JP5987742B2 - Walking assistance device and walking assistance method - Google Patents

Description

  The present invention relates to a walking assistance device and a walking assistance method.

  As this type of technology, Patent Document 1 discloses a powered artificial knee joint. Patent Document 1 describes the stance phase, the previous swing phase, and the swing phase as biomechanical characteristics of the lower limbs when walking on a horizontal ground. The stance phase, the previous swing phase, and the swing phase are repeated in this order when walking on a horizontal ground. The stance phase begins with heel contact. The swing phase begins with the toes off. The front swing leg period is a period in which the swinging of the upper leg and the bending of the knee are performed prior to the transition from the stance phase to the swing leg period. And in patent document 1, the transition determination from a stance period to a front swing leg period is performed based on the presence or absence of a detached ground and a knee joint angle.

JP 2012-516717 A

  The above-mentioned front swing leg period is recognized as indispensable for normal walking in the fields of biomechanics and clinical gait analysis. However, the transition determination from the stance phase to the previous swing phase disclosed in Patent Document 1 leaves room for improvement in terms of the determination accuracy of the transition determination.

  Therefore, an object of the present invention is to improve the determination accuracy of the transition determination from the stance phase of the affected leg to the previous swing phase.

A walking assist device that is attached to a user's affected leg and assists the user's walking by controlling a joint angle of the knee joint of the affected leg, wherein the joint angle of the knee joint of the affected leg is increased or decreased. Knee joint driving means for causing the floor to be detected, a floor reaction force center detecting means for detecting the center of the floor reaction force as the center of the floor reaction force of the affected leg, and an upper leg angle detecting means for detecting the angle of the upper leg of the affected leg. An upper leg angular velocity detecting means for detecting an angular velocity of the upper leg of the affected leg; and a control means for controlling the knee joint driving means, wherein the control means comprises the floor reaction force center, the angle, A walking assistance device is provided that determines that the affected leg has transitioned from the stance phase to the previous swing phase based on the angular velocity. According to the above configuration, the determination accuracy of the transition determination of the affected leg from the stance phase to the front swing phase is improved.
The control means does not determine that the affected leg has transitioned from the stance phase to the front swing leg phase unless the floor reaction force center is closer to the toes.
The control means does not determine that the affected leg has transitioned from the stance phase to the front swing phase until it detects a decrease in the angular velocity of the upper thigh at the end of the stance phase of the affected leg.
When the control means detects that the floor reaction force center is closer to the toe and the angular velocity of the upper thigh is decelerated at the end of the stance phase of the affected leg, the affected leg is moved from the stance phase to the stance phase. It is determined that the transition to the previous swing phase has occurred.
A walking assistance method using a walking assistance device attached to a user's affected leg and controlling a joint angle of a knee joint of the affected leg to assist the user's walking, the floor reaction force of the affected leg Based on the floor reaction force center as the center of the leg, the angle of the upper leg of the affected leg, and the angular velocity of the upper leg of the affected leg, the affected leg has transitioned from the stance phase to the front swing leg phase. A walking assist method for determining is provided. According to the above method, the determination accuracy of the transition determination of the affected leg from the stance phase to the front swing phase is improved.
If the floor reaction force center is not close to the toes, it is not determined that the affected leg has transitioned from the stance phase to the front swing phase.
It is not determined that the affected leg has transitioned from the stance phase to the front swing phase until a decrease in the angular velocity of the upper leg is detected at the end of the stance phase of the affected leg.
When the floor reaction force center is closer to the toe and the deceleration of the angular velocity of the upper thigh at the end of the stance phase of the affected leg is detected, the affected leg moves from the stance phase to the front swing leg phase. It is determined that a transition has occurred.

  According to the present invention, the determination accuracy of the transition determination from the stance phase of the affected leg to the previous swing phase is improved.

