JP2017086296A - Motion assist apparatus and program for controlling motion assist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motion assist apparatus, even when a detection result of a knee joint angle sensor includes a variation due to chattering phenomenon, capable of safely starting or terminating an assist of motion of the knee joint or the like.SOLUTION: In an assist of bending motion of the knee joint, the motion assist apparatus starts an assist when knee joint angle data θk become a first on threshold THon1 on the basis of the first on threshold THon1 corresponding to a start of the assist of the motion and a first off threshold THoff1 corresponding to termination of the assist, and when the knee joint angle data become the first off threshold THoff1, terminates the assist. Then, a difference D1 between the first on threshold THon1 and the first off threshold THoff1 is defined as a difference corresponding to variation due to chattering phenomenon.SELECTED DRAWING: Figure 7

Description

  The present invention belongs to the technical field of motion assist devices and motion assist control programs. More specifically, the present invention relates to motion assist devices that assist the operation of the lower limb joint of a patient or the like and a program for the motion assist device. Belongs to the technical field.

  In recovery training and the like performed by patients with knee disease (so-called rehabilitation, hereinafter simply referred to as “rehabilitation”), the patient has been performing necessary rehabilitation by himself / herself with the assistance of, for example, a physical therapist. It was. On the other hand, in recent years, research / development related to other dynamic recovery training using a driving source such as a motor (rehabilitation performed using external force) has been performed. For such passive rehabilitation, a so-called wearable walking assist robot that is worn on the patient's body and assists the movement of the knee joint during walking is used. This walking assist robot is attached to the lower limbs (upper and lower limbs) of the patient's knee joint using a harness or the like, and assists the movement of the knee joint (in other words, forcibly moves). To work. That is, the walking assist robot operates to move the knee joint so that the movement as the knee joint in an appropriate walking pattern is realized. Accordingly, the patient can perform necessary rehabilitation by walking independently so as to follow the movement by the walking assist robot.

  As a device for assisting human walking that can be used for the above-mentioned rehabilitation, for example, there is a walking assist device described in Patent Document 1 below. In this walking assist device, in the walking assist robot attached to the patient's knee joint while walking on the floor surface, the insole sensor that detects the heel off, the knee joint angle sensor, and the hip joint angle sensor Is used as a trigger to assist the flexion and extension of the knee joint with a motor. In the following description, the knee joint angle sensor and the hip joint angle sensor are simply referred to as a “knee joint angle sensor or the like”. The knee joint angle is defined as the angle of the knee joint that increases when the knee joint is bent (ie, the knee is bent), and the hip joint angle increases when the leg is bent forward and the hip joint is bent. Is defined as the angle of the hip joint.

JP 2013-111379 A (FIG. 1 etc.)

  However, in the technique disclosed in Patent Document 1, the timing at which the knee joint angle sensor or the like reaches the set threshold (in other words, the timing at which the trigger is turned on / off) is alternately switched several times in a short time. There has been a problem that a phenomenon of continuous detection occurs. This phenomenon is called “chattering phenomenon” and is caused by electrical noise generated in the knee joint angle sensor or the like, or unstable (for example, non-directional) movement of the patient. To do. At this time, in particular, regarding the angle of the knee joint, it reaches the setting threshold in the knee joint flexion in which the knee joint changes in the increasing direction (that is, trigger on), and reaches the setting threshold in the knee joint extension in which the knee joint changes in the decreasing direction. Therefore, the auxiliary operation may be started at an unintended timing. More specifically, for example, after the saddle sensor detects that the heel has left the walking surface, the assist of the bending motion is started from the timing when the set joint threshold is reached in the direction in which the angle of the knee joint increases. For example, if the heel leaves the walking surface when the angle of the knee joint exceeds the set threshold (that is, the knee joint is bent to some extent), the assist of the bending motion of the knee joint is not started and the walking assist is started. The robot continues to wait for the timing at which the knee joint angle increases to reach the threshold (that is, trigger-on). And if the patient continues walking including knee flexion and subsequent extension as it is, chattering that occurs when moving the knee joint in the direction of extending the knee joint (that is, the direction in which the angle of the knee joint decreases) Only when the walking assist robot is “trigger-on” at that time will it be detected (false detection). And as a result, the knee joint will begin to bend in the vicinity of the timing when the soles of the knee joint extend after landing, which is a very dangerous state for the patient. There was a problem.

  Therefore, the present invention has been made in view of the above problems, and one example of the problem is that the chattering phenomenon occurs in a knee joint angle sensor or the like, and the detection result includes fluctuation due to the chattering phenomenon. Another object of the present invention is to provide a motion assist device that can safely start or end motion assist of a knee joint or the like and a control program for the motion assist device.

  In order to solve the above-described problem, the invention according to claim 1 is an operation assisting device that assists the operation of the joint of the lower limb of the person being assisted, and can be attached to a portion of the lower limb corresponding to the joint. And an auxiliary means such as a drive unit for assisting the operation of the joint including at least one of a bending action or an extension action, and a detecting means such as a knee joint angle sensor for detecting the angle of the joint in the direction of bending the joint. , Start threshold value information indicating a start threshold value corresponding to the angle at which the assisting operation by the assisting unit should be started, and an end threshold value that is an end threshold value different from the start threshold value and corresponding to the angle at which the assisting should be ended. The detected angle is based on the storage threshold value information indicating storage unit such as a storage unit that stores each of the threshold values, and the stored start threshold value information and end threshold information. Control means such as a CPU for controlling the auxiliary means to start the assistance when the start threshold is reached and to end the assistance when the detected angle reaches the end threshold; The difference between the start threshold value and the end threshold value is a difference corresponding to the variation included in the detection result of the angle.

