This application is based upon and claims the benefit of priority from Japanese patent application No. 2019-221879, filed on Dec. 9, 2019 the disclosure of which is incorporated herein in its entirety by reference.
The present disclosure relates to a walking state determination apparatus, a walking assistance apparatus, and a non-transitory computer readable medium.
A walking training system which is used when a trainee performs walking training is known. In the walking training system, since it is necessary to appropriately assist the trainee in walking in accordance with the walking state of the trainee, the walking state of the trainee who is under the training (for example, whether the state of the leg for which the walking training is performed is in a swing state or a stance state) needs to be determined. Patent Literature 1 (Japanese Unexamined Patent Application Publication No. 2013-123532) discloses a technique of detecting a plurality of discrimination periods (early/late swing phases and a stance phase) in the gait cycle using an acceleration sensor configured to detect acceleration of a thigh that rotates about a hip joint and an angular velocity sensor configured to detect an angular velocity of a lower-leg part that rotates about a knee joint in the walking motion. Patent Literature 1 further discloses that timings at which the thigh and the lower-leg part have electrical stimulation applied thereto are controlled based on the aforementioned detection result.
The technique disclosed in Patent Literature 1 has a problem that with the use of the acceleration sensor and the angular velocity senor, errors accumulate when the acceleration speed or the angular velocity information are integrated, and thus the walking state cannot be detected accurately. Further, there is also a problem that calculation processing (filtering processing) becomes complicated when the acceleration sensor or the angular velocity sensor is used.
The present disclosure has been made in view of the background mentioned above. An object of the present disclosure is to provide a walking state determination apparatus that can accurately detect a walking state of a person by performing simple calculation processing.
A first exemplary aspect is a walking state determination apparatus for determining a walking state of a person including:
In the walking assistance system configured to assist the trainee in walking, it is necessary to determine the walking state of the trainee who is under the training in order to appropriately assist the trainee in walking in accordance with the trainee's walking state. In the walking state determination apparatus, a distance from a prescribed part of a lower limb of a person to which the distance measurement sensor is attached to the floor surface is detected by the distance measurement sensor while the person is walking. The distance from the distance measurement sensor attached to the prescribed part of the lower limb of the person to the floor surface detected by the distance measurement sensor changes while the person is walking. Therefore, the walking state of the person can be determined based on the distance to the floor surface detected by the distance measurement sensor. Further, it is possible to accurately determine the walking state of the person by performing, in the calculation unit, relatively simple calculation processing such as comparing time series data of the distance from the prescribed part of the lower limb of the person to the floor surface in the gait cycle acquired in advance with the detection value of the distance measurement sensor.
Further, the calculation unit may be configured to determine that the walking state of the person is at a timing at which the lower limb to which the distance measurement sensor is attached transits from a swing state to a stance state when the detection value of the distance measurement sensor that was exceeding a predetermined first threshold value falls below the first threshold value.
Further, the calculation unit may be configured to determine that the walking state of the person is at a timing at which the lower limb to which the distance measurement sensor is attached transits from a stance state to a swing state when the detection value of the distance measurement sensor that was equal to or lower than a predetermined second threshold value exceeds the second threshold value.
Further, the calculation unit may be configured to determine the walking state of the person according to a rate of change of the detection value of the distance measurement sensor.
In some embodiments, a position where the distance measurement sensor is attached is a calf region of the person. As a result of intensive research conducted by the present inventors, it was understood that when the distance measurement sensor is attached to a calf region of a person, the detection value of the distance from the calf region to which the distance measurement sensor is attached to the floor surface measured by the distance measurement sensor changed most conspicuously while the person was walking. Therefore, when the distance measurement sensor is attached to a calf region of a person, the walking state of the person can be distinguished particularly accurately.
A second exemplary aspect is a walking assistance apparatus configured to assist a motion of a knee joint of a trainee in accordance with a walking state of the trainee, the walking assistance apparatus including:
With this configuration, a walking state of a person can be detected accurately by performing simple calculation processing whereby it is possible to appropriately assist a trainee in walking.
A third exemplary aspect is a non-transitory computer readable medium that stores a control program for a walking state determination apparatus for determining a walking state of a person, the control program configured to cause a computer of the walking state determination apparatus to execute the steps of:
A walking state of a person can be accurately detected by performing simple calculation processing.
According to the present disclosure, it is possible to accurately detect the walking state of the person by performing simple calculation processing.
The above and other objects, features and advantages of the present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present disclosure.
Hereinafter, the present disclosure will be described through embodiments of the present disclosure. However, the embodiments are not intended to limit the scope of the present disclosure according to the claims. For clarifying the explanation, the following description and the drawings are partially omitted and simplified where appropriate. The same symbols are assigned to the same elements in the drawings and duplicated explanations thereof are omitted where appropriate.
A walking state determination apparatus (system) according to the present embodiment is applied to a walking training system and determines a walking state of a person (a trainee). First, a configuration of a walking training system that employs the walking state determination apparatus according to the present embodiment will be described.
