JP2007054616A - Controller for walking assistance device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a walking assistance device capable of stably applying a desired lifting force for reducing weight to be born by user's legs to a user. <P>SOLUTION: The walking assistance device 1 is equipped with a receiving part 2 for receiving part of the body weight of the user A applied from the above and a pair of right and left leg links 3R, 3L connected to the receiving part 2 via first joints 10R, L. Foot sole mounting parts 15 at lower ends of respective leg links 3 are each mounted on the foot sole of each leg of the user A. Respective leg links 3 are connected to the receiving part 2 such that, among supporting forces acting on the leg links 3 from the floor side when respective legs of the user A are standing legs, the line of action of the supporting force transmitted from the third joint 14 of the leg links 3 to low thigh frames 13 passes, in a sagittal plane, from the third joints 14 to a specific point P positioned above the receiving part 2 within the width in the front-rear direction of the contact face between the receiving part 2 and the user A. The supporting force is controlled to a prescribed target value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a walking assistance device that assists a user (person) in walking.

Conventionally, as this type of walking assistance device, for example, the one shown in FIG. 4 of Patent Document 1 is known. In FIG. 4 of Patent Document 1, a pair of left and right leg links are extended from a frame carried on the user's torso, and the foot member at the lower end of each leg link is used as the foot of the user. Attach to. Then, a part of the user's weight is supported by a saddle-shaped support portion extending from the frame to the user's crotch. Each leg link includes a first joint (corresponding to a hip joint) close to the frame, a second joint (corresponding to a knee joint) at an intermediate portion, and a third joint (corresponding to an ankle joint) at the lower end.
Japanese Patent Laid-Open No. 7-112035

  In the walking assist device having the structure as shown in FIG. 4 of Patent Document 1, the first joint of each leg link is provided on the back side of the user. For this reason, for example, even if only the second joint of each leg link is driven by the actuator to support a part of the weight of the user, the upward force acting on the frame on the back side of the user and the user Coupled force is generated by the downward force acting on the support portion. Then, due to this couple, the support portion is in a forward downward posture. For this reason, it is considered that it is difficult to cause a desired lifting force to act stably on the user while supporting a part of the weight of the user, easily causing a shift of the contact portion with respect to the support portion of the user. In addition, it is possible to cancel the couple by driving the first joint. However, in that case, complicated cooperative control of the actuators of the first joint and the second joint of each leg link is required. Moreover, in the thing of the said patent document 1, when making lifting force act on a user from a support part, the lifting force will be shared by the left and right leg links. However, the thing of patent document 1 does not have the technique which distributes the lifting force appropriately to each leg link. For this reason, there is a possibility that a force that does not match the movement of each leg of the user may act on each leg of the user.

  The present invention has been made in view of such a background, and provides a walking assist device capable of stably acting on a user a desired lifting force for reducing the weight that the user should bear on the leg. The purpose is to provide. It is another object of the present invention to provide a walking assistance device that can appropriately share the lifting force with leg links corresponding to each leg of the user.

In order to achieve such an object, the first aspect of the walking assistance device of the present invention includes a receiving portion disposed between the bases of both legs of the user so as to receive a part of the weight of the user from above, A pair of left and right thigh frames connected to the receiving portion via a first joint, a pair of left and right thigh frames connected to each thigh frame via a second joint, and a third joint to each lower thigh frame, respectively. A pair of left and right foot mounting portions that are connected to each other and attached to the foot of each of the left and right legs of the user, and are grounded when each of the user's legs is a standing leg, and the first of the left side A left actuator that drives a second joint among the joints of the left leg link constituted by the joint, the thigh frame, the second joint, the lower leg frame, the third joint, and the foot mounting portion, and the right first joint and thigh Frame, second And a right actuator for driving a second joint among the joints of the right leg link constituted by a node, a lower leg frame, a third joint, and a foot mounting portion, and the second joint of each leg link is driven by the actuator A walking assist device adapted to cause an upward lifting force to act on the user from the receiving portion,
When the line of support force acting on the lower leg frame from the third joint of the leg link corresponding to the leg when each leg of the user becomes a standing leg, when the leg link is viewed in the sagittal plane of the user Further, each leg link is connected to the receiving portion from the third joint so as to pass through a predetermined point located above the receiving portion within the width in the front-rear direction of the contact surface between the receiving portion and the user. And
Means for causing the lifting force to act on the user by controlling each actuator so that the support force is a control target force and the control target force becomes a predetermined target value for each leg link. Features.

  According to the first aspect of the present invention, the supporting force (vector) transmitted from the third joint of each leg link to the crus frame is from the third joint in the direction before and after the contact portion between the receiving portion and the user. It occurs toward the predetermined point existing above the receiving part within the width. For this reason, the line of action of the load (gravity corresponding to a part of the weight of the user) applied from the user to the receiving part (up and down passing through the center of gravity of the load distributed on the contact surface between the user and the receiving part) The deviation between the direction line) and the action line of the supporting force acting on the lower leg frame from the third joint of each leg link can be made sufficiently small. That is, the couple generated in the receiving portion by the load applied from the user to the receiving portion and the supporting force acting on the lower leg frame from the third joint of each leg link can be sufficiently reduced. As a result, it is possible to stabilize the position or posture of the receiving portion with respect to the user. In the present invention, as described above, the support force from the third joint of each leg link toward the predetermined point is set as the control target force. Then, the lifting force is applied to the user by driving the actuators so that the control target force becomes a predetermined target value for each leg link. Thereby, it becomes possible to make a required lifting force act on a user stably.

  In the present invention, the supporting force (vector) acting on the lower leg frame from the third joint of each leg link is a part of the weight of the user (weight supported by the lifting force acting on the user from the receiving portion). The weight obtained by subtracting the weight of the lower part of the third joint of each of the left and right leg links (such as the foot mounting portion) from the total weight of the walking assist device (this weight is generally the total weight of the walking assist device) This is equivalent to the share of each leg link out of the total support force for supporting the sum total on the floor.

  More specifically, in the first invention, the first joint of each leg link is configured such that the leg link is swingable at least in the front-rear direction with the predetermined point as a swing center point. It is preferable that the thigh frame is a joint that connects the thigh frame and the receiving portion (second invention).

  Alternatively, the first joint of each leg link is a joint that connects the thigh frame of the leg link and the receiving portion so that the leg link can swing in the front-rear direction and the left-right direction, and at least It is preferable that the pivot center point in the front-rear direction of the leg link is located above the receiving portion as the predetermined point (third invention).

  According to these second and third inventions, the support force acting on the lower leg frame from the third joint of each leg link is the swing of the leg link from the third joint of the leg link in the front-rear direction. The vector goes to the center point (that is, the predetermined point). The front-rear swing center point of the leg link (hereinafter referred to as the front-rear swing center point in this section) is the width in the front-rear direction of the contact surface between the receiving part and the user when viewed in the sagittal plane. It exists in the position above a receiving part. For this reason, for example, when the line of action of the load from the user to the receiving portion shifts forward of the front / rear swing center point due to the forward tilt of the upper body of the user and the receiving portion is in the forwardly lowered posture, the user The point of application of the force to the receiving portion is displaced rearward below the front / rear swing center point. As a result, the position and posture of the receiving portion tend to converge automatically in a state where the line of action of the load from the user to the receiving portion passes through the center point of front and rear oscillation. In a state where the line of action of the load applied from the user to the receiving portion passes through the center point of back-and-forth swing, the load and the supporting force transmitted from the third joint of each leg link to the lower leg frame are even. Since no force is generated, the position of the receiving portion relative to the user is stabilized. Thus, according to the 2nd invention or the 3rd invention, position shift of a receiving part to a user can be prevented. As a result, the lifting force from the receiving portion to the user can be stabilized. In the third invention, the swing center point of the leg link in the left-right direction may be above or below the receiving portion.

  Supplementally, in the second invention, the first joint is configured as follows, for example. That is, a pair of left and right arc-shaped or elliptical arc-shaped guide rails (a part of the arc of the circumference of the ellipse) are connected to the receiving portion so that the center of the arc exists on the upper side of the receiving portion. The first joint can be configured by supporting the thigh frame of each leg link on the guide rail so as to swing along the guide rail. In the third aspect of the invention, for example, each of the guide rails is connected to the receiving portion via a shaft pin in the front-rear direction so that the guide rail around the axis of the shaft pin can swing. . Thereby, the 1st joint in the 3rd invention can be constituted.

  In the first to third aspects of the invention, the left actuator and the right actuator are connected to the thigh frame at locations closer to the receiving part than the second joint, respectively, and the driving force of each actuator is It is preferable to include a pair of left and right power transmission means for transmitting to the second joint (fourth invention).

  According to the fourth aspect of the invention, since each actuator having a relatively large weight is provided at a location near the receiving portion, the actuator of the free leg side actuator can be used during the walking motion of the user equipped with the walking assist device. The inertial force accompanying the movement can be reduced. Therefore, the burden on the user can be reduced. Examples of the power transmission means include a wire and a rod, or a tube or a shaft through which a fluid passes.

  In the first to fourth aspects of the invention, more specifically, regarding the control of the control target force, the pedaling force of each leg of the user is output from the first force sensor provided in each foot mounting portion. Treading force measuring means for measuring based on the detected force value, target lifting force setting means for setting a target lifting force that is a target value of upward lifting force that acts on the user from the receiving portion, and each leg link A second force sensor interposed between the lower joint of the lower leg frame and the third joint, or between the third joint of each leg link and the foot mounting portion, and the output of the second force sensor Control target force measuring means for measuring the support force actually acting on the lower leg frame from the third joint of each leg link as a control target force, the target lifting force, and the walking assist device Of the lower part of each of the second force sensors The sum of the support force for supporting the weight on the floor by subtracting the weight from the total weight of the walking assist device, or the sum of the support force for supporting the target lifting force and the entire weight of the walking assist device on the floor A total target lifting force determining means for determining the total target lifting force, and distributing the total target lifting force to each leg link in accordance with a ratio of the pedaling force of the left leg and the right leg of the user. A distribution means for determining a target share which is a target value of the left leg link and a target share which is a target value of the right leg link of the total target lifting force, and the left side Based on the control target force of the leg link and the target share of the left leg link, the left actuator is controlled so that the difference between the control target force of the left leg link and the target share approaches zero, and Right leg Actuator control means for controlling the right actuator based on the control target force of the right leg link and the target share of the right leg link so that the difference between the control target force of the right leg link and the target share approaches zero (5th invention).

  According to the fifth aspect of the present invention, the total weight of the walking assist device is calculated by using the target lifting force set by the target lifting force setting means and the total weight of the lower portion of each second force sensor in the walking assist device. The total of the support force for supporting the weight subtracted from the weight (hereinafter, this weight is referred to as weight X in this column) or the target lifting force and the total weight of the walking assist device for supporting the floor. The total with the support force is determined as the total target lifting force. This total target lifting force is the sum of the load applied by the user to the receiving portion (the force that balances the lifting force) and the weight corresponding to the weight X or the total weight of the walking assist device. This means the supporting force necessary to support the floor. In general, the weight X and the total weight of the walking assist device are substantially equal.

  Further, in the fifth aspect, the total target lifting force is distributed according to the ratio of the pedaling force of the right leg and the pedaling force of the left leg measured by the pedaling force measuring means. Thereby, the target share of the left leg link and the target share of the right leg link in the total lifting force are determined. In this case, the ratio between the pedaling force of the user's right leg and the pedaling force of the left leg measured by the pedaling force measuring means indicates how the user intends to support his / her weight on the floor with each leg. Reflects. For example, if the pedaling force of the left leg is larger than the pedaling force of the right leg, the user tries to support his / her weight mainly by the right leg. Therefore, the total target lifting force is distributed to each leg link of the walking assist device according to the ratio of the pedaling force of the right leg and the left leg of the user, and the target share of each leg link is determined. The target lifting force can be distributed to each leg link so as to match the motion state of each leg desired by the person. That is, the ratio between the target burden for the right leg link and the target burden for the left leg link, in accordance with the ratio of the right leg treading force and the left treading force that reflects the desired movement of each leg. Can be determined. More specifically, for example, the target lifting burden of the right leg link is the ratio of the target lifting burden of the right leg link to the target lifting force between the pedaling force of the user's right leg and left leg. What is necessary is just to determine so that it may become the same as the ratio of the right pedaling force with respect to the sum total. The left leg link target lifting share is the ratio of the left leg link target lifting load to the target lifting force, and the ratio of the left pedaling force to the sum of the right leg pedaling force and the left leg pedaling force of the user. What is necessary is just to determine so that it may become. Supplementally, the target share of the left leg link has a meaning as the target value of the control target force of the left leg link, and the target share of the right leg link is the target of the control target force of the right leg link. It has meaning as a value.

  In the fifth invention, the control target force of the left leg link measured by the control target force measuring means (the support force actually acting on the lower leg frame from the third joint of the left leg link) and the distribution means are determined. The left actuator is controlled so that the difference between the control target force of the left leg link and the target share approaches zero based on the target share of the left leg link. Similarly, the right leg link control target force (support force actually acting on the lower leg frame from the third joint of the right leg link) measured by the control target force measuring means and the right leg link determined by the distributing means The right actuator is controlled so that the difference between the control target force of the right leg link and the target share approaches zero based on the target share.

  By controlling each actuator in this way, the actual burden on each leg link can be reliably controlled to the target burden. At this time, the actual lifting force acting on the user from the receiving portion can be controlled to the target lifting force.

  Thus, in the fifth aspect of the invention, the total target lifting force is shared by the left and right leg links so as to conform to the motion state of each leg desired by the user while considering the weight of the walking assist device. The target lifting force can be appropriately applied to the user from the receiving portion. As a result, the burden on each leg of the user can be more effectively reduced.

