Patent Grant
9974706
1. Technical Field
The present invention relates to a driving device and a driving method.
2. Related Art
In the past, driving devices worn on hands to assist movements of fingers in a wearing state, that is, to flex and stretch (bend and spread) finger joints, have been proposed as in a finger movement auxiliary device disclosed in JP-A-2002-345861 and a wearing type movement support device disclosed in JP-A-2011-115248.
However, it is difficult to detect whether wearers wearing driving devices are attempting to bend their fingers or spread their fingers, that is, the intention of the wearers in regard to the movements. The above-mentioned technologies of the related art have the problem that it is difficult to appropriately support (assist) flexing and stretching movements of fingers although the postures or positions of the fingers can be controlled. This problem is common to driving devices assisting motions of various parts such as toes, elbows, wrists, knees, necks, and waists, as well as driving devices assisting motions of the finger joints of human beings. This problem is also common to driving devices assisting motions of biological parts of animals and non-biological parts of robots or the like, as well as human beings.
An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.
(1) An aspect of the invention provides a driving device. The driving device includes: a wearable mechanism that is worn on a wearing part; an actuator that drives the wearable mechanism; and first and second force sensors that are provided on the wearable mechanism and detect a force. The first and second force sensors are provided at positions at which a first detected value obtained from the first force sensor and a second detected value obtained from the second force sensor are changed in response to a motion of the wearing part. When a difference between the first and second detected values is less than a pre-decided first threshold value and the first or second detected value is greater than a pre-decided second threshold value, the actuator drives the wearable mechanism so that the second detected value is constant.
In the driving device according to the aspect of the invention, the wearable mechanism can be driven according to the first detected value detected by the first force sensor and the second detected value detected by the second force sensor. Specifically, when the difference between the first and second detected values is less than the pre-decided first threshold value and the first or second detected value is greater than the pre-decided second threshold value, the actuator drives the wearable mechanism so that the second detected value is constant.
(2) In the driving device according to the aspect of the invention described above, the actuator may drive the wearable mechanism based on the first or second detected value when the difference between the first and second detected values is equal to or greater than the first threshold value. The driving device according to this aspect of the invention can assist the movement of the wearing part by detecting a motion state of the wearing part on which the wearable mechanism is worn according to the first detected value detected by the first force sensor and the second detected value detected by the second force sensor and driving the wearable mechanism.
(3) In the driving device according to the aspect of the invention described above, the wearing part may be a finger. The first force sensor may be disposed on a dorsal side of the finger. The second force sensor may be disposed on a ventral side of the finger. The driving device according to this aspect of the invention can assist a motion of a finger by detecting a motion state of the finger on which the wearable mechanism is worn by the first and second force sensors and driving the wearable mechanism based on the first and second detected values.
(4) In the driving device according to the aspect of the invention described above, the first and second force sensors may be disposed to face each other in a direction in which the finger is rotated. The driving device according to this aspect of the invention can exclude a moment component in bending and spreading motions of the finger from the detected values detected by the first and second force sensors and detect the motion state of a part of the finger with high accuracy.
(5) In the driving device according to the aspect of the invention described above, the wearable mechanism may include at least one of assistant units including an assistant portion that is disposed on the dorsal side of the finger and an interposing portion that is fixed to the assistant portion and interposes the finger to cover the ventral side of the finger. The first force sensor may be disposed on a surface of the assistant portion on the dorsal side of the finger. The second force sensor may be disposed on a surface of the interposing portion on the ventral side of the finger. The driving device may include a control unit that controls a movement of the actuator. Here, a) the control unit may determine that a movement state is a free stop state in which a hand including the finger does not grip a gripping target and stops when the difference between the first and second detected values is less than the first threshold value and the first or second detected value is less than the second threshold value, b) the control unit may determine that the movement state is a grip force maintenance state in which the hand grips the gripping target with a constant grip force when the difference between the first and second detected values is less than the first threshold value and the first or second detected value is equal to or greater than the second threshold value, c) the control unit may determine that the movement state is a free grasp movement state in which the hand grips the gripping target from the state in which the hand does not grip the gripping target when the difference between the first and second detected values is equal to or greater than the first threshold value, the second detected value is greater than the first detected value, and the first detected value is less than the second threshold value, d) the control unit may determine that the movement state is a grip progress state in which the hand grips the gripping target from the state in which the hand grips the gripping target when the difference between the first and second detected values is equal to or greater than the first threshold value, the second detected value is greater than the first detected value, and the first detected value is equal to or greater than the second threshold value, e) the control unit may determine that the movement state is a grip release movement state in which the hand opens from the state in which the hand grips the gripping target when the difference between the first and second detected values is equal to or greater than the first threshold value, the second detected value is equal to or less than the first detected value, and the second detected value is equal to or greater than the second threshold value, and f) the control unit may determine that the movement state is a free release movement state in which the hand opens from the state in which the hand does not grip the gripping target when the difference between the first and second detected values is equal to or greater than the first threshold value, the second detected value is equal to or less than the first detected value, and the second detected value is less than the second threshold value.
The driving device according to this aspect of the invention can determine a movement state of the hand based on the first detected value detected by the first force sensor and the second detected value detected by the second force sensor and the actuator can drive the wearable mechanism based on the movement state, so that a motion of the hand, specifically, a motion of the finger on which the driving device is worn, can be assisted.
(6) In the driving device according to the aspect of the invention described above, the wearable mechanism may include at least one of assistant units including an assistant portion that is disposed on the dorsal side of the finger and an interposing portion that is fixed to the assistant portion and interposes the finger to cover the ventral side of the finger. The first force sensor may be disposed on a surface of the assistant portion on the dorsal side of the finger. The second force sensor may be disposed on an opposite surface of the interposing portion to the ventral side of the finger. The first detected value may be a value obtained by subtracting an offset value according to a wearing pressure occurring when the wearable mechanism is worn on the finger. The driving device may include a control unit that controls a movement of the actuator. Here, a) the control unit may determine that a movement state is a free stop state in which a hand including the finger does not grip a gripping target and stops when the difference between the first and second detected values is less than the first threshold value and the second detected value is equal to or less than the second threshold value, b) the control unit may determine that the movement state is a grip force maintenance state in which the hand grips the gripping target with a constant grip force when the difference between the first and second detected values is less than the first threshold value and the second detected value is equal to or greater than the second threshold value, c) the control unit may determine that the movement state is a free grasp movement state in which the hand grips the gripping target from the state in which the hand does not grip the gripping target when the difference between the first and second detected values is equal to or greater than the first threshold value, the second detected value is equal to or less than the second threshold value, and the first detected value is less than the second detected value, d) the control unit may determine that the movement state is a grip progress state in which the hand grips the gripping target from the state in which the hand grips the gripping target when the difference between the first and second detected values is equal to or greater than the first threshold value, the second detected value is greater than the second threshold value, and the first detected value is less than the second detected value, e) the control unit may determine that the movement state is a grip release movement state in which the hand opens from the state in which the hand grips the gripping target when the difference between the first and second detected values is equal to or greater than the first threshold value, the second detected value is greater than the second threshold value, and the first detected value is equal to or greater than the second detected value, and f) the control unit may determine that the movement state is a free release movement state in which the hand opens from the state in which the hand does not grip the gripping target when the difference between the first and second detected values is equal to or greater than the first threshold value, the second detected value is equal to or less than the second threshold value, and the first detected value is equal to or greater than the second detected value.