The walking assistance apparatus 2 is, for example, worn on an affected leg of the trainee U who performs the walking training and assists the trainee U in walking. The trainee U performs the walking training in a state in which the walking assistance apparatus 2 is worn on his/her knee joint. The walking assistance apparatus 2 applies a resisting force in a flexing direction of the knee joint.
The walking assistance apparatus 2 includes a supporter 21, a damper 22, an upper leg frame 23, and a lower leg frame 24. A short lower limb gear 25 (partially omitted in
The supporter 21 includes a surface fastener 21a for wearing the walking assistance apparatus 2 on the knee joint. The trainee U winds the supporter 21 around the leg part and fixes it to the leg part with the surface fastener 21a. The surface fastener 21a is provided above and below the knee joint, specifically, to a front side of the upper leg UL and a front side of the lower leg LL. By using the surface fastener 21a, the trainee U can easily wear/take off the walking assistance apparatus 2. Further, it is possible to prevent the walking assistance apparatus 2 from being displaced from the knee joint of the trainee U. By employing the surface fastener 21a, the trainee U can adjust the degree of feeling of tightness. Further, a fixing band 21b may be provided in order to prevent the surface fastener 21a from being unfastened or the supporter 21 from being displaced.
The upper-leg frame 23 and the lower-leg frame 24 are attached to a side part of the supporter 21. The upper-leg frame 23 is arranged along the upper leg UL. The lower-leg frame 24 is arranged along the lower leg LL. The upper-leg frame 23 and the lower-leg frame 24 are connected to each other through the damper 22. The damper 22 is, for example, a rotary damper, and is located at a side part of the knee joint. Specifically, the damper 22 is positioned at the level of the knee joint so that a rotation axis Ax of the damper 22 roughly coincides with the axis of the knee joint. The upper-leg frame 23 and the lower-leg frame 24 configure a link mechanism that is rotatable about the rotation axis Ax of the damper 22.
The damper 22 applies a resisting force in the flexing direction of the knee joint. For example, the damper 22 reduces its speed of rotation in the flexing direction of the knee joint by utilizing the viscous drag of fluid such as oil. In some embodiments, the damper 22 is a unidirectional damper that applies the resisting force in only one direction. The damper 22 moves freely so as not to apply the resisting force in the extending direction of the knee joint. The damper 22 adjusts the resisting force by a control unit described later.
The short lower limb gear 25 is provided at a lower side of the supporter 21. As shown in
Note that the configuration of the walking assistance apparatus 2 described above is merely an example and it is not to be limited thereto. It is possible to employ an arbitrary walking assistance apparatus that is worn on the leg part of the trainee U and assists the trainee in walking.
Referring again to
The control device 35 has a hardware configuration having a microcomputer at the center thereof, the microcomputer being configured of, for example, a CPU (Central Processing Unit) that performs operation processing, control processing etc., a ROM (Read Only Memory) that stores an operation program, a control program and the like executed by the CPU, a RAM (Random Access Memory) that stores various data, and an interface (I/F) that inputs/outputs a signal to/from the outside. The CPU, the ROM, the RAM, and the interface unit are connected with one another through, for example, a data bus.
As shown in
The fixing unit 4c is for fixing the distance measurement sensor 4a to a prescribed part of the trainee, and examples of which include a band such as a medical supporter. The position at which the distance measurement sensor 4a is attached is desirably a calf region of the lower limb of the trainee U. As a result of intensive research conducted by the present inventors, it was understood that when the distance measurement sensor 4a is attached to a calf region of a person, a detection value of the distance from the distance measurement sensor to the floor surface measured by the distance measurement sensor 4a changed most conspicuously while the person was walking. Therefore, when the distance measurement sensor 4a is attached to a calf region of a person, identification of the walking state of the person can be performed particularly accurately.
The calculation unit 4b determines the walking state of the trainee based on the distance L from the prescribed leg part to which the distance measurement sensor 4a is attached to the floor surface G detected by the distance measurement sensor 4a. The calculation unit 4b has a hardware configuration having a microcomputer at the center thereof, the microcomputer being configured of, for example, a CPU (Central Processing Unit) that performs operation processing, control processing etc., a ROM (Read Only Memory) that stores an operation program, a control program and the like executed by the CPU, a RAM (Random Access Memory) that stores various data, and an interface (I/F) that inputs/outputs a signal to/from the outside. The CPU, the ROM, the RAM, and the interface unit are connected with one another through, for example, a data bus.
Next, a method for determining the walking state of the trainee will be described. Note that in the following explanation,
In the walking training system 1, in order to appropriately assist the trainee in walking in accordance with the trainee's walking state, it is necessary to determine the trainee's walking state during the training. In the walking motion, while the trainee's leg on which the walking assistance apparatus 2 is worn (here, the right leg) is in the stance state, the force applied on the leg is relatively large whereas while the trainee's leg on which the walking assistance apparatus is worn is in the swing state, the force applied on the leg is relatively small. Therefore, the walking assistance apparatus 2 needs to assist the trainee in walking at least while the trainee's leg on which the walking assistance apparatus 2 is worn is in the stance state by making the resistance value of the damper of the walking assistance apparatus 2 relatively large. That is, it is necessary to detect a timing at which the leg on which the walking assistance apparatus 2 is worn transits from the swing state to the stance state (a first timing), and to make the resistance value of the damper of the walking assistance apparatus 2 relatively large.
