable of detecting a load around a heel of the right foot of the wearer. Although not shown, the load detection unit 71R also includes a wireless communication unit that wirelessly transmits detection signals from the load detection units 72R, 73R to the operation unit R1, a power supply of the communication unit, and the like. Similarly, the load detection unit 71L includes load detection units 72L, 73L, a wireless communication unit, a power supply, and the like, which are the same as those of the load detection unit 71R, and a description thereof will be omitted.
A control device 61 (see
The acceleration detection unit 75 is, for example, an acceleration sensor, and for example, is provided in the backpack portion 37, and detects a body motion acceleration, which is an acceleration of motion of a part of a body of the wearer (in this case, an upper body of the wearer). Since the backpack portion 37 is fixed to the back of the wearer, the acceleration detection unit 75 detects a body motion acceleration av in a spine-parallel direction along a back surface of the wearer (see
As will be described later, the control device 61 corrects the object mass (object weight) obtained based on the detection signals from the load detection units 72L, 72R, 73L, 73R using the body motion acceleration az obtained based on the detection signal from the acceleration detection unit 75, so as to obtain the load-related amount (in this case, the object mass or the object weight after correction).
The body wearing tool 2 (see
[Appearance of Body Wearing 2 (
As illustrated in
[Overall Structure of Frame Portion 30 (
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[Overall Structure of Waist Support Portion 10 (
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[Configuration of Backpack Portion 37 and Periphery of Backpack Portion 37 (
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Even when the upper body of the wearer is leaning forward, the cushion 37G (or a back rest portion 37C) that contacts the back is elongated from the shoulders toward the waist of the wearer, so that the actuator units (4R, 4L) that output the assist torques can be supported appropriately. Further, even when the upper body of the wearer is leaning left or right, the cushion 37G (or a back rest portion 37C) is in contact with a bending center on the back of the wearer, so that the actuator units (4R, 4L) that output the assist torques can be supported appropriately.
As illustrated in
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[Overall Structure of Jacket Portion 20 (
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[Overall Configuration of Right Actuator Unit 4R and Left Actuator Unit 4L (
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The output link 50R includes an assist arm 51R (corresponding to a first link), a second link 52R, a third link 53R, and a thigh wearing portion 54R (corresponding to a body holding portion). The assist arm 51R is rotated around a rotation axis 40RY by a synthetic torque obtained by synthesizing the assist torque generated by the electric motor in the torque generation unit 40R and a wearer torque due to the motion of the thigh of the wearer. One end of the second link 52R is connected to a tip end of the assist arm 51R in a manner rotatable around a rotation axis 51RJ, and one end of the third link 53R is connected to the other end of the second link 52R in a manner rotatable around the rotation axis 52RJ. The thigh wearing portion 54R is connected to the other end of the third link 53R via a third joint portion 53RS (in this case, a spherical joint).
Next, a link mechanism of the right actuator unit 4R will be described in detail with reference to
In the output link 50R illustrated in
One end of the second link 52R is coupled with the tip end of the assist arm 51R by a first joint portion 51RS in a manner rotatable around the rotation axis 51RJ. The first joint portion 51RS has a coupling structure in which a degree of freedom is one that allows the second link 52R to rotate around the rotation axis 51RJ with respect to the assist arm 51R.
One end of the third link 53R is coupled with the other end of the second link 52R by a second joint portion 52RS in a manner rotatable around the rotation axis 52RJ. The second joint portion 52RS has a coupling structure in which a degree of freedom is one that allows the third link 53R to rotate around the rotation axis 52RJ with respect to the second link 52R.
The thigh wearing portion 54R is coupled with the other end of the third link 53R by the third joint portion 53RS (e.g., a spherical joint). Therefore, the third joint portion 53RS between the third link and the thigh wearing portion 54R (body holding portion) has a coupling structure in which a degree of freedom is three. As described above, a total number of degrees of freedom of the output link 50R illustrated in
The total number of degrees of freedom of the output link 50R may be any number of three or more. For example, the third joint portion 53RS may be configured such that the thigh wearing portion 54R is rotatable around the rotation axis with respect to the other end of the third link 53R (i.e., degree of freedom is one). Since the degree of freedom of the first joint portion 51RS is “one” and the degree of freedom of the second joint portion 52RS is “one”, the total number of degrees of freedom of the output link in this case is 3 (the sum of one plus one plus one equals three). It is more preferable to provide a stopper that limits rotation ranges of the second link and the third link.
In the output link 50RA illustrated in
An end portion of the second link 52RA is coupled with the tip end of the assist arm 51R by the first joint portion 51RS in a manner rotatable around the rotation axis 51RJ. The first joint portion 51RS has a coupling structure in which a degree of freedom is one that allows the second link 52RA to rotate around the rotation axis 51RJ with respect to the assist arm 51R.
The second link 52RA and the second joint portion 52RS are integrated, and a side of one end of the third link 53RA that is reciprocally slidable along a slide axis 52RSJ in a longitudinal direction is connected to the second link 52RA by the second joint portion 52RS. The second joint portion 52RS has a coupling structure in which a degree of freedom is one that allows the third link 53RA to slide along the slide axis 52RSJ with respect to the second link 52RA.
The thigh wearing portion 54R is coupled with the other end of the third link 53RA by the third joint portion 53RS (e.g., a spherical joint). Therefore, the third joint portion 53RS between the third link 53RA and the thigh wearing portion 54R (body holding portion) has a coupling structure in which a degree of freedom is three. As described above, a total number of degrees of freedom of the output link 50RA illustrated in
Since the total number of degrees of freedom may be any number of 3 or more, the third joint portion 53RS may have a coupling structure in which a degree of freedom is one such that the thigh wearing portion 54R is rotatable around the rotation axis. It is more preferable to provide a stopper that limits a rotation range of the second link 52RA and a slide range of the third link 53RA.
[Internal Structure of Torque Generation Unit 40R in Right Actuator Unit 4R (
Next, members accommodated in the cover 41RB of the torque generation unit 40R (see
In addition, outlet ports 33RS, 33LS (connection ports) of cables for actuator drive, control, and communication are provided on portions of the actuator units (4R, 4L) close to the frame portion 30. Cables (not shown) respectively connected to the outlet ports 33RS, 33LS of the cables are disposed along the frame portion 30 and are connected to the backpack portion 37.
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The speed reducer 42R has a set gear reduction ratio nG (1<nG), and when the speed-reducing shaft 42RA is rotated by a rotation angle (θL,R), the speed-increasing shaft 42RB is rotated by a rotation angle nGθL,R. When the speed-increasing shaft 42RB is rotated by the rotation angles nGθL,R, the speed reducer 42R rotates the speed-reducing shaft 42RA by the rotation angle θL,R. The transmission belt 43RB is hung on the pulley 43RA, to which the speed-increasing shaft 42RB of the speed reducer 42R is connected, and the pulley 43RC. Therefore, the wearer torque from the assist arm 51R is transmitted to the pulley 43RC via the speed-increasing shaft 42RB, and the assist torque from the electric motor 47R is transmitted to the speed-increasing shaft 42RB via the spiral spring 45R and the pulley 43RC. A pulley reduction ratio nP, which is a ratio of the speed-reducer-side pulley 43RA to the motor-side pulley 43RC (pulley reduction ratio=speed-reducer-side pulley 43RA:motor-side pulley 43RC=nP:1), is set. For example, the gear reduction ratio nG is set to about 50, and the pulley reduction ratio nP is set to about 88/60.