  In the first to fourth aspects of the invention, as a form different from the fifth aspect of the invention, the pedal force of each leg of the user is indicated by the output of the first force sensor provided on each foot mounting portion. A treading force measuring means for measuring based on the detected value is interposed between the lower end of the lower leg frame of each leg link and the third joint, or between the third joint of each leg link and the foot mounting portion. A control target force that measures the support force actually acting on the lower leg frame from the third joint of each leg link as a control target force based on the second force sensor and the force detection value indicated by the output of the second force sensor. A target assist ratio that sets a target assist ratio that is a target value of the ratio of the force to be assisted by the walking assist device out of the total pedaling force that is the sum of the pedaling force of each leg of the user and the measuring means. Setting means and the target assist ratio for each leg of the user; Of the upward lifting force to be applied to the user from the receiving portion by multiplying the pedaling force, the target lifting share that is the target value of the left leg link share and the target value of the right leg link share A target lifting share determining means for determining a target lifting share, and a weight obtained by subtracting the total weight of the lower part of each second force sensor of the walking assist device from the total weight of the walking assist device. The support force for supporting the floor on the floor or the support force for supporting the entire weight of the walking assist device on the floor is determined according to the ratio of the pedal force of the left leg and the right leg of the user. Distributing means for determining the share of the left leg link and the share of the right leg link of the support force as the share of the target device support force of each leg link by distributing to the links, and the left leg link Goals Determining the sum of the lifting load share and the target device supporting force share as a target value of the control target force of the left leg link, and the sum of the target lifting share of the right leg link and the target device supporting force share Based on the control target force target value determination means for determining the control target force of the right leg link, the control target force of the left leg link, and the target value of the control target force of the left leg link, The left actuator is controlled so that the difference between the control target force of the left leg link and the target value approaches zero, and based on the control target force of the right leg link and the target value of the control target force of the right leg link. The actuator control means for controlling the right actuator may be provided so that the difference between the control target force of the right leg link and the target value approaches zero (sixth invention).

  In the sixth aspect of the present invention, the target assist ratio set by the target assist ratio setting means is multiplied by the pedaling force of each leg of the user measured by the pedaling force measuring means, thereby acting on the user from the receiving portion. Of the upward lifting force to be generated, a target lifting burden for the left leg link and a target lifting burden for the right leg link are determined. That is, by multiplying the measured user's left leg treading force by the target assist ratio, the target lifting burden for the left leg link is determined, and the measured user's right leg treading force is multiplied by the target assist ratio. Thus, the target lifting share for the right leg link is determined. The sum of the target lifting burden for the left leg link and the target lifting burden for the right leg link corresponds to the target value of the total lifting force acting on the user from the receiving portion. This substantially balances the force obtained by multiplying the total pedaling force of the user by the target assist ratio.

  In this case, the pedaling force of the user's right leg and the pedaling force of the left leg measured by the pedaling force measuring means is as follows. It reflects the intention of supporting. Therefore, by determining the target lifting share of each leg link as described above, the target value of the total lifting force from the receiving part to the user so as to match the operating state of each leg desired by the user. (The sum of the target lifting burden for each leg link) can be distributed to each leg link.

  Furthermore, in the sixth aspect of the invention, the floor is supported by a weight obtained by subtracting the total weight of the lower part of each second force sensor from the total weight of the walking assist device (that is, the weight X). The supporting force or the supporting force for supporting the entire weight of the walking assist device on the floor is determined according to the ratio of the pedaling force of the left leg and the pedaling force of the right leg measured by the pedaling force measuring means. Distribute to each leg link. Thereby, the share of the left leg link and the share of the right leg link in the target value of the support force are determined as the target device support force share of each leg link, respectively. That is, the support force for supporting the weight X or the total weight of the walking assist device on the floor in accordance with the ratio of the pedaling force of the right leg and the pedaling force of the left leg reflecting the motion of each leg desired by the user. (This means the force that balances the gravity corresponding to the weight X of the walking assist device or the total weight. In the following, this device support force is distributed to each leg link) and the target device support force burden of each leg link is distributed. Minutes are determined. More specifically, for example, the target device supporting force share of the right leg link is the ratio of the target device supporting force share of the right leg link to the target value of the device supporting force, which is the pedaling force of the user's right leg And the ratio of the right pedaling force to the total pedaling force of the left leg. Similarly, the target device supporting force share of the left leg link is the ratio of the target device supporting force share of the left leg link to the target value of the device supporting force, and the pedaling force of the user's right leg and left leg It may be determined so as to be the same as the ratio of the pedal force of the left leg to the sum of.

  In the sixth aspect of the present invention, the sum of the left leg link target lifting load determined by the target lifting load determining means and the left leg link target device supporting force share determined by the distributing means is the left leg link. The target value of the control target force of the link is determined. Similarly, the control of the right leg link is the sum of the target lifting burden of the right leg link determined by the target lifting burden determining means and the target device supporting force share of the right leg link determined by the distributing means. It is determined as the target value of the target force. Supplementally, the target value of the control target force of the left leg link and the target value of the control target force of the right leg link in the sixth invention are respectively the target share of the left leg link and the right leg link in the sixth invention. This is equivalent to the target share.

  As a result, the target value of the control target force of each leg link is determined so as to match the ratio of the right leg pedaling force and the left leg pedaling force reflecting the movement of each leg desired by the user. It becomes. In this case, the target value of the control target force of each leg link is the sum of the target lifting share of the leg link and the target device support force share. Therefore, the sum of the target value of the control target force for both leg links is the sum of the lifting force to be applied to the user from the receiving portion and the supporting force for supporting the weight X or the total weight of the walking assist device on the floor. It corresponds to.

  Further, in the sixth invention, based on the control target force of the left leg link measured by the control target force measuring means and the target value of the control target force of the left leg link determined by the control target force target value determining means. Thus, the left actuator is controlled so that the difference between the control target force of the left leg link and the target value approaches zero. Similarly, based on the control target force of the right leg link measured by the control target force measurement means and the target value of the control target force of the right leg link determined by the control target force target value determination means, the right leg link The right actuator is controlled so that the difference between the leg link control target force and the target value approaches zero.

  As a result, the actual control target force of each leg link (this is the load that is actually applied from the user to the receiving portion (the force that balances the upward lifting force that actually acts on the user from the receiving portion) and the walking assistance (Corresponding to the actual burden of each leg link with respect to the total support force for supporting the weight X or the total weight of the device) can be reliably controlled to the target value. At this time, the actual lifting force acting on the user from the receiving portion can be controlled to a lifting force equivalent to a force obtained by multiplying the total pedaling force of the user by the target assist ratio.

  Accordingly, in the sixth aspect of the invention, the target assist ratio is set to the total weight of the user with the left and right leg links so as to conform to the operation state of each leg desired by the user while considering the weight of the walking assist device. The lifting force can be appropriately applied to the user from the receiving portion while sharing the lifting force that supports the multiplied weight. As a result, the burden on each leg of the user can be more effectively reduced.

  Therefore, according to the sixth aspect of the invention, while reducing the user's mounting site on each leg, the user himself / herself can reduce the force to be supported on the floor with the leg, and the auxiliary force (lifting force) for the reduction. ) Can be appropriately shared by leg links corresponding to each leg of the user.

  Supplementally, in the first to sixth inventions described above, the receiving portion is seated, for example, by the user straddling the seating portion (the seating portion is positioned between the bases of both legs of the user). (E.g., saddle-shaped). In this case, the first joint of each leg link is preferably provided below the receiving portion. Further, the first joint of each leg link, for example, allows not only the swinging motion of each leg link in the front-rear direction but also the free rotation about two axes that enables the inner and outer rotation of each leg link. It is preferable that the joint has a degree. Further, the first joint is a joint having a degree of freedom of rotation about three axes so that the rotation of each leg link about the vertical axis (internal rotation / external rotation of each leg link) is possible. It may be. The second joint of each leg link may be, for example, a joint having a degree of freedom of rotation about one axis in the left-right direction, or may be a direct acting joint. The third joint of each leg link is preferably a joint having a degree of freedom of rotation about three axes, but may be a joint having a degree of freedom of rotation about two axes including the pitch direction. Further, the foot mounting portion of each leg link includes, for example, an annular member for inserting the foot of the user who wears the foot mounting portion from the toe side of the leg link, and the leg link via the annular member. It is preferable that it is connected to the third joint.

  Further, the first force sensor of each foot mounting portion may be mounted on the foot so that, for example, when each leg of the user is a stance leg, the leg is interposed between the bottom surface of the foot of the stance leg and the floor. Provided in the section. Alternatively, for example, when the foot mounting portion of each leg link includes the annular member, a foot supporting member that supports the user's foot is not in contact with the annular member inside the annular member. Arrange in a state. Then, the foot support member is suspended from the annular member via the first force sensor.

  A first embodiment of the present invention will be described below with reference to the drawings. In addition, this 1st Embodiment is embodiment of the said 1st-5th invention among this invention.

  First, with reference to FIGS. 1-3, the structure of the walking assistance apparatus of this embodiment is demonstrated. 1 is a side view of the walking assist device 1, FIG. 2 is a sectional view taken along the line II in FIG. 1, and FIG. 3 is a sectional view taken along the line III-III in FIG. In addition, the walking assistance apparatus 1 of these FIGS. 1-3 is shown in the state which equipped and operated it to the user A (it shows with a virtual line). In this case, the illustrated user A stands up in an almost upright posture. However, in FIG. 2, in order to facilitate understanding of the structure of the walking assist device 1, the user A takes a posture in which both legs are opened to the left and right.

  With reference to FIG. 1 and FIG. 2, the walking assist device 1 supports a part of the weight of the user A (the weight that the user supports with his / her own leg (standing leg) is less than the own body weight). It is a weight relief assist device. The walking assist device 1 includes a seating portion 2 on which a user A is seated, and a pair of left and right leg links 3L and 3R connected to the seating portion 2. The leg links 3L and 3R have the same structure. In FIG. 1, the leg links 3 </ b> L and 3 </ b> R are aligned in the left-right direction of the user A (direction perpendicular to the paper surface of FIG. 1) with the same posture. In this state, they overlap in the drawing (the left leg link 3L is located on the front side of the drawing).

  Here, in the description of the embodiment of the present specification, the symbol “R” is used to mean that it relates to the right leg of the user A or the right leg link 3R of the walking assist device 1, and the symbol “L”. Is used to mean that it is related to the left leg of the user A or the left leg link 3L of the walking assist device 1. However, the symbols R and L are often omitted when it is not necessary to distinguish between left and right.

  The seat 2 is saddle-shaped, so that the user A straddles the seat 2 (so that the seat 2 is placed between the bases of both legs of the user A). It can be seated on the upper surface (seat surface). By this sitting, a part of the weight of the user A is given to the seating portion 2 from above. The seat 2 corresponds to the receiving part in the present invention.

  Further, as shown in FIG. 1, the front end 2f and the rear end 2r of the seating portion 2 protrude upward, so that the seating position (position in the front-rear direction) of the user A with respect to the seating portion 2 is achieved. Is regulated between the front end 2f and the rear end 2r of the seating portion 2. Note that the front end 2f of the seat 2 is formed in a bifurcated shape as shown in FIG.

  Each leg link 3 includes a thigh frame 11 connected to the lower surface of the seating portion 2 via a first joint 10, a crus frame 13 connected to the thigh frame 11 via a second joint 12, A foot mounting portion 15 connected to the lower leg frame 13 via a third joint 14 is provided.

  The first joint 10 of each leg link 3 is a joint corresponding to the hip joint of the user A, and the swinging motion of the leg link 3 about the left-right axis (the swinging motion of the leg link 3 in the front-rear direction), This is a joint that enables swinging motion (inner rotation / abduction motion) around the axis in the front-rear direction. The first joint 10 is disposed below the seating portion 2, and is located on a front-rear axis C indicated by a one-dot chain line in FIG. 1 at a location near the front side and a rear end location of the lower surface portion of the seating portion 2. A pair of shaft pins 20f and 20r arranged coaxially with each other, brackets 21f and 21r rotatably supported by the shaft pins 20f and 20r, and a circle fixed to the lower ends of these brackets 21f and 21r, respectively. An arc-shaped guide rail 22 and a plate 23 supported on the guide rail 22 so as to be movable along the guide rail 22 are provided. The thigh frame 11 extends from the plate 23 obliquely forward and downward. The thigh frame 11 is a substantially rod-shaped member, and is configured integrally with the plate 23.

  Each shaft pin 20f, 20r is fixed to the seating portion 2 via bearings 24f, 24r whose both ends (front and rear end portions) are fixed to the lower surface portion of the seating portion 2. The upper end portion of the bracket 21f is fitted to the outer periphery of the intermediate portion of the shaft pin 20f, is pivotally supported by the shaft pin 20f, and is rotatable about the axis C of the shaft pin 20f. Similarly, the upper end of the bracket 21r is fitted to the outer periphery of the intermediate portion of the shaft pin 20r, is pivotally supported by the shaft pin 20r, and is rotatable about the axis C of the shaft pin 20r. Accordingly, the guide rails 22 of the first joints 10 swing together with the brackets 21f and 21r about the axis C of the shaft pins 20f and 20r as the rotation axis. In the present embodiment, the first joints 10R and 10L of the leg links 3R and 3L have a common rotation axis C, and the shaft pins 20f and 20r are connected to the first joint 10R of the leg link 3R and the leg link 3L. The first joint 10L is shared. That is, the bracket 21fR of the right first joint 10R and the bracket 21fR of the left first joint 10L are both supported by the common shaft pin 20f, and the bracket 21rR of the right first joint 10R and the left first joint. All 10L brackets 21rL are pivotally supported by a common shaft pin 20r.