  In order to solve the above-mentioned problem, a seventh aspect of the invention is a computer provided with the control means and the storage means in the operation assisting device according to any one of the first to sixth aspects. And function as the control means and the storage means.

  According to the invention described in claim 1 or claim 7, start threshold information indicating a start threshold to start assisting movement of the lower limb joint, end threshold information indicating an end threshold to end the assist, Based on the above, assistance starts when the angle of the joint reaches the start threshold, and assistance ends when the angle reaches the end threshold. At this time, the difference between the start threshold value and the end threshold value is a difference corresponding to the variation included in the joint angle detection result. Therefore, since the start and end of the joint motion assistance is controlled based on two threshold values (start threshold value and end threshold value) having a difference corresponding to the variation included in the detection result, even if the variation is included, It is possible to safely start or end joint operation assistance.

  In order to solve the above problem, the invention according to claim 2 is the motion assisting device according to claim 1, wherein the detected angle of the joint at which the difference bends in the direction of the motion is the start. After reaching the threshold, the detected angle including the variation is configured to be the difference that becomes the end threshold that does not reach.

  According to the invention described in claim 2, in addition to the operation of the invention described in claim 1, the difference between the start threshold value and the end threshold value is determined after the angle of the joint that bends in the direction of movement reaches the start threshold value. Since this is a difference that becomes an end threshold value that does not reach the angle including the fluctuation, it is possible to reliably absorb the fluctuation of the angle of the joint and start or end the movement assistance of the joint safely.

  In order to solve the above-mentioned problem, the invention according to claim 3 is the movement assisting device according to claim 1 or 2, wherein the start threshold value and the end threshold value used during the bending operation, and the extension. The end threshold value and the start threshold value used during operation are configured to be different.

  According to invention of Claim 3, in addition to the effect | action of the invention of Claim 1 or Claim 2, the start threshold value and end threshold value used at the time of bending operation | movement, and the end threshold value and start threshold value used at the time of extension operation | movement Therefore, it is possible to set an appropriate threshold value corresponding to the contents of each operation.

  In order to solve the above-described problem, the invention according to claim 4 is configured such that in the movement assist device according to any one of claims 1 to 3, the joint is a knee joint or a hip joint. Is done.

  According to the invention described in claim 4, in addition to the action of the invention described in any one of claims 1 to 3, since the joint of the lower limb is a knee joint or a hip joint, It is possible to safely start or end the assisting of the bending operation or the extension operation in.

  In order to solve the above-mentioned problem, the invention according to claim 5 is the movement assist device according to any one of claims 1 to 4, wherein the storage means is a right leg of the person being assisted. The start threshold information and the end threshold information indicating the start threshold and the end threshold, respectively, and the start threshold information indicating the start threshold and the end threshold corresponding to the left leg of the assistant, Ending threshold information is stored separately, and the control means is attached to the auxiliary means attached to the right leg and to the left leg based on each start threshold and each end threshold. And the auxiliary means are configured to be controlled separately and independently.

  According to the invention described in claim 5, in addition to the operation of the invention described in any one of claims 1 to 4, the start threshold information and end threshold information corresponding to the right leg, and the left leg Corresponding start threshold information and end threshold information are stored separately, and based on each start threshold and each end threshold, auxiliary means attached to the right leg and auxiliary means attached to the left leg Are controlled separately. Therefore, even when the left and right legs are in different states, the operation of each joint can be started or ended safely.

  In order to solve the above-mentioned problem, according to a sixth aspect of the present invention, in the motion assisting device according to any one of the first to fifth aspects, at least one of the start threshold value and the end threshold value is provided. Further provided is a changing means such as an operation unit used for changing.

  According to the invention described in claim 6, in addition to the operation of the invention described in any one of claims 1 to 5, at least one of the start threshold value and the end threshold value can be changed. According to the state of the person being assisted, it is possible to start or end joint operation assistance appropriately and safely.

  According to the present invention, based on the start threshold information indicating the start threshold to start assisting the movement of the lower limb joint and the end threshold information indicating the end threshold to end the assist, the joint angle is determined to be the start threshold. Assistance is started when it becomes, and assistance is terminated when the angle reaches the end threshold. At this time, the difference between the start threshold value and the end threshold value is a difference corresponding to the variation included in the joint angle detection result.

  Therefore, since the start and end of joint operation assistance are controlled based on two threshold values (start threshold value and end threshold value) having a difference corresponding to the variation included in the joint angle detection result, the variation is included. However, it is possible to safely start or end joint operation assistance.

