JP5724312B2 - Rehabilitation assist device - Google Patents

Description

  The present invention relates to a rehabilitation assisting device that assists a rehabilitation operation in which a user rotates a joint according to a predetermined motion pattern.

  Powered devices that are attached to the user's arm or leg and assist the movement of the arm or leg have been developed. For example, Patent Document 1 discloses a brace equipped with an actuator that is worn along a leg from a user's waist and applies torque to each of a hip joint and a knee joint. The device of Patent Document 1 controls an actuator based on leg myoelectric potential. Such a brace has the same multi-link articulated mechanism as the robot, and is therefore sometimes called a robot suit or an exoskeleton type brace. Such a device has the potential as a rehabilitation tool as well as a tool for making up for the lack of muscular strength necessary to achieve a desired action in the user's social life.

Japanese Patent Laid-Open No. 2005-23003

  In rehabilitation, it is important that a moderate load is applied to the user's joint and that the user can move the joint greatly. The device of Patent Document 1 and the like has a first purpose of compensating for a shortage of muscular strength necessary to achieve the target action, so that the target action can be achieved (that is, the user can The joint can be moved a lot), but the torque is large enough to reliably achieve the desired motion, so the load on the user may be small enough for rehabilitation purposes was there. The present specification provides a rehabilitation assisting device that can give a moderate load to a user's joint and allows the user to move the joint greatly.

  The rehabilitation assisting device disclosed in the present specification does not give auxiliary torque while the user can move the joint by his / her own force when the user rotates the joint according to a predetermined operation pattern. Give and assist the user to move the joint to the end of the motion pattern. By doing so, it is possible to perform a large operation while giving an appropriate load to the user.

  One embodiment of the rehabilitation assisting device disclosed in this specification is as follows. The rehabilitation assisting device is a device for assisting a rehabilitation operation in which a user rotates a joint according to a predetermined operation pattern. The rehabilitation assisting device includes a proximal device and a distal device that are attached to a proximal portion and a distal portion of a joint to be rehabilitated, and an actuator, an angle sensor, and a controller. Here, the “proximal site” means a user site that is connected to the rehabilitation target joint and is located closer to the rehabilitation target joint. For example, when the rehabilitation target joint is an elbow joint, the upper arm corresponds to the proximal portion. When the joint to be rehabilitated is a shoulder joint, the user's trunk corresponds to the proximal portion. The same applies to the “distal site”.

  The proximal device and the distal device are connected rotatably at a position coaxial with the rotation axis of the joint to be rehabilitated. The actuator rotates the distal brace relative to the proximal brace. The angle sensor measures the rotation angle of the distal brace. The controller stores a target pattern describing a change with time of the target angle of the distal device rotation angle, and executes follow-up control for causing the distal device rotation angle to follow the target pattern by the actuator. Further, the controller sets the follow-up control to the resting state at the time of starting the rehabilitation operation, and sets the distal device to the passively rotatable state. The controller specifies an angle difference between the target angle on the target pattern corresponding to the elapsed time from the start time of the rehabilitation operation and the measured rotation angle. Then, the controller starts the follow-up control when the specified angle difference exceeds a predetermined allowable angle difference. Here, the controller starts the follow-up control from the position on the target pattern corresponding to the time point when the angle difference exceeds the allowable angle difference.

  The above rehabilitation assisting device does not generate assisting torque while the user can move the joint along the target pattern by himself, and can follow the target pattern when the angle difference exceeds the allowable angle difference, that is, by himself. When it is gone, torque is applied to the user's joint so that the joint moves along the rest of the target pattern. For this reason, after a moderate load is applied to the user and the user cannot move the joint by himself, the user can move the joint to the end of the target pattern by the assist torque of the rehabilitation assisting device.

  The “predetermined motion pattern”, which is a rehabilitation target motion, is a motion pattern realized by a target pattern describing a temporal change in the target angle of the distal-side brace rotation angle. In other words, the target pattern represents a change over time in the angle of the rehabilitation target joint corresponding to the “predetermined motion pattern” that is the rehabilitation target motion.