  The plate 23 of the first joint 10 of each leg link 3 is disposed adjacent to the guide rail 22 in a posture parallel to the plane including the arc of the guide rail 22. A carrier 26 having a plurality of (for example, four) rotatable rollers 25 is fixed to the plate 23 as shown in FIG. The same number of rollers 25 of the carrier 26 are engaged with the upper surface (inner peripheral surface) and the lower surface (outer peripheral surface) of the guide rail 22 so as to roll freely. Accordingly, the plate 23 is movable along the guide rail 22. In this case, the positional relationship between the guide rail 22 and the seating portion 2 and the radius of the arc of the guide rail 22 are such that the center point P of the arc of the guide rail 22 indicates that the walking assist device 1 is a sagittal plane as shown in FIG. When viewed, it is set so as to exist above the seating portion 2 within the width in the front-rear direction of the contact surface between the seating portion 2 and the user A. The center point P corresponds to a predetermined point in the present invention.

  Due to the configuration of the first joint 10 described above, the thigh frame 11 integrated with the plate 23 can swing around the rotation axis C in the front-rear direction of the user A. By this swinging motion, the inner and outer motions of each leg link 3 are made possible. Further, the thigh frame 11 integrated with the plate 23 passes around the center point P around the axis in the left-right direction passing through the center point (predetermined point) P (more precisely, perpendicular to the plane including the arc of the guide rail 22). It can be swung freely (around the axis). By this swinging motion, the swinging motion of each leg link 3 forward and backward is made possible. In the present embodiment, the first joint 10 is a joint that enables rotational movement about two axes in the front-rear direction and the left-right direction. However, the first joint is configured so that it can rotate around the vertical axis (internal and external rotation of each leg link 3) (that is, it can rotate around three axes). May be. Alternatively, the first joint may be a joint that allows only a rotational movement around one axis in the left-right direction (a joint that enables only a swinging movement of each leg link 3 forward and backward).

  Further, as shown in FIG. 1, the plate 23 of the first joint 10 of each leg link 3 is directed from the position of the carrier 26 toward the rear side of the seating portion 2 when the walking assist device 1 is viewed in the sagittal plane. It is extended. At the rear end of the plate 23, there is an electric motor 27 and a rotary encoder 28 as a rotation angle detecting means for detecting the rotation angle of the rotor of the electric motor 27 (rotation angle from a predetermined reference position). It is attached coaxially. In the present embodiment, the second joint 12 among the first to third joints 10, 12, and 14 of each leg link 3 is driven, and the electric motor 27 is an actuator that drives the second joint 12. It is. The rotary encoder 28 has a function as a displacement amount sensor that detects the displacement amount (rotation angle) of the second joint 12. The rotation angle detected by the rotary encoder is used to measure the rotation angle (bending angle) of the second joint 12. The electric motor 27L of the left leg link 3L and the electric motor 28R of the right leg link 3R correspond to the left actuator and the right actuator in the present invention, respectively. Each actuator may use a hydraulic or pneumatic actuator. Each actuator may be fixed to the rear part of the seating part 2 via an appropriate bracket, for example. Alternatively, each actuator may be attached to the second joint 12 of each leg link 3 so that the second joint 12 is directly driven. Further, the displacement amount sensor for detecting the displacement amount of the second joint 12 may be directly attached to the second joint 12 of each leg link 3. Furthermore, the displacement amount sensor may be constituted by a potentiometer or the like instead of the rotary encoder.

  The second joint 12 of each leg link 3 is a joint corresponding to the knee joint of the user A, and is a joint that allows the leg link 3 to extend and bend. The second joint 12 has a horizontal axis between the lower end of the thigh frame 11 and the upper end of the lower leg frame 13 (more precisely, the axis in the direction perpendicular to the plane including the arc of the guide rail 22). The lower leg frame 13 is rotatable relative to the thigh frame 11 around the axis of the axis pin 29. The second joint 12 is provided with a stopper (not shown) that restricts the rotatable range of the crus frame 13 relative to the thigh frame 11.

  The lower leg frame 13 of each leg link 3 is generally rod-shaped and extends obliquely downward from the second joint 12 of the leg link 3. More specifically, the crus frame 13 includes a lower crus frame 13b constituting a portion near the third joint 14, and a rod-like upper crus frame 13a constituting a portion above the lower crus frame 13b. The force sensor 30 (this corresponds to the second force sensor in the present invention) is interposed between and connected to each other. The lower leg frame 13b is sufficiently shorter than the upper leg frame 13a. Thereby, the force sensor 30 is arranged in the vicinity of the third joint 14. The force sensor 30 is a force sensor referred to as a Kistler sensor (registered trademark), and includes three translational forces (two axial forces perpendicular to the surface of the force sensor 30 and two parallel to the surface and orthogonal to each other. This is a triaxial force sensor for detecting an axial translational force. However, in this embodiment, as described later, only the detected value of the biaxial translational force among the detected triaxial translational forces is used. Therefore, the force sensor 30 may be constituted by a biaxial force sensor that detects a biaxial translational force.

  A pulley 31 is fixed to the upper end of the upper crus frame 13 a of the crus frame 13 so as to be rotatable integrally with the crus frame 13 around the shaft pin 29 of the second joint 12. Fixed to the outer peripheral portion of the pulley 31 are ends of a pair of wires 32 a and 32 b as driving force transmitting means for transmitting the rotational driving force of the electric motor 27 to the pulley 31. These wires 32 a and 32 b are drawn in the tangential direction of the pulley 31 from two locations facing each other in the diameter direction of the outer peripheral portion of the pulley 31. The wires 32 a and 32 b pass through a rubber tube (wire protection tube) (not shown) piped along the thigh frame 11 and are connected to a rotation drive shaft (not shown) of the electric motor 27. In this case, one of the wires 32 a and 32 b is wound around the pulley 31 by the normal rotation of the rotation drive shaft of the electric motor 27 and the other is pulled out from the pulley 31. Tension is applied to the wires 32 a and 32 b from the electric motor 27 so that the other of the wires 32 a and 32 b is wound around the pulley 31 and the other is pulled out from the pulley 31. Thereby, the rotational driving force of the electric motor 27 is transmitted to the pulley 31 via the wires 32a and 32b, and the pulley 31 is rotationally driven (the lower leg frame 13 to which the pulley 31 is fixed is The shaft pin 29 of the two joints 12 is rotated about the axis).

  In addition, the lower end part of the lower leg frame 13b of the lower leg frame 13 is a bifurcated portion 13bb formed in a bifurcated shape, as shown in FIG.

  The third joint 14 of each leg link 3 is a joint corresponding to the ankle joint of the user A. In the present embodiment, as shown in FIG. 3, the third joint 14 is constituted by a free joint 33 (see FIG. 3) that can rotate around three axes. It is interposed in the bifurcated portion 13bb of the crus frame 13b, and connects the lower end portion (bifurcated portion 13bb) of the crus frame 13 and the connecting portion 34 on the upper part of the foot mounting portion 15. As a result, the foot mounting portion 15 can rotate with respect to the crus frame 13 with three degrees of freedom. Note that the rotation range of the foot mounting portion 15 around the axis in the front-rear direction is regulated by the bifurcated portion 13bb of the lower leg frame 13.

  The foot mounting portion 15 of each leg link 3 includes a shoe 35 to be worn on each foot of the user A, and a hook-shaped annular member housed inside the shoe 35 and having an upper end fixed to the connecting portion 34. And a member 36. As shown in FIG. 3, the annular member 36 has its flat bottom plate abutted against the inner bottom surface of the shoe 35, and curved portions connected to both ends of the bottom plate abutd against the side wall along the cross section of the shoe 35. It is accommodated inside the shoe 35 as described above. A flexible insole member 37 (not shown in FIG. 1) is inserted into the shoe 35 so as to cover the bottom surface of the shoe 35 and the bottom plate portion of the annular member 36. The connecting portion 34 is inserted into the shoe 35 through the opening of the shoelace mounting portion of the shoe 35.

  When the foot mounting portion 15 of each leg link 3 is mounted on each foot of the user A, the toe side portion of the foot is passed through the inside of the annular member 36 and the bottom surface of the foot is The foot mounting portion 15 is attached to the foot by inserting the foot of the user A into the shoe 35 through the mouth of the shoe 35 so that the insole member 37 is laid and further tightening the shoelace. It has come to be.

  In addition, on the lower surface of the insole member 37 of the foot mounting portion 15, a location on the front side of the shoe 35 (location on the front side of the bottom plate portion of the annular member 36) and a location on the rear side (the bottom plate portion of the annular member 36). The force sensors 38 and 39 are attached to the rear side portion). The front-side force sensor 38 is disposed so as to be almost directly below the MP joint (medium joint joint) of the foot of the user A wearing the foot mounting portion 15. Further, the rear side force sensor 39 is disposed so as to be almost directly below the foot heel. In the present embodiment, these force sensors 38 and 39 are in a direction perpendicular to the bottom surface (grounding surface) of the foot mounting portion 15 (in a state where the legs of the user A are standing legs, the direction is substantially perpendicular to the floor surface). It is a uniaxial force sensor that detects a translational force. Hereinafter, the force sensors 36 and 37 are referred to as an MP sensor 38 and a heel sensor 39, respectively. The MP sensor 38 and the heel sensor 39 together constitute a first force sensor in the present invention. Here, the insole member 37 does not necessarily have to be a rigid plate, and may be made of a soft (flexible) material. When the insole member 37 is made of a flexible material, by providing a plurality of first force sensors on the lower surface side of the insole member 37, it is possible to accurately detect the force applied to each part of the bottom surface of the user A's foot. it can. On the other hand, when the insole member 37 is formed of a rigid plate, it is easy to detect the pedaling force of the user A's entire foot. For this reason, the number of first force sensors installed on the lower surface side of the insole member 37 can be reduced.

  The above is the structural configuration of the walking assist device 1 of the present embodiment. Supplementally, each foot mounting portion 15 is mounted on each foot of the user A, and the walking assist device 1 is operated as described later (while the second joint 12 is driven by the electric motor 27). In a state where the person A is seated on the seating portion 2, when the user A and the walking assist device 1 are viewed on the front face (when viewed from the front side of the user A), for example, the thigh frame 11L of the left leg link 3L Extends along the inner surface of the left leg of the user A (see FIG. 2), and the second joint 12L at the lower end of the second link 11L is also located inside the left leg. Although not shown in the drawing, the lower leg frame 13L connected to the second joint 12L has the upper part of the lower leg frame 13L (the upper part of the upper lower leg frame 13L) from the second joint 12L as viewed from the front face. It extends along the inner surface of the left leg. The lower portion of the lower leg frame 13L is gradually curved and is formed so as to reach directly above the foot of the left leg on the front side of the shin of the left leg. The same applies to the right leg link 3R.

  When the user A having a normal body stands in an upright posture, the second joints 12 of the leg links 3 protrude forward from the legs of the user A as shown in FIG. That is, the length of the thigh frame 11 and the length of the lower leg frame 13 are set so that the sum of the lengths is slightly longer than the crotch dimension of the leg of the user A having a normal body shape. Due to the setting of the lengths of the thigh frame 11 and the crus frame 13 and the stopper provided in the second joint 12 described above, a singular point state where the thigh frame 11 and the crus frame 13 are aligned, The state where the frame 11 and the lower leg frame 13 are bent opposite to the state shown in FIG. 1 does not occur. As a result, it is possible to prevent the walking assist device 1 from being disabled due to the singular point state or the reverse bending state of each leg link 3.

  The second joint of each leg link 3 may be a direct acting joint.

  In the walking assist device 1 configured as described above, as will be described in detail later, each electric motor 27 causes each of the second joints 12 to be mounted with the foot mounting portion 15 mounted on the foot of each leg of the user A. By generating torque, an upward lifting force is applied to the user A from the seating portion 2. At this time, for example, in a state where both legs of the user A are standing up (legs that support the weight of the user A) (a so-called both-leg supporting period), both foot mounting portions 15 and 15 are placed on the floor. A ground reaction force acts on each grounding surface. The floor reaction force acting on the ground contact surface of each foot mounting portion 15 is a floor reaction force such that the resultant force balances the sum of the gravity acting on the user A and the gravity acting on the walking assist device 1, that is, The force for supporting the total weight of the user A and the walking assist device 1 on the floor (translational force. This force is referred to as the total support force below). When the leg of the user A is walking together with the leg link 3 of the walking assist device 1, the total support force is more accurately determined by the movement of the free leg of the user A and the walking assist device 1. Although the force which supports the inertial force which generate | occur | produces is also added, in the walking auxiliary device 1 of this embodiment, the heavy electric motor 27 (actuator) and the encoder 28 are arrange | positioned not near the knee of each leg link 3, but near the waist. . Moreover, since the part restrained (mounted) by the user A of each leg link 3 is only the foot mounting part 15, there are few mounting members to the user A and each leg link 3 is lightweight. . For this reason, the said inertia force accompanying the exercise | movement of the free leg of the walking assistance apparatus 1 is a thing small enough.

  In this case, in the walking assist device 1 of the present embodiment, only the both foot mounting portions 15 and 15 are mounted and restrained by the user A. Each foot mounting portion 15 is provided with the annular link member 36. For this reason, the gravity acting on the walking assistance device 1 and the load (downward translational force) that the walking assistance device 1 receives from the user A via the seating portion 2 hardly act on the user A, It acts on the floor surface from the both leg links 3 and 3 via the annular link members 36 and 36 of the both foot mounting portions 15 and 15.