The spiral spring 45R has a spring constant Ks, and has a spiral shape having an inner end portion 45RC on a center side and an outer end portion 45RA on an outer peripheral side. The inner end portion 45RC of the spiral spring 45R is fitted into a groove portion 47RB formed on the output shaft 47RA of the electric motor 47R. The outer end portion 45RA of the spiral spring 45R is wound into a cylindrical shape, and a transmission shaft 43RE provided on the flange portion 43RD of the pulley 43RC is fitted in the outer end portion 45RA so as to support the outer end portion 45RA (the pulley 43RC is integrated with the flange portion 43RD and the transmission shaft 43RE). The pulley 43RC is supported in a manner rotatable around a rotation axis 47RY, and the transmission shaft 43RE, which protrudes toward the spiral spring 45R, is provided in the vicinity of an outer peripheral edge of the flange portion 43RD which is integrated with the transmission shaft 43RE. The transmission shaft 43RE is fitted in the outer end portion 45RA of the spiral spring 45R, and moves the position of the outer end portion 45RA around the rotation axis 47RY. The bearing 46R is provided between the output shaft 47RA of the electric motor 47R and the pulley 43RC. That is, the output shaft 47RA is not fixed to the pulley 43RC, and the output shaft 47RA can freely rotate with respect to the pulley 43RC. The pulley 43RC is rotationally driven by the electric motor 47R via the spiral spring 45R. In the above configuration, the output shaft 47RA of the electric motor 47R, the bearing 46R, the pulley 43RC having the flange portion 43RD, and the spiral spring 45R are disposed coaxially along the rotation axis 47RY.
The spiral spring 45R stores the assist torque transmitted from the electric motor 47R, stores the wearer torque transmitted via the assist arm 51R, the speed reducer 42R, the pulley 43RA, and the pulley 43RC by the motion of the thigh of the wearer, and as a result, stores a synthetic torque obtained by synthesizing the assist torque and the wearer torque. The synthetic torque stored in the spiral spring 45R rotates the assist arm 51R via the pulley 43RC, the pulley 43RA and the speed reducer 42R. With the above configuration, the output shaft 47RA of the electric motor 47R is connected to the output link (in the case of
The synthetic torque stored in the spiral spring 45R is obtained based on an angular change amount from a no-load state and the spring constant, and for example, is obtained based on the rotation angle of the assist arm 51R (obtained by the output link rotation angle detection unit 43RS), and the rotation angle of the output shaft 47RA of the electric motor 47R (obtained by the motor rotation angle detection unit 47RS) and the spring constant Ks of the spiral spring 45R. Then, a wearer torque is extracted from the obtained synthetic torque, and an assist torque corresponding to the wearer torque is output from the electric motor.
As illustrated in
As described above, the control device 61 can detect the rotation angle and the rotation direction of the spiral spring 45R from the no-load state based on the detection signal from the output link rotation angle detection unit 43RS and the detection signal from the motor rotation angle detection unit 47RS, and can detect the torque (synthetic torque) with the rotation angle, the rotation direction and the spring constant of the spiral spring 45R. In this case, the output link rotation angle detection unit 43RS, the motor rotation angle detection unit 47RS, and the spiral spring 45R correspond to a torque detection unit, and the control device 61 can detect a torque-related amount (in this case, the synthetic torque) related to the torque based on the forward-leaning angle detected by using the output link rotation angle detection unit 43RS (corresponding to an angle detection unit).
In the above description, the electric motor 47R, the spiral spring 45R, the motor rotation angle detection unit 47RS, and the output link rotation angle detection unit 43RS are all provided in the right actuator unit 4R. Although not shown, an electric motor 47L, a spiral spring 45L, a motor rotation angle detection unit 47LS, and an output link rotation angle detection unit 43LS are similarly provided in the left actuator unit 4L. When described in the following description, the electric motor 47L, the spiral spring 45L, the motor rotation angle detection unit 47LS, or the output link rotation angle detection unit 43LS refers to that provided in the left actuator unit 4L, although not illustrated.
[Appearance, Configuration, etc. of Operation Unit R1 (
Next, the operation unit R1 which allows the wearer to easily adjust an assist state of the power assist suit 1 will be described with reference to
As illustrated in
The main operation unit R1A is a switch for starting and stopping assist control by the power assist suit 1 upon operation from the wearer. As illustrated in
The gain automatic/manual switching operation unit R1BS is a switch that switches a gain (magnitude) of the assist torque between being automatically adjusted and manually adjusted by the wearer. When the gain automatic/manual switching operation unit R1BS is set to an “AUTOMATIC” side, operation of the gain up operation unit R1BU and the gain down operation unit R1BD is disabled, and the control device 61 detects the mass (or weight) of the object held by the wearer and automatically adjusts the magnitude of the assist torque according to the detected mass (or weight) of the object. When the gain automatic/manual switching operation unit R1BS is set to a “MANUAL” side, the operation of the gain up operation unit R1BU and the gain down operation unit R1BD is enabled, and the control device 61 changes the magnitude of the assist torque according to the operation of the gain up operation unit R1BU and the gain down operation unit R1BD. In order to detect the mass (or weight) of the object, it is necessary to measure the mass (or weight) of the wearer, and the body weight measurement operation unit R1K is used when the wearer causes the control device to measure his/her mass as will be described later. At the time of automatic gain, a learning model generated by machine learning (such as a neural network) may be used to adjust the gain (the learning model may be provided in a storage unit for learning in the control device 61 so as to perform learning operation and to adjust the gain, or a learning model of another power assist suit may be stored in the storage unit using the communication unit 64 or the like to perform the learning operation and to adjust the gain).
The gain up operation unit R1BU is a switch that increases the gain of the assist torque generated by the power assist suit upon operation from the wearer when the gain automatic/manual switching operation unit R1BS is set to the “MANUAL” side, and the gain down operation unit R1BD is a switch that reduces the gain of the assist torque generated by the power assist suit upon operation from the wearer. For example, as shown in “OPERATION UNIT GAIN (WHEN “GAIN SETTING=MANUAL”)” in
The increase rate automatic/manual switching operation unit R1CS is a switch that switches an increase rate of the assist torque (a timing for applying the assist torque) between being automatically adjusted and manually adjusted by the wearer. When the increase rate automatic/manual switching operation unit R1CS is set to an “AUTOMATIC” side, operation of the increase rate up operation unit R1CU and the increase rate down operation unit R1CD is disabled, and the control device 61 automatically adjusts the increase rate of the assist torque (the timing for applying the assist torque). When the increase rate automatic/manual switching operation unit R1CS is set to a “MANUAL” side, the operation of the increase rate up operation unit R1CU and the increase rate down operation unit R1CD is enabled, and the control device 61 changes the increase rate of the assist torque according to the operation of the increase rate up operation unit R1CU and the increase rate down operation unit R1CD. At the time of automatic increase rate, a learning model generated by machine learning (such as a neural network) may be used to adjust the increase rate (the learning model may be provided in a storage unit for learning in the control device 61 so as to perform learning operation and to adjust the increase rate , or a learning model of another power assist suit may be stored in the storage unit using the communication unit 64 or the like to perform the learning operation and to adjust the increase rate).