FIG. 1 is a front view of a user with a walking assist device attached to the right leg. FIG. 2 is a side view of the user with the walking assistance device attached to the right leg. FIG. 3 is a perspective view of the floor reaction force sensor. FIG. 4 is a functional block diagram of the control device. FIG. 5 is a bottom view of the floor reaction force sensor. FIG. 6 is a diagram showing a target trajectory of the knee joint angle. FIG. 7 is a phase plan view of the upper leg angle and the upper leg angular velocity. FIG. 8 shows measured values such as floor reaction force. FIG. 9 is a flow of the walking assistance method. FIG. 10 is a flow of the walking assistance method. FIG. 11 is a flow of the walking assistance method.

  In the present specification, the “lower leg” is composed of the upper leg and the lower leg. “Upper leg angle” means an angle around the pitch axis of the upper leg. “Upper thigh angular velocity” means an angular velocity around the pitch axis of the upper thigh. “Knee joint angle” means a joint angle around the pitch axis of the knee joint. “Knee joint angular velocity” means the angular velocity of the joint angle around the pitch axis of the knee joint. “Ankle joint angle” means a joint angle around the pitch axis of the ankle joint. “Healthy leg” means a leg that allows the user to freely increase or decrease the knee joint angle. “Affected leg” means a leg for which the user cannot freely increase or decrease the knee joint angle. “Standing period” is a period starting from the heel contact. The “free leg period” is a period that starts when the toes leave. The “front swing leg period” is a period in which the swinging of the upper leg and the bending of the knee are performed prior to the transition from the stance period to the swing leg period.

  1 and 2 show a user U whose right leg, which is one of the lower limbs, is an affected leg. The walking assist device 1 is attached to the right leg of the user U. The walking assist device 1 assists the user U in walking by controlling the joint angle of the knee joint of the right leg.

  The walking assist device 1 includes an upper thigh link 2, a lower thigh link 3, a foot link 4, a floor reaction force sensor 5, a support link 6, a control device 7, a knee joint mechanism 8, a knee joint angle sensor 9, and an actuator 10 (knee joint drive). Means), an ankle joint mechanism 11, an ankle joint angle sensor 12, a hip joint mechanism 13, and a hip joint angle sensor 14 (upper leg angle detection means).

  The upper leg link 2 is provided along the longitudinal direction of the upper leg U1 of the right leg of the user U, and is fixed to the upper leg U1 with a belt or the like.

  The lower leg link 3 is provided along the longitudinal direction of the lower leg U2 of the right leg of the user U, and is fixed to the lower leg U2 with a belt or the like.

  The floor reaction force sensor 5 is provided on the sole of the foot U3 of the right leg of the user U, and is fixed to the foot U3 with a belt or the like. The floor reaction force sensor 5 is for detecting the floor reaction force of the right leg of the user U. As shown in FIG. 3, the floor reaction force sensor 5 includes a rectangular sensor holding body 15 and four load sensors 16A to 16D. The load sensor 16A and the load sensor 16B are arranged at two corners on the toe side of the sensor holding body 15, respectively. The load sensor 16C and the load sensor 16D are disposed at two corners on the heel side of the sensor holding body 15, respectively. The load sensor 16A outputs floor reaction force data f1 corresponding to the detected floor reaction force. The load sensor 16B outputs floor reaction force data f2 corresponding to the detected floor reaction force. The load sensor 16C outputs floor reaction force data f3 corresponding to the detected floor reaction force. The load sensor 16D outputs floor reaction force data f4 corresponding to the detected floor reaction force. The floor reaction force sensor 5 outputs floor reaction force data f1 to f4 to the control device 7.

  The control device 7 is provided on the waist U4 of the user U, and is fixed to the waist U4 with a belt or the like.

  The upper leg link 2 and the lower leg link 3 are connected by a knee joint mechanism 8. In the knee joint mechanism 8, the upper thigh link 2 and the lower thigh link 3 are relatively rotatable. The rotation axis of the relative rotation of the upper leg link 2 and the lower leg link 3 in the knee joint mechanism 8 coincides with the pitch axis. A knee joint angle sensor 9 is attached to the knee joint mechanism 8. The knee joint angle sensor 9 is for detecting a relative angle between the upper leg link 2 and the lower leg link 3 in the knee joint mechanism 8, that is, a knee joint angle. The knee joint angle sensor 9 outputs knee joint angle data. An actuator 10 is attached to the knee joint mechanism 8. The actuator 10 is for rotating the lower leg link 3 relative to the upper leg link 2. That is, the actuator 10 increases or decreases the knee joint angle by applying torque to the knee joint of the right leg of the user U.