  Therefore, both the leg links 3 and 3 of the walking assistance device 1 include the gravity acting on the walking assistance device 1 and the load received by the walking assistance device 1 from the user A via the seating portion 2 out of the total supporting force. Supporting force to support The walking assist device 1 bears this supporting force via the both leg links 3 and 3. Hereinafter, the support force borne by the walking assist device 1 in this way is referred to as an assist device burden support force. In other words, the auxiliary device burden supporting force supports the entire weight of the walking auxiliary device 1 and the weight corresponding to the load received by the seat A 2 from the user A (part of the weight of the user A) on the floor. It is a support force for. When both legs of the user A are standing legs (when the both foot mounting portions 15 of the walking assistance device 1 are in contact with the ground), the auxiliary device burden supporting force is shared by both the leg links 3 and 3. (A part of the support force of the auxiliary device burden support force is borne by one leg link 3 and the remaining support force is borne by the other leg link 3). Further, when only one leg of the user A is a standing leg (when the other leg is a free leg), all of the auxiliary device burden supporting force is borne by the leg link 3 on the standing leg side. . Hereinafter, the support force borne by each leg link 3 (the support force acting on each leg link 3) of the auxiliary device burden support force is referred to as the leg link support force, and the support force borne by the right leg link 3 is the right side. The leg link support force and the support force borne by the left leg link 3 are referred to as the left leg link support force. The sum of the left leg link support force and the right leg link support force coincides with the auxiliary device burden support force.

  On the other hand, on both legs of the user A, the support force obtained by subtracting the auxiliary device burden support force from the total support force acts from the floor side, and the user A bears the support force on the legs. It becomes. Hereinafter, the support force borne by the user A in this way is referred to as the user support force. In other words, the user-bearing support force is a support for supporting the weight, which is obtained by subtracting the weight corresponding to the load that the user A acts on the seating portion 2 of the walking assist device 1 from the weight of the user A. It is power. When both legs of the user A are standing legs, the user burden support force is shared by both legs of the user A (part of the user burden support force is supported by one leg). And the remaining leg is borne by the other leg). Further, when only one leg of the user A is a standing leg, all of the user burden supporting force is borne by the one leg. Hereinafter, of the user-borne support force, the support force borne by each leg (the support force acting on each leg from the floor side) is referred to as the user leg support force, and the support force borne by the right leg is the user. The right leg support force and the support force borne by the left leg are called the user left leg support force. The sum of the user left leg support force and the user right leg support force coincides with the user burden support force. In addition, the force that the user A presses the foot of each leg against the floor in order to support himself / herself is referred to as the stepping force of the leg. The pedaling force of each leg is a force that balances the user leg support force.

  Supplementally, since the force sensor 30 provided in each leg link 3 is provided on the upper side of the third joint 14, the force sensor 30 of the leg link 3 is detected from the leg link supporting force related to the leg link 3. A support force obtained by subtracting a support force for supporting the weight of the side portion (eg, foot mounting portion 15) acts on the force sensor 30. The force sensor 30 detects a component in the triaxial direction (or a component in the biaxial direction) of the acting supporting force. In other words, the force acting on each force sensor 30 (this corresponds to the force to be controlled in the present invention) is the sum of the weight of the lower part of each force sensor 30 from the total weight of the walking assist device 1. Of the total support force for supporting the subtracted weight and the weight corresponding to the load applied to the seating portion 2 from the user A, this corresponds to the share of the leg link 3 provided with the force sensor 30. To do. Further, the sum of the supporting forces detected by the both force sensors 30 and 30 is obtained by subtracting the sum of the weights of the lower portions of the force sensors 30 from the total weight of the walking assist device 1 and the user A To the total support force for supporting the weight corresponding to the load applied to the seating portion 2 (hereinafter, the force sensor 30 is referred to as the support force sensor 30). The total sum of the weights of the lower portions of the supporting force sensors 30 of the walking assistance device 1 is sufficiently smaller than the total weight of the walking assistance device 1. For this reason, the support force acting on each support force sensor 30 is substantially equal to the leg link support force. Furthermore, each supporting force sensor 30 is provided close to the third joint 14 of the leg link 3 provided with the supporting force sensor 30. For this reason, the supporting force acting on the supporting force sensor 30 is a translational force acting on the crus frame 13 from the third joint 14 of the leg link 3 (of the leg link supporting force, the third force is applied to the crus frame 13 from the floor side). Is substantially equal to the supporting force transmitted through the joint 14. Hereinafter, the sum of the supporting force acting on each supporting force sensor 30 or the translational force acting on the lower leg frame 13 from the third joint 14 of each leg link 3 is referred to as the total lifting force. Moreover, the share of each leg link 3 in the total lifting force is referred to as the total lifting force share.

  The sum of the forces acting on the MP sensor 38L and the heel sensor 39L of the left foot mounting portion 15L corresponds to the user left leg supporting force (or the treading force of the left leg), and the MP sensor of the right foot mounting portion 15R. The sum of the forces acting on the 38R and the heel sensor 39R corresponds to the user's right leg supporting force (or the right leg pedaling force). In this embodiment, the MP sensor 38 and the heel sensor 39 are uniaxial force sensors. However, for example, a biaxial force sensor or a triaxial force sensor that also detects a translational force in a direction substantially parallel to the bottom surface of the shoe 33. But you can. The MP sensor 38 and the heel sensor 39 are desirably sensors that can detect at least a translational force in a direction substantially perpendicular to the bottom surface or floor surface of the shoe 33.

  Next, the control device of the walking assist device 1 configured as described above will be described.

  FIG. 4 is a block diagram schematically showing the configuration (hardware configuration) of the control device 50. As shown in the figure, the control device 50 includes an arithmetic processing unit 51 constituted by a microcomputer (CPU, RAM, ROM) and an input / output circuit (A / D converter, etc.) and respective drivers for the electric motors 27R, 27L. Lifting force setting key switch for setting a target value of the magnitude of the lifting force (upward translational force acting on the user A from the seating portion 2) by the circuits 52R and 52L and the walking assist device 1 53, a lifting control ON / OFF switch 54 for selecting whether or not to generate the lifting force of the user A, a power supply battery 55, and a connection to the power supply battery 55 via a power switch 56 (ON / OFF switch) When the power switch 56 is turned ON (closed), power is supplied from the power battery 55 to the circuits 51, 52R, and 52L of the control device 50. It includes a power supply circuit 57 for. The lifting force setting key switch 53 corresponds to the target lifting force setting means in the present invention.

  The control device 50 is fixed to the rear end portion of the seating portion 2 or the plates 23R and 23L via a bracket (not shown). Further, the lifting force setting key switch 53, the lifting control ON / OFF switch 54, and the power switch 56 are operably mounted on the outer surface of a casing (not shown) of the control device 50. The lift force setting key switch 53 is a numeric key switch so that a desired target value of the lift force can be set directly or can be selectively set from a plurality of types of target values prepared in advance. Alternatively, it is composed of a plurality of selection switches.

  The control device 50 is connected to the MP sensors 38R and 38L, the saddle sensors 39R and 39L, the supporting force sensors 30R and 30L, and the rotary encoders 28R and 28L through connection lines (not shown). Output signals from these sensors are input to the arithmetic processing unit 51. In addition, operation signals for the lifting force setting key switch 53 and the lifting control ON / OFF switch 54 (signals indicating the operating state of these switches) are also input to the arithmetic processing unit 51. Further, the control device 50 is connected to the electric motors 27R and 27L through connection lines (not shown) so as to flow currents from the driver circuits 52R and 52L to the electric motors 27R and 27L, respectively. And the arithmetic processing part 51 determines the command value (henceforth an instruction | indication current value) of the energizing current of each electric motor 27R and 27L by the arithmetic processing (control processing) mentioned later. The arithmetic processing unit 51 controls the torque generated by the electric motors 27R and 27L by controlling the driver circuits 52R and 52L with the indicated current value.

  The output signals (voltage signals) of the MP sensors 38R and 38L, the heel sensors 39R and 39L, and the supporting force sensors 30R and 30L are amplified by a preamplifier near these sensors and then input to the control device 50. Also good. The output signals of the MP sensors 38R and 38L, the eyelid sensors 39R and 39L, and the supporting force sensors 30R and 30L are amplified, and the voltage values are A / D converted and taken into the arithmetic processing unit 51.

  The arithmetic processing unit 51 includes functional means as shown in the block diagram of FIG. 5 as main functional means. This functional means is a function realized by a program stored in the ROM.

  Referring to FIG. 5, the arithmetic processing unit 51 includes a right pedal force measurement processing means 60R to which output signals from the MP sensor 38R and the heel sensor 39R of the right leg link 3R are input, and the MP sensor 38R and the heel of the left leg link 3L. And a left treading force measurement processing means 60L to which an output signal of the sensor 39R is input. The right pedaling force measurement processing means 60R measures the magnitude of the pedaling force of the right leg of the user A (the magnitude of the user's right leg supporting force) from the voltage values of the output signals of the MP sensor 38R and the heel sensor 39R. It is a means to perform. Similarly, the left treading force measurement processing means 60L determines the magnitude of the treading force of the left leg of the user A (the magnitude of the user left leg supporting force) from the voltage values of the output signals of the MP sensor 38L and the heel sensor 39L. It is a means for performing processing to measure. The pedaling force measurement processing means 60R and 60L correspond to the pedaling force measurement means in the present invention.

  The arithmetic processing unit 51 includes a right knee angle measurement processing unit 61R and a left knee angle measurement processing unit 61L to which output signals (pulse signals) of the rotary encoders 28R and 28L are respectively input. These knee angle measurement processing means 61R and 61L are means for measuring the bending angle (displacement amount of the second joint 12) at the second joint 12 of the corresponding leg link 3 from the input signals. Since the second joint 12 of each leg link 3 corresponds to the knee joint of the leg link 3, the bending angle at the second joint is hereinafter referred to as the knee angle. These knee angle measurement processing means 61R and 61L correspond to the joint displacement amount measurement means in the present invention.

  Further, the arithmetic processing unit 51 receives the right support force measurement process in which the output signal of the support force sensor 30R of the right leg link 3R and the knee angle of the right leg link 3R measured by the right knee angle measurement processing means 61R are input. Left side support force measurement processing in which the means 62R, the output signal (output voltage) of the support force sensor 30L of the left leg link 3L, and the knee angle of the left leg link 3L measured by the left knee angle measurement processing unit 61L are input. Means 62L. The right support force measurement processing means 62R acts on the support force sensor 30R of the right leg link support force based on the input output signal of the support force sensor 30R and the measured value of the knee angle of the right leg link 3R. It is means for performing processing for measuring the supporting force, that is, the total lifting force share of the right leg link 3R. Similarly, the left support force measurement processing means 62L is based on the input output signal of the support force sensor 30L and the measurement value of the knee angle of the left leg link 3L, and the support force sensor 30L of the left leg link support force. Means for performing a process of measuring the supporting force acting on the left leg link 3L, that is, the total lifting force share of the left leg link 3L. These supporting force measurement processing means 62R and 62L correspond to the control target force measuring means in the present invention.

  The arithmetic processing unit 51 receives the measurement values of the measurement processing means 60R, 60L, 61R, 60L, 62R, and 62L and the operation signals of the lifting force setting key switch 53 and the lifting control ON / OFF switch 54. A left / right target share determination means 63 is provided. The left and right target share determination means 63 determines a target total lifting force, which is a target value of the total lifting force, based on the input value, and a target value for a share of each leg link 3 with respect to the target total lifting force. That is, it is means for performing processing for determining a target value for the total lifting force share of each leg link 3 (hereinafter simply referred to as a control target value). The control target value corresponds to a target share in the present invention (fourth invention).

  Further, the arithmetic processing unit 51 controls the right leg link 3R control target determined by the right leg link load determination unit 63 and the total lifting force share of the right leg link 3R measured by the right support force measurement processing unit 62R. Values are input by the right feedback manipulated variable determining means 64R, the left lifting force measurement processing means 62L and the left leg link 3L total lifting force share and the left and right target share determining means 63. The left feedback operation amount determining means 64L to which the control target value of the left leg link 3L is inputted, the total lifting force share of the right leg link 3R measured by the right support force measurement processing means 62R, and the left and right target share The control target value of the right leg link 3R determined by the determination unit 63 and the knee angle of the right leg link 3R measured by the right knee angle measurement processing unit 61R. Are input by the right feedforward manipulated variable determining means 65R, the left leg link 3L total lifting force share measured by the left supporting force measurement processing means 62L, and the left and right target share determining means 63. Left-side feedforward manipulated variable determining means 65L to which the control target value of the left-side leg link 3L and the knee angle of the left-side leg link 3L measured by the left-side knee angle measurement processing means 61L are input. Each feedback manipulated variable determiner 64 determines the feedback manipulated variable (each electric motor so that the deviation converges to 0 by a predetermined feedback control law from the deviation between the input measurement value of the total lifting force share and the control target value. 27 for calculating the feedback component of the indicated current value with respect to 27. Each feedforward manipulated variable determining means 65 is configured to measure the total lifting force share according to a predetermined feedforward control law from the input measurement value of the total lifting force share, the control target value, and the knee angle measurement value. Is a means for calculating a feedforward manipulated variable (a feedforward component of the command current value for each electric motor 27) for setting the control target value to.

  Then, the arithmetic processing unit 51 adds the feedback operation amount calculated by the right feedback operation amount determination unit 64R and the feedforward operation amount calculated by the right feedforward operation amount determination unit 65R to thereby add the right leg link 3R. Addition processing means 66R for obtaining an instruction current value for electric motor 27R, feedback operation amount calculated by left feedback operation amount determination means 64L, and feedforward operation amount calculated by left feedforward operation amount determination means 65R Thus, there is provided addition processing means 66L for obtaining an indicated current value for the electric motor 27L of the left leg link 3L.