It is a state figure at the time of mounting the walk auxiliary device concerning an embodiment on a patient. It is a state figure at the time of mounting | wearing the patient's both legs with the drive unit which concerns on embodiment. It is a block diagram which shows the structure of the walking assistance apparatus which concerns on embodiment. It is a flowchart which shows the operation example which produces | generates the control pattern etc. in the walking assistance apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the bending angle of the knee joint part and hip joint part in the walking assistance apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the patient's walking pattern which concerns on embodiment. It is a figure explaining each threshold value relevant to the assist operation | movement of the knee joint which concerns on embodiment, (a) is a figure which illustrates the threshold value used at the time of the start of the said assist operation | movement, (b) is completion | finish of the said assist operation | movement. It is a figure which illustrates the threshold value used sometimes. It is a flowchart which shows the example of control operation in the walking assistance apparatus which concerns on embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to FIGS. 1 to 8. In addition, embodiment described below is embodiment at the time of applying this invention with respect to the walking assistance apparatus which assists the operation | movement of the knee joint in walking as a recovery training etc. of the patient with a knee disease, for example. The patient corresponds to an example of a “subject” according to the present invention.

  1 is a state diagram when the walking assist device according to the embodiment is attached to a patient, FIG. 2 is a state diagram when the drive unit according to the embodiment is attached to both legs of the patient, and FIG. FIG. 4 is a block diagram illustrating a configuration of a walking assist device according to the embodiment, and FIG. 4 is a flowchart illustrating an operation example of generating a control pattern and the like in the walking assist device. 5 is a schematic diagram showing an example of the bending of the knee joint and the hip joint in the walking assist device, FIG. 6 is a schematic diagram showing an example of the walking state of the patient according to the embodiment, and FIG. It is a figure explaining each threshold value relevant to the assist operation | movement of the knee joint which concerns on embodiment, and FIG. 8 is a flowchart which shows the control operation example in the walk assistance apparatus which concerns on embodiment.

  As shown in FIGS. 1 and 2, the walking assist device S according to the embodiment is an example of auxiliary means attached to a patient's lower limbs (both legs) by a detachable tape-like fixture or a fixture 6 such as a band. A pair of drive units 10 are provided. In the following description, the drive unit 10 for the left leg is referred to as the drive unit 11, and the drive unit 10 for the right leg is described as the drive unit 12. In addition, when a description common to the drive unit 11 and the drive unit 12 is performed, the drive unit 10 is generally described. The walking assist device S corresponds to an example of the “motion assist device” according to the present invention.

  As shown in FIG. 1, one drive unit 10 (ie, for either the right leg or the left leg) is attached to a joint portion of a patient's knee 5 and is a link that flexes and extends the knee joint. The mechanism part 3 and the link mechanism part 8 which is attached to the joint part of the patient's crotch part 9 to bend and extend the hip joint are attached.

  First, as shown in FIG. 1, the link mechanism unit 3 includes, for example, a first link 3a attached to the side surface of the upper leg rest 4 wound around the patient's thigh and a lower leg wound around the patient's lower leg. A second link 3b attached to the side surface of the abutment 7, and a third link 3c that obtains power from the drive unit 10 and swings the second link 3b in the front-rear direction of walking with respect to the first link 3a. Composed. The first link 3a is attached so as to extend from the patient's waist side to the knee portion 5 side, and the second link 3b is attached so as to extend from the patient's knee portion 5 side to the tip (ground) side of the leg. And the 1st link 3a and the 2nd link 3b are connected so that rotation in the patient's knee part 5 vicinity is possible.

  The connecting portion incorporates a knee joint angle sensor that outputs knee joint angle data indicating an angle formed by the first link 3a and the second link 3b. This knee joint angle sensor is realized by, for example, a so-called potentiometer. Moreover, the edge part of the 3rd link 3c is connected with the center vicinity of the 2nd link 3b. Each of the upper leg rest 4 and the lower leg rest 7 includes a pair of leg rest members (not shown), and the leg rest members are arranged so as to cover the circumference of the patient's thigh and lower leg. The fixing device 6 is detachably attached. The upper leg rest 4 and the lower leg rest 7 are formed by molding, for example, polypropylene resin, and a stretchable sponge member (not shown) or the like is attached to a portion in contact with the user's thigh. . The knee joint angle sensor corresponds to an example of “detecting means” according to the present invention.

  On the other hand, as shown in FIG. 1, the link mechanism portion 8 includes a first link 8 a attached to the side surface of the upper leg rest 4 and a second link 8 b attached to the side portion of the belt 23 wound around the patient's waist. And comprising. The first link 8a is attached to extend from the patient's buttocks side to the knee 5 side, and the second link 8b is attached to extend from the patient's waist side to the buttocks side. And the 1st link 8a and the 2nd link 8b are connected so that rotation in the patient's crotch part 9 vicinity is possible. The connecting portion also incorporates a hip joint angle sensor that outputs hip joint angle data indicating an angle formed by the first link 8a and the second link 8b. This hip joint angle sensor is also realized by a so-called potentiometer, for example.

  Further, as shown in FIG. 2, a communication unit 20 for data communication between the drive unit 11 and the drive unit 12 is detachably attached to the drive unit 11 and the drive unit 12 which are respectively attached to both legs. The communication unit 20 includes a cable 21 and a relay box 22 containing a communication board, a control board, a battery, and the like disposed in the middle of the cable 21, and is attached to the patient's waist by the belt 23. It is done. In addition, the communication unit 20 includes a communication head 25 including communication terminals that can communicate data without contact at both ends of the cable 21. On the other hand, the housing 10a of the drive unit 10 is provided with a hole 10b into which the communication head 25 can be inserted, and the communication head 25 can be attached to and detached from the hole 10b. The control board in the relay box 22 is equipped with a CPU, which will be described later, for controlling the operation as the walking assist device S according to the embodiment. Furthermore, the drive unit 10 includes a communication head (not shown) capable of receiving power or communicating predetermined data inside the housing 10a. And the communication head 25 is inserted in the hole 10b which the housing | casing 10a of the drive unit 10 has, and is electrically connected to the communication head which is not shown in figure without contact, and data communication is possible.