  Returning to FIG. 1 and FIG. 2, a foot link 4 is attached to the floor reaction force sensor 5. The lower leg link 3 and the foot link 4 are connected by an ankle joint mechanism 11. In the ankle joint mechanism 11, the crus link 3 and the foot link 4 are relatively rotatable. The rotation axis of relative rotation of the crus link 3 and the foot link 4 in the ankle joint mechanism 11 coincides with the pitch axis. An ankle joint angle sensor 12 is attached to the ankle joint mechanism 11. The ankle joint angle sensor 12 is for detecting a relative angle between the crus link 3 and the foot link 4 in the ankle joint mechanism 11, that is, an ankle joint angle. The ankle joint angle sensor 12 outputs ankle joint angle data.

  A support link 6 is attached to the control device 7. The support link 6 and the upper thigh link 2 are connected by a hip joint mechanism 13. In the hip joint mechanism 13, the support link 6 and the upper leg link 2 are relatively rotatable. The rotation axis of the relative rotation of the support link 6 and the upper leg link 2 in the hip joint mechanism 13 coincides with the pitch axis. A hip joint angle sensor 14 is attached to the hip joint mechanism 13. The hip joint angle sensor 14 is for detecting a relative angle between the support link 6 and the upper leg link 2 in the hip joint mechanism 13. In other words, the hip joint angle sensor 14 is for detecting the upper leg angle. The hip joint angle sensor 14 outputs upper leg angle data θ.

  As shown in FIG. 4, each data output from the floor reaction force sensor 5, the knee joint angle sensor 9, the ankle joint angle sensor 12, and the hip joint angle sensor 14 is input to the control device 7. The control device 7 is electrically connected to the actuator 10.

  The control device 7 includes a CPU 50 (Central Processing Unit), a RAM 51 (Random Access Memory), and a ROM 52 (Read Only Memory). The ROM 52 stores a walking assistance program. This walking assistance program is read out by the CPU 50 and executed on the CPU 50, so that the hardware such as the CPU 50 can be connected to the floor reaction force center calculation unit 53, the thigh angular velocity calculation unit 54, the ground takeoff determination unit 55, The knee joint angle trajectory generating unit 56 and the actuator control unit 57 (control means) function.

  In the present embodiment, the floor reaction force center detection means is realized by the floor reaction force sensor 5 and the floor reaction force center calculation unit 53. The upper thigh angular velocity detecting means is realized by the hip joint angle sensor 14 and the upper thigh angular velocity calculating unit 54.

(Floor reaction force center calculation unit 53)
Based on the floor reaction force data f1 to f4 output from the floor reaction force sensor 5, the floor reaction force center calculation unit 53 detects the floor reaction force center as the center of the floor reaction force of the right leg of the user U. In the present embodiment, the floor reaction force center detection means is realized by the floor reaction force sensor 5 and the floor reaction force center calculation unit 53. FIG. 5 shows the floor reaction force sensor 5 viewed from the floor side. In FIG. 5, the direction toward the toes is positive on the X axis, and the direction toward the heel is negative on the X axis. The direction toward the little finger is positive on the Y axis, and the direction toward the thumb is negative on the Y axis. As shown in FIG. 5, the position coordinates of the load sensors 16A to 16D are known. Accordingly, the floor reaction force center calculation unit 53 calculates the X coordinate data xc of the floor reaction force center using the following equation (1).

(Upper thigh angular velocity calculation unit 54)
The crus angular velocity calculation unit 54 calculates crus angular velocity data θ dots by time-differentiating the crus angle data θ output from the hip joint angle sensor 14.

