JP5120209B2 - Walking assist device - Google Patents

Description

  The present invention relates to a walking assistance device that is attached to a user's lower leg and foot to assist walking. In particular, the present invention relates to a walking assistance device that includes an elastic member that applies a restoring force to the swinging of the ankle in the dorsiflexional buckling direction.

For example, Patent Literature 1 and Patent Literature 2 disclose walking assist devices in which an elastic member is attached between a lower leg brace attached to a user's lower leg and a leg brace attached to a foot. The “foot” in the present specification means a part ahead of the ankle joint of the leg. When the user swings the foot relative to the lower leg, the elastic member generates a restoring force that returns the foot orthosis to the neutral position. With this restoring force, the user can hold the foot in a neutral position without requiring his own force.
In these walking assist devices, the length of the elastic member is adjusted so that the posture in which the ankle is substantially perpendicular is the neutral position.

JP-A-9-103443 JP-A-9-206347

  When walking on the horizontal plane, the neutral position of the foot orthosis is appropriate such that the ankle joint is substantially perpendicular. However, on the uphill, the angle of the foot when landing is shifted to the dorsiflexion direction than when walking on a horizontal plane, and on the downhill, it is shifted to the bottom flexion direction than when walking on a horizontal plane. Similarly, at the climbing step, the foot angle at the time of landing shifts in the dorsiflexion direction than when walking on the horizontal plane, and at the descending step, shifts in the buckling direction than when walking on the horizontal plane. A walking assist device that can change the neutral position in accordance with the state of the walking surface is desired.

  The present invention can be embodied in a walking assist device in which a leg brace attached to a user's lower limb and a leg brace attached to a foot are connected so as to be swingable. Such a walking assistance device is also called a lower limb orthosis. When the foot orthosis is attached to the user, the foot orthosis swings in the dorsiflexion / bend flexion direction of the ankle substantially coaxially with the user's ankle joint. This walking assist device includes an elastic member that has one end connected to the lower leg brace and the other end connected to the leg brace, and generates a restoring force that returns the swinging leg brace to the neutral position. The walking assist device includes an actuator that changes a neutral position of the elastic member. By providing the actuator, the walking assist device can change the neutral position even during walking. The actuator may be operated by a user's switch operation. However, as will be described later, it is preferable that the actuator automatically operate according to the inclination or step of the walking surface.

  The elastic member may typically be a spring. The actuator may typically be a motor. In the present specification, the “actuator” may include a controller that controls the operation.

  The walking assist device of the present invention preferably further includes an inclination angle sensor that detects the inclination of the walking surface in the front-rear direction. The actuator moves the neutral position in the dorsiflexion direction when walking on a horizontal plane when the slope is climbing, and moves the neutral position in the buckling direction than when walking on a horizontal plane when the slope is down. Alternatively, the walking assist device may include a step sensor that detects a step on the walking surface in front of the user instead of the tilt angle sensor. In this case, the actuator moves the neutral position in the dorsiflexion direction when walking on a horizontal plane when the step is climbing, and moves the neutral position in the bottom bending direction than when walking on a horizontal plane when the step is down. In any case, since the neutral position is automatically adjusted according to the inclination or the step of the walking surface, the walking assist device can appropriately assist the walking at the inclination or the step. The walking assist device may include both an inclination sensor and a step sensor.

  It is also preferable that the actuator moves the neutral position when the leg is in the free leg state. Such a walking assistance device can adjust the neutral position for each step of the pedestrian. Further, when the leg is in the free leg state, no load is applied to the ankle. Therefore, such a walking assistance device can automatically change the neutral position without applying unnecessary load to the user.

  When the technical idea of changing the neutral position according to the state of the walking surface is further developed, the walking assist device changes the neutral position so that the bottom surface of the foot orthosis and the walking surface are at a predetermined angle before landing. Get. Such a walking assist device includes an angle sensor that measures an angle formed by the bottom surface of the foot orthosis and the walking surface when the leg with the foot orthosis is on the free leg. Then, the actuator moves the neutral position based on the output of the angle sensor so that the footwear bottom surface and the walking surface of the free leg before landing have a predetermined angle. Such a walking assist device can more appropriately assist the user's walking motion. As the “predetermined angle”, an appropriate angle formed by the walking surface and the foot at the landing timing may be determined based on ergonomics. For example, in the climbing step, the “predetermined angle” is zero, that is, an angle at which the walking surface and the bottom surface of the foot orthosis are substantially parallel.