  The joint to be rehabilitated is typically an elbow joint, a knee joint, or a hip joint. When the hip joint or the knee joint is a rehabilitation target joint, the “predetermined motion pattern” may be a walking motion pattern.

  As a device for making the distal device passively rotatable, there is, for example, a clutch provided on a power transmission path from an actuator to the distal device. Further, it is also possible to make the distal device passively rotatable by controlling the actuator. In that case, the controller is configured to execute control that causes the actuator to output a torque having a magnitude that cancels the mechanical resistance torque in the power transmission path from the actuator to the distal device.

  Alternatively, if a direct drive motor that does not have a speed reduction mechanism on the power transmission path to the distal device is used as the actuator, the distal device can be easily passively rotated. In this case, the controller can make the distal brace passively rotatable by stopping the power supply to the direct drive motor. Further, when a pneumatic actuator that moves the piston by pneumatic pressure is used as the actuator, the controller opens the cylinder opening valve that allows the pneumatic internal space and the outside of the pneumatic actuator to open, so that the distal device can be passively rotated. You can also

  When the walking motion is a rehabilitation target motion, rehabilitation is preferably performed for each step. In that case, the temporal change in the joint target angle corresponding to the swing leg movement may be set as the target pattern, and the timing at which the leg leaves the ground may be set in the controller as the rehabilitation start timing. If comprised in that way, a user can perform rehabilitation assistance automatically for every walk cycle, without a user performing any switch operation.

  One aspect of the rehabilitation assisting device for walking is as follows. The target pattern is data describing the change over time of the target angle of the knee angle or the target angle around the hip joint pitch axis during the swing leg period. Then, the controller specifies the angle difference between the target angle on the target pattern corresponding to the elapsed time and the measured rotation angle, with the timing at which the leg has taken off as the rehabilitation operation start time. The takeoff timing can be detected by providing a ground sensor on the sole. Alternatively, the takeoff timing can be estimated from the myoelectric potential of the user. Since the change pattern of myoelectric potential during walking is generally determined, the controller compares the measured myoelectric potential with the myoelectric potential change pattern corresponding to the pre-stored takeoff timing to determine the takeoff timing. Can be identified.

  The technology disclosed in the present specification provides a rehabilitation assisting device that can give an appropriate load to a user's joint and allows the user to move the joint greatly.

It is a perspective view of a rehabilitation assistance apparatus. It is a flowchart figure of the process which the controller of a rehabilitation assistance apparatus performs. It is a figure explaining the function of a rehabilitation assistance apparatus.

  The schematic of the rehabilitation assistance apparatus 100 of an Example is shown in FIG. The rehabilitation assisting device 100 is a device that assists rehabilitation of walking motion. The rehabilitation assisting device 100 includes a leg brace 10 that is worn on the leg of the user U and a controller 12 that controls the leg brace 10. In this example, it is assumed that the user U is a patient whose left leg is healthy but cannot move the right leg freely. That is, the rehabilitation assisting device 100 supports the rehabilitation of the right leg movement during walking, particularly the free leg movement.

  Before describing the rehabilitation assisting apparatus 100, the coordinate system will be described. As shown in FIG. 1, the front of the user U is taken as the X axis, the side is taken as the Y axis, and the vertically upper side is taken as the Z axis. In the technical field of robots, generally, an axis (X axis) extending in the front-rear direction of the robot (human body) is referred to as a roll axis, and an axis (Y axis) extending to the side of the robot (human body) is referred to as a pitch axis. The axis extending in the (Z axis) is called the yaw axis.

  The structure of the leg orthosis 10 will be described. The leg brace 10 includes a thigh link 20, a crus link 30, and a foot link 40. The thigh link 20, the lower leg link 30, and the foot link 40 are attached to the affected leg UA (here, the right leg) of the user U who needs assistance. Specifically, the thigh link 20 is attached to the thigh UB, the lower leg link 30 is attached to the lower leg UD, and the foot link 40 is attached to the foot UE.