(Earth contact / landing determination unit 55)
Based on the floor reaction force data f <b> 1 to f <b> 4 output from the floor reaction force sensor 5, the contact / separation determination unit 55 determines the contact and takeoff of the right leg of the user U by the following equations (2) and (3). judge. Specifically, when the sum of the floor reaction force data f1 to f4 is larger than the threshold value F0, the grounding / separation determining unit 55 determines that the right leg of the user U is grounded as shown in the following formula (2). judge. On the other hand, if the sum of the floor reaction force data f1 to f4 is smaller than the threshold value F1, as shown in the following formula (3), it is determined that the right leg of the user U is off.

(Knee joint angle trajectory generator 56)
The knee joint angle trajectory generating unit 56 generates a target trajectory of the knee joint angle in the front swing leg period and the swing leg period.

  The knee joint angle trajectory generator 56 generates a target trajectory of the knee joint angle in the front swing leg period by the following equations (4) and (5). In the following formula (4), qd (t) is a target trajectory of the knee joint angle. q0 is the knee joint angle at the start of the front swing leg period. The q0 dot is the knee joint angular velocity at the start of the front swing leg period. t is time. t0 is the time at the start of the previous swing phase. The following equation (4) continues to accelerate the knee joint angle at a certain angular acceleration. Recent research in the biomechanics field has revealed that the angular acceleration of the knee joint angle during the anterior swing leg period increases in the same manner as the walking speed increases. Therefore, in order to incorporate this knowledge, the inventors of the present application assume that the walking speed V is multiplied by the proportional constant k by the angular acceleration a of the knee joint angle in the front swing leg period, as shown in the following formula (5). . As a result, the angular acceleration a of the knee joint angle in the previous swing leg period increases in proportion to the increase in walking speed V. The walking speed V can be calculated geometrically using the upper leg angle and the knee joint angle, the length of the upper leg link 2 and the length of the lower leg link 3. The walking speed V may be calculated by first estimating the stride and dividing this by the time required for one step, as disclosed in Japanese Patent Application Laid-Open No. 201212021354. Alternatively, the walking speed V may be estimated based on the upper leg angular velocity data θ dot.

  The knee joint angle trajectory generation unit 56 generates a target trajectory of the knee joint angle in the swing leg period by the following equations (6) to (9). In the following formulas (6) and (7), q1 is the knee joint angle at the start of the swing phase. The q1 dot is the knee joint angular velocity at the start of the swing phase. t1 is the time at the start of the swing phase. T is the length of the swing period.

  FIG. 6 shows the target trajectory of the knee joint angle generated by the knee joint angle trajectory generation unit 56 in the front swing leg period and the swing leg period. In FIG. 6, the horizontal axis represents time, and the vertical axis represents knee joint angle. As shown in FIG. 6, the target trajectory of the knee joint angle is that the knee joint angle is accelerated in the bending direction according to the walking speed V in the previous swing leg period, and the bending speed until the next contact is made in the swing leg period. This is to slow down the knee and extend the knee joint. The proportionality constant k may be appropriately optimized by several trials.

(Actuator control unit 57)
The actuator control unit 57 controls the actuator 10. The actuator control unit 57 includes a stance phase control mode as a control mode when the right leg of the user U is in the stance phase, and a front swing phase as a control mode when the right leg of the user U is in the antegrade phase. A control mode and a swing phase control mode as a control mode when the right leg of the user U is in the swing phase. The actuator control unit 57 repeats the stance phase control mode, the previous swing phase control mode, and the swing phase control mode in this order. The actuator control unit 57 determines that the right leg of the user U has transitioned from the stance phase to the front swing phase based on the floor reaction force center, the upper thigh angle, and the upper thigh angular velocity. At the same time, the control mode of the actuator control unit 57 is switched from the stance phase control mode to the previous swing phase control mode. Specifically, in order for the actuator control unit 57 to determine that the right leg of the user U has transitioned from the stance phase to the front swing phase, the following first condition regarding the center of the floor reaction force and the upper leg angle and It is a requirement that the second condition regarding the upper thigh angular velocity is satisfied at the same time.