The driving device according to this aspect of the invention can also determine a movement state of the hand based on the first detected value detected by the first force sensor and the second detected value detected by the second force sensor and the actuator can drive the wearable mechanism based on the movement state, so that a motion of the hand, specifically, a motion of the finger on which the driving device is worn, can be assisted.
(7) In the driving device according to the aspect of the invention described above, the control unit may switch a driving state of the wearable mechanism by the actuator based on the determined movement state. The driving device according to this aspect of the invention can assist a movement of the hand according to the determined movement state, specifically, a motion of the finger on which the driving device is worn. For example, a motion can be quickened in a free hand case and a motion can be slowed in a grip case.
(8) In the driving device according to the aspect of the invention described above, the actuator may include a piezoelectric driving device that generates a driving force driving the wearable mechanism. The piezoelectric driving device may include a vibration plate having first and second surfaces and a vibration structure disposed on at least one of the first and second surfaces of the vibration plate. The vibration structure may include a piezoelectric substance and first and second electrodes that interpose the piezoelectric substance. In the driving device according to this aspect of the invention, the actuator can be configured to have a simple, miniature, and thin structure, and thus the driving device can be miniaturized and thinned.
(9) Another aspect of the invention provides a driving device. The driving device includes: a wearable mechanism that is worn on a wearing part; an actuator that drives the wearable mechanism; and first and second force sensors that are provided on the wearable mechanism and detect a force. The first and second force sensors are provided at positions at which a first detected value obtained from the first force sensor and a second detected value obtained from the second force sensor are changed in response to a motion of the wearing part. When a difference between the first and second detected values is less than a pre-decided first threshold value, the first or second detected value is greater than a pre-decided second threshold value, and the wearable part comes into contact with an object provided with a third force sensor detecting a force, the actuator drives the wearable mechanism so that the second and third detected values are constant.
In the driving device according to this aspect of the invention, it can be confirmed that the wearable mechanism is driven so that the second detected value is constant, from the fact that the third detected value detected by the third force sensor is constant.
(10) Still another aspect of the invention provides a driving device assisting a motion of a living body. The driving device includes a wearable mechanism that is worn on a wearing part; an actuator that drives the wearable mechanism; and a plurality of first force sensors that are disposed between the wearable mechanism and the wearing part. In the driving device according to this aspect of the invention, a deviation or a distribution of a force generated between the wearable mechanism and the wearing part depending on the position of the wearing part can be detected with the plurality of first force sensors when the wearing part on which the wearable mechanism is worn moves. Therefore, the force generated between the wearable mechanism and the wearing part can be detected with high accuracy and the motion state of the wearing part on which the wearable mechanism is worn can be detected with high accuracy.
(11) In the driving device according to the aspect of the invention described above, the actuator may drive the wearable mechanism based on the plurality of first detected values changed in response to a motion of the wearing part and obtained from the plurality of first force sensors. The driving device according to this aspect of the invention can detect a motion state of the wearing part on which the wearable mechanism is worn with high accuracy based on the plurality of first detected values obtained by the plurality of first force sensors and can drive the wearable mechanism according to the motion state of the wearing part. Accordingly, it is possible to assist the movement of the wearing part.
(12) The driving device according to the aspect of the invention described above may include at least one second force sensor that is disposed to face the plurality of first force sensors with the wearing part therebetween. The driving device according to this aspect of the invention can also detect a force generated between the wearing part and the wearable mechanism put on the side of the second force sensor disposed to face the first force sensors with the wearing part therebetween.
(13) In the driving device according to the aspect of the invention described above, the actuator may drive the wearable mechanism based on a plurality of first detected values and at least one second detected value which are a plurality of first detected values obtained from the plurality of first force sensors and at least one second detected value obtained from at least the one second force sensor and which are changed in response to a motion of the wearing part. The driving device according to this aspect of the invention can detect a motion state of the wearing part on which the wearable mechanism is worn with high accuracy and drive the wearable mechanism according to the motion state of the wearing part based on the plurality of first detected values detected by the plurality of first force sensors and the second detected value detected by at least one second force sensor, the first force sensors and at least one second force sensor being disposed to face each other with the wearing part therebetween. Accordingly, it is possible to assist the movement of the wearing part.
(14) The driving device according to the aspect of the invention described above may include the plurality of second force sensors that are disposed to face the plurality of first force sensors with the wearing part therebetween. In the driving device according to this aspect of the invention, a distribution of a contact force between the wearing part and the wearable mechanism on the side of the first force sensors can be detected by the plurality of first force sensors, and a deviation or a distribution of a force generated between the wearable mechanism and the wearing part depending on the position of the wearing part on which the wearable mechanism is worn on the side of the second force sensors opposite to the first force sensors can be detected by the plurality of second force sensors. Therefore, it is possible to detect the force generated between the wearable mechanism and the wearing part with higher accuracy. The motion state of the wearing part on which the wearable mechanism is worn can be detected with higher accuracy based on the plurality of first detected values detected by the plurality of first force sensors and the second detected values detected by the plurality of second force sensors, and the wearable mechanism can be driven according to the motion state of the wearing part. Accordingly, it is possible to assist the movement of the wearing part.
(15) In the driving device according to the aspect of the invention described above, a pressure reception plate that is disposed to come into contact with the plurality of first force sensors may be provided between the plurality of first force sensors and the wearing part. In the driving device according to this aspect of the invention, a force generated between the assist driving device and the wearing part can be efficiently transferred to the plurality of first force sensors via the pressure reception plate. Therefore, it is possible to improve the detection accuracy of the contact force by the first force sensors.
(16) In the driving device according to the aspect of the invention described above, the wearing part may be a finger and the plurality of first force sensors may be disposed at least in the longitudinal direction of the finger on the side of the dorsal side of the finger. The driving device according to this aspect of the invention can detect the deviation or the distribution of the force generated between the wearable mechanism and the finger with high accuracy, detect the motion state of the finger on which the wearable mechanism is worn with high accuracy, and drive the wearable mechanism according to the motion state of the finger. Accordingly, it is possible to assist the movement of the finger with high accuracy.
(17) In the driving device according to the aspect of the invention described above, the actuator may include a piezoelectric driving device that generates a driving force driving the wearable mechanism. The piezoelectric driving device may include a vibration plate having first and second surfaces and a vibration structure disposed on at least one of the first and second surfaces of the vibration plate. The vibration structure may include a piezoelectric substance and first and second electrodes that interpose the piezoelectric substance. In the driving device according to this aspect of the invention, the actuator can be configured to have a simple, miniature, and thin structure, and thus the driving device can be miniaturized and thinned.
The aspects of the invention can be implemented in various forms such as a driving method of driving the driving device as well as the driving device.
The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
Hereinafter, examples of a finger joint driving device worn on fingers which are wearing parts to support (assist) bending or spreading movements of the fingers will be described as a driving device according to the invention. In embodiments to be described below, the same reference numerals are given to members with the same configurations and the description thereof will be sometimes omitted or simplified.