  Next, the configuration of the walking assist device S of the embodiment will be described more specifically with reference to FIG.

  As shown in FIG. 3, the walking assist device S of the embodiment includes a right foot drive system R, a left foot drive system L, a CPU (Central Processing Unit) 42 provided on the control board in the relay box 22, An operation unit 41 that is provided at a position where a patient or a physical therapist can operate and has an operation button for performing a command operation on the CPU 42, and a position that is connected to the CPU 42 and is visible to the patient or the physical therapist. And a display unit 40 including a liquid crystal display provided. The CPU 42 stores software such as a control program for controlling the operating system and the walking assist device S, a control pattern generation program for generating a control pattern, data such as detected data and a generated control pattern. A storage unit (not shown) is included. The storage unit is configured by a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk, a silicon disk, or the like. At this time, the CPU 42 corresponds to an example of the “control unit” according to the present invention, the operation unit 41 corresponds to an example of the “change unit” according to the present invention, and the storage unit corresponds to the “storage unit” according to the present invention. It corresponds to an example.

  The drive system for each leg (right foot drive system R and left foot drive system L) includes the drive unit 10, the fixture 6, the upper leg rest 4, the lower leg rest 7, and the knee joint angle sensor 16, respectively. The link mechanism unit 3 including the link mechanism unit 8 including the hip joint angle sensor 15 and the sole sensor 17 are included. The drive unit 10 includes a DC motor 50, a gear unit 52 connected to each link, and a clutch unit 51 that transmits a driving force from the DC motor 50 to each link via the gear unit 52. It is. At this time, the DC motor 50 is a DC motor driven by, for example, a PWM (Pulse Width Modulation) method, and the DC motor 50 and the clutch unit 51 correspond to an example of “auxiliary means” according to the present invention.

  In the above configuration, the control of the rotation direction and rotation speed of the DC motor 50 and the control of the release / connection in the clutch unit 51 are performed by the CPU 42, respectively. Further, as shown in FIG. 1, the sole sensor 17 is attached to the soles of the right foot and the left foot, respectively, and signals to the CPU 42 indicating that each leg has left the floor or the ground and grounded them. Output. The knee joint angle sensor 16 generates the knee joint angle data and outputs it to the CPU 42, and the hip joint angle sensor 15 generates the hip joint angle data and outputs it to the CPU 42.

  Next, control pattern generation in the walking assistance device S having the configuration described with reference to FIGS. 1 to 3 will be specifically described with reference to FIGS. 4 to 7.

  When using the walking assist device S according to the embodiment, first, the walking assist device S is mounted on a patient, and a control pattern generation process for controlling assisting walking motion using the walking assist device S is performed. Done. That is, as shown in FIG. 4, when the walking assist device S is attached to the patient and the power is turned on, the left and right clutch portions 51 are released (step S1). Specifically, the CPU 42 of the walking assist device S opens the clutch unit 51 after the power is turned on, and interrupts transmission of the driving force from the DC motor 50 to the link mechanism unit 3. As a result, the link mechanism unit 3 can freely move without being affected by the resistance force of the permanent magnet or the like of the DC motor 50, and the patient can freely move the knee joint.

  Next, the CPU 42 acquires data of the hip joint angle sensor 15 and determines a correction value for the hip joint angle (step S2). Here, when the patient 60 wearing the walking assist device S is in a stationary state, the CPU 42 acquires hip joint angle data indicating the angle θH formed by the first link 8a and the second link 8b from the hip joint angle sensor 15, and the angle A correction value for θH is used. And CPU42 memorize | stores the acquired hip joint angle data in the said memory | storage part of CPU42.

  At this time, as shown in FIG. 5, the angle θk at the knee joint of the knee 5 of the patient 60 is measured with reference to the thigh of the patient 60 (corresponding to the first link 3a). The angle θH at the hip joint of the patient's crotch 9 is measured with reference to the trunk of the patient 60 (corresponding to the second link 8b), and the thigh of the patient 60 may be in front of the walking direction from the reference. The case of being positive (plus) and behind the walking direction is negative (minus). The walking surface 65 is a floor or the ground.

  Next, while the patient 60 wearing the walking assist device S walks about three or four steps, the walking assist device S acquires data of the hip joint angle sensor 15, the knee joint angle sensor 16, and the sole sensor 17. (Step S3). Specifically, the CPU 42 acquires hip joint angle data indicating the angle θH from the hip joint angle sensor 15, and receives knee joint angle data indicating the angle θk formed by the first link 3 a and the second link 3 b from the knee joint angle sensor 16. get. In the following description, the knee joint angle data indicating the angle θk formed by the first link 3a and the second link 3b is simply referred to as “knee joint angle data θk”. Further, regarding the sole sensor 17, the CPU 42 acquires from the sole sensor 17 a signal indicating that the leg has moved away from the walking surface 65 such as the floor or the ground and touched them. Then, the CPU 42 stores the acquired hip joint angle data, knee joint angle data, and signals from the sole sensor 17 in the storage unit.