<First condition>
If the floor reaction force center of the right leg of the user U is not close to the toes, the actuator control unit 57 does not determine that the right leg of the user U has transitioned from the stance phase to the front swing phase. The actuator control unit 57 requests that the floor reaction force center of the right leg of the user U is closer to the toe when determining that the right leg of the user U has transitioned from the stance phase to the front swing phase.

  If the user U is walking normally, the floor reaction force center should be closer to the toes at the end of the stance phase. Therefore, by monitoring the X coordinate data xc of the floor reaction force center calculated by the above formula (1), the user U is walking normally and the right leg of the user U is at the end of the stance phase. Can be detected. That is, when the X coordinate data xc exceeds a predetermined value, the actuator control unit 57 determines that the first condition is satisfied. When the X coordinate data xc is equal to or smaller than the predetermined value, the actuator control unit 57 determines that the first condition is not satisfied.

<Second condition>
The actuator control unit 57 does not determine that the right leg of the user U has transitioned from the stance period to the front swing period until it detects a decrease in the angular velocity of the upper thigh at the end of the stance period of the right leg of the user U. The actuator controller 57 requests that the angular velocity of the upper leg be detected at the end of the stance phase of the right leg of the user U when determining that the right leg of the user U has transitioned from the stance phase to the front swing phase. To do.

  FIG. 7 shows a phase plan view of upper leg angle data θ and upper leg angular velocity data θ dots in a healthy leg. In the phase plan view, the horizontal axis represents the upper leg angle data θ, and the vertical axis represents the upper leg angular velocity data θ dots. In the phase plan view, correspondences between the upper leg angle data θ and the upper leg angular velocity data θ dots are plotted in large quantities at a predetermined sampling period. Hereinafter, the correspondence between the upper leg angle data θ and the upper leg angular velocity data θ dots is simply referred to as a phase. When swinging the upper leg in the walking direction, the upper leg angular velocity data θ dot is negative. When moving the upper leg in the direction opposite to the walking direction, the upper leg angular velocity data θ dot is positive. When the upper leg is swung in the walking direction, the upper leg angle data θ decreases. When the upper thigh is moved in the direction opposite to the walking direction, the upper thigh angle data θ increases. When the upper leg is parallel to the vertical, the upper leg angle data θ is set to zero. In the phase plan view, the region (upper half) in which the upper leg angular velocity data θ dot is positive generally corresponds to the stance phase, and the region (lower half) in which the upper leg angular velocity data θ dot is negative is approximately the swing phase. It corresponds to. The phase is a clockwise trajectory.

  According to FIG. 7, the phase changes rapidly in the upper right region. This is considered due to the fact that the pedestrian started to generate torque at the hip joint in order to swing the upper leg forward. In other words, it can be read that the pedestrian starts swinging the upper leg forward before the upper leg actually starts moving forward. Therefore, the actuator control unit 57 determines the determination line R on the phase plan view of FIG. 7 as a timing to read that the pedestrian is about to swing out the upper leg before the upper leg actually starts moving forward. And the deceleration of the upper leg angular velocity at the end of the stance phase of the user U is detected by the phase straddling the determination line R clockwise.

  The determination line R is represented by the following formula (10). In the following formula (10), θ0 is a constant.

  Based on the above equation (10), the actuator control unit 57 determines that the second condition is satisfied when the following equation (11) becomes true. On the other hand, if the following formula (11) becomes false, it is determined that the second condition is not satisfied.

  Here, FIG. 8 shows a Gait Report (http://www.innsport.com/related-products/data-sets/uw-l-gait-data-set.aspx) issued by the University of Wisconsin-LaCrosse. In FIG. 8, the floor reaction force, the upper leg angle, and the knee joint angle of the attention leg are shown at the same time. According to FIG. 8, (a) The floor reaction force has hardly decreased at the beginning of the front swing leg period, (b) the knee begins to bend near the start of the front swing leg stage, (c) the front swing The findings of (a) to (c) that the swinging of the upper thigh has not yet started at the beginning of the leg phase can be obtained. According to (a), it can be seen that the floor reaction force cannot determine the transition from the stance phase to the previous swing phase. According to (b), the knee begins to bend before the floor reaction force disappears, and the existence of the front swing leg period is clearly recognized. According to (c), when the transition determination from the stance phase to the previous swing phase is performed at the moment when the upper thigh angular velocity is reversed, it is understood that the transition determination timing is too late. On the other hand, since the actuator control unit 57 performs the transition determination from the stance phase to the front swing phase at an appropriate timing before the thigh angular velocity is reversed, the front leg phase of the healthy leg is determined as the affected leg. It is possible to reproduce it skillfully.