The increase rate up operation unit R1CU and the increase rate down operation unit R1CD are switches that adjust fast/slow of the increase rate of the assist torque (the timing for applying the assist torque) generated by the power assist suit by an operation from the wearer when the increase rate automatic/manual operation unit R1CS is set to the “MANUAL” side. For example, as shown in “OPERATION UNIT INCREASE RATE (WHEN “INCREASE RATE=MANUAL”)” in
The control device R1E of the operation unit R1 transmits operation information via the first communication unit R1EA (see
Upon receiving the operation information, the control device 61 of the backpack portion 37 stores the received operation information, and transmits, via the communication unit 64, response information including battery information indicating a state of a battery of a power supply unit 63 used to drive the power assist suit and assist information indicating an assist state (see
For example, when either one of the spiral springs 45L, 45R of the left actuator unit 4L or the right actuator unit 4R exceeds an output limit of a spring torque, an icon of “ABNORMALITY 1” (see
When the control device 61 receives the operation information from the control device R1E (see
The power assist suit has three motion modes for generating assist torque for assisting the motion of the wearer, and the motion modes include a lowering mode, a lifting mode, and a walking mode. The lowering mode is a motion mode for assisting an object lowering operation by the wearer. The lifting mode is a motion mode for assisting an object lifting operation by the wearer. The walking mode is a motion mode for assisting a walking motion of the wearer. As will be described in detail later, the control device 61 automatically switches the above-described three motion modes based on the torques applied to the left actuator unit 4L and the right actuator unit 4R (see
As shown in the example of “CONTROL DEVICE MOTION MODE” in
As described above, via the operation of the operation unit R1, the wearer can easily perform adjustment for setting the desired assist state. Further, since the battery remaining amount, the error information, and the like are displayed on the display unit R1D of the operation unit R1, the wearer can easily grasp the state of the power assist suit. A form of the various types of information displayed on the display unit R1D is not limited to the example illustrated in
[Input and Output of Control Device 61 (
As illustrated in
The operation information from the operation unit R1, a detection signal from the motor rotation angle detection unit 47RS (a detection signal corresponding to an actual motor shaft angle θrM,R of the (right) electric motor 47R), a detection signal from the (right) output link rotation angle detection unit 43RS (a detection signal corresponding to an actual link angle θL,R of the assist arm 51R), and the like are input to the control device 61. The control device 61 obtains the rotation angle of the (right) electric motor 47R based on the input signals, and outputs a control signal corresponding to the obtained rotation angle to the motor driver 62 (the same applies to the (left) electric motor).
[Control Block (
Next, a processing procedure of the control device 61 will be described with reference to the flowchart illustrated in
[Overall Processing Flow (
The flowchart illustrated in
In step S010, the control device 61 executes the processing of S100 (see
In step S015, the control device 61 executes the processing of S150 (see
In step S018, the control device 61 determines whether at least one of a first failure flag and a second failure flag is set to ON in the failure detection processing of step S015. The control device 61 ends the processing if at least one of the first failure flag or the second failure flag is ON (Yes), and proceeds to step S020 if neither of the first failure flag and the second failure flag is ON (No).
When the processing proceeds to step S020, the control device 61 executes the processing of S200 (see
In step S025, the control device 61 executes the processing of S300 (see
In step S030, the control device 61 determines whether the motion mode determined in step S020 is the lifting mode. The control device 61 proceeds to step S045 if the motion mode is the lifting mode (Yes), and proceeds to step S035 if the motion mode is not the lifting mode (No).
When the processing proceeds to step S035, the control device 61 determines whether the motion mode determined in step S020 is the lowering mode. The control device 61 proceeds to step S040R if the motion mode is the lowering mode (Yes), and proceeds to step S050 if the motion mode is not the lowering mode (No). The processing in steps S030, S035 corresponds to the selection block B54 illustrated in
When the processing proceeds to step S040R, the control device 61 executes the processing of SD000R (see
In step S040L, the control device 61 executes the processing of SD000L (not shown), and proceeds to step S060R. The processing of SD000L is a processing of obtaining a control command value of the (left) actuator unit 4L in the lowering motion, corresponds to the lowering assist torque calculation block B51 illustrated in
When the processing proceeds to step S045, the control device 61 executes the processing of SU000 (see
When the processing proceeds to step S050, the control device 61 executes the processing of SW000 (not shown), and proceeds to step S060R. The processing of SW000 is a processing of obtaining the control command values of the (right) actuator unit 4R and the (left) actuator unit 4L in the walking motion, corresponds to the walking assist torque calculation block B53 illustrated in
In step S060R, the control device 61 performs feedback control of the (right) electric motor based on the (right) assist torque command value obtained in step S060R or SU000 or SW000, and proceeds to step S060L.
In step S060L, the control device 61 performs feedback control of the (left) electric motor based on the (left) assist torque command value obtained in the SD000L or SU000 or SW000, and ends the processing. The processing of steps S060R, S060L corresponds to the control command value calculation block B60 illustrated in
[Details of S100: Adjustment Determination, Input Processing, and Torque Change Amount, etc. Calculation (
Next, details of the processing in step S100 according to step S010 illustrated in
The control device 61 stores a (right) link angle θL,R(t) before update as a previous (right) link angle θL,R(t−1), and stores a (left) link angle θL,L(t) before update as a previous (left) link angle θL,L(t−1). Further, the control device 61 detects a current (right) link angle by using the output link rotation angle detection unit 43RS (corresponding to the angle detection unit; see
The control device 61 obtains and stores a (right) link angle change amount ΔθL,R(t) according to the following Equation (1), and obtains and stores a (left) link angle change amount ΔθL,L(t) according to Equation (2). The (right) link angle change amount ΔθL,R(t), and the (left) link angle change amount ΔθL,L(t) correspond to angular-velocity-related amounts. The output link rotation angle detection unit 43RS corresponds to the torque detection unit.
(Right) link angle change amount ΔθL,R(t)=(right) link angle θL,R(t)−(right) link angle θL,R(t−1) (Equation 1)
(Left) link angle change amount ΔθL,L(t)=(left) link angle θL,L(t)−(left) link angle θL,L(t−1) (Equation 2)
The control device 61 obtains and stores a (right) wearer torque change amount τS,R(t) according to the following Equation (3), and obtains and stores a (left) wearer torque change amount τS,L(t) according to Equation 4. Ks is the spring constant of the spiral spring 45R.
(Right) wearer torque change amount τS,R(t)=Ks*ΔθL,R(t) (Equation 3)
(Left) wearer torque change amount τS,L(t)=Ks*ΔθL,L(t) (Equation 4)
The control device 61 obtains and stores a (right) synthetic torque (t) according to the following Equation (5), and obtains and stores the (left) synthetic torque (t) according to Equation 6.
(Right) synthetic torque (t)=Ks*θL,R(t) (Equation 5)
(Left) synthetic torque (t)=Ks*θL,L(t) (Equation 6)
The control device 61 detects the motor shaft angle of the (right) electric motor 47R based on the detection signal from the motor rotation angle detection unit 47RS of the (right) electric motor 47R, and stores (updates) the (right) actual motor shaft angle θrM,R(t). Similarly, the control device 61 detects a motor shaft angle of the (left) electric motor based on the detection signal from the motor rotation angle detection unit of the (left) electric motor (not illustrated), and stores (updates) a (left) actual motor shaft angle θrM,L(t).