  Next, the CPU 42 determines a threshold value for the signal based on the acquired signal from the sole sensor 17 (step S4). Specifically, the CPU 42 determines that the signal from the sole sensor 17 has changed from “LOW” to “HIGH” and the signal from the sole sensor 17 has changed from “HIGH” to “LOW”. The threshold value for this is set by a method set in advance based on the signal acquired from the sole sensor 17. At this time, the threshold value for determining that the signal from the sole sensor 17 has changed from “LOW” to “HIGH” is a threshold value for determining that the patient's heel has moved away from the floor surface 65 due to the walking. Hereinafter, this threshold value is referred to as a “foot sensor on threshold value”. On the other hand, the threshold value for determining that the signal from the foot sensor 17 has changed from “HIGH” to “LOW” determines that the patient's heel has reached the floor 65 (grounded) by the walking. This threshold is hereinafter referred to as “foot sensor off threshold”.

  Next, the CPU 42 specifies the patient's walking cycle, swing phase, and stance phase based on the signal from the foot sensor 17 (step S5). Specifically, as shown in FIG. 6, the CPU 42 changes the signal from the foot sensor 17 from “LOW” to “HIGH” (that is, the leg of the patient 60 is separated from the walking surface 65). The period from the time point when the signal changes from “HIGH” to “LOW” (that is, when the leg touches the walking surface 65) until the point when the signal becomes “HIGH” again is the walking cycle. As specified. In other words, this walking cycle corresponds to a period from when the patient 60 leaves the heel until the next time the heel leaves the heel. Next, as shown in FIG. 6, the CPU 42 determines whether the signal from the sole sensor 17 changes from “LOW” to “HIGH” to the time when the signal changes from “HIGH” to “LOW”. The period is specified, and the period from when the signal changes from “HIGH” to “LOW” until the point when the signal changes to “HIGH” is specified as the stance period. In other words, the swing leg period corresponds to a period from the time when the patient 60's heel leaves the next landing time, and the stance period is from the time when the patient 60's heel rests until the next time the bed leaves. It corresponds to a period. Furthermore, in FIG. 6, the stance phase refers to a period during which the patient's 60 weight is applied to one of the left and right legs during walking, and the swing phase refers to the patient on either leg during the walking. Is a period during which the body weight is not applied (in other words, a period in which the leg is moved away from the walking surface 65 in order to move to the next stance phase).

  Next, the CPU 42 specifies the peak portion of the knee joint angle data (step S6). Specifically, the CPU 42 specifies the peak position θkp at which the knee joint angle data indicating the acquired angle θk is the maximum during the swing phase, that is, the extreme timing at which the knee joint bending angle is the maximum value. As shown in FIG. 5, the maximum value of the knee joint bending angle at this extreme timing is a state in which the knee joint is most bent with respect to the thigh of the patient 60.

  Next, the CPU 42 sets each threshold value of knee joint angle data for assisting each of the knee joint bending operation and the extension operation of the patient 60, and the following trigger signal associated therewith (step S7). In the following description, the knee joint bending motion of the patient 60 is simply referred to as “flexing motion”, and the knee joint stretching motion is simply referred to as “extension motion”. In this case, a transition is made from the bending operation to the extending operation with the extreme value timing as a boundary.

  That is, as step S7 in FIG. 4, the CPU 42 exemplifies the first example illustrated in FIG. 7A as the threshold value of the knee joint angle data for starting assisting the bending motion in the swing leg period based on the operation in the operation unit 41, for example. A 1-on threshold THon1 and a first off-threshold THoff1 are set. 7 (a) and 7 (b), as exemplified as respective enlarged views, the knee joint angle data θk detected in the bending motion during the swing phase increases or fluctuates due to chattering phenomenon. is decreasing.

  At this time, the first on-threshold value THon1 according to the embodiment is determined after the timing t when the knee joint angle data θk exceeds the first on-threshold value THon1 for the first time in the swing phase (see FIG. 7A). This is a threshold value for changing the trigger signal TG for driving from “LOW” to “HIGH”. Here, as illustrated in FIG. 7A, the trigger signal TG according to the embodiment starts from “LOW” at a timing t when the knee joint angle data θk first exceeds the first ON threshold THon1 in the swing leg period. After “HIGH” is set, “HIGH” is set to be maintained. Once the value is set to “HIGH”, even if the knee joint angle data θk rises as a whole and falls below the first ON threshold THon1 due to the occurrence of the chattering phenomenon, the trigger signal TG It is set to maintain the “HIGH” state. In contrast, the first off threshold THoff1 according to the embodiment is a threshold for stopping the DC motor 50 by setting the trigger signal TG for driving the DC motor 50 to “LOW”. Then, after the knee joint angle data θk exceeds the first on-threshold value THon1 for the first time during the swing leg period, the CPU 42 again falls below the first on-threshold value THon1 due to the occurrence of the chattering phenomenon. It is set as the value of the knee joint angle data θk that is smaller than the peak PK1 that is greeted. That is, after the knee joint angle data θk once exceeds the first on threshold THon1, the DC motor 50 does not stop unless it falls below the first off threshold THoff1, but in this case the first on threshold THon1 and the first off threshold The difference D1 from THoff1 is a value that can absorb fluctuations that can be included in the knee joint angle data θk due to chattering (in other words, the first off threshold THoff1 is smaller than the peak PK1). Thus, even if a chattering phenomenon occurs, it is possible to prevent accidents from occurring due to the sudden stop of the assist of the bending operation. If the knee joint angle data θk falls below the first off threshold value THoff1 for a normal reason other than the chattering phenomenon, the driving of the DC motor 50 is normally stopped.