(Operation)
Next, the operation of the walking assist device 1 will be described with reference to FIGS.

  First, the control device 7 performs abnormality determination and safety processing (S300). Specifically, the control device 7 determines whether the time of the previous swing phase has become too long, has landed in the middle of the swing phase, has an abnormality in the sensor system, etc. To monitor. For example, if the user U's right leg can't take off well and the front swing leg period becomes too long, the posture is likely to have collapsed, and the bending motion of the knee joint will accelerate too much The control device 7 once drives the knee in the extending direction and shifts to the standby state.

  Next, the control device 7 determines whether or not the current control mode of the actuator control unit 57 is the stance phase control mode (S310). If it is determined that the current control mode of the actuator controller 57 is the stance phase control mode (S310: YES), the control device 7 moves the process to S400 in FIG. On the other hand, if it determines with the present control mode of the actuator control part 57 not being a stance phase control mode (S310: NO), the control apparatus 7 will advance a process to S320. In S320, the control device 7 determines whether or not the current control mode of the actuator controller 57 is the swing phase control mode (S320). If it is determined that the current control mode of the actuator control unit 57 is the swing phase control mode (S320: YES), the control device 7 advances the process to S330. On the other hand, if it is determined that the current control mode of the actuator control unit 57 is not the swing phase control mode (S320: NO), the control device 7 moves the process to S500 of FIG.

  In S330, the knee joint angle trajectory generation unit 56 generates a target trajectory for extending the knee to the end of the swing phase as shown in FIG. 6 (S330). Next, the ground / landing determination unit 55 determines whether the right leg of the user U is grounded (S340). If the ground contact / separation determination unit 55 determines that the right leg of the user U is not in contact with the ground (S340: NO), the actuator control unit 57 drives the actuator 10 according to the target trajectory generated by the knee joint angle trajectory generation unit 56. (S350). On the other hand, when the grounding / landing determination unit 55 determines that the right leg of the user U is grounded (S340: YES), the control device 7 changes the current control mode of the actuator control unit 57 from the swing phase control mode to the stance phase control. The mode is changed (S360), and the process is terminated. The processing of S330 to S360 is processing unique to the swing phase control mode.

  In S400 of FIG. 10, the control device 7 determines whether the knee joint of the right leg of the user U is sufficiently extended (S400). When it is determined that the knee joint of the right leg of the user U is not sufficiently extended (S400: NO), the control device 7 updates the knee target angle so that the knee is extended with the set time constant (S410), and processing To S420. On the other hand, when it is determined that the knee joint of the right leg of the user U is sufficiently extended (S400: YES), the control device 7 advances the process to S420. In S420, the actuator control unit 57 determines whether the floor reaction force center is closer to the toes (S420). When it is determined that the floor reaction force center is not close to the toes (S420: NO), the actuator control unit 57 drives the actuator 10 as necessary (S430). When it is determined that the floor reaction force center is closer to the toes (S420: YES), the actuator controller 57 determines whether the phase crosses the determination line R (S440). When it is determined that the phase does not cross the determination line R (S440: NO), the actuator control unit 57 drives the actuator 10 as necessary (S430). On the other hand, when it is determined that the phase crosses the determination line R (S440: YES), the actuator control unit 57 changes the current control mode of the actuator control unit 57 to the previous swing phase control mode (S450), Each initial value of the above equation (4) is set (S460), the free leg time T is calculated (S470), the angular acceleration a is calculated (S480), and the actuator 10 is driven as necessary (S430). . S400 to S480 are processing unique to the stance phase control mode.