As illustrated in
Here, when using the gear reduction ratio nG, the pulley reduction ratio nP, and the (right) link angle θL,R(t), the pulley rotation angle θP,R(t)=θL,R(t)*nP*nG. From the above, the (right) spring torque τSP,R(t) can be expressed by the following Equation (6-1). Further, since θS,R(t)=θL,R(t)*nG when based on a sub-encoder rotation angle θS,R(t) which is a rotation angle of the output link rotation angle detection unit 43RS in
(Right) spring torque τSP,R(t)=Ks*(θL,R(t)*nG*nP−θrM,R(t)) (Equation 6-1)
(Right) spring torque τSP,R(t)=Ks*(θS,R(t)*nP−θrM,R(t)) (Equation 6-2)
Similarly, a (left) spring torque τSP,L(t), which is a torque stored in the spiral spring of the left actuator unit, can be obtained according to the following (Equations 6-3) and (Equations 6-4) using the (left) link angle θL,L(t), the gear reduction ratio nG, the pulley reduction ratio nP, a sub-encoder rotation angle θS,L(t) of the output link rotation angle detection unit of the left actuator unit, and the (left) actual motor shaft angle θrM,L(t).
(Left) spring torque τSP,L(t)=Ks*(θL,L(t)*nG*nP−θrM,L(t)) (Equation 6-3)
(Left) spring torque τSP,L(t)=Ks*(θS,L(t)*nP−θrM,L(t)) (Equation 6-4)
The above (right) spring torque τSP,R(t) corresponds to a right-torque-related amount, which is a torque related to the right wearer torque input from the right thigh of the wearer to the right actuator unit and the right assist torque generated by the right actuator unit. The right-torque-related amount detection unit that detects the right-torque-related amount detects the swing angle of the right thigh with respect to the waist of the wearer. As illustrated in
The control device 61 obtains and stores the (right) spring torque τSP,R(t) and the (left) spring torque τSP,L(t) according to the above calculation equations. The above corresponds to the torque change amount calculation block B30 illustrated in
[S150: Failure Detection Processing (
Next, details of the processing in step S150 according to step S015 illustrated in
After the processing of S150, the control device 61 proceeds to step S151. As illustrated in
In step S152, the control device 61 executes the processing of S1600L (not shown), and then proceeds to step S153. The processing of S1600L is a processing of detecting a failure of the (left) actuator unit 4L. The processing of S1600L executed in step S152 shows the processing procedure executed for the (left) actuator unit 4L, which, however, is the same as the processing procedure of S1600R executed for the (right) actuator unit 4L, and detailed description thereof will be omitted.
In step S153, the control device 61 reads the first failure flag from a RAM, and determines whether the first failure flag is set to “ON”. As will be described later, the first failure flag is set to “ON” in a case where at least one of the (right) spring torque τSP,R(t) (see
The control device 61 proceeds to step S154 if it is determined that the first failure flag is set to “ON” (S153: YES). In step S154, the control device 61 notifies that the power assist suit 1 has exceeded the output limit, and then proceeds to step S155. For example, the control device 61 outputs a notification command instructing the control device R1E (see
In step S155, the control device 61 stops supply of power to the electric motor 47R (see
As a result, since the supply of power to the electric motors 47R, 47L is stopped, the torques applied to the spiral springs 45R, 45L disappear, the (right) spring torque τSP,R and the (left) spring torque τSP,L become “0”, and the spiral springs 45R, 45L can be prevented from breaking. Further, since the supply of power to the electric motors 47R, 47L is stopped, the assist torques return to “0” due to the spring forces of the spiral springs 45R, 45L (taking a time of about 0.5 seconds to 0.7 seconds), so that it is possible to prevent a sudden load from being applied to the waist of the wearer and to prevent the waist from being damaged. In this way, it is possible to provide a highly reliable power assist suit 1 without causing a sense of discomfort, such has feeling a sudden load, to the wearer.
On the other hand, the control device 61 proceeds to step S156 if it is determined in step S153 that the first failure flag is set to “OFF” (S153: NO). In step S156, the control device 61 reads the second failure flag from the RAM, and determines whether the second failure flag is set to “ON”.
Here, as will be described later, the output link rotation angle detection unit 43RS is determined as failing and the second failure flag is set to “ON” if an absolute value of a difference between a (right) first output link rotation torque τO1R (first rotation torque) of the output link 50R (see
Further, as will be described later, the output link rotation angle detection unit 43LS is determined as failing and the second failure flag is set to “ON” if an absolute value of a difference between a (left) first output link rotation torque Toil, (first rotation torque) of the output link 50L (see
The control device 61 proceeds to step S157 if it is determined that the second failure flag is set to “ON” (S156: YES). In step S157, the control device 61 notifies that either one of the output link rotation angle detection unit 43RS or the output link rotation angle detection unit 43LS fails, and then proceeds to step S155. The control device 61 ends the processing of S150 and returns (proceeds to step S018 in
For example, the control device 61 outputs a notification command instructing the control device R1E (see
In step S155, the control device 61 stops supply of power to the electric motor 47R (see
As a result, since the supply of power to the electric motors 47R, 47L is stopped, the torques applied to the spiral springs 45R, 45L disappear, and the (right) spring torque τSP,R and the (left) spring torque τSP,L become “0”. As a result, it is possible to stop output of inappropriate assist torques by the electric motors 47R, 47L. In this way, it is possible to provide a highly reliable power assist suit 1 that can output an appropriate assist torque with the electric motors 47R, 47L without causing a sense of discomfort to the wearer when assisting lifting motion and lowering motion of the object.
[S1600R: Failure Detection Processing of Right Actuator Unit]
Next, details of the processing of S1600R executed in step S151 illustrated in
The processing of S1600L executed in step S152 shows the processing procedure executed for the (left) actuator unit 4L, which, however, is the same as the processing procedure of S1600R executed for the (right) actuator unit 4L.
As illustrated in
The control device 61 may calculate the first output link rotation torque (first rotation torque) τO1,R(t) of the output link 50R corresponding to the (right) spring torque τSP,R(t) according to the following Equation 21, and may also determine whether the first output link rotation torque τ01,R(t) is equal to or greater than a maximum torque τO1,MAX (e.g., 22 Nm) that can be generated without breaking the spiral spring 45R. Here, nG (1<nG) is a reduction ratio of the speed reducer 42R, and nP is the pulley reduction ratio of the pulley 43RA to the pulley 43RC.
τO1,R(t)=τSP,R(t)*nP*nG (Equation 21)
The control device 61 proceeds to step S1602R if it is determined that the (right) spring torque τSP,R(t) is equal to or greater than the maximum torque (torque threshold) τSP,max that can be generated without breaking the spiral spring 45R (S1601: YES). In step S1602R, the control device 61 reads the first failure flag from the RAM, sets the first failure flag to “ON”, stores the first failure flag in the RAM again, and then ends the processing of S1600R and returns (proceeds to step S152 in
On the other hand, the control device 61 determines that the spiral spring 45R is not to fail (e.g., deform, break, etc.) and proceeds to step S1603R if it is determined that the (right) spring torque τSP,R(t) is smaller than the maximum torque (torque threshold) τSP,MAX that can be generated without breaking the spiral spring 45R (S1601: NO).
In step S1603R, the control device 61 determines whether a rotation amount of the speed-increasing shaft 42RB detected by the output link rotation angle detection unit 43RS is equal to or smaller than NS pulses (e.g., 4 pulses) during TS (msec) (e.g., during about 2 msec). The output link rotation angle detection unit 43RS outputs about 1000*NS pulses (e.g., 4096 pulses) during one rotation of the speed-increasing shaft 42RB.