The finger joint driving device 1 is assumed to be worn on a hand 100 of, for example, a person for which trouble occurs in bending or spreading of fingers due to an accident, illness, or the like, a person of which a grip force becomes weak, or an aged person of which a force becomes weak due to aging. In the embodiment, the finger joint driving device 1 is worn on an index finger 101 and is used to assist flexing and stretching (that is, rotation) of the finger joints of the index finger 101. The finger joint driving device 1 includes a first base portion 2, a first link portion 3, a second link portion 4, and a second base portion 5. These members are connected in order from the wrist side to the finger tip side. These four members 2 to 5 are referred to as a “first member 2,” a “second member 3,” a “third member 4,” and a “fourth member 5.” As illustrated in
The first base portion 2 is disposed on the side of a hand back 105 of a proximal joint part 102 of the index finger 101 in the wearing state. The first base portion 2 is a member which has a block form of which the outside appearance is flat. The first base portion 2 is worn on the proximal joint part 102 of the index finger 101 using a first wearing band 20A. The first wearing band 20A is configured as a band body of which a length can be adjusted. Each end 201 is fixed to each side surface 22 of the first base portion 2. The first wearing band 20A is wrapped on the side of a hand palm 106 of the proximal joint part 102 of the index finger 101, that is, on the rear of the sheet surface of
The second base portion 5 is disposed on the side of the finger tip side from the first base portion 2, that is, the side of the hand back 105 of a middle joint part 103 of the index finger 101. The second base portion 5 is a member with has a block form of which the outside appearance is flat. The second base portion 5 is worn on the middle joint part 103 of the index finger 101 using a second wearing band 20B, as in the first base portion 2.
The first link portion 3 is provided on the finger tip side of the first base portion 2. The first link portion 3 is a member of which a whole length is longer than the whole length of the first base portion 2 or the second base portion 5. The first link portion 3 includes a top plate 31 and side walls 32 protruding from both edges of the top plate 31. The first base portion 2 is interposed between the two side walls 32. Each side wall 32 and a side surface 22 of the first base portion 2 are connected to each other via a rotation support portion 11. The rotation support portion 11 is configured to have a shaft (not illustrated) which is installed in one of the side wall 32 and the first base portion 2 and a bearing (not illustrated) which is installed in the other thereof and into which the shaft is inserted. When a rotation axis O107 is assumed at the time of rotation by flexing and stretching of a proximal interphalangeal joint 107 between the proximal joint part 102 and the middle joint part 103 of the index finger 101, a rotation axis O11 of the rotation support portion 11 is parallel to the rotation axis O107. The first link portion 3 can be rotated around the rotation axis O11 with respect to the first base portion 2 by the rotation support portion 11 with such a configuration.
The second link portion 4 is provided on the finger tip side of the first link portion 3. The second link portion 4 includes a sliding portion 41 that slides with respect to the second base portion 5 and a protrusion portion 42 that protrudes from the sliding portion 41.
As illustrated in
The protrusion portion 42 of the second link portion 4 is inserted into two side walls 32 of the first link portion 3. The protrusion portion 42 and each side wall 32 are connected to each other via a rotation support portion 12. The rotation support portion 12 is configured to have a shaft (not illustrated) which is installed in one of the protrusion portion 42 and the side wall 32 and a bearing (not illustrated) which is installed in the other thereof and into which the shaft is inserted. A rotation axis O12 of the rotation support portion 12 is parallel to the rotation axis O107. As in the first link portion 3, the second link portion 4 can be rotated around the rotation axis O12 parallel to the rotation axis O107 by the rotation support portion 12 with such a configuration. Since the rotation axis O11 and the rotation axis O12 are each parallel to the rotation axis O107, the proximal interphalangeal joint 107 can be easily flexed and stretched by the finger joint driving device 1 while an excessive force is prevented from being applied to the proximal interphalangeal joint 107.
The materials for the first base portion 2, the first link portion 3, the second link portion 4, and the second base portion 5 are not particularly limited. For example, various resin materials such as polyethylene or various metal materials such as aluminum can be used. The materials for the first wearing band 20A and the second wearing band 20B are not particularly limited. For example, various rubber materials such as silicon rubber can be used.
As illustrated in
The first force sensor S1 is a force sensor that detects a force applied from the surface 51 of the second base portion 5 to the dorsal side of the middle joint part 103 and a force applied from the dorsal side of the middle joint part 103 to the side of the surface 51 of the second base portion 5 when the rotation of the proximal interphalangeal joint 107 is assisted by the actuator 6A to be described below. The second force sensor S2 is a force sensor that detects a force applied from the ventral side of the middle joint part 103 to the side of the second wearing band 20B and a force applied from a gripping target (not illustrated) to the ventral side of the middle joint part 103 via the second wearing band 20B when the gripping target is gripped by the index finger 101. The detected values detected by the first force sensor S1 and the second force sensor S2 are used for the control unit 10 to control a movement of the actuator 6A. The control unit 10 controls a movement state of the actuator 6A based on the detected values detected by the first force sensor S1 and the second force sensor S2, specifically, a rotation state of the first link portion 3, so that the proximal interphalangeal joint (second joint) 107 is flexed and stretched.
The piezoelectric driving device 64 is a laminate that includes two sets of vibration structures 65 including five piezoelectric elements 651 and a vibration plate 66 inserted to be laminated between the vibration structures. The vibration structure is also referred to as a “vibrator.”
Each of the five piezoelectric elements 651 of the vibration structures 65 includes a piezoelectric substance and first and second electrodes that interpose the piezoelectric substance (none of which is illustrated). One of the first and second electrodes may serve as a common electrode. The piezoelectric elements 651 are electrically connected to the control unit 10 (see
A protrusion 67 is provided at an end of the piezoelectric driving device 64. On both side surfaces of the piezoelectric driving device 64, a plurality of support portions 68 supporting the piezoelectric driving device 64 are provided at positions corresponding to a vibrating joint. These support portions 68 are integrated with the vibration plate 66. The plurality of support portions 68 protruding from the same side surface of the vibration plate 66 are preferably connected via a connection plate 69.
Thus, in the finger joint driving device 1, the rotation of the first link portion 3 can be reliably performed using the piezoelectric driving device 64. Further, the piezoelectric driving device 64 can contribute to realization of miniaturization or thinness of the finger joint driving device 1.
The control unit 10 (see
A movement of the finger joint driving device 1 with the above-described configuration will be schematically described. For the finger joint driving device 1, in the state illustrated in
The wearer (user) of the finger joint driving unit 1 can flex and stretch a distal interphalangeal joint 109 or his or her thumb, middle finger, ring finger, or little finger of the index finger 101 (see
In the finger joint driving unit 1 in the wearing state, the first base portion 2 is disposed in the proximal joint part 102 of the index finger 101 and the second base portion 5 is disposed in the middle joint part 103 in the embodiment, but the invention is not limited to this disposition. For example, in the wearing state, the first base portion 2 may be disposed on the hand back 105 and the second base portion 5 may be disposed in the proximal joint part 102 of the index finger 101. In this case, a metacarpophalangeal joint (third joint) 108 can be flexed and stretched by the finger joint driving unit 1. Further, in the wearing state, the first base portion 2 may be disposed in the middle joint part 103 of the index finger 101 and the second base portion 5 may be disposed in a distal joint part 104. In this case, the distal interphalangeal joint (first joint) 109 can be flexed and stretched by the finger joint driving unit 1. In the wearing state, the first base portion 2 may be disposed in the middle joint part 103 of the index finger 101 and the second base portion 5 may be disposed on the opposite side to the finger tip from the first base portion 2, that is, in the proximal joint part 102 on the wrist side. In this case, as in the wearing state of the embodiment, the proximal interphalangeal joint 107 can be flexed and stretched by the finger joint driving unit 1.