  The feedback manipulated variable determining means 64R and 64L, the feedforward manipulated variable determining means 65R and 65L, and the addition processing means 66R and 66L correspond to the actuator control means in the present invention.

  The above is the outline of the arithmetic processing function of the arithmetic processing unit 51.

  Next, the control process of the control apparatus 50 of this embodiment is demonstrated including the detailed description of the process of the arithmetic process part 51. FIG. In the walking assist device 1 of the present embodiment, no driving force is applied to the second joints 12 of the leg links 3 in a state where the power switch 56 is turned off. For this reason, each joint 10, 12, 14 can be freely moved. In this state, each leg link 3 is folded by its own weight. In this state, after each foot mounting portion 15 is mounted on each foot of the user A, the user A or an attendant assistant lifts the seating portion 2 and places it on the inseam of the user A.

  Next, when the power switch 56 is turned on, power is supplied to each circuit of the control device 50, and the control device 50 is activated. And when this control apparatus 50 starts, the said arithmetic processing part 51 will perform the process demonstrated below with a predetermined | prescribed control processing period.

  In each control processing cycle, the arithmetic processing unit 51 first executes the processing of the treading force measurement processing means 60R and 60L. This process will be described with reference to FIG. FIG. 6 is a block diagram showing a processing flow of the treading force measurement processing means 60R and 60L. The pedaling force measurement processing means 60R and 60L have the same processing algorithm. For this reason, in FIG. 6, the parts related to the left pedaling force measurement processing means 60L are shown in parentheses.

  The processing of the right pedal force measurement processing means 60R will be described representatively. First, the detection value of the MP sensor 38R of the leg link 3R (the detection value of the force indicated by the output voltage value of the MP sensor 38R) and the detection value of the heel sensor 39R (The detected value of the force indicated by the output voltage of the eyelid sensor 39R) is passed through a low-pass filter in S101 and S102, respectively. The low-pass filter removes high-frequency components such as noise from the detection values of these sensors 38R and 39R, and the cut-off frequency is 100 Hz, for example.

  Next, the outputs of these low-pass filters are added in S103. Thereby, provisional measurement value FRF_p_R of the pedaling force of the right leg of the user A is obtained. The provisional measurement value FRF_p_R includes an error due to the tightening of the shoelace of the right foot attachment portion 15R.

  Therefore, in the present embodiment, the provisional measurement value FRF_p_R is further converted in S104 to finally obtain the measurement value FRF_R of the pedaling force of the right leg of the user A. The conversion process of S104 is performed according to the table shown in FIG. That is, when FRF_p_R is equal to or less than a predetermined first threshold value FRF1, the measured value FRF_R is set to zero. As a result, it is possible to prevent a minute error amount from being obtained as the measured value FRF_R due to the tightening of the shoelace of the foot mounting portion 15R. When the provisional measurement value FRF_p_R is larger than the first threshold value FRF1 and equal to or less than the second threshold value FRF2 (> FRF1), the value of the measurement value FRF_R is linearly increased as the value of FRF_p_R increases. When FRF_p_R exceeds the second threshold value FRF2, the value of FRF_R is held at a predetermined upper limit value (the value of FRF_R when FRF_p_R is equal to the second threshold value FRF2). The reason for setting the upper limit value of FRF_R will be described later.

  The above is the processing of the right pedal force measurement processing means 60R. The same applies to the processing of the left treading force measurement processing means 60L.

  Next, the arithmetic processing unit 51 sequentially performs the processing of the knee angle measurement processing means 61R and 61L and the processing of the supporting force measurement processing means 62R and 62L. These processes will be described below with reference to FIGS. FIG. 8 is a block diagram showing the processing flow of the knee angle measurement processing means 61R and 61L and the processing of the supporting force measurement processing means 62R and 62L. Note that the processing algorithms of the knee angle measurement processing means 61R and 61L are the same. Further, the processing algorithms of the supporting force measurement processing means 62R and 62L are the same. For this reason, in FIG. 8, the left knee angle measurement processing unit 61L and the left support force measurement processing unit 62L are shown in parentheses.

  The processing of the right knee angle measurement processing means 61R and the right support force calculation means 62R will be described representatively. First, the processing of S201 and S202 is executed by the right knee angle measurement processing means 61R, and the knee angle of the right leg link 3R is determined. A measured value θ1_R of (the bending angle of the leg link 3R at the second joint 12R) is obtained. In S201, the provisional measurement value θ1p_R of the knee angle of the leg link 3R is calculated from the output of the rotary encoder 28R.

  Here, referring to FIG. 9, in the present embodiment, the center point P (the point P serving as the center of rotation of the swinging motion of the thigh frame 11R in the front-rear direction) related to the first joint 10R of the leg link 3R. An angle formed by a line segment S1 connecting the center point of the second joint 12R and a line segment S2 connecting the center point of the second joint 12R and the center point of the third joint 14R. θ1_R is measured as the knee angle of the right leg link 3R. The same applies to the knee angle of the left leg link 3L. In addition, in FIG. 9, the principal part structure of the leg link 3 is shown typically.

  In this case, in S201, the thigh frame 11R of the leg link 3R and the crus frame 13R are in a predetermined posture relationship (for example, the posture state in FIG. 1), that is, the knee angle θ1_R is a predetermined value. The rotation amount of the second joint 12R in a state of being in the state is used as a reference, and the rotation amount from this reference rotation position (rotation angle change amount, which is proportional to the rotation amount of the rotor of the electric motor 27R) is the output signal of the rotary encoder 28R. Measure from Then, a value obtained by adding the measured rotation amount of the second joint 12R to the knee angle value of the leg link 3R at the reference rotation position (which is stored in advance in a memory not shown) is used as the provisional measurement. Obtained as the value θ1p_R.

  Since the provisional measurement value θ1p_R may include a high-frequency noise component, the measurement value θ1p_R of the knee angle of the leg link 3R is finally obtained by passing this θ1p_R through a low-pass filter in S202. .

  The above is the processing of the right knee angle measurement processing means 61R. The same applies to the processing of the left knee angle measurement processing means 61L.

  Supplementally, in the present embodiment, the angle θ1 formed by the line segments S1 and S2 is measured as the knee angle of the leg link 3 because the measured value of the angle θ1 is determined by the left and right target share determination means 63 which will be described in detail later. This is because it is used for processing. In this case, in the walking assist device 1 of the present embodiment, the angle formed by the axis of the thigh frame 11 of each leg link 3 and the line segment S1 is constant. Accordingly, in each knee angle measurement processing means 61, for example, an angle formed by the axis of the thigh frame 11 of the leg link 3 and the line segment S2 related to the crus frame 13 is obtained as a knee angle of the leg link 3 and will be described later. The angle θ1 may be obtained from the knee angle by the processing of the left / right target share determination means 63.

  After the measurement value θ1_R of the knee angle of the leg link 3R is obtained as described above, the processing of the right support force measurement processing means 62R is executed in S203, and the measurement value θ1_R of the knee angle obtained in S202 and the support From the detected value of the force sensor 30R (the detected value of the biaxial force indicated by the voltage value of the output signal of the supporting force sensor 30R), the supporting force acting on the supporting force sensor 30R (that is, the total lifting force of the leg link 3R). The measured value Fankle_R is calculated. Details of this processing will be described with reference to FIG.

  The supporting force (total lifting force share) Fankle_R acting on the supporting force sensor 30R of the leg link 3R is substantially equal to the translational force acting on the crus frame 13R from the third joint 14R of the leg link 3R as described above. The translational force is substantially equal to a vector (a vector having the line segment S3 as an action line) from the third joint 14R toward the longitudinal swing center point P of the leg link 3R. Accordingly, the direction of Fankle_R is a direction parallel to the line segment S3 connecting the center point of the third joint 14 of the leg link 3R and the center point P of the front-rear swing in the walking assistance device 1 of the present embodiment.

  Here, strictly speaking, the direction of Fankle_R depends on the frictional force and gravity at the first to third joints 10, 12, and 14, acceleration / deceleration during walking, and the magnitude of the total lifting force of the walking assist device 1. The line segment S3 may be slightly non-parallel. However, since these influences are minute, in the present embodiment, these influences are ignored.

  On the other hand, the supporting force sensor 30R has a force Fz in the z-axis direction perpendicular to the surface (upper surface or lower surface) of the supporting force sensor 30R and a surface perpendicular to the z axis and parallel to the surface of the supporting force sensor 30R as shown in the figure. A force Fx in the x-axis direction is detected. The x-axis and the z-axis are coordinate axes fixed to the supporting force sensor 30R, and are axes parallel to a plane including the arc of the guide rail 22. At this time, the detected Fz and Fx are the z-axis direction component and the x-axis direction component of Fankle_R, respectively. Therefore, as shown in the figure, if the angle formed by Fankle_R and the z-axis is θk, Fankle_R can be calculated from the detected values of Fz and Fx and θk by the following equation (1).

Fankle_R ＝ Fx ・ sinθk ＋ Fz ・ cosθk (1)

Further, the angle θk is obtained as follows. That is, assuming that the angle formed by the line segment S2 and the line segment S3 (= the angle formed by the direction of Fankle and the line segment S2) is θ2, the line segment S1 in the triangle having the line segments S1, S2, and S3 as three sides. Each length L1, L2 of S2 is a fixed value (a known value determined in advance). The angle θ1 formed by the line segments S1 and S2 is the measured value θ1_R obtained as described above by the right knee angle measurement processing means 61R. Therefore, the angle θ2 is obtained by geometric calculation from the lengths L1 and L2 of these line segments S1 and S2 (these values are stored in advance in the memory) and the measured value θ1_R of the angle θ1.

  Specifically, the following relational expressions (2) and (3) are established in a triangle having the line segments S1, S2 and S3 as three sides. L3 is the length of the line segment S3.

L3 ² = L1 ² + L2 ² -2 · L1 · L2 · cosθ1 (2)
L1 ² = L2 ² + L3 ² -2, L2, L3, cosθ2 (3)

Therefore, L3 is calculated from the values of L1 and L2 and the measured value of the angle θ1 by the equation (2), and the angle θ2 is calculated from the calculated value of L3 and the values of L1 and L2 by the equation (3). Can be calculated.

  Furthermore, if the angle formed by the z-axis and the line segment S2 is θ3, this angle θ3 is a constant value determined in advance by the mounting angle with respect to the lower leg frame 13 of the support force sensor 30. Then, by subtracting the angle θ2 calculated as described above from the constant angle θ3 (this value is stored and held in advance in a memory not shown), the angle θk necessary for the calculation of the equation (1) is obtained. A value is determined.

  Therefore, in the present embodiment, in the process of S203 of the right support force measurement processing means 62R, the above equation (1) is obtained from θk calculated as described above and the detection values Fx and Fz of the support force sensor 30 of the leg link 3R. A measurement value Fankle_R for the total lifting force share of the right leg link 3R is obtained.

  The above is the details of the processing in S203 of the right supporting force measurement processing means 62R. The same applies to the processing of the left supporting force measuring means 62L.

  In the present embodiment, the support force sensor 30 is a three-axis force sensor or a two-axis force sensor, and the measurement value Fankle for the total lifting force share of each leg link is obtained by the equation (1). Even if the supporting force sensor 30 is a uniaxial force sensor, the measurement value Fankle can be obtained. For example, when the support force sensor 30 is a sensor that detects only the force Fx in the x-axis direction of FIG. 9, the measurement value Fankle can be obtained by the following equation (4). Further, when the support force sensor 30 is a sensor that detects only the force Fz in the z-axis direction of FIG. 9, the measurement value Fankle can be obtained by the following equation (5).

Fankle = Fx / sinθk (4)
Fankle = Fz / cosθk (5)

However, when these equations (4) or (5) are used, if the angle θk becomes a value close to 0 degrees or 90 degrees, the accuracy of the value of Fankle deteriorates. Therefore, it is desirable to obtain the measured value of Fankle by the equation (1).

  The measured value Fankle may be obtained by obtaining the square root of the sum of the square value of Fx, the square value of Fz, and the sum. In this case, the measured value θ1 of the knee angle is not necessary.

  Supplementally, the processes of the measurement processing means 60, 61, 62 described above are not necessarily performed in order, and may be performed in parallel by time division or the like. However, when θ1 is used in the processing of the supporting force measurement processing means 62R and 62L, it is necessary to perform the processing of the knee angle measurement processing means 61R and 61L before the processing of the supporting force measurement processing means 62R and 62L. .

  In the present embodiment, the supporting force sensor 30 (second force sensor) for measuring the total lifting force share of each leg link 3 is used as the third joint 14 and the lower leg frame 13 (more precisely, the upper lower leg frame). 13a). However, the supporting force sensor may be interposed between the third joint 14 and the foot mounting portion 15 (for example, between the third joint 14 and the connecting portion 34 of the foot mounting portion 15). In this case, the rotation angle of the third joint 14 is measured, and the support force detected by the support force sensor between the third joint 14 and the foot mounting portion 15 is coordinate-transformed, whereby the third joint 14 The supporting force acting on the lower leg frame 13 can be measured.

  Next, the arithmetic processing unit 51 executes the processing of the left / right target share determination means 63. This process will be described in detail below with reference to FIG. FIG. 10 is a block diagram showing the flow of processing of the left / right target share determination means 63.