Then, the control device 61 determines that the output link 50R is rotating, and ends the processing of S1600R and returns (proceeds to step S152 in
On the other hand, the control device 61 determines that the output link 50R is almost not rotating, and proceeds to step S1604R if it is determined that the rotation amount of the speed-increasing shaft 42RB detected by the output link rotation angle detection unit 43RS is equal to or smaller than NS pulses (e.g., 4 pulses) during TS (msec) (e.g., during about 2 msec) (S1603: YES). In step S1604R, the control device 61 calculates the first output link rotation torque (first rotation torque) τO1,R(t) of the output link 50R corresponding to the (right) spring torque τSP,R(t) according to Equation 21, and stores the first output link rotation torque τO1,R(t) in the RAM.
Subsequently, in step S1605R, the control device 61 acquires a current value IR supplied to the electric motor 47R via the motor driver 62, and then proceeds to step S1606R. In step S1606R, the control device 61 calculates a second output link rotation torque (second rotation torque) τO2,R(t) of the output link 50R from the current value IR supplied to the electric motor 47R according to the following Equation 22, and stores the second output link rotation torque τO2,R(t) in the RAM. Here, KA is a motor constant (Nm/A) of the electric motor 47R, nG (1<nG) is the reduction ratio of the speed reducer 42R, and nP is the pulley reduction ratio of the pulley 43RA to the pulley 43RC.
τO2,R(t)=KA*IR*nP*nG (Equation 22)
Thereafter, in step S1607R, the control device 61 calculates, according to the following Equation 23, an absolute value of a moving average during S seconds (e.g., during about 0.5 seconds) of a value obtained by subtracting the second output link rotation torque (second rotation torque) τO2,R(t) calculated according to Equation 22 from the first output link rotation torque (first rotation torque) τO1,R(t) calculated according to Equation 21 during TS (msec) (e.g., during about 2 sec), stores the value as a (right) torque error ΔτR(t) in the RAM, and then proceeds to step S1608R. Note that τO1,R(t−1) is a previously calculated first output link rotation torque (first rotation torque), and τO2,R(t−1) is a previously calculated second output link rotation torque (second rotation torque).
ΔτR(t)=|((τO1,R(t−1)−τO2,R(t−1))*((S/TS)−1)+(τO1,R(t)−τO2,R(t)))÷(S/TS)| (Equation 23)
In step S1607R, for example, the control device 61 may be configured as follows. The control device 61 calculates a value obtained by subtracting the second output link rotation torque (second rotation torque) τO2,R(t) from the first output link rotation torque (first rotation torque) τO1,R(t) per TS (msec) (e.g., per 2 msec) during S seconds (e.g., during 0.5 seconds), and sums the values. Then, the control device 61 may calculate an absolute value of an average value of the total value and store the absolute value in the RAM as the (right) torque error ΔτR(t), and then proceed to step S1608R.
In step S1608R, the control device 61 reads from the RAM the (right) torque error ΔτR(t) calculated and stored in step S1607R. Then, the control device 61 determines whether the (right) torque error ΔτR(t) is equal to or greater than an error threshold τLM (e.g., about 3.8 Nm). The error threshold τLM is determined via experiments, computer aided engineering (CAE) analysis, and the like, and is stored in the storage portion 67 in advance.
The control device 61 determines that the output link rotation angle detection unit 43RS does not fail and ends the processing of S1600R and returns (proceeds to step S152 in
On the other hand, the control device 61 proceeds to step S1609R if it is determined that the (right) torque error ΔτR(t) is equal to or greater than the error threshold τLM (e.g., about 3.8 Nm) (S1608R: YES). In step S1609R, the control device 61 reads the second failure flag from the RAM, sets the second failure flag to “ON”, stores the second failure flag in the RANI again, and then ends the processing of S1600R and returns (proceeds to step S152 in
[Details of S200: Motion Mode Determination (
Next, details of the processing in step S200 according to step S020 illustrated in
After the processing of S200, the control device 61 proceeds to step S210. Then, in step S210, the control device 61 determines whether a condition is satisfied that the (right) spring torque τSP,R(t) is a torque toward the forward-leaning direction of the wearer and is greater than the first predetermined threshold, and that the (left) spring torque τSP,L(t) is a torque toward the forward-leaning direction of the wearer and is greater than the first predetermined threshold. For example, a value of the first predetermined threshold is 0 (zero). The control device 61 proceeds to step S240A if the condition is satisfied (Yes), and proceeds to step S220 if the condition is not satisfied (No). The (right) spring torque τSP,R(t) and the (left) spring torque τSP,L(t) are positive (>0) if being torques in the forward-leaning direction of the wearer, and are negative (<0) if being torques in a rearward-leaning direction of the wearer.
The control device 61 may use a value set in the storage unit in advance as the first predetermined threshold, or may adjust the value of the first predetermined threshold using a learning model generated by machine learning (neural network or the like). When machine learning is used for adjustment, the learning model may be provided in the storage unit for learning in the control device 61 so as to perform learning operation and to adjust the first predetermined threshold, or a learning model of another power assist suit may be stored in the storage unit using the communication unit 64 or the like to perform the learning operation and to adjust the first predetermined threshold.
When the processing proceeds to step S220, the control device 61 determines whether a condition is satisfied that the (right) spring torque τSP,R(t) is a torque toward the rearward-leaning direction (opposite to the forward-leaning direction) of the wearer and is smaller than the second predetermined threshold, and that the (left) spring torque τSP,L(t) is a torque toward the rearward-leaning direction (opposite to the forward-leaning direction) of the wearer and is smaller than the second predetermined threshold. For example, a value of the second predetermined threshold is 0 (zero). The control device 61 proceeds to step S240B if the condition is satisfied (Yes), and proceeds to step S230 if the condition is not satisfied (No).
The control device 61 may use a value set in the storage unit in advance as the second predetermined threshold, or may adjust the value of the second predetermined threshold using a learning model generated by machine learning (neural network or the like). When machine learning is used for adjustment, the learning model may be provided in the storage unit for learning in the control device 61 so as to perform learning operation and to adjust the second predetermined threshold, or a learning model of another power assist suit may be stored in the storage unit using the communication unit 64 or the like to perform the learning operation and to adjust the second predetermined threshold.
When the processing proceeds to step S230, the control device 61 determines whether [the (right) link angle θL,R(t)+the (left) link angle θL,L(t)]/2 is equal to or smaller than a first motion determination angle θ1, and the (right) synthetic torque (t)*the (left) synthetic torque (t) is smaller than a first motion determination torque τ1. The control device 61 proceeds to step S240C if [the (right) link angle θL,R(t)+the (left) link angle θL,L(t)]/2 is equal to or smaller than the first motion determination angle θ1, and the (right) synthetic torque (t)*the (left) synthetic torque (t) is smaller than the first motion determination torque τ1 (Yes), and ends the processing of S200 and returns (proceeds to step S025 of
When the processing proceeds to step S240A, the control device 61 stores the “lowering mode” as the motion mode, ends the processing of S200, and returns (proceeds to step S025 in
When the processing proceeds to step S240B, the control device 61 stores the “lifting mode” as the motion mode, ends the processing of S200, and returns (proceeds to step S025 in
When the processing proceeds to step S240C, the control device 61 stores the “walking mode” as the motion mode, ends the processing of S200, and returns (proceeds to step S025 in
[Details of S300: Load Determination (Determination of Gain Cp) (
Next, details of the processing in step S300 according to step S025 illustrated in
After the processing of S300 (see
As illustrated in
As illustrated in
In step S315, the control device 61 determines whether the gain automatic/manual switching operation unit R1BS (see
When the processing proceeds to step S320, the control device 61 determines whether an elapsed time after power-on is smaller than a predetermined time (e.g., smaller than 0.2 to 2 [sec]), proceeds to step S330 if smaller than the predetermined time (Yes), and proceeds to step S325 if equal to or larger than the predetermined time (No).