  (First Embodiment) A walking assistance device 100 of the first embodiment will be described with reference to FIG. The walking assistance device 100 includes a leg brace 12 attached to the lower leg of the user U and a foot brace 14 attached to the leg of the user U. The lower leg device 12 and the foot device 14 are connected by a joint 16 so as to be relatively rotatable. When the walking assist device 100 is mounted on the user U, the rotation axis of the joint 16 is positioned substantially coaxially with the pitch axis of the user U's ankle. The pitch axis means an axis extending in the left-right direction of the human body. That is, the joint 16 couples the foot brace 14 to the lower leg brace 12 so as to be able to swing in the dorsiflexion and plantar flexion directions. Note that “dorsal flexion” means that the foot is bent in a direction in which the toes are brought closer to the shin, and “bottom flexion” means that the foot is bent in a direction in which the toes are extended.

  A motor 20 having a rotation axis extending in the pitch axis direction is attached to the crus orthosis 12. A support beam 22 extending rearward is fixed to the rotating shaft of the motor 20. A spring 30 (elastic member) and a damper 32 are connected in parallel between the rear end of the support beam 22 and the buttocks of the foot orthosis 14. In other words, one end of the spring 30 is connected to the lower leg orthosis 12 and the other end is connected to the foot orthosis 14. FIG. 1 shows a state in which the spring 30 has a natural length. In other words, the neutral position of the foot orthosis 14 is when the lower leg orthosis 12 and the foot orthosis 14 form a substantially right angle. The neutral position at this time is called a reference position. In other words, the neutral position means an angle formed between the lower leg orthosis and the leg orthosis when the spring 30 has a natural length.

  The spring 30 of the walking assist device 100 provides a restoring force that returns the swinging foot orthosis to the neutral position. The damper 32 acts so that the restoring force gradually increases. The walking assist device 100 assists the walking of a pedestrian by applying a restoring force to return to a neutral position on a foot that swings when landing or leaving the floor.

  When the motor 20 is rotated as indicated by an arrow in FIG. 1, the tip of the support beam 22 moves up and down, and the position of the upper end of the spring 30 moves. When the position of the upper end of the spring 30 moves up and down, the neutral position of the foot orthosis shifts in the dorsiflexion / bend flexion direction. When the tip of the support beam 22 moves upward, the neutral position shifts in the bottom bending direction from the reference position. Conversely, when the tip of the support beam 22 moves downward, the neutral position shifts to the dorsiflexion side with respect to the reference position.

  An inclination sensor 40 is attached to the foot orthosis 14. In addition, ground sensors 42a and 42b are attached to the front and rear of the sole of the foot orthosis 14, respectively. The inclination sensor 40 detects an inclination angle in the front-rear direction of the foot orthosis 14 with respect to the vertical direction. The ground sensors 42a and 42b detect whether or not the foot orthosis 14 is in contact with the walking surface.

  The walking assist device 10 includes a controller (not shown), and controls the motor 20 based on the outputs of the inclination sensor 40 and the ground sensors 42a and 42b. The operation of the walking assist device 10 will be described. The controller obtains the inclination angle of the foot orthosis 14 when both of the two ground sensors 42a and 42b detect contact with the walking surface. The inclination angle is obtained from the output of the inclination sensor 40.

  The controller controls the rotation angle of the motor 20, that is, the rotation angle of the support beam 22 so that the neutral position of the foot orthosis becomes the reference position when the walking surface is horizontal. When the walking surface is climbing, the controller controls the rotation angle of the motor 20 to move the neutral position of the foot orthosis in the dorsiflexion direction from the reference position. When the walking surface is descending, the controller controls the rotation angle of the motor 20 to move the neutral position of the foot orthosis in the plantar bending direction from the reference position. Here, “up” and “down” mean the inclination of the user in the front-rear direction. More specifically, the controller adjusts the neutral position so that the bottom surface of the foot orthosis 14 when the user's lower leg is substantially along the vertical direction is substantially parallel to the walking surface.

  The effect of the walking assist device 100 will be described. When the foot is in contact with the hill, the angle between the pedestrian's foot and the lower leg becomes smaller than when walking on a horizontal walking surface. On the other hand, when the foot is in contact with the downhill, the angle between the pedestrian's foot and the lower leg is larger than when walking on a horizontal walking surface. The walking assist device 100 moves the neutral position of the foot orthosis 14 in the dorsiflexion direction when the user walks uphill. That is, in this case, the angle formed by the lower leg brace 12 and the foot brace 14 at the neutral position is smaller than the angle when walking on a horizontal plane. On the other hand, when the user walks downhill, the walking assist device 100 moves the neutral position of the foot orthosis in the plantar bending direction. That is, in this case, the angle formed by the lower leg device 12 and the foot device 14 at the neutral position is larger than the angle when walking on a horizontal plane. The walking assist device 100 gives a neutral position suitable for the inclination of the walking surface by shifting the neutral position in the same direction as the inclination direction of the walking surface.