A part (wearing part) of the hand 100 on which the finger joint driving device 1 is worn is the index finger 101 in the embodiment, but the invention is not limited thereto. For example, the wearing part may be a thumb, a middle finger, a ring finger, or a little finger.
The actuator 6A serves to rotate the first link portion 3 in the embodiment, but the invention is not limited thereto. The actuator 6A may serve to rotate the second link portion 4. Even in this case, the second link portion 4 can be reliably rotated, thereby contributing to the realization of miniaturization or thinness of the finger joint driving device 1.
The first base portion (first member) 2, the first link portion (second member) 3, the second link portion (third member) 4, and the second base portion (fourth member) 5, the first wearing band 20A, and the second wearing band 20B correspond to a “wearable mechanism” according to the invention. The second base portion 5 corresponds to an “assistant portion” according to the invention, the second wearing band 20B corresponds to an “interposing portion,” and the second base portion 5 and the second wearing band 20B correspond to “assistant units.”
At a start time point of
Then, at time t3, when the index finger 101 comes into contact with a gripping target, a positive force applied according to the extent that the index finger 101 grips the gripping target is applied to the second force sensor S2 and a positive force is also applied to the first force sensor S1 from the dorsal side of the middle joint part 103, and thus the output difference |s1−s2| is decreased. At this time, the rotation velocity of the first link portion 3 is decreased. However, with the decrease in the rotation velocity, a force (torque) driving the first link portion 3 by the actuator 6A increases to enhance a grip force of the index finger 101. Then, a movement state of the finger joint driving device 1 from a time point at which the output of the first force sensor S1 is equal to or greater than a grip determination threshold value Tb at time t4 is assumed to be a “grip progress state U1” in which the gripped gripping target is further gripped tightly. At this time, the movement velocity of the first link portion 3 by the actuator 6A is further decreased toward “0” in a considerably small state, but a force (torque) driving the first link portion 3 by the actuator 6A is further increased. Then, at a time point at which the output difference |s1−s2| is less than the movement determination threshold value Ta at time t5, the movement state of the finger joint driving device 1 becomes a state in which the grip force of the gripping target is maintained. This state is referred to as a “grip force maintenance state U5.” In this state, the output of the first force sensor S1 is substantially the same as the output of the second force sensor S2, a constant assist force is applied by the finger joint driving device 1, and the gripping target is gripped by a constant grip force with the hand 100.
At the end of the grip force maintenance state U5, when the wearer starts a movement of opening the hand 100, the output of the second force sensor S2 is less than the output of the first force sensor S1 and decreases. At time t6, the output difference |s1−s2| is equal to or greater than the movement determination threshold value Ta. From here, the movement state of the finger joint driving device 1 becomes a “grip release movement state U3” in which a movement of opening the hand 100 and separating the gripping target from the hand 100 starts, from the grip force maintenance state U5. In this case, the movement velocity of the first link portion 3 by the actuator 6A gradually increases from “0” and the assist force accordingly decreases. Then, the opening of the hand 100 becomes large, the outputs of the first force sensor S1 and the second force sensor S2 decrease, and the movement state of the finger joint driving device 1 becomes a “free release movement state U4” from a time point at which the output of the second force sensor S2 is less than the grip determination threshold value Tb at time t7. Then, the gripping target is actually released at a time point when the output of the second force sensor S2 becomes “0” at time t8, the hand 100 actually becomes free, and the assist force becomes “0.” In the free release movement state U4, a positive force is applied to the first force sensor S1 with the movement of opening the hand 100. At this time, the actuator 6A rotates the first link portion 3 at a movement velocity according to the output difference |s1−s2|, so that the rotation of the proximal interphalangeal joint 107 is assisted, the spreading of the index finger 101 is assisted, and the opening of the hand 100 is assisted.
Then, immediately before the movement in which the wearer opens the hand 100 stops, the output of the first force sensor S1 also decreases and the output difference |s1−s2| is less than the movement determination threshold value Ta at time t9. At this time, the movement state of the finger joint driving device 1 returns to the “free stop state U6” in which the movement in which the wearer opens the hand 100 stops. The movement of the finger joint driving device 1 illustrated in
First, in step S102, the values of the outputs of the first force sensor S1 and the second force sensor S2 are acquired. In step S104, whether the wearer has a movement intention is determined. Specifically, whether the wearer has the movement intention is determined depending on whether the output difference |s1−s2| between the first force sensor S1 and the second force sensor S2 is equal to or greater than the movement determination threshold value Ta. For example, at time t2 and time t6 of
When it is determined in step S104 that the wearer has the movement intention, the output of the first force sensor S1 is subsequently compared to the output of the second force sensor S2 and a movement direction intended by the wearer is determined in step S106. As will be described, when the output of the second force sensor S2 is greater than the output of the first force sensor S1, the movement direction is determined to be a hand gripping direction (finger bending direction) and the processes of steps S108 to S114 are performed. When the output of the second force sensor S2 is equal to or less than the output of the first force sensor S1, the movement direction is determined to be a hand opening direction (finger spreading direction) and the processes of steps S118 to S124 are performed.
When the movement direction is determined to be the hand gripping direction, it is determined in step S108 whether the output of the first force sensor S1 is equal to or greater than the grip determination threshold value Tb. Here, when it is determined that the output of the first force sensor S1 is less than the grip determination threshold value Tb, the movement state of the finger joint driving device 1 becomes the free grasp movement state U2 (see
Conversely, when it is determined in step S106 that the movement direction is the hand opening direction, the output of the second force sensor S2 is equal to or greater than the grip determination threshold value Tb in step S118 as in step S108. Here, when it is determined that the output of the second force sensor S2 is equal to or greater than the grip determination threshold value Tb, the movement state of the finger joint driving device 1 becomes the grip release movement state U3 (see
When it is determined in step S104 that the wearer has no movement intention, it is determined whether the output of the first force sensor S1 is equal to or greater than the grip determination threshold value Tb. Here, when it is determined that the output of the first force sensor S1 is equal to or greater than the grip determination threshold value Tb, the movement state of the finger joint driving device 1 is determined to be the grip force maintenance state U5 (see
In the above-described control flow, the values of the outputs of the two force sensors S1 and S2 are acquired and the movement state of the finger joint driving device 1 is determined through the determination (whether there is an intention to move the hand) of the movement intention based on the acquired output values, the determination of the movement direction (the gripping/opening of the hand), and the gripping determination (grip/free). Specifically, the movement state of the finger joint driving device 1 is determined to be one of the grip progress state U1, the free grasp movement state U2, the grip release movement state U3, the free release movement state U4, the grip force maintenance state U5, and the free stop state U6. Then, the actuator 6A is allowed to drive the first link portion 3 so that the finger joint driving device 1 moves according to the movement state. Thus, the movement intention of the wearer is detected based on the outputs of the two force sensors S1 and S2 and the finger joint driving device 1 can be moved according to the movement intention. Thus, the hand 100 wearing the finger joint driving device 1, more specifically, the movement of the index finger 101, can be assisted. As understood from the above description, the movement determination threshold value Ta and the grip determination threshold value Tb correspond to the first threshold value and the second threshold value according to the invention.