When the processing proceeds to step S330, the control device 61 determines whether |the current body motion acceleration av| is equal to or smaller than a predetermined threshold and |the current body motion acceleration aw| is equal to or smaller than a predetermined threshold (that is, the wearer TS is in a substantially stationary state), proceeds to step S340B if equal to or smaller than the predetermined threshold (Yes), and proceeds to step S350 if larger than the predetermined threshold (No).
When the processing proceeds to step S340B, the control device 61 integrates the current drag F, counts a number of times of integration, and proceeds to step S350.
When the processing proceeds to step S325, the control device 61 determines whether the elapsed time after power-on is the predetermined time (the same value as the “predetermined time” in step S320), proceeds to step S340A if being the predetermined time (Yes), and proceeds to step S350 if not the predetermined time (No).
When the processing proceeds to step S340A, the control device 61 averages the integrated value obtained in step S340B (the integrated value of the drag F) using the number of times of integration, so as to obtain an average wearer drag Fav of only the wearer TS. Then, the control device 61 divides the average wearer drag Fav by the gravitational acceleration g to obtain and store the wearer mass M (M=Fav/g), and proceeds to step S350. The wearer mass M is preferably stored in a nonvolatile memory.
The control device 61 may calculate the wearer mass M by using the drag F detected when the body weight measurement operation unit R1K (see
When the processing proceeds to step S350, the control device 61 determines whether the current drag F is greater than the wearer mass M*g+a predetermined load (e.g., 2 to 3 [kg]*g, where g is the gravity acceleration), proceeds to step S355 if larger (Yes), and proceeds to step S360B if not larger (No).
When the processing proceeds to step S355, the object mass m is calculated by, for example, the following [Calculation Method 1 of Cargo Mass m] or [Calculation Method 2 of Cargo Mass m], and the processing proceeds to step S360A.
[Calculation Method 1 of Cargo Mass m]
As illustrated in
[Calculation Method 2 of Cargo Mass m]
As illustrated in
When the processing proceeds to step S360A, the control device 61 converts the obtained object mass m to the value of the gain Cp, ends the processing of S300, and returns (proceeds to step S030 in
When the processing proceeds to step S360B, the control device 61 determines that the wearer TS does not hold the object BG (object mass m=0), and thus regards that the gain Cp=0, ends the processing of S300, and returns (proceeds to step S030 in
When the processing proceeds to step S360C, the control device 61 uses the gain number of the “OPERATION UNIT GAIN” illustrated in
[Details of SD000R: (Right) Lowering (
Next, details of the processing in step SD000R according to step S040R illustrated in
After the processing of SD000R, the control device 61 proceeds to step SD010R. Then, in step SD010R, the control device 61 determines whether the (right) link angle θL,R(t) is equal to or smaller than a first lowering angle θd1, proceeds to step SD015R if equal to or smaller than the first lowering angle θd1 (Yes), and proceeds to step SD020R if not (No). For example, when the first lowering angle θd1 is a forward-leaning angle of about 10 [°], and when θL,R(t)≤θd1, the control device 61 determines that lowering stars lifting ends.
When the processing proceeds to step SD015R, the control device 61 initializes (resets to zero) a (right) integrated assist amount, and proceeds to step SD020R.
When the processing proceeds to step SD020R, the control device 61 calculates a (right) assist amount based on the (right) increase rate Cs,R, the (right) wearer torque change amount τs,R(t), and a wearer torque change amount−assist amount characteristic (
In step SD025R, the control device 61 adds the (right) assist amount obtained in step SD020R to the (right) integrated assist amount (that is, integrates the obtained (right) assist amount), and proceeds to step SD030R.
In step SD030R, the control device 61 calculates a (right) lowering torque limit value based on the gain Cp, the (right) link angle (forward-leaning angle) θL,R(t), and a forward-leaning angle−lowering torque limit value characteristic (see
In step SD035R, the control device 61 determines whether |the (right) integrated assist amount| is equal to or smaller than |the (right) lowering torque limit value|, proceeds to step SD040R when |the (right) integrated assist amount| is equal to or smaller than |the (right) lowering torque limit value| (Yes), and proceeds to step SD045R if not (No).
When the processing proceeds to step SD040R, the control device 61 stores the (right) integrated assist amount as the (right) lowering assist torque (that is, the (right) assist torque command value τs,cmd,R(t)), and ends the processing (proceeds to step S060R in
When the processing proceeds to step SD045R, the control device 61 stores the (right) lowering torque limit value as the (right) lowering assist torque (that is, the (right) assist torque command value τs,cmd,R(t)), and ends the processing (proceeds to step S060R in
In the above steps SD035R, SD040R, SD045R, the control device 61 sets a smaller one among |the (right) integrated assist amount| and |the (right) lowering torque limit value| as the (right) lowering assist torque.
In the above processing,
When the wearer stops the forward-leaning operation and change of the forward-leaning angle stops (ΔθL,R(t)=0, ΔθL,L(t)=0) (in the example of
[Details of SU000: Lifting (
Next, details of the processing in step SU000 according to step S045 illustrated in
After the processing of SU000, the control device 61 proceeds to step SU010. Then, in step SU010, the control device 61 executes the processing of SS000 (see
In step SU015, the control device 61 determines whether the timing is a timing for the motion state S to transition from 0 to 1, proceeds to step SU020 if being the timing for the motion state S to transition from 0 to 1 (Yes), and proceeds to step SU030 if not (No).
When the processing proceeds to step SU020, the control device 61 substitutes 0 (zero) into a (right) virtual elapsed time tmap,R(t) and a (left) virtual elapsed time tmap,L(t), and substitutes 0 (zero) into a (right) lifting assist torque (the (right) assist torque command value τs,cmd,R(t)) and a (left) lifting assist torque (the (left) assist torque command value τs,cmd,L(t)). Thereafter, the control device 61 proceeds to step SU030.
[Determination of Motion State S=1 and Processing When Motion State S=1 (
When the processing proceeds to step SU030, the control device 61 determines whether the motion state S determined in step SU020 is 1, proceeds to step SU031 when the motion state S is 1 (Yes), and proceeds to step SU040 if not (No).
When the processing proceeds to step SU031, the control device 61 adds a task period (for example, 2 [ms], when the processing illustrated in
In step SU032, the control device 61 determines whether the increase rate is “AUTOMATIC INCREASE RATE”, proceeds to step SU033R when being “AUTOMATIC INCREASE RATE” (Yes), and proceeds to step SU034 if not (No).
When the processing proceeds to step SU033R, the control device 61 executes the processing of SS100R (see
In step SU034, the control device 61 determines whether the (right) increase rate Cs,R and the (left) increase rate Cs,L are equal, proceeds to step SU037R when the (right) increase rate Cs,R and (left) increase rate Cs,L are equal (Yes), and proceeds to step SU035 if not (No).
When the processing proceeds to step SU035, the control device 61 determines whether the (right) increase rate Cs,R is larger than the (left) increase rate Cs,L, proceeds to step SU036A when the (right) increase rate Cs,R is larger than the (left) increase rate Cs,L (Yes), and proceeds to step SU036B if not (No).
When the processing proceeds to step SU036A, the control device 61 substrates the (right) increase rate Cs,R into the (left) increase rate Cs,L, and proceeds to step SU037R.