  (Second Embodiment) Referring to FIG. 2, a walking assist device 200 of the second embodiment will be described. The walking assist device 100 of the second embodiment is different from the walking assist device 100 of the first embodiment in that it includes an image sensor 50 instead of the inclination sensor 40 and the ground sensors 42a and 42b. Since other configurations are the same as those of the walking assist device 100 of the first embodiment, description thereof is omitted.

  The image sensor 50 is attached to the lower leg orthosis 12. The image sensor 50 captures a walking surface in front of the user U's foot. A controller (not shown) detects a front step from the image captured by the image sensor 50. Furthermore, the controller determines whether the front step is an up step or a down step. A method for detecting an ascending step or a descending step from an image can be realized by applying a known image processing technique.

  When the climbing step is detected, the controller and the actuator move the neutral position in the dorsiflexion direction than when walking on a horizontal plane. Further, the controller and the actuator move the neutral position in the bottom bending direction when walking on a horizontal plane when a descending step is detected. The timing for changing the neutral position is immediately before the foot to which the walking assist device 200 is attached contacts the ground.

  When climbing a level difference, the angle formed by the pedestrian's foot and lower leg is longer than when walking on a horizontal walking surface. On the other hand, when descending the step, the angle formed by the pedestrian's foot and lower leg is longer than when walking on a horizontal walking surface. When the user climbs the step, the walking assist device 200 moves the neutral position of the foot orthosis 14 in the dorsiflexion direction. On the other hand, when the user steps down, the walking assistance device 100 moves the neutral position of the foot orthosis 14 to the bottom. The user U wearing the walking assist device 200 can easily climb (fall) the step.

  (Third Embodiment) A walking assist device according to the third embodiment will be described. The walking assistance device of the third embodiment has the same configuration as the walking assistance device 200 of the second embodiment shown in FIG. The walking assist device of the present embodiment is different from the walking assist device 200 of the first embodiment in the processing in the controller. The image sensor 50 is attached so that the user's U toes are included in the imaging range. That is, the image of the image sensor 50 includes the planned landing surface and the tip of the foot. The controller measures an angle formed by the planned landing surface and the bottom surface of the foot from the image of the image sensor 50. A method for measuring an angle from an image can also be realized by applying an existing image processing technique. The bottom surface of the user U is parallel to the bottom surface of the foot orthosis 14. Therefore, the angle measured by the controller is equal to the angle formed by the walking surface scheduled to land and the bottom surface of the foot orthosis 14. Based on the measured angle, the controller controls the motor 20 so that the neutral position of the foot orthosis 14 becomes a predetermined angle. As the “predetermined angle”, an appropriate angle formed by the walking surface and the foot at the landing timing may be determined based on ergonomics. For example, in the climbing step, the “predetermined angle” is zero, that is, an angle at which the walking surface and the bottom surface of the foot orthosis are substantially parallel.

  When the walking assist device of the present embodiment is used, even if the user U does not apply force to the ankle, the angle of the sole with respect to the walking surface at the moment of landing is adjusted to a predetermined angle. In addition, the angle of the sole at the time of landing can be changed according to the inclination or level difference of the walking surface. This walking assistance device adjusts the sole of the landing to an appropriate angle in accordance with the inclination and level difference of the walking surface. This walking assist device can assist the user U so that his / her foot can land smoothly regardless of whether the walking surface is an uphill or a downhill.

  A modification of the walking assistance device of the above-described embodiment will be described. The walking assist device may include a plurality of distance sensors instead of the image sensor 50. Even with a plurality of distance sensors, it is possible to measure the presence or absence of a front step and the inclination of the walking surface.

  Next, with reference to FIG. 3 and FIG. 4, the modification of the mechanism of a walk assistance apparatus is demonstrated. In FIGS. 3 and 4, illustrations of sensors that should be included in the walking assistance device are omitted. 3 and 4 only need to include the sensors 40, 42a, and 42b included in the walking assist device 100 of the first embodiment. Alternatively, the walking assistance device of FIGS. 3 and 4 may include the image sensor 50 provided in the walking assistance device 200 of the second embodiment.

  The walking assist device 300 shown in FIG. 3 includes a spring 330a and a damper 332a on the rear side of the lower limb, and includes springs 330b and 332b on the front side of the lower limb. The spring 330a and the damper 332a are the same as the spring 30 and the damper 32 in the walking assist device 100 of the first embodiment. A support beam 322 extending linearly in the front-rear direction of the lower limb is attached to the rotation shaft of the motor 20. A spring 330 a and a damper 332 a are attached to the rear end of the support beam 322, and a spring 330 b and a damper 332 b are attached to the front end of the support beam 322. The spring 330 b and the damper 332 b are connected to the foot orthosis 14 in front of the joint 16. That is, the springs 330 a and 330 b are arranged on both sides of the rotation axis of the joint 16.

  The rotation shaft of the motor 20 supports the support beam 322 at the center in the longitudinal direction. When the front end of the support beam 322 is lowered, the rear end is raised. At this time, the front end and the rear end of the support beam 322 move by the same distance.