  First, in S301, as described above, the measurement value Fankle_R for the total lifting force share of the right leg link 3R and the measurement value Fankle_L for the total lifting force share of the left leg link 3L obtained by each supporting force measurement processing unit 62 as described above. And the total lifting force Fankle_t is calculated. As described above, the total lifting force Fankle_t is the supporting force acting on each supporting force sensor 30 or the translational force acting on the lower leg frame 13 from the third joint 14 of each leg link 3 with respect to the both leg links 3 and 3. This corresponds to the measured value of the sum. Further, the total lifting force Fankle_t is substantially equal to the assisting device burden supporting force.

  Next, a value obtained by subtracting an output value of S307 and an output value of S312 described later from the total lifting force Fankle_t, and the lifting force set from the seating portion 2 to the user A set by the lifting force setting key switch 53 In S302, one of the total lifting force setting values corresponding to (target lifting force) is an operation signal of the lifting control ON / OFF switch 54 (whether the switch 54 is ON or OFF). Are selectively output in accordance with the signal shown in FIG. In this case, in this embodiment, when the user A wants to receive a lifting force from the seating portion 2, the lifting control ON / OFF switch 54 is turned ON, and otherwise, the lifting control ON / OFF switch 54 is turned OFF. ing. In S302, when the lifting control ON / OFF switch 54 is OFF, the total lifting force Fankle_t is selected and output. When the lifting control ON / OFF switch 54 is ON, the total lifting force setting value is selected and output.

  Supplementally, the total lifting force setting value is for supporting the weight obtained by subtracting the total weight of the lower part of each supporting force sensor 30 from the total weight of the walking assist device 1 to the lifting force setting value by the key switch 53. The magnitude of the supporting force (that is, the supporting force that balances the gravity generated by the subtracted weight) is added. The magnitude of the support force is stored in advance in a memory (not shown). The total weight of the lower part of the supporting force sensor 30 is sufficiently smaller than the total weight of the walking assist device 1. For this reason, the magnitude of the supporting force for supporting the entire weight of the walking assist device 1 (the supporting force that balances the gravity acting on the entire walking assist device 1) is added to the set value of the lifting force (target lifting force). The total lifting force setting value may be used. Alternatively, the total lifting force setting value may be directly input by operating the key switch 53.

  The output of S302 is then passed through a low pass filter in S303, thereby determining the target total lifting force. This low-pass filter of S303 is used when the output of S302 changes suddenly (when the total lifting force setting value is changed, or when the output of S302 subtracts the output value of S307 and S312 described later from the total lifting force Fankle_t). The target total lifting force is prevented from abruptly changing, and thus the lifting force acting on the user A from the seating portion 2 is abruptly changed. It is for avoidance. The cutoff cutoff frequency of the low-pass filter is, for example, 0.5 Hz. In addition, the process of S301-S303 is corresponded to the total target lifting force determination means in this invention.

  Next, in S304, based on the magnitude of the measured value FRF_R of the right leg treading force and the magnitude of the measured value FRF_L of the tread force of the left leg obtained by each of the treading force measurement processing means 60 as described above, the target total lifting force A distribution ratio, which is a ratio for distributing to the left and right leg links 3, is determined. This distribution ratio includes a right distribution ratio that is a distribution ratio of the target total lifting force to the right leg link 3R and a left distribution ratio that is a distribution ratio to the left leg link 3L, and the sum of both distribution ratios is 1. It is.

  In this case, the right distribution ratio is determined as the ratio of the magnitude of FRF_R to the sum of the magnitude of the measurement value FRF_R and the magnitude of the measurement value FRF_L, that is, FRF_R / (FRF_R + FRF_L). Similarly, the left distribution ratio is determined as the ratio of the magnitude of FRF_L to the sum of the magnitude of the measurement value FRF_R and the magnitude and sum of the measurement value FRF_L, that is, FRF_L / (FRF_R + FRF_L). In this case, in a state where one leg of the user A is a standing leg and the other leg is a free leg (that is, one leg is supported), the distribution ratio corresponding to the leg that is a free leg is 0, and the leg is a standing leg. The distribution ratio corresponding to the legs is 1. The process of S304 may be performed in parallel with the processes of S301 to S303.

  Here, the reason why the upper limit value is set for the measurement value FRF of the pedaling force of each leg in the conversion process of S104 of each pedaling force measurement processing means 60 (see FIG. 6) will be described. In a state where both legs of the user A are standing legs (that is, in a state in which both legs are supported), the provisional measurement value FRF_p of the pedaling force of each leg generally does not change smoothly and tends to frequently change. In such a case, when the left / right distribution ratio is determined based on the provisional measurement value FRF_p, the distribution ratio changes frequently, and the share ratio of each leg link 3 in the target total lifting force changes frequently. It's easy to do. As a result, minute fluctuations in the lifting force that acts on the user A from the seating portion 2 are likely to occur, and as a result, the user A may be uncomfortable. For this reason, in this embodiment, an upper limit value of the measurement value FRF of the treading force of each leg is set to prevent a situation in which the left / right distribution ratio changes frequently in the state of both-leg support period. In this case, in the both-leg support period, the right and left distribution ratios are basically maintained at ½ except for the period immediately after the start and the period immediately before the end. Is stable.

  In FIG. 7, when the provisional measurement value FRF_p_R (L) of the leg force of each leg of the user A is equal to or more than the threshold value FRF1, the measurement value FRF_R (L) of the pedal force increases linearly. The measured value FRF_R (L) may be acquired based on a table determined to do so. The threshold values FRF1, FRF2, etc. of the table for obtaining FRF_R (L) from the provisional measurement value FRF_p depend on the feeling of lifting force preferred by the user A, the weight of the walking assist device 1, the calculation capability of the control device 50, etc. And may be determined as appropriate.

  Returning to the description of FIG. 10, next, the processes of S305 and S310 are executed. Note that the processing of these processing S305 and 310 may be performed in parallel with the processing of S301 to S303 or the processing of S304.

  The process of S305 is a process for obtaining an operating force for generating a spring-like posture restoring force on the right leg link 3R, and the process of S310 is a spring-like posture restoring force applied to the left leg link 3L. It is the process which calculates | requires the operation force for generating. Hereinafter, these operating forces are referred to as spring restoring forces.

  Since the algorithm of the process of S305 and the process of S310 are the same, the process of S305 related to the right leg link 3R will be representatively described below with reference to FIG.

  In the process of S305, first, using the measured value θ1_R of the knee angle of the leg link 3R obtained by the process of the right knee angle measurement processing unit 61R as described above, the line segment S3 of FIG. Length L3, that is, the length L3 of the line segment S3 connecting the center point of the third joint 14 of the leg link 3R and the center point P of the front-rear swing is calculated. Then, a value obtained by subtracting a predetermined reference value L3S from the calculated L3 (L3-L3S) and a predetermined spring constant k is obtained as the spring restoring force of the right leg link 3R.

  That is, the spring restoring force is calculated by the following equation (6).

Spring restoring force = k · (L3-LS3) (6)

The process of S310 related to the left leg link 3L is the same. The spring restoring force of each leg link 3 calculated as described above restores the posture of the leg link 3 so that the length L3 of the line segment S3 in FIG. 9 matches the reference value L3S. This corresponds to the supporting force (the required value of the supporting force) that should be additionally applied to the walking assist device 1.

  In this embodiment, the spring restoring force is obtained by a proportional control law as a feedback control law, but may be obtained by other methods such as a PD control law. The length L3 of the line segment S3 is equal to the length obtained by adding a substantially constant offset value to the distance between the third joint 14 of each leg link 3 and the seat 2. For this reason, calculating the spring restoring force so that the deviation (L3-L3S) approaches 0 means that the distance between the third joint 14 of each leg link 3 and the seating portion 2 and a predetermined reference value (from L3S). This is equivalent to calculating the spring restoring force so that the deviation from the value obtained by subtracting the offset value approaches 0.

  Next, the processes of S306 to S309 related to the right leg link 3R and the processes of S311 to S314 related to the left leg link 3L are executed. In the processing of S306 to S309 relating to the right leg link 3R, first, in S306, the target total lifting force obtained in S303 is multiplied by the right distribution ratio. Thereby, the basic target value for the total lifting force share as the share by the right leg link 3R of the target total lifting force is determined. This basic target value is determined from each supporting force sensor based on the share of the right leg link 3R in the target lifting force, which is the target lifting force that acts on the user A from the seating portion 2, and the total weight of the walking assist device 1. This means the total sum of the support force for supporting the weight obtained by subtracting the total weight of the lower part of 30 (or the total weight of the walking assist device 1) and the burden on the right leg link 3R.

  Further, in S307, the spring restoring force obtained in S305 is multiplied by the right distribution ratio. Then, the value of the multiplication result (this corresponds to the correction amount for the target burden in the present invention) is added to the basic target value for the total lifting force share of the right leg link 3R in S308, thereby making the right leg link 3R. The provisional target value Tp_Fankle_R for the total lifting force share is obtained. Then, the provisional target value Tp_Fankle_R is passed through a low-pass filter in S309, so that a control target value T_Fankle_R that is a target value for the total lifting force share of the right leg link 3R is finally obtained. The low-pass filter of S309 is for removing noise components associated with fluctuations in the knee angle θ1. The cutoff frequency is 15 Hz, for example.

  Similarly, in the processing of S311 to S314 regarding the left leg link 3L, first, in S311, the target total lifting force obtained in S303 is multiplied by the left distribution ratio. Thereby, the basic target value of the total lifting force share as the share by the left leg link 3L of the target total lifting force is determined. This basic target value is determined from each supporting force sensor based on the share of the left leg link 3L in the target lifting force that is a target value of the lifting force that acts on the user A from the seating portion 2 and the total weight of the walking assist device 1. 30 means the sum total of the load of the left leg link 3L in the supporting force for supporting the weight obtained by subtracting the total weight of the lower part of 30 (or the total weight of the walking assist device 1).

  In S312, the spring restoring force obtained in S310 is multiplied by the left distribution ratio. Then, the value of the multiplication result (which corresponds to the correction amount for the target burden in the present invention) is added to the basic target value for the total lifting force share of the left leg link 3L in S313, thereby left leg link 3L. The provisional target value Tp_Fankle_L for the total lifting force share is obtained. Then, the provisional target value Tp_Fankle_L is passed through a low-pass filter in S314, so that a control target value T_Fankle_L that is a target value for the total lifting force share of the left leg link 3L is finally obtained. For example, when the target total lifting force, which is the output of S303, is 200 N (Newton), and the left / right distribution ratio (output of S304) according to the left / right pedaling force of the user A is 0.4: 0.6 The output of S306 is 120N and the output of S311 is 80N.

  The above is the processing of the left / right target share determination means 63. As described above, basically, the control target values T_Fankle_L and T_Fankle_R of the left and right leg links 3 are determined so that the ratio of the left and right pedaling forces of the user A is the same. Further, spring restoring forces related to the left leg link 3L and the right leg link 3R are added to the control target values T_Fankle_L and T_Fankle_R, respectively. Note that the sum of the spring restoring force added to the control target value T_Fankle_L and the spring restoring force added to the control target value T_Fankle_R is the weighting factor of the left and right distribution ratios of the spring restoring forces calculated in S305 and S310, respectively. Is a weighted average value. Therefore, the sum of the control target values T_Fankle_L and T_Fankle_R is obtained by adding the weighted average value of the spring restoring force to the target total lifting force determined in S303.

  Note that the processing of S304, S306, and S311 corresponds to the distribution means in the present invention.

  After executing the processing of the left and right target share determination means 63 as described above, the arithmetic processing unit 51 performs the processing of the feedback operation amount determination means 64R and 64L and the feedforward operation amount determination means 65R and 65L sequentially or in parallel. And run.

  The processing of the feedback manipulated variable determining means 64R and 64L will be described with reference to FIG. FIG. 11 is a block diagram showing the flow of processing of the feedback manipulated variable determining means 64R, 64L. Since the algorithms of the feedback manipulated variable determining means 64R and 64L are the same, in FIG. 11, those relating to the left feedback manipulated variable determining means 64L are shown in parentheses.

  The processing of the right feedback manipulated variable determining means 64R will be described representatively. First, the control target value T_Fankle_R of the right leg link 3R determined by the left and right target share determining means 63 and the right support force measurement processing means 62 are described. A deviation (T_Fankle_R−Fankle_R) from the measured value Fankle_R of the total lifting force share of the measured right leg link 3R is calculated in S401. The deviation is multiplied by gains Kp and Kd in S402 and S403, respectively. Further, the calculation result of S403 is differentiated in S404 (“s” in the figure means a differential operator), and the differential value and the calculation result of S402 are added in S405. Thereby, the operation amount Ifb_R of the current of the right electric motor 27 is calculated by the PD control law as the feedback control law so that the deviation (T_Fankle_R−Fankle_R) converges to zero. The manipulated variable Ifb_R means a feedback component of the command current value of the right electric motor 27.

  In this case, in this embodiment, the values of the gains Kp and Kd are variably set in S406 according to the measured value θ1_R of the knee angle of the leg link 3R. This is because the sensitivity of the change in the lifting force of the seating portion 2 with respect to the current change (torque change) of the electric motor 27R changes depending on the knee angle of the leg link 3R. In this case, the greater the knee angle θ1_R is (the longer the leg link 3R is), the higher the sensitivity of the lifting force of the seating portion 2 to the current change (torque change) of the electric motor 27R. For this reason, in S406, based on a data table (not shown), basically, the larger the measured value θ1_R of the knee angle of the leg link 3R, the smaller the gains Kp and Kd are. Set the values of gains Kp and Kd.

  The above is the processing of the right feedback manipulated variable determining means 64R. The same applies to the processing of the left feedback manipulated variable determining means 64L. In the present embodiment, the lifting force can be controlled stably at high speed by using a PD control law as a feedback control law. However, a feedback control law other than the PD control law may be used.