When the processing proceeds to step SU036B, the control device 61 substrates the (left) increase rate Cs,L into the (right) increase rate Cs,R, and proceeds to step SU037R
When the processing proceeds to step SU037R, the control device 61 executes the processing of SS170R (see
[Determination of Motion State S=2 and Processing When Motion State S=2 (
When the processing proceeds to step SU040, the control device 61 determines whether the motion state S determined in step SU020 is 2, proceeds to step SU041 when the motion state S is 2 (Yes), and proceeds to step SU050 if not (No).
When the processing proceeds to step SU041, the control device 61 determines whether the (previous) motion state S is 1, proceeds to step SU042 when the (previous) motion state S is 1 (Yes), and proceeds to step SU047 if not (No).
When the processing proceeds to step SU042, the control device 61 substitutes 0 (zero) into the (right) virtual elapsed time tmap,R(t) and the (left) virtual elapsed time tmap,L(t), and proceeds to step SU047. The processing of step SU042 is executed when the motion state S transitions from 1→2.
When the processing proceeds to step SU047, the control device 61 obtains a |maximum value| corresponding to the gain Cp based on the gain Cp and a time−lifting torque characteristic (see
[Determination of Motion State S=3 and Processing When Motion State S=3 (
When the processing proceeds to step SU050, the control device 61 determines whether the motion state S determined in step SU020 is 3, proceeds to step SU051 when the motion state S is 3 (Yes), and proceeds to step SU060 if not (No).
When the processing proceeds to step SU051, the control device 61 obtains the maximum value corresponding to the gain Cp based on the gain Cp and the time−lifting torque characteristic (see
In step SU57, the control device 61 obtains a (right) torque damping rate τd,R based on the gain Cp, the (right) wearer torque change amount τS,R(t), and an assist ratio−torque damping rate characteristic (see
(Right) assist torque command value τs,cmd,R(t)=(temporary) τs,cmd,R(t)*(right) torque damping rate τd,R (Equation 7)
(Left) assist torque command value τs,cmd,L(t)=(temporary) τs,cmd,L(t)*(left) torque damping rate τd,L (Equation 8)
For example, when the gain Cp=1, the control device 61 obtains a damping coefficient τs,map,thre=Tb2 based on a gain−damping coefficient characteristic illustrated in
(Right) assist ratio=[τs,map,thre−(right) wearer torque change amount τS,R(t)]/τs,map,thre (Equation 9)
(Left) assist ratio=[τs,map,thre−(left) wearer torque change amount τS,L(t)]/τs,map,thre (Equation 10)
Then, the control device 61 obtains the (right) torque damping rate τd,R, based on the (right) assist ratio and the assist ratio−torque damping rate characteristic (see
[Determination of Motion State S=4 and Processing When Motion State S=4 (
When the processing proceeds to step SU060, the control device 61 determines whether the motion state S determined in step SU020 is 4, proceeds to step SU061 when the motion state S is 4 (Yes), and proceeds to step SU077 if not (No).
When the processing proceeds to step SU061, the control device 61 adds the task period (for example, 2 [ms], when the processing illustrated in
In step SU62, the control device 61 substitutes a current τs,cmd,R(t) into a (previous) τs,cmd,R(t−1), substitutes a current τs,cmd,L(t) into a (previous) τs,cmd,L(t−1), the processing proceeds to step SU067.
In step SU067, the control device 61 obtains and stores the (right) assist torque command value τs,cmd,R(t) according to the following Equation (11), and obtains and stores the (left) assist torque command value τs,cmd,L(t) according to Equation (12). The damping coefficient K1 is a coefficient set in advance, and is set to 0.9, for example. Then, the control device 61 ends the processing and returns (proceeds to step S060R in
(Right) assist torque command value τs,cmd,R(t)=K1*(previous) τs,cmd,R(t−1) (Equation 11)
(Left) assist torque command value τs,cmd,L(t)=K1*(previous) τs,cmd,L(t−1) (Equation 12)
[Processing When Motion State S=5 (
When the processing proceeds to step SU077, the control device 61 obtains and stores the (right) assist torque command value τs,cmd,R(t) according to the following Equation (13), and obtains and stores the (left) assist torque command value τs,cmd,L(t) according to Equation (14). Then, the control device 61 ends the processing and returns (proceeds to step S060R in
(Right) assist torque command value τs,cmd,R(t)=0 (Equation 13)
(Left) assist torque command value τs,cmd,L(t)=0 (Equation 14)
As described above, at the time of the lifting operation, the control device 61 causes the motion state S to sequentially transition from 0 to 5 according to the lifting state, and obtains the (right) lifting assist torque (the (right) assist torque command value τS,cmd,R(t)) and the (left) lifting assist torque (the (left) assist torque command value τs,cmd,L(t)) in accordance with the calculation method set in advance corresponding to each motion state S.
[Details of SS000: Motion State Determination (
Next, details of the processing in step SS000 according to step SU010 illustrated in
[Case Where Motion State S=0]
A procedure for determining the motion state S will be described below with reference to the state transition diagram illustrated in
[Case Where Motion State S=1]
When the motion state S=1, the control device 61 causes the motion state S to transition from 1 to 2 when an event ev12 is detected. When the event ev12 is not detected, the control device 61 maintains the motion state S=1. The event ev12 is satisfied, for example, when the (right) virtual elapsed time tmap,R(t)≥the (right) tmap,thre1 is satisfied, or when the (left) virtual elapsed time tmap,L(t)≥the (left) tmap,thre1 is satisfied, or when either one of the (right) link angle (forward-leaning angle) θL,R(t) and the (left) link angle (forward-leaning angle)) θL,L(t) becomes the forward-leaning angle close to the end of the lifting operation is satisfied. The (right) tmap,thre1 is determined based on the (right) increase rate Cs,R, and the increase rate−transition time characteristic (see
[Case Where Motion State S=2]
When the motion state S=2, the control device 61 causes the motion state S to transition from 2 to 3 when an event ev23 is detected. When the event ev23 is not detected, the control device 61 maintains the motion state S=2. The event ev23 is satisfied, for example, when the (right) wearer torque change amount τS,R(t) or the (left) wearer torque change amount τS,L(t) becomes relatively weak close to the end of the lifting operation, or when the (right) link angle (forward-leaning angle) θL,R(t) or the (left) link angle (forward-leaning angle) θL,L(t) becomes a forward-leaning angle close to the end of the lifting operation.
[Case Where Motion State S=3]
When the motion state S=3, the control device 61 causes the motion state S to transition from 3 to 4 when an event ev34 is detected. When the event ev34 is not detected, the control device 61 maintains the motion state S=3. The event ev34 is satisfied, for example, when the (right) wearer torque change amount τS,R(t)≥τs,map,thre, or the (left) wearer torque change amount τS,L(t)≥τs,map,thre, or the (right) link angle (forward-leaning angle) θL,R(t) or the (left) link angle (forward-leaning angle θL,L(t) becomes a forward-leaning angle close to the end of the lifting operation. Note that τs,map,thre is determined based on the gain Cp and the gain−damping coefficient characteristic (see
[Case Where Motion State S=4]
When the motion state S=4, the control device 61 causes the motion state S to transition from 4 to 5 when an event ev45 is detected. When the event ev45 is not detected, the control device 61 maintains the motion state S=4. The event ev45 is satisfied, for example, when the (right) virtual elapse time tmap,R(t)≥a state determination time t41 (e.g., about 0.15 [sec]), or the (left) virtual elapsed time tmap,L(t)≥the state determination time t41 (e.g., about 0.15 [sec]).