  A walking assistance device 400 shown in FIG. 4 includes a linear actuator 420 instead of the motor 20 of FIG. The linear actuator 420 is fixed to the lower leg brace 12 after the user U's knee. A linear motion shaft of the linear motion actuator 420 is connected to the support beam 322. A linear actuator 420 rotates the support beam 322.

  Even if the mechanism of the walking assist device 100 shown in FIG. 1 is replaced with the mechanism shown in FIG. 3 or FIG. 4, the effect of the present invention can be obtained. Further, the effect of the present invention can be achieved even if the mechanism of the walking assist device 200 shown in FIG. 2 is replaced with the mechanism shown in FIG. 3 or FIG.

  The walking assist device of the above embodiment may include a switch that specifies the rotation angle of the motor. The user can adjust the neutral position as desired by operating the switch. The walking assist device including the switch may not include the sensor.

  A preferred modification of the walking assistance device of the embodiment will be described. In the mechanism shown in FIG. 3 and FIG. 4, springs are arranged before and after the lower limbs. Each spring is supported at the front and rear ends of the support beam. At this time, the distance from the rotation center of the support beam to the front end is equal to the distance from the rear end. Therefore, in the mechanism shown in FIGS. 3 and 4, the amount of extension of one spring is equal to the amount of contraction of the other spring. Instead of such a configuration, the distance from the rotation center of the support beam to the front end of the support beam may be different from the distance to the rear end.

  Further, when the springs are arranged before and after the lower limbs, it is also preferable that each spring has a mechanism that generates a force only in one of the compression direction and the extension direction from the neutral position. For example, by configuring at least one of the connection member between the spring and the foot orthosis or the connection member between the spring and the lower leg orthosis with a wire, a mechanism in which no force acts in the compression direction can be realized. At this time, the spring constants of the front and rear leg springs should be different. By installing such a mechanism, different forces can be generated in the dorsiflexion direction and the bottom flexion direction.

  Moreover, you may arrange | position the spring from which a spring constant differs before and behind a leg. Or you may arrange | position the damper from which a damping coefficient differs before and behind a leg.

  It is also preferable to arrange a spring having a non-linear elastic characteristic that does not expand or contract unless a constant force is applied from the initial angle. By arranging such a spring, natural bottom bending can be avoided.

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. For example, the elastic member that connects the leg brace and the lower leg brace may be a helical spring instead of the coil spring.
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.

The schematic diagram of the walking assistance apparatus of 1st Example is shown. The schematic diagram of the walking assistance apparatus of 2nd Example is shown. The modification of the mechanism of a walking assistance device is shown. The other modification of the mechanism of a walking assistance device is shown.

Explanation of symbols

10: walking assist device 12: leg orthosis 14: foot orthosis 16: joint 20: motor 22: support beam 30: spring 32: damper 40: tilt sensor 42a, 42b: ground sensor 30: controller 32: notification module 40: headphones 42 : Arm motion sensor

Claims (5)

A lower leg brace attached to the user's lower leg;
A foot orthosis attached to the user's foot and pivotally connected to the lower leg orthosis;
An elastic member having one end connected to the lower leg orthosis and the other end connected to the foot orthosis, and generating a restoring force to return the rocked foot orthosis to the neutral position;
An actuator that changes the neutral position by moving the position of one end of the elastic member;
A walking assistance device comprising: It has an inclination angle sensor that detects the inclination of the walking surface in the front-rear direction,
The actuator moves the neutral position in the dorsiflexion direction when walking on a horizontal plane when the slope is climbing, and moves the neutral position in the bottom bending direction than when walking on a horizontal plane when the slope is down. Item 2. The walking assist device according to Item 1. It has a step sensor that detects the step on the walking surface in front of the user.
The actuator moves the neutral position in the dorsiflexion direction when walking on a horizontal plane when the step is climbing, and moves the neutral position in the buckling direction than when walking on a horizontal plane when the step is down. Item 2. The walking assist device according to Item 1.   The walking assisting device according to claim 2 or 3, wherein the actuator moves the neutral position when the leg is in a free leg state. A lower leg brace attached to the user's lower leg;
A foot orthosis attached to the user's foot and pivotally connected to the lower leg orthosis;
An elastic member having one end connected to the lower leg orthosis and the other end connected to the foot orthosis, and generating a restoring force to return the rocked foot orthosis to the neutral position;
An actuator that changes the neutral position by moving the position of one end of the elastic member;
An angle sensor that measures an angle formed by the bottom surface of the foot brace and the walking surface when the leg wearing the leg brace is in a free leg state, and
A walking assist device, wherein the actuator moves the neutral position so that the bottom surface of the foot brace and the walking surface of the free leg before landing are at a predetermined angle.

Images