  Next, as step S7 in FIG. 4, the CPU 42 further illustrates, for example, in FIG. 7B as a threshold value of knee joint angle data for ending the assisting of the extension operation in the swing leg period based on the operation in the operation unit 41. A second on threshold THon2 and a second off threshold THoff2 are set.

  At this time, the second off threshold THoff2 according to the embodiment is the trigger signal TG after the timing t (see FIG. 7B) when the knee joint angle data θk first falls below the second off threshold THoff2 in the swing leg period. This is a threshold value for stopping the DC motor 50 that has been driven so far from “HIGH” to “LOW”. Here, as illustrated in FIG. 7B, the trigger signal TG according to the embodiment starts from “HIGH” at a timing t when the knee joint angle data θk first falls below the second off-threshold value THoff2 during the swing phase. After “LOW” is set, “LOW” is set to be maintained. Once the value is set to “LOW”, even if the knee joint angle data θk decreases as a whole and becomes the second off threshold THoff2 or more again due to the occurrence of the chattering phenomenon, the trigger signal TG is “ It is set to maintain the “LOW” state. On the other hand, the second on threshold THon2 according to the embodiment is a threshold for driving the stopped DC motor 50 by changing the trigger signal TG from “LOW” to “HIGH”. Then, after the knee joint angle data θk falls below the second off threshold value THoff2 for the first time in the swing leg period, the CPU 42 again becomes equal to or more than the second off threshold value THoff2 due to the occurrence of the chattering phenomenon. It is set as the value of the knee joint angle data θk that is larger than the peak PK2 that is greeted. That is, after the knee joint angle data θk once falls below the second off threshold THoff2, the DC motor 50 is driven again when the second on threshold THon2 is exceeded. In this case, the second off threshold THoff2 and the second on threshold are turned on. The difference D2 from the threshold THon2 is a value that can absorb fluctuations that can be included in the knee joint angle data θk due to the chattering phenomenon (in other words, the second ON threshold THon2 is a value that is larger than the peak PK2). Thus, even if a chattering phenomenon occurs, it is possible to prevent accidents from occurring due to the sudden resumption of the assist of the bending operation. If the knee joint angle data θk exceeds the second on-threshold value THon2 for a normal reason other than the chattering phenomenon, the driving of the DC motor 50 is resumed normally.

  Next, the CPU 42 generates a drive signal pattern for knee joint control (step S8). Specifically, the CPU 42 generates the drive signal in which the duty ratio in the PWM method changes, for example, in a trapezoidal shape along the time axis. Then, the CPU 42 corresponds to the first on-threshold value THon1 and the first off-threshold value THoff1, and the second on-threshold value THon2 and the second off-threshold value THoff2, respectively. The time until the timing is set in advance as the bending assist time, and the time until the drive stop timing of the DC motor 50 after the extreme value timing is set as the extension assist time based on, for example, an operation in the operation unit 41. The CPU 42 also generates a control pattern of the generated drive signal, the first on threshold value THon1 and the first off threshold value THoff1, the second on threshold value THon2 and the second off threshold value THoff2, the extreme value timing, the bending assist time, and the above. Each extension assistance time is stored in the storage unit.

  Next, the operation | movement at the time of control in the walking assistance apparatus S is demonstrated using FIG.

  In the control operation of the walking assist device S, the CPU 42 controls the control pattern of the drive signal, the first on threshold THon1 and the first off threshold THoff1, the second on threshold THon2 and the second off threshold THoff2, and the extreme timing. And the said bending | flexion assistance time and the said extension assistance time are read from a memory | storage part (step S10). The CPU 42 assists the operation of the patient 60 wearing the walking assist device S according to the control pattern and the like.

  That is, when the operation assistance is started, the CPU 42 monitors, for example, whether or not the signal from the sole sensor 17 of one leg (for example, the right leg) of the patient 60 is equal to or more than the sole sensor ON threshold value. (Step S11). If the signal from the sole sensor 17 is not equal to or greater than the sole sensor ON threshold in the monitoring in step S11 (step S11; NO), the CPU 42 continues monitoring. On the other hand, in the monitoring of step S11, when the signal from the sole sensor 17 of the right foot drive system R exceeds the foot sensor ON threshold by the patient 60 raising the right leg (step S11; YES), the CPU 42 next It is determined whether or not the knee joint angle data θk has exceeded the first ON threshold THon1 for the first time and the trigger signal TG has changed from “LOW” to “HIGH” (see FIG. 7A, step S12). At this time, since the first on threshold THon1 and the first off threshold THoff1 are set as illustrated in FIG. 7A, even if the knee joint angle data θk includes fluctuation due to chattering phenomenon. The trigger signal TG can be normally shifted from “LOW” to “HIGH”.