The state in which a constant grip force is maintained in the grip force maintenance state U5 includes a state in which a grip force is changed within a constant change range so that the constant grip force is maintained. For example, this state may be a state in which a grip force is maintained to be constant as a whole while the outputs of the first force sensor S1 and the second force sensor S2 are changed using the state in which the constant grip force can be obtained as a criterion. As an assist force given by the actuator 6A in the grip force maintenance state U5, for example, the following various forces can be used.
(1) a constant force which is not temporally changed
(2) a force which is changed periodically in a fluctuating manner but can constantly maintain a grip state
(3) a force which is changed at random in a fluctuating manner but can constantly maintain a grip state
Such forces have substantially the same operation in the sense that assisting is performed to stably grip a gripping target. Thus, a term “the constant force” in the present specification has a wide meaning of various forces such as the foregoing (1) to (3) in a broad sense. On the other hand, the phrase “the constant force that does not change temporally” has a narrow meaning including the foregoing (1) and including neither the foregoing (2) nor the foregoing (3). The width of the fluctuation of the force is preferably within, for example, ±0.001 N/mm2. The grip force maintenance state U5 can be confirmed according to a method to be described below. When a force changes in a fluctuating manner, the detected values detected by the two force sensors S1 and S2 also change in a fluctuating manner in response to the change in the force.
As illustrated in
As understood from the above description, by confirming the value (detected value) of the output of the third force sensor S3, it is possible to confirm that the grip force by the finger joint driving device 1 is maintained to have the constant magnitude in the grip force maintenance state U5.
The finger joint driving device 1B according to the embodiment is different from the finger joint driving device 1 according to the first embodiment in that the second force sensor S2 is provided not on the surface of the second wearing band 20B facing the ventral side of the middle joint part 103 but on the surface of the second wearing band 20B opposite to the middle joint part 103. The finger joint driving device 1B according to the embodiment is different in a control operation performed by the control unit 10 according to a difference of the disposition of the second force sensor S2. The finger joint driving device 1B according to the embodiment is the same as the finger joint driving device 1 according to the first embodiment in the other points. Thus, description of only a control operation performed by the control unit 10 will be added.
As illustrated in
When the wearer starts a movement in a bending direction of the index finger 101 in order to grip the gripping target at time t1, the outputs of the first force sensor S1 and the second force sensor S2 are changed. Specifically, the output (s1−BL) of the first force sensor S1 becomes less than the output (“0”) of the second force sensor S2. Then, the movement state of the finger joint driving device 1B becomes the free grasp movement state U2 from a time point at which an output difference |s2−(s1−BL)| is equal to or greater than the movement determination threshold value Ta at time t2. At this time, the actuator 6A rotates the first link portion 3 at a movement velocity according to the output difference |s2−(s1−BL)| so that the index finger 101 is bent and the gripping of the hand 100 is assisted.
Then, at time t3, when the index finger 101 comes into contact with the gripping target, a positive force according to the extent that the index finger 101 grips the gripping target is applied to the second force sensor S2 and a positive force is also applied to the first force sensor S1 from the dorsal side of the middle joint part 103, and thus the movement state of the finger joint driving device 1B becomes the grip progress state U1 from the free grasp movement state U2. In this case, the movement velocity of the first link portion 3 by the actuator 6A decreases to be in the state in which the movement velocity decreases toward “0.” However, a driving force (torque) according to the output difference |s2−(s1−BL)| is applied from the actuator 6A to the first link portion 3 as an assist force to assist the gripping of the gripping target. Thus, the outputs of the first force sensor S1 and the second force sensor S2 increase while the output of the second force sensor S2 remains to be greater than the output (s1−BL) of the first force sensor S1, and the assist force increases to assist the grip force by which the gripping target is tightly gripped with the hand 100 (see
Then, at a time point at which the output difference |s2−(s1−BL)| is less than the movement determination threshold value Ta at time t5, the movement state of the finger joint driving device 1B becomes the grip force maintenance state U5. In this state, the output (s1−BL) of the first force sensor S1 is substantially the same as the output of the second force sensor S2, a constant assist force is applied by the finger joint driving device 1B, the gripping target is gripped by a constant grip force with the hand 100.
In the final of the grip force maintenance state U5, when the wearer starts a movement of opening the hand 100, the output (s1−BL) of the first force sensor S1 is less than the output of the second force sensor S2 and decreases. When the output difference |s2−(s1−BL)| is equal to or greater than the movement determination threshold value Ta at time t6, the movement state of the finger joint driving device 1B becomes the grip release movement state U3 from the grip force maintenance state U5. Then, the outputs of the first force sensor S1 and the second force sensor S2 decrease in response to an increase in the opening of the hand 100 and the gripping target is released at a time point at which the output of the second force sensor S2 becomes “0.” Here, when the output difference |s2−(s1−BL)| is equal to or greater than the movement determination threshold value Ta, as illustrated in
Then, immediately before the movement in which the wearer opens the hand 100 stops, the output of the first force sensor S1 also decreases and the output difference |s2−(s1−BL)| is less than the movement determination threshold value Ta. At this time, the movement state of the finger joint driving device 1B returns to the “free stop state U6.” The movement of the finger joint driving device 1B illustrated in
After the values of the outputs of the first force sensor S1 and the second force sensor S2 are acquired in step S102, whether the movement state is the grip state is determined in step S204. Specifically, it is determined whether the acquired output value of the second force sensor S2 is greater than “0.” Further, “0” corresponds to the grip determination threshold value Tb. For example, before time t3 of
When it is determined that the movement state is the grip state, it is determined in step S206 whether the wearer has a movement intention. Specifically, it is determined whether the output difference |s2−(s1−BL)] is equal to or greater than the movement determination threshold value Ta. For example, it is determined that the wearer has the movement intention at time t2 to time t5 and at time t6 to time t8 of
When it is determined that the movement state is not the grip state (non-grip state (free hand state)), it is determined in step S210 whether the wearer has a movement intention, as in step S206. In step S210, the movement state is not the grip state and the output of the second force sensor S2 is “0.” Therefore, whether the wearer has the movement intention is determined depending on whether the output difference |s1−BL| between the base value BL and the first force sensor S1 is equal to or greater than the movement determination threshold value Ta. For example, at time t2 to time t3 and time t8 to time t9 of
When it is determined in step S206 that the wearer has the movement intention at the grip state, the output of the second force sensor S2 is compared to the output (s1−BL) of the first force sensor S1 and a movement direction intended by the wearer is determined in step S208. When the output of the second force sensor S2 is greater than the output (s1−BL) of the first force sensor S1, the movement direction is determined to be a hand gripping direction (finger bending direction), the movement state of the finger joint driving device 1B is the grip progress state U1 (see
Conversely, when it is determined in step S206 that the wearer has no movement intention in the grip state, the movement state of the finger joint driving device 1B is the grip force maintenance state U5 (see