  The thigh link 20 and the crus link 30 are connected on both sides of the user's knee joint UC. Specifically, the thigh link 20 and the crus link 30 are rotatably connected by a pair of knee joints 25 positioned coaxially with the user's knee joint. A motor 26, an angle sensor 27, and a clutch 28 are built in the outer knee joint 25. The motor 26 swings the crus link 30 around the knee pitch axis. Hereinafter, an angle formed by the thigh link 20 and the crus link 30 is referred to as a knee angle. The angle measured by the angle sensor 27 is the swing angle of the crus link 30 with respect to the thigh link 20, but the angle also corresponds to the knee angle formed by the user's U thigh UB and the crus UD. The clutch 28 is disposed in the middle of the torque transmission path between the motor 26 and the joint 25. The controller 12 controls the release / engagement of the clutch 28. When the clutch 28 is released, the joint 25 can be passively rotated, i.e., can rotate freely according to an external force. The clutch 28 is a type that engages when electric power is supplied and opens when the electric power is cut off. The clutch 28 is open while the controller 12 is stopped.

  The lower leg link 30 and the foot link 40 are connected on both sides of the user's ankle joint. Specifically, the lower leg link 30 and the foot link 40 are rotatably connected by a pair of ankle joints 34 that are positioned coaxially with the pitch axis of the user's ankle joint. The ankle joint 34 does not include an actuator, and the foot link 40 swings passively according to the swing of the user U's foot. A ground sensor 32 is disposed on the sole of the foot link 40, and detects whether the affected leg (right leg) of the user U is grounded or floating.

  The controller 12 incorporates a small computer and a battery, supplies power to each part of the leg brace 10 via the cable 16, and controls the operation of each part of the leg brace 10. The controller 12 is attached to the trunk (waist) of the user U by the wearing belt 14. The controller 12 controls the motor 26 and the clutch 28 based on the sensor data of the angle sensor 27 and the ground sensor 32.

  The rehabilitation assisting apparatus 100 assists the free leg motion of the affected leg (right leg) in accordance with the walking motion of the user U. More specifically, the rehabilitation assisting device 100 applies torque to the knee joint of the user U's right swing leg to assist the swing motion of the leg of the right swing leg. However, the rehabilitation assisting apparatus 100 does not drive the actuator while the user U can move the right swing leg by himself, and drives the actuator after the user U cannot properly move the lower leg of the right swing leg by himself. Assist the movement until the legs land. FIG. 2 shows a flowchart of processing (rehabilitation support processing) executed by the controller 12. FIG. 3 shows a knee angle target pattern stored in the controller 12 and a graph of changes in the actual knee angle.

  First, the target pattern will be described. The symbol At in FIG. 3 indicates the target pattern. The target pattern At indicates a change with time of a knee angle (oscillation angle around the pitch axis of the lower leg) when a healthy person walks. The target pattern At starts at timing T0 and ends at timing T2. The target pattern At is data of a change in knee angle over time during the swing leg period, and the timing T0 corresponds to the takeoff timing, and the timing T2 corresponds to the landing timing. FIG. 3A schematically shows the lower part of the human body as a line drawing. The solid line shows the right leg (except the top solid line). Note that the uppermost solid line in FIG. 3A represents the trunk. As shown in FIG. 3A, in this embodiment, the knee angle A (target knee angle At, actual knee angle As) is defined as an angle formed by a straight line extending from the longitudinal direction of the thigh and the longitudinal direction of the lower leg. The The knee angle Ak = 0 when the knee is fully extended. When the knee bends at a right angle, the knee angle Ak = + 90 degrees. As shown in FIG. 3A, the time when the knee is bent the most corresponds to the case where the knee angle is the maximum. The controller 12 controls the motor 26 so that the right knee angle of the user U follows the target pattern At.