  In S500 of FIG. 11, the knee joint angle trajectory generator 56 generates a target trajectory for accelerating the knee in the bending direction based on the set angular acceleration a (S500). Next, the ground and takeoff determination unit 55 determines whether or not the right leg of the user U has taken off (S510). When the ground contact / separation determination unit 55 determines that the right leg of the user U has not taken off (S510: NO), the actuator control unit 57 performs an actuator operation based on the target trajectory generated by the knee joint angle trajectory generation unit 56. 10 is driven (S515). On the other hand, when the ground contact / separation determination unit 55 determines that the right leg of the user U has taken off (S510: YES), the actuator control unit 57 changes the current control mode of the actuator control unit 57 from the previous swing leg control mode. The mode is changed to the swing phase control mode (S520), the initial values of the above equation (6) are set (S530), and the actuator 10 is driven as necessary (S515). S500 to S530 are processes specific to the front swing phase control mode.

  As mentioned above, although preferred embodiment of this invention was described, the said embodiment has the following characteristics.

(1) The walking assistance device 1 is attached to the right leg (affected leg) of the user U, and assists the walking of the user U by controlling the knee joint angle of the right leg. The walking assist device 1 includes an actuator 10 (knee joint driving means) that increases and decreases the knee joint angle of the right leg, and a floor reaction force center detection means (floor) that detects the floor reaction force center as the center of the floor reaction force of the right leg. Reaction force sensor 5 and floor reaction force center calculation unit 53), hip joint angle sensor 14 (upper leg angle detecting means) for detecting the angle of the upper leg of the right leg, and upper leg for detecting the angular velocity of the upper leg of the right leg. Angular velocity detection means (hip joint angle sensor 14 and upper leg angular velocity calculation unit 54) and an actuator control unit 57 (control unit) that controls the actuator 10 are provided. The actuator controller 57 determines that the right leg has transitioned from the stance phase to the front swing phase based on the floor reaction force center, angle, and angular velocity. According to the above configuration, the determination accuracy of the transition determination from the stance phase of the right leg to the previous swing phase is improved.

(2) The actuator control unit 57 does not determine that the right leg has transitioned from the stance phase to the front swing phase unless the floor reaction force center is closer to the toes.

(3) The actuator control unit 57 does not determine that the right leg has transitioned from the stance phase to the front swing phase until it detects a decrease in the angular velocity of the upper leg at the end of the stance phase of the right leg.

(4) When the actuator control unit 57 detects the deceleration of the angular velocity of the upper thigh at the end of the stance phase of the right leg when the center of the floor reaction force is closer to the toes and the right leg moves from the stance phase to the front swing phase It is determined that transition has been made.

(5) In the walking assistance method using the walking assistance device 1 that is attached to the right leg of the user U and controls the knee joint angle of the right leg to assist the walking of the user U, the floor reaction force of the right leg is reduced. Based on the floor reaction force center as the center, the angle of the upper leg of the right leg, and the angular velocity of the upper leg of the right leg, it is determined that the right leg has transitioned from the stance phase to the front swing phase. According to the above method, the determination accuracy of the transition determination from the stance phase of the right leg to the front swing phase is improved.

  In the above embodiment, the upper leg angle is detected by the hip joint angle sensor 14, but the upper leg angle may be detected by attaching a gyro sensor to the upper leg instead.

DESCRIPTION OF SYMBOLS 1 Walking assistance apparatus 2 Upper leg link 3 Lower leg link 4 Foot link 5 Floor reaction force sensor 6 Support link 7 Control apparatus 8 Knee joint mechanism 9 Knee joint angle sensor 10 Actuator 11 Ankle joint mechanism 12 Ankle joint angle sensor 13 Hip joint mechanism 14 Hip joint Angle sensor 15 Sensor holding body 16A Load sensor 16B Load sensor 16C Load sensor 16D Load sensor 53 Floor reaction force center calculation unit 54 Upper leg angular velocity calculation unit 55 Ground takeoff determination unit 56 Knee joint angle trajectory generation unit 57 Actuator control unit f1 Floor Reaction force data f2 Floor reaction force data f3 Floor reaction force data f4 Floor reaction force data
U user
U1 upper leg
U2 lower leg
U4 waist
R judgment line