When it is determined in step S210 that the wearer has the movement intention at the non-grip state (free hand state), the movement direction intended by the wearer is determined in step S212, as in step S208. When the output of the second force sensor S2 is greater than the output (s1−BL) of the first force sensor S1, it is determined that the movement direction is the direction in which the hand grips, the movement state of the finger joint driving device 1B is the free grasp movement state U2 (see
Conversely, when it is determined in step S210 that the wearer has no movement intention in the non-grip state (free hand state), the movement state of the finger joint driving device 1B is the free stop state U6 (see
In the above-described embodiment, the movement intention of the wearer is detected based on the outputs of the two force sensors, that is, the first force sensor S1 and the second force sensor S2, and the finger joint driving device 1B is operated according to the movement intention, so that the hand 100 wearing the finger joint driving device 1B, more specifically, the movement of the index finger 101, can be assisted, for example, as in
By confirming the value (detected value) of the output of the third force sensor S3 using the gripping target provided with the third force sensor S3 even in the grip force maintenance state U5 according to the embodiment, as in the first embodiment, it is possible to confirm that the grip force by the finger joint driving device 1B is maintained to have a constant magnitude (see
When the output (s1−BL) of the first force sensor S1 is assumed to be the first force sensor S1, the control flow illustrated in
A finger joint driving device 1001 according to the embodiment is different from the finger joint driving device 1 according to the first embodiment in that the first force sensor S1 is substituted with a plurality of first force sensors S11 and the second force sensor S2 is substituted with a second force sensor S12, and a pressure reception plate Ps entirely extending across the plurality of first force sensors S11 are further provided. The finger joint driving device 1001 according to the embodiment is also different from the finger joint driving device 1 according to the first embodiment in the control operation performed by the control unit 10 according to the disposition of the plurality of first force sensors S11. The finger joint driving device 1001 according to the embodiment is the same as the finger joint driving device 1 in the other points. Accordingly, the differences from the finger joint driving device 1 according to the first embodiment will be described below.
In the finger joint driving device 1001, as illustrated in
That is, the first force sensors S11 and the second force sensor S12 face each other with the middle joint part 103 therebetween. The first force sensors S11 and the second force sensor S12 are preferably disposed to face each other in a direction in which the index finger 101 rotates. As will be described below, the reason why this disposition is preferable is that when the person intends to bend and spread the index finger 101, it is easy to estimate the bending and spreading intention based on detected values detected by the first force sensors S11 and the second force sensor S12. However, the invention is not limited to this disposition. The first force sensors S11 may be disposed on the dorsal side of the finger and the second force sensor S12 may be disposed on the ventral side of the finger with the index finger 101 (the middle joint part 103) therebetween.
The plurality of first force sensors S11 is a force sensor that detects a force applied from the side of the surface 51 of the second base portion 5 to the dorsal side of the middle joint part 103 and a force applied from the dorsal side of the middle joint part 103 to the side of the surface 51 of the second base portion 5 when the rotation of the proximal interphalangeal joint 107 is assisted by the actuator 6A to be described below. The one second force sensor S12 is a force sensor that detects a force applied from the ventral side of the middle joint part 103 to the side of the second wearing band 20B and a force applied from a gripping target (not illustrated) to the ventral side of the middle joint part 103 via the second wearing band 20B when the index finger 101 is allowed to grip the gripping target. The pressure reception plate Ps is provided to suppress distribution of the force applied from the surface 51 of the second base portion 5 to the dorsal side of the middle joint part 103 and the force applied from the dorsal side of the middle joint part 103 to the side of the surface 51 of the second base portion 5 and to efficiently these forces to the two first force sensors S11. However, the pressure reception plate Ps can be omitted. The force applied from the side of the surface 51 of the second base portion 5 to the dorsal side of the middle joint part 103 and the force applied from the dorsal side of the middle joint part 103 to the side of the surface 51 of the second base portion 5 are referred to as “forces generated between the second base portion 5 and the middle joint part 103 of the index finger 101.”
The detected values detected by the plurality of first force sensors S11 and the one second force sensor S12 are used for the control unit 10 to control the operation of the actuator 6A. The control unit 10 controls a movement state of the actuator 6A based on the detected values detected by the two first force sensors S11 and the one second force sensor S12, specifically, a rotation state of the first link portion 3, to bend and spread the proximal interphalangeal joint (second joint) 107.
The first base portion (first member) 2, the first link portion (second member) 3, the second link portion (third member) 4, the second base portion (fourth member) 5, the first wearing band 20A, and the second wearing band 20B correspond to a “wearable mechanism” according to the invention. The second base portion 5 corresponds to an “assistant portion” according to the invention, the second wearing band 20B corresponds to an “interposing portion,” and the second base portion 5 and the second wearing band 20B corresponds to “assistant units.”
First, in step S302, the values of the outputs of the plurality of first force sensors S11 and the one second force sensor S12 are acquired. In step S304, whether the wearer has a movement intention is determined. Specifically, whether the wearer has the movement intention is determined depending on whether the absolute value |s12−Σs11| which is the output difference between a sum of the outputs (s11) of the plurality of first force sensors S11 and the output (s12) of the second force sensor S12 is equal to or greater than the movement determination threshold value Ta. The value of the movement determination threshold value Ta is confirmed and set in advance experimentally in consideration of, for example, prevention of an erroneous movement or determination possibility of a movement intention of the wearer. As will be described below, when it is determined that the wearer has the movement intention, the processes of steps S306 to S322 are performed. When it is determined that the wearer has no movement intention, the process of step S330 is performed. A pressure from the wearing band at the time of the wearing actually is related to the first force sensors S11 and the second force sensor S12. However, it is here assumed that the pressure is calibrated and the output is “0.”
When it is determined in step S304 that the wearer has the movement intention, a movement direction intended by the wearer is determined in step S306. Specifically, the movement direction intended by the wearer is determined depending on whether a difference (s12−Σs11) between the output of the second force sensor S12 and the sum of the outputs of the plurality of first force sensors S11 is greater than “0,” that is, the output of the second force sensor S12 is greater than the sum (Σs11) of the outputs of the plurality of first force sensors. As will be described, when the output difference (s12−Σs11) is greater than “0,” the movement direction is determined to be a hand gripping direction (finger bending direction) and the processes of steps S310 to S312 are performed. When the output difference (s12−Σs11) is equal to or less than “0,” the movement direction is determined to be a hand opening direction (finger spreading direction) and the processes of steps S320 to S322 are performed.
When the movement direction is determined to be the hand gripping direction, a movement velocity (grasp movement velocity) or a movement distance (grasp movement distance) at which the hand grips is decided according to the output difference |s12−Σs11| in step S310. Then, in step S312, the actuator 6A is instructed of the hand gripping movement (grasp movement) of the decided movement velocity or movement distance and the actuator 6A rotates the first link portion 3 based on the instructed movement velocity or movement distance.