[Case Where Motion State S=5]
When the motion state S=5, the control device 61 causes the motion state S to transition from 5 to 0 when an event ev50 is detected. When the event ev50 is not detected, the control device 61 maintains the motion state S=5. The event ev50 is the start of the lifting operation, and the motion state returns to S=0 after the lifting operation is completed.
[Details of SS100R: (Right) Increase Rate Switching Determination (
Next, details of the processing in step SS100R according to step SU033R illustrated in
After the processing of SS100R, the control device 61 proceeds to step SS110R. Then, in step SS110R, the control device 61 stores the current (right) increase rate Cs,R as a previous Cs,R, and proceeds to step SS115R.
In step SS115R, the control device 61 determines whether a switching stop counter is active, proceeds to step SS120R when the switching stop counter is active (Yes), and proceeds to step SS125R if not (No). The switching stop counter is a counter that is activated when the (right) increase rate Cs,R is switched (changed) in steps SS140R, SS145R.
When the processing proceeds to step SS120R, the control device 61 determines whether the switching stop counter is equal to or greater than a switching standby time, proceeds to step SS125R when the switching stop counter is equal to or greater than the switching standby time (Yes), and proceeds to step SS150R if not (No).
When the processing proceeds to step SS125R, the control device 61 obtains a switching lower limit τs,mas1(t) corresponding to a current lifting elapsed time tup(t) based on the lifting elapsed time tup(t) and a time−switching lower limit characteristic (see
In step SS130R, the control device 61 determines whether |the (right) wearer torque change amount τS,R(t)| is smaller than |the switching lower limit τs,mas1(t)|, proceeds to step SS145R if |the (right) wearer torque change amount τS,R(t)| is smaller than |the switching lower limit τs,mas1(t)| (Yes), and proceeds to step SS135R if not (No).
When the processing is advanced to step SS135R, the control device 61 determines whether |the (right) wearer torque change amount τS,R(t)| is larger than |the switching upper limit τs,mas2(t)|, proceeds to step SS140R if |the (right) wearer torque change amount τS,R(t)| is larger than |the switching upper limit τs,mas2(t)| (Yes), and proceeds to step SS150R if not (No).
When the processing proceeds to step SS140R, the control device 61 increases the value of the (right) increase rate Cs,R by 1 (guarding the maximum value=4), activates the switching stop counter, and proceeds to step SS150R.
When the processing proceeds to step SS145R, the control device 61 reduces the value of the (right) increase rate Cs,R by 1 (guarding the minimum value=−1), activates the switching stop counter, and proceeds to step SS150R.
When the processing proceeds to step SS150R, the control device 61 obtains the (right) tmap,thre1 based on the (right) increase rate Cs,R and the increase rate−transition time characteristic (see
In step SS155R, the control device 61 determines whether the current (right) increase rate Cs,R is equal to the previous Cs,R (see step SS110R), ends the processing and returns (returns to step SU033L in
When the processing proceeds to step SS160R, the control device 61 calculates a temporary lifting assist torque A1(t) based on the previous Cs,R, the (right) virtual elapsed time τmap,R(t), the time−assist amount characteristic (see
The control device 61 calculates a torque deviation reduced virtual elapsed time tmap,R(s), at which the temporary lifting assist torque A1(t) is reached, based on the current (present) (right) increase rate Cs,R, the time−assist amount characteristic (see
In the above description, the time−assist amount characteristic (see
[Details of SS170R: (Right) Assist Torque Calculation (
Next, details of the processing in step SS170R according to step SU037R illustrated in
After the processing of SS170R, the control device 61 proceeds to step SS175R. Then, in step SS175R, the control device 61 calculates the (temporary) τs,cmd,R(t) based on the current (present) (right) increase rate Cs,R, the (right) virtual elapsed time τmap,R(t), the gain Cp, the time−assist amount characteristic (see
In step SS177R, the control device 61 calculates a (right) torque upper limit value τs,max,R(t) based on the forward-leaning angle and the forward-leaning angle−maximum lifting torque characteristic (see
In step SS180R, the control device 61 determines whether |the (temporary) τs,cmd,R(t)| is larger than |the (right) torque upper limit value τs,max,R(t)|, proceeds to step SS185R when larger (Yes), and proceeds to step SS187R if not (No).
When the processing proceeds to step SS185R, the control device 61 stores the (right) torque upper limit value τs,max,R(t) as the (right) lifting assist torque (the (right) assist torque command value τs,cmd,R(t)), ends the processing, and returns (returns to step SU037L in
When the processing proceeds to step SS187R, the control device 61 stores the (temporary) τs,cmd,R(t) as the (right) lifting assist torque (the (right) assist torque command value τs,cmd,R(t)), ends the processing, and returns (returns to step SU037L in
As described above, the power assist suit 1 described in the present embodiment has a simple configuration and can be easily worn by the wearer. In addition, assist control for the lowering motion and assist control for the lifting motion are simple, and the object lifting operation and the object lowering operation can be appropriately assisted. Further, when assisting the object lifting motion or lowering motion, the magnitude of the assist torque can be automatically adjusted in accordance with the mass or weight of the object held by the wearer, so as to further prevent a sense of discomfort or dissatisfaction of the wearer (improve harmonization of the assist). Further, in a case where the wearer does not hold a object, it is possible to not generate unnecessary assist torque (it is possible to perform setting so as to substantially not generate the assist torque when the gain Cp=0), so as not to hinder the motion of the wearer who is not holding the load.
Various changes, additions, and deletions may be made to the structure, configuration, shape, appearance, processing procedure, and the like of the power assist suit of the present disclosure without departing from the scope of the present disclosure. For example, the processing procedure of the control device is not limited to the flowchart and the like described in the present embodiment. The spiral spring 45R (see
The power assist suit 1 described in the present embodiment describes an example in which a triglide or a buckle is used as the belt holding member for holding the belt in a tightened state. Although an example in which connection and release of the belt or the like are performed by a buckle has been described, connection and release of the belt or the like may be performed with a belt holding member different from the buckle. In addition, although the belt is passed through the triglide so that the stretched belt is not loosened, a belt holding member other than the triglide may be used. Further, a belt holding member having both functions of the triglide and the buckle may be used.
The description of the present embodiment describes an example in which the operation unit R1 includes both the gain up operation unit R1BU, the gain down operation unit R1BD and the increase rate up operation unit R1CU, the increase rate down operation unit R1CD, but may also include at least one of the gain up operation unit R1BU, the gain down operation unit R1BD and the increase rate up operation unit R1CU, the increase rate down operation unit R1CD.
The power assist suit 1 described in the present embodiment is described as an example in which the gain, the increase rate, and the like can be changed from the operation unit R1, but may also be provided with a communication unit 64 (see
The present embodiment describes an example in which the gain Cp is obtained by using the wearer mass M and the object mass m, whereas the gain Cp may be obtained using the wearer weight (M*g) and the object weight (m*g) by using the gravitational acceleration g.
The present embodiment describes an example in which the load detection units are provided under the left and right feet of the wearer, whereas gloves may be worn on right and left hands of the wearer, and the left and right gloves may be provided with load detection units. In this case, the object mass (or object weight) can be detected from the load detected by the load detection units, and the detected object mass (or object weight) can be converted into the gain Cp. Further, a plurality of switches for detecting presence or absence of a load may be provided instead of providing the load detection units under the left and right feet or on the left and right gloves. For example, if each switch is turned on at 2 [kg] or more, an approximate object weight can be detected according to a number of switches that are turned on.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-094439 | May 2019 | JP | national |
| 2019-094440 | May 2019 | JP | national |