Further, stratification of a gait cycle according to the “Rancho Los Amigos method” commonly used in clinical walking analysis is shown in correspondence with the graph shown in
In the graph shown in
As described above, in the walking motion, while the trainee's leg on which the walking assistance apparatus 2 is worn is in the swing state, the force applied on the leg is relatively small. Therefore, while the trainee's leg on which the walking assistance apparatus 2 is worn is in the swing state, the resistance value of the damper of the walking assistance apparatus 2 is made relatively small. In order to make the resistance value of the damper of the walking assistance apparatus 2 relatively small while the trainee's leg is in the swing state, a timing of transition from the swing state to the stance state (a second timing) needs to be detected.
In the graph shown in
When it is not determined in Step S102 that the detection value of the distance measurement sensor that was exceeding the predetermined first threshold value falls below the first threshold value, whether or not the detection value of the distance measurement sensor 4a that was equal to or lower than the predetermined second threshold value exceeds the second threshold value is determined (Step S105). When it is determined in Step S105 that the detection value of the distance measurement sensor 4a that was equal to or lower than the predetermined second threshold value exceeds the second threshold value, it is determined that the timing is the second timing at which the walking state of the trainee transits from the stance state to the swing state (Step S106), and the processing proceeds to Step S104. When it is not determined in Step S105 that the detection value of the distance detection sensor 4a that was equal to or lower than the predetermined second threshold value exceeds the second threshold value, the processing proceeds to Step S104.
The control unit 28 of the walking assistance apparatus 2 shown in
Making the resistance value of the damper of the walking assistance apparatus 2 relatively small includes the case where the resistance value of the damper is brought to zero (0). In this case, on/off control of turning-on the damper of the walking assistance apparatus 2 at the timing of transition from the swing state to the stance state and turning-off the damper of the walking assistance apparatus 2 at the timing of transition from the stance state to the swing state is performed in the control unit 28.
As described above, in the walking assistance apparatus 2 that assists the trainee in walking, it is necessary to determine the trainee's walking state during the training in order to appropriately assist the trainee in walking in accordance with the trainee's walking state. In the walking state determination apparatus 4, a distance from the distance measurement sensor 4a attached to a prescribed part of a lower limb of a person to the floor surface is detected by the distance measurement sensor 4a while the person is walking. The distance from the prescribed part of the lower limb of the person on which the distance measurement sensor 4a is attached to the floor surface detected by the distance measurement sensor 4a changes while the person is walking. Therefore, the walking state of the person can be determined based on the distance from the distance measurement sensor 4a to the floor surface detected by the distance measurement sensor 4a. Further, it is possible to accurately determine the walking state of the person by performing a relatively simple calculation processing such as comparing time series data of the distance from the prescribed part of the lower limb of the person to the floor surface in the gait cycle acquired in advance with the detection value of the distance measurement sensor 4a in the calculation unit 4b.
Determination of the walking state in the calculation unit 4b may be performed on the basis of a rate of change of the detection value of the distance measurement sensor 4a instead of on the basis of the predetermined threshold value. Specifically, the calculation unit 4b determines the first timing which is the timing of transition from the swing state to the stance state (the timing of transition from T8 to T1) based on whether or not the rate of change of the detection value of the distance measurement sensor 4a, that is, the inclination of the graph shown in
As described above, the distance measurement sensor of the walking state determination apparatus may be attached to either one of the trainee's lower limbs on which the walking assistance apparatus is worn. Therefore, the distance measurement sensor of the walking state determination apparatus may be attached to a shoe worn on either one of the lower limbs on which the walking assistance apparatus is worn.
Note that the present disclosure is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present disclosure.
The program can be stored and provided to a computer using any type of non-transitory computer readable media. Non-transitory computer readable media include any type of tangible storage media. Examples of non-transitory computer readable media include magnetic storage media (such as floppy disks, magnetic tapes, hard disk drives, etc.), optical magnetic storage media (e.g. magneto-optical disks), CD-ROM (compact disc read only memory), CD-R (compact disc recordable), CD-R/W (compact disc rewritable), and semiconductor memories (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.). The program may be provided to a computer using any type of transitory computer readable media. Examples of transitory computer readable media include electric signals, optical signals, and electromagnetic waves. Transitory computer readable media can provide the program to a computer via a wired communication line (e.g. electric wires, and optical fibers) or a wireless communication line.
From the disclosure thus described, it will be obvious that the embodiments of the disclosure may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims.
Number | Date | Country | Kind |
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2019-221879 | Dec 2019 | JP | national |