Conversely, when it is determined that the movement direction is the hand opening direction, the movement velocity (release movement velocity) or the movement distance at which the hand opens is decided according to the output difference |s11−Σs12| in step S320. As in step S312, in step S322, the actuator 6A is instructed of the hand opening movement (release movement) of the decided movement velocity or movement distance and the actuator 6A rotates the first link portion 3 based on the instructed movement velocity or movement distance.
When it is determined in step S304 that the wearer has no movement intention, the actuator 6A is instructed to maintain the immediately previous state (state maintenance) in which the movement velocity or movement distance is “0” and the actuator 6A operates to maintain the instructed state in step S330. For example, in the case of the state in which the hand 100 grips an object, the actuator 6A operates to maintain the driving state of the first link portion 3 at that time point. In the case of the free state in which the hand 100 grips nothing, the actuator 6A stops the movement in the state in which the position of the first link portion 3 is maintained at that time point.
As described above, in the finger joint driving device 1001 according to the embodiment, the values of the outputs of the plurality of first force sensors S11 and the value of the output of the one second force sensor are acquired, and the movement state of the finger can be detected with high accuracy through the movement intention determination (presence or absence of the intention to move the hand) and the movement direction determination (hand gripping [grasping]/opening [releasing]) based on the acquired output values. According to this result, the actuator 6A can be allowed to drive the first link portion 3. Thus, it is possible to assist the movement of the hand 100 wearing the finger joint driving device 1001, more specifically, the movement of the index finger 101. In particular, in the finger joint driving device 1001 according to the embodiment, the plurality of first force sensors S11 are disposed on the surface 51 of the second base portion 5 on the dorsal side of the middle joint part 103 in the longitudinal direction of the index finger 101 (see
In the case of the comparative example in which the one first force sensor S11 is disposed to face the second force sensor S12 with the middle joint part 103 of the index finger 101 therebetween, as illustrated in
In contrast, in the embodiment, as illustrated in
In the foregoing embodiment, the case in which the two first force sensors S11 are disposed in the longitudinal direction of the index finger 101 has been exemplified, but the invention is not limited thereto. Three or more first force sensors S11 may be disposed in the longitudinal direction of the index finger 101. The plurality of first force sensors S11 may be disposed in the transverse direction as well as the longitudinal direction. When the plurality of sensors are disposed, a distribution of the generated force can be detected more accurately. Thus, the force (the force by the wearer intends to spread his or her finger) operated when the wearer intends to open his or her hand can be detected with higher accuracy, the determination of the movement intention or the determination of the movement direction can be performed with higher accuracy, and the movement state of the finger can be detected with high accuracy.
In step S302B, the values of the outputs of the plurality of first force sensors S11 and the plurality of second force sensors S12 are acquired. In step S304B, whether the wearer has a movement intention is determined. Specifically, whether the wearer has the movement intention is determined depending on whether the absolute value |Σs12−Σs11| which is a difference between a sum of the outputs of the plurality of first force sensors S11 and a sum of the outputs of the second force sensors S12 is equal to or greater than the movement determination threshold value Ta.
When it is determined that the wearer has no movement intention, the actuator 6A is instructed to maintain the immediately previous state (state maintenance) in which the movement velocity or movement distance is “0” and the actuator 6A operates to maintain the instructed state in step S330.
Conversely, when it is determined that the wearer has the movement intention, the movement direction intended by the wearer is subsequently determined in step S306B. Specifically, the movement direction intended by the wearer is determined depending on whether a difference (Σs12−Σs11) between a sum (Σs12) of the outputs of the plurality of second force sensors 12 and a sum of the outputs of the plurality of first force sensors S11 is greater than “0,” that is, the sum (Σs12) of the outputs of the plurality of second force sensors S12 is greater than the sum (Σs11) of the outputs of the plurality of first force sensors.
When the output difference (Σs12−Σs11) is greater than “0,” it is determined that the movement direction is the hand gripping direction (the finger bending direction). In step S310, the movement velocity (grasp movement velocity) or the movement distance (grasp movement distance) at which the hand grips is decided according to the output difference |Σs12−Σs11|.
Then, in step S312, the actuator 6A is instructed of a hand gripping movement (grasp movement) at the decided movement velocity or movement distance and the actuator 6A is allowed to rotate the first link portion 3 based on the instructed movement velocity or movement distance.
Conversely, when the output difference (Σs12−Σs11) is equal to or less than “0,” it is determined that the movement direction is the hand opening direction (the finger spreading direction). In step S320, the movement velocity (release movement velocity) or the movement distance (grasp movement distance) at which the hand opens is decided according to the output difference |Σs11−Σs12|. As in step S312, in step S322, the actuator 6A is instructed of the hand opening movement (release movement) of the decided movement velocity or movement distance and the actuator 6A rotates the first link portion based on the instructed movement velocity or movement distance.
Even in the finger joint driving device 1001B according to the embodiment, the values of the outputs of the plurality of first force sensors S11 and the values of the outputs of the plurality of second force sensors are acquired, and the actuator 6A can be allowed to drive the first link portion 3 according to the results of the movement intention determination (presence or absence of the intention to move the hand) and the movement direction determination (hand gripping [grasping]/opening [releasing]) based on the acquired output values. Thus, it is possible to assist the movement of the hand 100 wearing the finger joint driving device 1001B, more specifically, the movement of the index finger 101. In particular, in the finger joint driving device 1001B according to the embodiment, the plurality of first force sensors S11 are disposed on the surface 51 of the second base portion 5 on the dorsal side of the middle joint part 103 in the longitudinal direction of the index finger 101 and the plurality of second force sensors S12 are disposed on the surface of the second wearing band 20B on the ventral side of the middle joint part 103 in the longitudinal direction of the index finger 101 (see
Even in the embodiment, three or more first force sensors S11 may be disposed in the longitudinal direction of the index finger 101. The plurality of first force sensors S11 may be disposed in the transverse direction as well as the longitudinal direction. Likewise, three or more second force sensors S12 may be disposed in the longitudinal direction of the index finger 101. The plurality of second force sensors S12 may be disposed in the transverse direction as well as the longitudinal direction. When the plurality of sensors are disposed, a distribution of the generated force can be detected more accurately. Thus, the force (the force by the wearer intends to spread his or her finger) operated when the wearer intends to open his or her hand and the force (that force with which the finger is bent) operated when the hand grips can be detected with higher accuracy, the determination of the movement intention or the determination of the movement direction can be performed with higher accuracy, and the movement state of the finger can be detected with high accuracy.
In step S302C, the values of the outputs of the plurality of first force sensors S11 are acquired. In step S304C, whether the wearer has a movement intention is determined. Specifically, whether the wearer has the movement intention is determined depending on whether the absolute value |Σs11| which is a sum of the outputs of the plurality of first force sensors S11 is equal to or greater than the movement determination threshold value Ta.
When it is determined that the wearer has no movement intention, the actuator 6A is instructed to maintain the immediately previous state (state maintenance) in which the movement velocity or movement distance is “0” and the actuator 6A operates to maintain the instructed state in step S330.