  The user turns on the main switch of the controller 12 and starts walking rehabilitation. The controller 12 executes each process according to the flowchart of FIG. As described above, since the clutch 28 is in an open state until the controller 12 supplies power, the clutch 28 is in an open state at the start of the rehabilitation support process in FIG. 2, that is, the lower leg link 30 is in a passively rotatable state. It is.

  The controller 12 monitors the output of the ground sensor 32 and specifies the timing at which the affected leg (right leg) leaves (S1: YES). When confirming the takeoff, the controller 12 starts a timer (S2). The timer is used to specify the elapsed time since the affected leg has left the ground. The controller 12 acquires the knee angle from the angle sensor 27 every sampling time (about 1 to 10 msec) (S3), and calculates the angle difference. Here, the controller 12 matches the takeoff timing specified by the output of the ground sensor 32 with the timing T0 of the target pattern in FIG. 3, and specifies the target angle on the target pattern corresponding to the elapsed time from the takeoff timing. The angle difference is calculated by subtracting the actual knee angle measured by the angle sensor 27 from the specified target angle. For example, ΔA in FIG. 3 indicates an angle difference at timing T1 (that is, target angle at timing T1−actual knee angle at timing T1).

  The controller 12 compares the angle difference with a predetermined allowable angle difference (S4). The allowable angle difference is predetermined according to the user, and is set to 15 degrees, for example. Note that the target angle at the takeoff timing is zero degrees, and the knee angle at the takeoff timing of the actual walking motion is usually zero degrees, so the angle difference remains within the allowable angle difference for a while from the takeoff timing. It is. While the angle difference is within the allowable angle difference, the controller 12 continues the comparison of the angle difference until the landing timing is detected (S4: NO, S5: NO). While the angle difference is within the allowable angle difference, the clutch 28 remains open, and the user must move the affected leg by himself. In other words, maintaining the clutch 28 in the disengaged state corresponds to the controller 12 placing the follow-up control in a resting state. The solid line indicated by the symbol As in FIG. 3 indicates the actual knee angle measured by the angle sensor 27. For a while from the takeoff timing T0, the user can swing the lower leg by himself and the knee angle As is kept close to the target angle At. As time elapses, it becomes difficult for the user to move the lower leg smoothly by himself, and the actual knee angle As departs from the target angle At. When the angle difference ΔA exceeds the allowable angle difference, the controller 12 starts follow-up control (S4: YES, S6). When starting the follow-up control, the controller 12 engages the clutch 28 and starts the follow-up control from the position on the target pattern corresponding to the time point when the angle difference ΔA exceeds the allowable angle difference. “Follow-up control” means that the motor 26 is controlled so that the swing angle of the lower leg link 30 follows the target pattern. When the follow-up control is started, the angle difference ΔA approaches zero. For example, when the angle difference ΔA exceeds the allowable angle difference at the timing T1 in FIG. 3, the controller 12 starts tracking control from the timing T1. When the follow-up control is started, the actual knee angle starts to follow the target pattern as indicated by the virtual line Ar in FIG. 3, and a smooth swing leg movement is realized.

  After starting the follow-up control, the controller 12 continues the follow-up control until the landing of the affected leg is detected (S7: NO). When the landing of the affected leg is detected, the controller 12 ends the follow-up control (S8). At the same time, the controller 12 releases the clutch 28 and returns the lower leg link 30 to a state in which it can passively rotate. Then, the controller 12 resets the timer (S9) and prepares for the next free leg operation of the affected leg.

  The advantages of the rehabilitation assisting device 100 will be described. As shown in FIG. 3, the rehabilitation assisting apparatus 100 allows the crus link 30 while the user can move the free leg knee joint so as to follow the target pattern by itself (between timings T0 and T1 in FIG. 3). Is in a passively rotatable state. It becomes difficult for the user to move the free leg knee joint by himself and the rehabilitation assisting apparatus 100 generates torque only when the knee angle is larger than the allowable angle difference and deviates from the target pattern. Lead to. In other words, the rehabilitation assisting device 100 uses the user's power while the user can move the knee joint by himself / herself, and after the swinging leg movement becomes difficult by himself / herself, the swinging leg movement is completed to the end. Apply torque to assist the affected leg. Since the rehabilitation assisting apparatus 100 completes the swing leg movement while maximally using the user's own power, the user can continue the walking rehabilitation movement.