  If the trigger signal TG has not changed from “LOW” to “HIGH” in the determination in step S12 (step S12; NO), the CPU 42 continues the determination as it is, and the patient 60 bends the knee joint of the right leg. When the joint angle data θk exceeds the first ON threshold THon1 for the first time and the trigger signal TG becomes “HIGH” (step S12; YES), the CPU 42 gradually increases the duty ratio in the PWM method in accordance with the control pattern of the drive signal. Then, the DC motor 50 of the right foot drive system R is started to be driven (step S13). Then, the driving force is transmitted to the link mechanism portion 3 via the gear portion 52 and the clutch portion 51, and bending assist of the knee joint portion of the patient's right leg is started.

  Next, the CPU 42 determines whether or not the bending assist time has elapsed since the start of driving of the DC motor 50 (step S14). When the bending assist time has not elapsed (step S14; NO), the CPU 42 next Then, it is determined whether or not the timing of switching from the assist of the bending operation to the assist of the extension operation has come due to the arrival of the extreme value timing (step S15). If it is determined in step S15 that the extremum timing has not arrived and the assist of the bending operation is continued (step S15; NO), the CPU 42 proceeds to step S14. On the other hand, if it is determined in step S15 that extreme timing has arrived and switching to assisting the next extension operation (step S15; YES), the CPU 42 causes the DC motor 50, the clutch unit 51, etc. to stop assisting in the bending operation. Control (step S16), and further control the DC motor 50, the clutch unit 51, etc. so as to start assisting the extension operation (step S17).

  Next, the CPU 42 determines whether or not the extension assisting time has elapsed from the start of assisting the extension operation at the extreme value timing (step S18). When the extension assisting time has not elapsed (step S18; NO), the CPU 42 next determines that the knee joint angle data θk is below the second off threshold THoff2 for the first time and the trigger signal TG changes from “HIGH” to “LOW”. It is determined whether or not (step S19). At this time, since the second off threshold value THoff2 and the second on threshold value THon2 are set as illustrated in FIG. 7B, even if the knee joint angle data θk includes fluctuation due to chattering phenomenon. The trigger signal TG can be normally shifted from “HIGH” to “LOW”.

  When the trigger signal TG is not “LOW” from “HIGH” in the determination in step S19 (step S19; NO), the CPU 42 returns to step S18 to determine whether the extension assist time has elapsed. On the other hand, when the patient 60 extends the knee joint of the right leg, the knee joint angle data θk first falls below the second off threshold THoff2, and the trigger signal TG changes from “HIGH” to “LOW” (step S19; YES). Alternatively, when the extension assist time has elapsed in the determination in step S18 (step S18; YES), the CPU 42 controls the DC motor 50, the clutch unit 51, etc. so as to stop the assist of the extension operation (step S20), and thereafter Then, the auxiliary operation according to the embodiment for the right leg is ended.

  When the left foot drive system L is attached, the CPU 42 performs the same control for the left foot drive system L.

  As described above, according to the operation of the walking assist device S according to the embodiment under the control of the CPU 42, for example, in assisting the bending motion, the first on-threshold value THon1 corresponding to the start of assisting in the flexing motion, and the assistance The assist is started when the knee joint angle data θk becomes the first on threshold THon1 based on the first off threshold THoff1 corresponding to the end of the knee joint angle data θk becomes the first off threshold THoff1. End assistance when At this time, the difference D1 between the first on threshold THon1 and the first off threshold THoff1 is a difference corresponding to the fluctuation due to the chattering phenomenon (that is, the fluctuation can be absorbed). Therefore, the start of the bending motion is controlled based on the two threshold values (the first on threshold value THon1 and the first off threshold value THoff1) having the difference D1 corresponding to the fluctuation caused by the chattering phenomenon, so that the fluctuation is included. In addition, it is possible to safely start assisting the bending motion of the knee joint. Similarly, the end of the extension operation is controlled based on two threshold values (second ON threshold value THon2 and second OFF threshold value THoff2) having a difference D2 corresponding to the fluctuation caused by the chattering phenomenon, so that the fluctuation is included. Even in this case, it is possible to safely end the assist of the knee joint extension operation.

  Further, since the difference D1 is the difference D1 that becomes the first off threshold THoff1 at which the angle including the fluctuation does not reach after the angle of the knee joint that bends in the direction of the bending motion reaches the first on threshold THon1, It is possible to securely absorb the fluctuation of the joint angle and to safely start the bending operation. Further, since the difference D2 is the difference D2 that becomes the second on threshold THon2 at which the angle including the fluctuation does not reach after the angle of the knee joint that bends in the direction of the extension operation reaches the second off threshold THoff2, the knee D It is possible to end the assistance of the extension operation safely by securely absorbing the fluctuation of the joint angle.

  Furthermore, the first on-threshold value THon1 and the first off-threshold value THoff1 used when assisting the bending operation are different from the second off-threshold value THoff2 and the second on-threshold value THon2 used when assisting the extension operation. An appropriate threshold value can be set corresponding to the content.

  Also, the first on threshold THon1, the first off threshold THoff1, the second off threshold THoff2, and the second on threshold THon2 corresponding to the right leg, the first on threshold THon1, the first off threshold THoff1, and the first corresponding to the left leg. When the 2 off threshold THoff2 and the second on threshold THon2 are separated, the right leg and the left leg are controlled independently based on each threshold. Even if they are different, the operation of each knee joint can be started or ended safely.