Conversely, when it is determined that the wearer has the movement intention, the movement direction intended by the wearer is subsequently determined in step S306C. Specifically, the movement direction intended by the wearer is determined depending on whether the sum (Σs11) of the outputs of the plurality of first force sensors S11 is less than the base value BL. The base value BL indicates a pressure applied to all of the plurality of first force sensors S11 at the time of the wearing.
When the sum (Σs11) of the outputs of the plurality of first force sensors S11 is less than the base value BL, it is determined that the movement direction is the hand gripping direction (the finger bending direction). In step S310, the movement velocity (grasp movement velocity) or the movement distance (grasp movement distance) at which the hand grips is decided according to the sum |Σs11| of the outputs of the plurality of first force sensors S11. Then, in step S312, the actuator 6A is instructed of a hand gripping movement (grasp movement) at the decided movement velocity or movement distance and the actuator 6A is allowed to rotate the first link portion based on the instructed movement velocity or movement distance.
Conversely, when the sum (Σs11) of the outputs of the plurality of first force sensors S11 is equal to or greater than the base value BL, it is determined that the movement direction is the hand opening direction (the finger spreading direction). In step S320, the movement velocity (release movement velocity) or the movement distance (grasp movement distance) at which the hand opens is decided according to the sum |Σs11| of the outputs of the plurality of first force sensors S11. As in step S312, in step S322, the actuator 6A is instructed of the hand opening movement (release movement) of the decided movement velocity or movement distance and the actuator 6A rotates the first link portion 3 based on the instructed movement velocity or movement distance.
Even in the finger joint driving device 1001C according to the embodiment, the values of the outputs of the plurality of first force sensors S11 are acquired, and the actuator 6A can be allowed to drive the first link portion 3 according to the results of the movement intention determination (presence or absence of the intention to move the hand) and the movement direction determination (hand gripping [grasping]/opening [releasing]) based on the acquired output values. Thus, it is possible to assist the movement of the hand 100 wearing the finger joint driving device 1001C, more specifically, the movement of the index finger 101. In particular, in the finger joint driving device 1001C according to the embodiment, the plurality of first force sensors S11 are disposed on the surface 51 of the second base portion 5 on the dorsal side of the middle joint part 103 in the longitudinal direction of the index finger 101 (see
Even in the embodiment, three or more first force sensors S11 may be disposed in the longitudinal direction of the index finger 101. The plurality of first force sensors S11 may be disposed in the transverse direction as well as the longitudinal direction. When the plurality of sensors are disposed, a distribution of the generated force can be detected more accurately. Thus, the force (the force by the wearer intends to spread his or her finger) operated when the wearer intends to open his or her hand and the force (the force with which the finger is bent) operated when the hand grips can be detected with higher accuracy, the determination of the movement intention or the determination of the movement direction can be performed with higher accuracy, and the movement state of the finger can be detected with high accuracy.
The invention is not limited to the foregoing embodiments and modes for carrying out the invention, but can be modified into various forms within the scope of the invention without departing from the gist of the invention and can also be modified as follows, for example.
The finger joint driving devices have been exemplified as the driving device according to the invention, but the invention is not limited thereto. Each of the units included in the finger joint driving device can be substituted with a unit having any configuration of the same function. Further, any constituent may also be added. In the foregoing embodiments, any two or more of the configurations (characteristics) may also be combined.
In the foregoing embodiments, the actuator 6A can serve to rotate the first link portion 3, but may serve to drive approach and separation of the second base portion 5 to and from the first base portion 2. The actuator 6A having the configuration in which the piezoelectric driving device is used as an actuator has been exemplified, but any other actuator can also be used. For example, a general small motor or an electronic actuator can also be used. For example, an actuator including a wire and a tensioner changing a tensile strength of the wire or an actuator including a hose and a pump changing a hydraulic pressure or a pneumatic pressure inside the hose can also be used.
In the foregoing embodiments, the driving device (finger joint driving device) assisting motions of joints of the fingers of people have been exemplified, but the invention is not limited thereto. The embodiment can also be applied to driving devices that assist motions of other biological parts such as toes, elbows, wrists, knees, necks, and waists of people. The embodiments can also be applied to driving devices that assist motions of biological parts of animals and non-biological parts of robots or the like, as well as human beings.
In the foregoing third to fifth embodiments, the sum of the outputs of the plurality of force sensors are simply used to determine the movement intention and determine the movement direction. A moment component by bending or spreading of a finger may be obtained based on a distribution of the values of the outputs of the respective sensors, only a vertical direction component to a sensor surface of each sensor may be separated, and the separated vertical direction component may be used.
In the foregoing third to fifth embodiments, the reason why the sum of the outputs of the plurality of sensors is used is that the cases in which the force sensors detecting a force are adopted as the sensors are exemplified. For example, when a pressure sensor detecting a force (pressure) per unit area is used as a sensor, an average value of the plurality of sensors may be obtained and the determination of the motion intention and the determination of the movement direction may be performed based on the acquired pressures. Further, the determination of the motion intention and the determination of the movement direction may be performed based on a force obtained by multiplying the acquired average value by a pressure reception area.
The invention is not limited to the above-described embodiments, the modes, and the modification examples, but can be implemented with various configurations within the scope of the invention without departing from the gist of the invention. For example, the technical characteristics of the embodiments, the modes, and the modification examples corresponding to the technical characteristics of the aspects described in the summary of the invention can be appropriately replaced or combined to resolve some or all of the above-described problems or to attain some or all of the above-describe advantages. When the technical characteristics are not described as requisites in the present specification, the technical characteristics can be appropriately deleted.
The entire disclosure of Japanese Patent Application No. 2014-111177, filed May 29, 2014 and 2014-123919, filed Jun. 17, 2014 are expressly incorporated by reference herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-111177 | May 2014 | JP | national |
| 2014-123919 | Jun 2014 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 7224102 | Miyazawa | May 2007 | B2 |
| 8029414 | Ingvast et al. | Oct 2011 | B2 |
| 8255079 | Linn et al. | Aug 2012 | B2 |
| 8425438 | Fujimoto et al. | Apr 2013 | B2 |
| 8849453 | Bergelin et al. | Sep 2014 | B2 |
| 20120029399 | Sankai | Feb 2012 | A1 |
| 20130219586 | Ihrke et al. | Aug 2013 | A1 |
| 20140288664 | Miyazawa | Sep 2014 | A1 |
| Number | Date | Country |
|---|---|---|
| H11-056931 | Mar 1999 | JP |
| 11-253504 | Sep 1999 | JP |
| 2000-070312 | Mar 2000 | JP |
| 2002-345861 | Dec 2002 | JP |
| 2004-320979 | Nov 2004 | JP |
| 2009-112578 | May 2009 | JP |
| 2010-502266 | Jan 2010 | JP |
| 2010-240285 | Oct 2010 | JP |
| 2011-067609 | Apr 2011 | JP |
| 2011-115248 | Jun 2011 | JP |
| 2013-180199 | Sep 2013 | JP |
| 2013-181271 | Sep 2013 | JP |
| 2014-068869 | Apr 2014 | JP |
| 2014-180298 | Sep 2014 | JP |
| 2014-184027 | Oct 2014 | JP |
| WO-2008-027002 | Mar 2008 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20150342818 A1 | Dec 2015 | US |