  Points to note about the rehabilitation assisting device disclosed in this specification will be described. The rehabilitation assisting apparatus 100 of the example is intended for rehabilitation of the knee joint. Therefore, the thigh link 20 corresponds to a proximal brace that is attached to the proximal part of the joint to be rehabilitated, and the crus link 30 corresponds to a distal brace. The technology disclosed in the present specification can be applied to a device for rehabilitation of a hip joint and an ankle joint. In the case of a device that is subject to rehabilitation of a hip joint, the rehabilitation assisting device includes a device mounted on the waist and a device mounted on the thigh, the former corresponding to the proximal device and the latter corresponding to the distal device. Such a rehabilitation assisting device includes an actuator that swings the thigh link with respect to the waist link.

  In the rehabilitation assisting apparatus 100 of the example, the grounding sensor 32 specifies the takeoff timing of the affected leg (right leg). For example, as described above, the takeoff timing may be specified by sensor data of a myoelectric potential sensor or an angle sensor that measures a joint angle of a leg as described above.

  The actuator that rotates the lower leg link is not limited to a motor. As described above, a pneumatic cylinder may be employed as the actuator. Further, the means for making the lower leg link in a passively rotatable state is not limited to the clutch, and may be realized by using a direct drive motor as described above.

  Furthermore, the technology disclosed in this specification can also be applied to a device that rehabilitates the elbow joint and a device that rehabilitates the shoulder joint. The rehabilitation assisting device for rehabilitation of the elbow joint has an arm brace that is connected to a brace that is worn on the upper arm and a brace that is worn on the forearm, and an actuator. The actuator is controlled so that the actual elbow angle follows the pattern. The upper arm brace corresponds to the proximal brace and the forearm brace corresponds to the distal brace. In this case, the rehabilitation assisting device includes means for signaling the start of rehabilitation (for example, a lamp or a buzzer), and the user moves the elbow joint by himself so as to follow the target pattern together with the signal. The rehabilitation assisting device starts follow-up control by the actuator when the angle difference between the actual elbow angle and the target elbow angle on the target pattern exceeds a predetermined allowable angle difference.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

10: Leg orthosis 12: Controller 20: Thigh link 25: Joint 26: Motor 27: Angle sensor 28: Clutch 30: Lower leg link 32: Ground sensor 100: Rehabilitation assisting device

Claims (2)

A rehabilitation assisting device for assisting a rehabilitation operation in which a user rotates a joint according to a predetermined motion pattern;
A proximal brace attached to a proximal site of the joint;
A distal brace rotatably coupled to the proximal brace and attached to a distal portion of the joint;
An actuator for rotating the distal brace relative to the proximal brace;
An angle sensor for measuring the rotation angle of the distal brace;
A controller that stores a target pattern describing a temporal change in the target angle of the distal-side appliance rotation angle, and that performs follow-up control that causes the distal-side appliance rotation angle to follow the target pattern by an actuator;
The controller is equipped with
At the start of rehabilitation operation, the follow-up control is set to a resting state, and the distal brace is set to a passively rotatable state.
Identify the angle difference between the target angle on the target pattern corresponding to the elapsed time from the start of the rehabilitation operation and the measured rotation angle,
The rehabilitation assisting device, wherein the follow-up control is started when the angle difference exceeds a predetermined allowable angle difference. The rehabilitation assisting device according to claim 1, wherein the rehabilitation assisting device assists walking rehabilitation.
The target pattern is data describing the change over time of the target angle of the knee angle or the target angle around the hip joint pitch axis during the swing leg period,
The controller specifies an angle difference between a target angle on a target pattern corresponding to an elapsed time and a measured rotation angle, with a timing at which the legs have taken off as a rehabilitation operation start time.

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