Claims (4)

A walking assistance device that is attached to a user's affected leg and assists the user's walking by controlling a knee joint angle that is an angle around the pitch axis of the knee joint between the upper leg and lower leg of the affected leg. There,
Knee joint driving means for increasing or decreasing the knee joint angle of the affected leg;
Upper leg angle detecting means for detecting an upper leg angle that is an angle around a pitch axis between the waist of the affected leg and the upper leg of the affected leg;
Upper leg angular velocity detection means for detecting an upper leg angular velocity that is an angular velocity around the pitch axis between the waist of the affected leg and the upper leg of the affected leg;
Control means for controlling the knee joint drive means;
With
The period starting from the heel contact of the affected leg and ending with the toe separation of the affected leg is defined as the stance phase of the affected leg, and the period starting from the toe separation of the affected leg and ending with the heel contact of the affected leg is determined. The leg swing phase, which is a part of the stance phase and is within a period ending with the toe off of the affected leg from the heel off of the affected leg, and the walking direction of the upper thigh of the affected leg If the period during which swinging to the knee and bending of the knee joint of the affected leg is performed is the pre-swing period,
When the phase corresponding to the upper leg angle and the upper leg angular velocity in a phase plan view of the upper leg angle and the upper leg angular velocity crosses a predetermined determination line in the phase plan view of the upper leg angle and the upper leg angular velocity, It is determined that the affected leg has transitioned to the previous swing leg period,
The predetermined determination line is a line that the phase straddles when the upper thigh angular velocity of the upper thigh is decelerated at the end of the stance phase of the affected leg.
Walking assistance device. The walking assist device according to claim 1,
When the upper thigh angle is θ and the upper thigh angular velocity, which is a derivative of the upper thigh angle, is θ dots, the control means, when the following equation is true, the phase is the predetermined determination line: Is determined to straddle
Walking assistance device.

However, when the upper thigh is swung in the walking direction, the upper thigh angular velocity is negative, the upper thigh angle is decreased, θ ₀ is a constant, and b is a positive number. A walking assistance method for assisting the user's walking by controlling a knee joint angle, which is an angle around a pitch axis of a knee joint between an upper leg and a lower leg of the affected leg, which is attached to the affected leg of the user. There,
The period starting from the heel contact of the affected leg and ending with the toe separation of the affected leg is defined as the stance phase of the affected leg, and the period starting from the toe separation of the affected leg and ending with the heel contact of the affected leg is determined. The leg swing phase, which is a part of the stance phase and is within a period ending with the toe off of the affected leg from the heel off of the affected leg, and the walking direction of the upper thigh of the affected leg If the period during which swinging to the knee and bending of the knee joint of the affected leg is performed is the pre-swing period,
The walking assist method includes:
An upper leg angle detecting step for detecting an upper leg angle that is an angle around a pitch axis between the waist of the affected leg and the upper leg of the affected leg;
Upper leg angular velocity detection step for detecting an upper leg angular velocity that is an angular velocity around the pitch axis between the waist of the affected leg and the upper leg of the affected leg;
In the phase plan view of the upper leg angle and the upper leg angular velocity, if the phase corresponding to the upper leg angle and the upper leg angular velocity crosses a predetermined determination line, the affected leg is moved to the front in the stance phase. A step of determining that a transition to the swing phase has occurred;
Including
The predetermined determination line is a line that the phase straddles when the upper thigh angular velocity of the upper thigh is decelerated at the end of the stance phase of the affected leg.
Walking assistance method. The walking assist method according to claim 3,
When the upper thigh angle is θ and the upper thigh angular velocity, which is a derivative of the upper thigh angle, is θ dots, it is determined that the phase has crossed the predetermined determination line when the following formula is true: To
Walking assistance method.

However, when swinging the upper thigh in the walking direction, the upper thigh angular velocity is negative, the upper thigh angle is decreased, θ0 is a constant, and b is a positive number.

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