  Next, the processing of the feedforward manipulated variable determining means 65R, 65L will be described with reference to FIG. FIG. 12 is a block diagram showing a processing flow of the feedforward manipulated variable determining means 65R, 65L. Since the algorithms of the feedforward manipulated variable determining means 65R and 65L are the same, the left feedforward manipulated variable determining means 65L is shown in parentheses in FIG.

  The processing of the right feedforward manipulated variable determining means 65R will be described representatively. In S501, the measured value θ1_R of the knee link of the leg link 3R measured by the knee angle measurement processing means 61R is differentiated to obtain the leg link 3R. The angular velocity ω1_R of the bending angle of the second joint 12 is calculated. Furthermore, in S502, the measured value θ1_R of the knee angle of the leg link 3R and the measured value Fankle_R of the total lifting force share of the leg link 3R measured by the support force measurement processing unit 62R are used. An actual tension T1 that is an actual tension of the wires 32a and 32b is calculated. The calculation process of the actual tension T1 will be described with reference to FIG. In FIG. 13, the leg link 3 is schematically illustrated. In FIG. 13, the same elements as those in FIG. 9 are denoted by the same reference numerals.

  First, the component Fankle_a orthogonal to the line segment S2 of the measurement value Fankle_R of the total lifting force share of the leg link 3R is calculated by the following equation (7).

Fankle_a ＝ Fankle_R ・ sinθ2 (7)

The angle θ2 is an angle formed by Fankle_R and the line segment S2, and this θ2 is calculated by geometric calculation using the measured value θ1_R as described with reference to FIG. (See equations (2) and (3)).

  Then, the moment M1 generated in the second joint 12 (the knee joint) is calculated by Fankle_R by multiplying the thus obtained Fankle_a by the length L2 of the line segment S2 as shown in the following equation (8). .

M1 = Fankle_a · L2 (8)

The moment generated in the pulley 31 by the actual tension T1 of the wires 32a and 32b is balanced with the moment M1 in a steady state. Therefore, the actual tension T1 of the wires 32a and 32b is calculated by further dividing the moment M1 by the effective radius r of the pulley 31 as shown in the following equation (9).

T1 = M1 / r (9)

The above is the details of the processing of S502.

  Returning to the description of FIG. 12, in S503, the target tension T2 of the wires 32a and 32b of the leg link 3R is calculated. This target tension T2 should be generated on the wires 32a and 32b corresponding to the control target value (target value for the total lifting force share) of the leg link 3R determined by the processing of the left and right target share determination means 63. It is tension. The calculation of the target tension T2 is the same as the calculation process in S502. More specifically, the control target value T_Fankle_R is calculated by replacing the Fankle_R on the right side of the equation (7) with the control target value T_Fankle_R of the leg link 3R determined by the processing of the left and right target share determination means 63. A component orthogonal to the line segment S2 (see FIG. 13) is calculated. Then, by using the calculated component instead of Fankle_a on the right side of the equation (8), the target moment of the second joint 12 of the leg link 3R is calculated. Further, the target tension T2 of the wires 32a and 32b is calculated by using the target moment instead of M1 on the right side of the equation (9).

  The above is the process of S503.

  After executing the processing of S501 to S503 as described above, in S504, a predetermined feed is performed using the angular velocity ω1_R of the second joint 12 calculated as described above, the actual tension T1 and the target tension T2 of the wires 32a and 32b. The operation amount Iff_R of the current of the electric motor 27R is determined by the forward process. The manipulated variable Iff_R means a feedforward component of the command current value of the electric motor 27R.

  In the process of S504, the manipulated variable Iff_R is calculated by the model equation represented by the following equation (10).

Iff_R = B1 · T2 + B2 · ω1_R + B3 · sgn (ω1_R) (10)
However, B2 = b0 + b1 · T1, B3 = d0 + d1 · T1

Here, B1 in the equation (10) is a constant coefficient, and B2 and B3 are coefficients represented by a linear function of the actual tension T1, as indicated by the proviso in the equation (10). Note that b0, b1, d0, and d1 are constants. Sgn () is a sign function.

  This equation (10) is a model equation representing the relationship among the current of the electric motor 27, the tension of the wires 32a and 32b, and the angular velocity ω1 of the second joint 12. The first term on the right side of equation (10) is the proportional term of tension, the second term is the viscous frictional force between the wires 32a and 32b and the pulley 31 and the rubber tube (the protective tube of the wires 32a and 32b). The corresponding term, the third term, means a term corresponding to the dynamic frictional force between the wires 32a, 32b and the pulley 31 or the rubber tube (the protective tube of the wires 32a, 32b). Note that a term corresponding to the angular acceleration of the second joint 12 (that is, a term corresponding to the inertial force) may be added to the right side of Expression (10).

  Supplementally, each constant B1, b0, b1, d0, d1 used for the calculation of Expression (10) minimizes in advance the square value of the difference between the value on the left side and the value on the right side of Expression (10). It is experimentally identified by such an identification algorithm. The identified constants B1, b0, b1, d0, d1 are stored in a memory (not shown) and used when the walking assist device 1 is operated.

  The above is the processing of the right feedforward manipulated variable determining means 65R. The same applies to the processing of the left feedforward manipulated variable determining means 65L.

  With reference to FIG. 5, as described above, after calculating the operation amounts Ifb_R, Iff_R of the electric motor 27R and the operation amounts Ifb_L, Iff_L of the electric motor 27L, the arithmetic processing unit 51 performs the addition process. The operation amounts Ifb_R and Iff_R are added by means 66R. Thereby, the command current value of the electric motor 27R is determined. Further, the arithmetic processing unit 51 adds the operation amounts Ifb_L and Iff_L by the addition processing means 66L. Thereby, the command current value of the electric motor 27L is determined. Then, the arithmetic processing unit 51 outputs these indicated current values to the driver circuits 52 associated with the respective electric motors 27. At this time, the driver circuit 52 energizes the electric motor 27 in accordance with the indicated current value.

  The control processing of the arithmetic processing unit 51 described above is executed at a predetermined control cycle. As a result, the torque generated by the electric motor 27 so that the measured value Fankle of the actual total lifting force share of each leg link 3 matches the control target value T_Fankle corresponding to the leg link 3 (so as to converge). As a result, the driving force of the second joint 12 (the knee joint) of the leg link 3 is operated.

  In the first embodiment described above, the line of action of the support force (translation force) transmitted from the third joint 14 of each leg link 3 to the crus frame 13 is from the center point of the third joint 14 to the seating portion 2. It is substantially equal to a straight line passing through the longitudinal swing center point P existing above the seating portion 2 within the width in the longitudinal direction of the contact surface with the user A. Each leg link 13 is swingable in the front-rear direction with respect to the seating portion 2 with the front-rear swing center point P as a fulcrum. For this reason, the position and posture of the seating part 2 are the points of action of the load applied to the seating part 2 from the user A (translational force that balances the lifting force from the seating part 2 to the user A). The center of gravity of the load distributed on the contact surface between the person A and the seating portion 2) is located immediately below the longitudinal swing center point P, that is, the line of action of the load passes through the longitudinal swing center point P. Equilibrate in a state where it is a straight line in the vertical direction. When the point of application of the load from the user A to the seating part 2 is displaced due to the inclination of the upper body of the user A, the position and posture of the seating part 2 automatically attempt to return to the above-described equilibrium state. . For this reason, when viewed in the sagittal plane, the action line of the load from the user A to the seating portion 2 and the support force (translation force) transmitted from the third joint 14 of each leg link 3 to the crus frame 13 The action line basically passes through a common point P. As a result, a state in which the action lines are separated in the front-rear direction and the load and the supporting force act on the seat portion 2 as a couple is avoided. Therefore, the seating part 2 can be prevented from being displaced with respect to the user A, and the position and posture of the seating part 2 can be stabilized. As a result, a desired lifting force can be stably and appropriately applied to the user A from the seat portion 2.

  Further, the total target lifting force is distributed to the left and right leg links 3L and 3R in accordance with the ratio between the pedaling force of the right leg and the left leg of the user A, and the total lifting force share of each leg link 3 is distributed. The total lifting force share is generated at each leg link 3. For this reason, in particular, when the lifting control ON / OFF switch 54 is ON, the lifting force (target lifting force) set by the key switch 53 is applied to the user A from the seating portion 2 smoothly and stably. The burden on each leg of the user A can be effectively reduced.

  Supplementally, as described above, the total target lifting force is determined based on the setting value (target lifting force) of the lifting force by the key switch 53 and the total weight of the walking assist device 1 in the lower part of each supporting force sensor 30. It is the sum of the amount of supporting force to support the weight minus the total weight (or the total weight of the walking assist device 1) (more precisely, the value of the addition result is passed through a low-pass filter) is there. Therefore, by determining the total lifting force share of each leg link 3 as described above, as a result, the target lifting force that is the target value of the lifting force that should be applied to the user A from the seating portion 2 is The left leg link 3L, 3R is distributed according to the ratio of the pedaling force of the right leg and the left leg of the user A. Then, the electric motors 27L, 27R of the leg links 3L, 3R so that the share of the distributed target lifting force of the leg links 3L, 3R acts on the seat portion 23 from the leg links 3L, 3R. Will be controlled.

  Furthermore, since a spring restoring force is generated in each leg link 3, a larger lifting force is obtained from the walking assist device 1 as the user A bends the knee deeper. This makes it easier for the user A to feel the assist feeling of the walking assist device 1. Further, by appropriately setting the value of the spring constant k relating to the spring restoring force (see the formula (6)), the posture of each leg link 3 can be prevented from diverging into an inappropriate posture. can do.

  In the state where the lifting control ON / OFF switch 54 is turned off, a value corresponding to the weight of the portion above the supporting force sensor 30 of the walking assist device 1 is determined as the total target lifting force. In this state, unless the user A intentionally puts a weight on the seating part 2, the seating part 2 can be brought into contact with the user A and balanced to a state in which no acting force is generated between them. Then, when the lifting control ON / OFF switch 54 is turned on from this state, a situation in which a sudden lifting force acts on the user A from the seating portion 2 by the low-pass filter (see S303 in FIG. 10). Thus, the lifting force can be applied to the user A smoothly.

  Furthermore, since the current instruction value of each electric motor 27 is determined using both the PD control law (feedback control law) and the feedforward control law, the lifting force can be controlled at high speed and stably.

  In the above-described embodiment, the spring restoring force is added to the target value (control target value) for the total lifting force share of each leg link 3, but the addition of the spring restoring force may be omitted. Good (specifically, the processing of S305, S307, S310, and S312 in FIG. 10 is omitted). In this case, Fankle_t obtained in S301 of FIG. 10 may be input to S302 as it is.

  Further, the guide rail 22 shown in FIG. 1 is not limited to an arc shape, but may be any other shape as long as the thigh frame 11 can swing in the front-rear direction, such as a part of an elliptical circumference (an elliptical arc). There may be. When the guide rail 22 is not arcuate, the position of the front / rear swing center point P varies within a predetermined region by the operation of the walking assist device 1. In this case, when obtaining Fankle, the rotational center of the thigh frame 11 at that moment is set as the forward / backward swing center point P at every predetermined calculation processing cycle. Then, the straight line connecting the center point P and the third joint 14 may be used as the Fankle action line, and the Fankle may be calculated in the same manner as in the above embodiment.

  Furthermore, when the walking assistance device 1 is provided with a brace (such as a waist belt) that prevents the seat 2 from rotating meaninglessly, the longitudinal swing center point P is the width of the seat 2 in the longitudinal direction. It is good also as a structure set to the position remove | deviated from the inside.

  Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the mechanical configuration of the walking assistance device of the present embodiment is the same as that of the first embodiment, and only a part of the control processing is different from the first embodiment. Therefore, in the description of the present embodiment, the same reference numerals as those in the first embodiment are used for the same components or the same function as in the first embodiment, and the description thereof is omitted. Moreover, this embodiment is an embodiment of the first embodiment and the first to fourth inventions and the sixth invention of the present invention.

  FIG. 14 is a block diagram showing functional means of the arithmetic processing unit 51 of the control device 50 in the present embodiment. As shown in the drawing, in this embodiment, instead of the lifting force setting key switch 53, the walking assist device 1 of the total pedaling force of the user A (the sum of the pedaling force of the left leg and the pedaling force of the right leg) is assisted. There is provided an assist ratio setting key switch 70 (which corresponds to the target assist ratio setting means in the present invention) for setting a target assist ratio that is a target value of the ratio of the power to the total pedaling force. The assist ratio setting key switch 70 is a numeric key switch so that a desired target value of the assist ratio can be set directly or can be selectively set from a plurality of types of target values prepared in advance. Alternatively, it is composed of a plurality of selection switches.

  An operation signal of the assist ratio setting key switch 70 (a set value of the target assist ratio indicated by the operation signal) is input to the left and right target share determination means 71 of the arithmetic processing unit 51. Here, in the present embodiment, the functional means of the arithmetic processing unit 51 is different from the first embodiment only in the processing of the left and right target share determination means 71, and the left and right target share determination means The processing of each functional means of the arithmetic processing unit 51 other than 71 is the same as that of the first embodiment. Therefore, the following description of the present embodiment will be focused on the processing of the left and right target share determination means 71.

  The left and right target share determination means 71 in this embodiment includes the measurement values of the measurement processing means 60R, 60L, 61R, 60L, 62R, and 62L, the assist ratio setting key switch 70, and the lifting control ON / OFF switch 54. The operation signal is input. Then, the left and right target share determination means 71 determines the control target value of each leg link 3 (the target of the support force transmitted from the third joint 14 of each leg link 3 to the crus frame 13 based on those input values. Value or a target value of the supporting force acting on the supporting force sensor 30 of the leg link 3) is determined.