  In this case, the drive unit 10 attached to the other leg of the patient 60 after the auxiliary operation for one step by the drive unit 10 (11) attached to any one leg of the patient 60 ends. You may make it control each drive unit 10 so that the auxiliary | assistant operation | movement for the next one step by (12) may be started. In this case, after the auxiliary operation for one step by the drive unit 10 attached to any one leg of the patient 60 is completed, the next one step by the drive unit 10 attached to any other leg. Since the auxiliary operation is started, it is possible to avoid a risk that occurs in the patient 60 due to the drive units 10 of both legs simultaneously starting the auxiliary operation.

  Furthermore, since each threshold value can be changed using the operation unit 41, it is possible to start or end the assist of the knee joint appropriately and safely according to the state of the patient 60.

  In the above-described embodiment, the case where the present invention is applied to the walking assist device S that assists walking as recovery training or the like of a patient having knee disease has been described. The present invention can also be applied to a movement assisting device that assists the movement of running or the like as part of recovery training or the like when assisting walking as recovery training or the like. In these cases, since the joint to be assisted is the knee joint or the hip joint, it is possible to safely start or end the assistance of the bending operation or the extension operation in the knee joint or the hip joint.

  In the above-described embodiment, the first on threshold value THon1 and the first off threshold value THoff1 used when assisting the bending operation and the second off threshold value THoff2 and the second on threshold value THon2 used when assisting the extension operation are different values. However, besides this, the first on-threshold value THon1 and the second on-threshold value THon2 can be set to the same value, and the first off-threshold value THoff1 and the second off-threshold value THoff2 can be set to the same value. Even in this case, the control by the CPU 42 using the respective threshold values during the bending operation and the extension operation is the same as the control by the CPU 42 according to the embodiment.

  Furthermore, a program corresponding to the flowchart shown in FIG. 4 or FIG. 8 is recorded on a recording medium such as an optical disk or a hard disk, or is acquired and stored via a network such as the Internet, and is stored in a general-purpose microcomputer. It is also possible to cause the microcomputer to operate as the CPU 42 according to the embodiment by reading and executing the above.

  As described above, the present invention can be used in the field of motion assist devices, and is particularly noticeable when applied to the field of motion assist devices that assist recovery training such as walking or running of a patient. An effect is obtained.

3, 8 Link mechanism part 3a, 8a First link 3b, 8b Second link 3c Third link 4 Upper leg rest 5 Knee part 6 Fixing tool 7 Lower leg rest 9 Crotch part 10, 11, 12 Drive unit 10a Case 10b Hole part 15 Hip joint angle sensor 16 Knee joint angle sensor 17 Foot sensor 20 Communication unit 21 Cable 22 Relay box 23 Belt 25 Communication head 40 Display part 41 Operation part 42 CPU
50 DC motor 51 Clutch part 52 Gear part S Walking assist device R Right foot drive system L Left foot drive system
THon1 first on threshold
THoff1 first off threshold
THon2 second on threshold
THoff2 Second off threshold

Claims (7)

In the movement assist device that assists the movement of the joints of the lower limbs of the person being assisted,
Auxiliary means that can be attached to a portion of the lower limb corresponding to the joint and assists the operation of the joint including at least one of a bending operation and an extending operation;
Detecting means for detecting an angle of the joint in a direction of bending the joint;
Start threshold value information indicating a start threshold value corresponding to the angle at which the assisting of the operation should be started by the assisting means, and an end threshold value different from the start threshold value and corresponding to the angle at which the assist should be ended. Storage means for storing the end threshold information shown,
Based on the stored start threshold information and end threshold information, the assist starts when the detected angle becomes the start threshold, and when the detected angle becomes the end threshold Control means for controlling the auxiliary means to end the auxiliary;
With
The difference between the start threshold value and the end threshold value is a difference corresponding to the fluctuation included in the detection result of the angle. The motion auxiliary device according to claim 1,
The difference is a difference that becomes the ending threshold at which the detected angle including the fluctuation does not reach after the detected angle of the joint bending in the direction of the movement reaches the start threshold. A motion assisting device. In the movement auxiliary device according to claim 1 or 2,
The operation assisting device, wherein the start threshold value and the end threshold value used during the bending operation are different from the end threshold value and the start threshold value used during the extension operation. In the movement auxiliary device according to any one of claims 1 to 3,
The motion assisting device, wherein the joint is a knee joint or a hip joint. In the movement auxiliary device according to any one of claims 1 to 4,
The storage means includes the start threshold information and the end threshold information indicating the start threshold and the end threshold corresponding to the right leg of the assistant, the start threshold corresponding to the left leg of the assistant, and The start threshold information and the end threshold information respectively indicating the end threshold are stored separately,
The control means separately controls the auxiliary means attached to the right leg and the auxiliary means attached to the left leg based on the start threshold value and the end threshold value. A motion assisting device characterized by that. In the movement auxiliary device according to any one of claims 1 to 5,
A motion assisting device, further comprising changing means used to change at least one of the start threshold value and the end threshold value.   A motion assisting device that causes the motion assisting device according to any one of claims 1 to 6 to function as the control unit and the storage unit. Control program.

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