  The left / right target share determining means 71 determines the control target value of each leg link 3 in each control processing cycle of the arithmetic processing unit 51 as described below. FIG. 15 is a block diagram showing the flow of the processing.

  First, in S1301, the measurement value Fankle_R for the total lifting force share of the right leg link 3R and the measurement value Fankle_L for the total lifting force share of the left leg link 3L obtained by each supporting force measurement processing unit 62 are added. The Thereby, the total lifting force Fankle_t is calculated.

  Next, the sum of the subtraction force measurement values FRF_R and FRF_L obtained by subtracting the auxiliary device weight support force described later from the total lifting force Fankle_t and the pedal force measurement processing means 60, that is, the measurement of the total pedal force From the value (FRF_R + FRF_L), an actual assist ratio, which is a ratio of the force actually supported by the walking assist device 1 out of the total pedaling force to the total pedaling force, is obtained in S1302. Specifically, the supporting force necessary to support the weight obtained by subtracting the total weight of the lower portion of each supporting force sensor 30 from the total weight of the walking assist device 1 (the supporting force that balances the gravity corresponding to the weight). ) Or a supporting force necessary to support the entire weight of the walking assist device 1 (a supporting force that balances the gravity corresponding to the entire weight) is defined as the assist device weight supporting force, and the magnitude of the assist device weight supporting force. Is stored in advance in a memory (not shown). Then, a value obtained by subtracting this auxiliary device weight supporting force from the total lifting force Fankle_t (this means an upward lifting force currently acting on the user A from the seating portion 2) is a measured value of the total pedaling force. Divide by (FRF_R + FRF_L). Thereby, the actual assist ratio is obtained. That is, the actual assist ratio is obtained by the calculation of actual assist ratio = (Fankle_t−auxiliary device weight support force) / (FRF_R + FRF_L).

  Next, one of the actual assist ratio and the set value of the target assist ratio set by the assist ratio setting key switch 70 is an operation signal (the switch) of the lifting control ON / OFF switch 54 in S1303. 54 is selectively output according to a signal indicating whether 54 is ON or OFF. Specifically, when the lifting control ON / OFF switch 54 is OFF, the actual assist ratio obtained in S1302 is selected and output. When the lifting control ON / OFF switch 54 is ON, the set value of the target assist ratio is selected and output.

  Next, the output of S1303 is passed through a low-pass filter in S1304, thereby determining a practical target assist ratio as a target assist ratio to be actually used. The low-pass filter of S1304 is used when the output of S1303 changes suddenly (when the target assist ratio setting value is changed, or when the output of S1303 is switched from the actual assist ratio to the target assist ratio setting value). This is to prevent the practical target assist ratio from changing suddenly, and in turn, to prevent the lifting force acting on the user A from the seating portion 2 from changing suddenly. The cutoff cutoff frequency of the low-pass filter is, for example, 0.5 Hz.

  Next, in step S1305, the practical target assist ratio is multiplied by the measurement value FRF_R of the pedaling force of the right leg of the user A obtained by the right pedaling force measurement processing unit 60R. Thus, the right target lifting burden, which is the target value of the burden on the right leg link 3R, of the lifting force from the seat 2 to the user A is determined. Similarly, in S1306, the practical target assist ratio is multiplied by the measurement value FRF_L of the pedaling force of the left leg of the user A obtained by the left pedaling force measurement processing unit 60L. Thus, the right target lifting burden, which is the target value of the burden on the left leg link 3L, of the lifting force from the seating section 2 to the user A is determined.

  Note that the processing of S1301 to S1306 corresponds to the target lifting burden determining means in the fifth and sixth inventions.

  Next, in step S1307, the auxiliary device weight support force is determined based on the measured value FRF_R of the right leg pedaling force and the measured value FRF_L of the left leg pedaling force obtained by each of the pedaling force measurement processing means 60. A distribution ratio which is a ratio for distributing to the left and right leg links 3 is determined. The process of S1307 is the same as the process of S304 of FIG. 10 in the first embodiment.

  Next, in S1308, the auxiliary device weight support force is multiplied by the right distribution ratio obtained in S1307. Thereby, the right target apparatus supporting force share which is the target value of the burden of the right leg link 3R in the auxiliary apparatus weight supporting force is obtained. Similarly, in S1311, the auxiliary device weight supporting force is multiplied by the left distribution ratio obtained in S1307. Thereby, the left target apparatus supporting force share which is the target value of the burden of the left leg link 3L in the auxiliary apparatus weight supporting force is obtained. Note that the processing of S1307, S1308, and S1311 may be performed in parallel with the processing of S1301 to S1306.

  Next, the processes of S1309 and S1310 related to the right leg link 3R and the processes of S1312 and S1313 related to the left leg link 3L are executed. In the processing of S1309 and S1310 related to the right leg link 3R, first, in S1309, the right target apparatus supporting force share obtained in S1308 is added to the right target lifting share obtained in S1305. Thereby, the provisional control target value Tp_Fankle_R as the provisional value of the control target value of the right leg link 3R is determined. Then, the provisional target value Tp_Fankle_R is passed through a low-pass filter in S1310, so that the control target value T_Fankle_R for the right leg link 3R is finally obtained. The low pass filter of S1309 is for removing noise components associated with fluctuations in the knee angle θ1. The cutoff frequency is 15 Hz, for example.

  Similarly, in the processing of S1312, S1313 related to the left leg link 3L, first, in S1312, the left target device supporting force share obtained in S1311 is added to the left target lifting burden obtained in S1306. Thereby, the provisional control target value Tp_Fankle_L as the provisional value of the control target value of the left leg link 3L is determined. Then, the provisional target value Tp_Fankle_L is passed through a low-pass filter in S1313, so that the control target value T_Fankle_L for the left leg link 3L is finally obtained.

  The control target value of each leg link 3 determined as described above is the sum of the auxiliary device weight supporting force and the total lifting force from the seat 2 to the user A (that is, the total lifting force). Means the target value of the share of each leg link 3.

  The above is the processing of the left and right target share determining means 71 in the present embodiment. Supplementally, the process of calculating the left and right target lifting burdens in S1305 and S1306 is obtained by multiplying the sum of the measured values FRF_R and FRF_L of the left and right leg tapping force of the user A by the practical target assist ratio (this is seating) Is equivalent to distributing the right and left leg links 3 according to the right distribution ratio and the left distribution ratio.

  Note that the processing in S1307, S1308, and S1311 corresponds to the distribution means in the fifth and sixth inventions. Furthermore, the processing of S1309, S1310, S1312, and S1313 corresponds to the control target force target value determining means in the sixth invention.

  In the second embodiment described above, the action line of the support force (translation force) transmitted from the third joint 14 of each leg link 3 to the crus frame 13 is from the center point of the third joint 14 to the seating portion 2. It becomes a straight line passing through the longitudinal swing center point P existing above the seating portion 2 within the width in the longitudinal direction of the contact surface with the user A. Each leg link 13 is swingable in the front-rear direction with respect to the seating portion 2 with the front-rear swing center point P as a fulcrum. Therefore, similarly to the first embodiment, the seating portion 2 can be prevented from being displaced with respect to the user A, and the position and posture of the seating portion 2 can be stabilized. As a result, a desired lifting force can be stably and appropriately applied to the user A from the seating portion 2.

  Further, the target value of the total lifting force to be applied to the user A from the seating portion 2 is distributed to the left and right leg links 3L and 3R in accordance with the ratio of the pedaling force of the right leg and the left leg of the user A. At the same time, the assisting device weight supporting force for supporting the total weight of the walking assisting device 1 is distributed to the left and right leg links 3L, 3R in accordance with the ratio of the pedaling force of the right leg and the left leg of the user A. . As a result, a control target value that is a target value for the total lifting force share of each leg link 3 is determined, and a support force of this control target value is generated at each leg link 3. For this reason, in particular, when the lifting control ON / OFF switch 54 is ON, a lifting force corresponding to the assist ratio set by the key switch 70 is applied to the user A from the seating portion 2 smoothly and stably. The burden on each leg of the user A can be effectively reduced.

  When the lifting control ON / OFF switch 54 is turned off, the actual assist ratio is determined as the practical target assist ratio. For this reason, in this state, unless the user A intentionally puts a weight on the seating portion 2, the seating portion 2 is brought into contact with the user A and balanced to a state where no acting force is generated between them. Can do. In this state, when the lifting control ON / OFF switch 54 is turned ON, a sudden lifting force is applied to the user A from the seating portion 2 by the low-pass filter (see S1304 in FIG. 15). Thus, the lifting force can be applied to the user A smoothly.

  Furthermore, since the current instruction value of each electric motor 27 is determined by using both the PD control law (feedback control law) and the feedforward control law, the lifting force can be controlled at high speed and stably as in the first embodiment. .

  In the second embodiment, adding the spring restoring force described in the first embodiment to the control target values T_Fankle_L and T_Fankle_R is omitted. However, as in the first embodiment, the spring restoring force of each leg link 3 may be determined and added to each control target value T_Fankle_L, T_Fankle_R.

  In the first and second embodiments, the operation control of the electric motors 27R and 27L is performed even when the lifting control ON / OFF switch 54 is OFF. However, when the switch 54 is in the OFF state, for example, while performing the arithmetic processing of the arithmetic processing unit 51, the output to each driver circuit 52 is stopped and the energization to each electric motor 27 is stopped. Good. By doing so, at the moment when the lifting control ON / OFF switch 54 is turned ON, a lifting force corresponding to the slight force (or zero) that the user A has applied to the seating portion 2 is generated. . Then, until the final total lifting force is exhibited, the effect of the low-pass filter (see S303 in FIG. 1) reduces the impact on the user A and increases the generation of the lifting force. Transition can be realized very smoothly. Further, the power consumption of each electric motor 27 when the switch 54 is in the OFF state can be reduced.

  Moreover, in the said 1st and 2nd embodiment, although the receiving part was comprised by the saddle-shaped seat part 2, it can also be comprised, for example by a flexible member. Hereinafter, an embodiment in this case will be described as a third embodiment. In the third embodiment, for example, as shown in FIG. 16, the belt 100 is wrapped around the waist of the user A (however, it is not necessary to completely fix the belt 100 to the user A). Two harness-shaped flexible members 101L and 10R as receiving portions are suspended from the lower end. One end of each flexible member 101R, 101L is fixed to the belt 100 on the front side of the user A, and the other end is fixed to the belt 100 on the back side of the user A. The flexible member 101R passes through the inside of the base of the right leg of the user A and contacts the crotch part of the user A, and the flexible member 101L passes the inside of the base of the left leg of the user A. It passes through and touches user A's crotch. Thereby, the crotch part of each flexible member 101R, L functions as a receiving part that receives a part of the weight of the user A from above. Further, the thigh frame 11 of each leg link 3 swings at least in the front-rear direction via the first joints 102 provided on the left and right sides of the belt 100 (swing with the first joint 102 as a fulcrum). Is extended so that it is possible. In this case, when viewed in the sagittal plane, the swing center point (predetermined point in the present invention) exists above the receiving portions of the flexible members 101R and 101L. The configuration of the lower part from the thigh frame 11 of each leg link 3 may be the same as that of the first embodiment and the second embodiment. Note that the actuator that drives the second joint is attached to the second joint, for example.

  In each of the first and second embodiments, the table of FIG. 7 is used in each pedal force measurement processing means 60. For example, a provisional measurement value FRF_p of the pedal force of each leg using a table as shown in FIG. May be converted into a measured value FRF. Hereinafter, an embodiment in this case will be described as a fourth embodiment. The table of FIG. 17 in the fourth embodiment is defined so that FRF becomes a negative value when provisional measurement value FRF_p is smaller than threshold value FRF1. More specifically, in the table of FIG. 17, when FRF_p is a value between the threshold value FRF1 and a slightly lower threshold value FRF3 (FRF3> 0 in this example), FRF is linearly reduced as FRF_p decreases. As FRF_p becomes smaller than the threshold value FRF3 (including the case of FRF_p <0), FRF is maintained at a constant negative value (the value of FRF when FRF_p = FRF3).

  Here, when the user A is walking, for example, when the right leg is lifted, the outputs of the MP sensor 38R and the heel sensor 39R become very small values (near 0) or negative values depending on the motion acceleration at that time. The provisional measurement value FRF_p_R is smaller than the threshold value FRF1. At this time, the measured value FRF_R of the right leg pedaling force obtained using the table of FIG. 17 is a negative value.

  When the negative measured value FRF_R is obtained using the table of FIG. 17 as described above, in the first embodiment, the process of FIG. 10 (the process of the left and right target share determination means 63 is performed). ) Is changed as follows, for example. That is, in S304 of FIG. 10, when a negative measured value FRF_R is obtained, the ratio of both distribution ratios is set to a predetermined ratio. For example, when FRF_R <0 as described above, left distribution ratio: right distribution ratio = 1.1: −0.1. That is, of the left distribution ratio and the right distribution ratio, the distribution ratio corresponding to the negative FRF is set to a predetermined negative value (-0.1 in this embodiment), and the other distribution ratio is set to a positive predetermined value. Value (1.1 in this embodiment). The predetermined values are preferably determined so that the sum of the left distribution ratio and the right distribution ratio is 1. Then, the processing of S306 and S311 is performed using this distribution ratio. At this time, for example, when the target total lifting force that is the output of S303 in FIG. 10 is 200 N, the outputs of S306 and S311 are −20 N and 220 N, respectively. Note that the leg (the right leg in the above example) for which the provisional measurement value FRF_p smaller than the threshold value FRF1 is determined to be a free leg, and the spring restoring force calculation process in S305 or S310 corresponding to the free leg. Is not performed (the spring restoring force corresponding to the free leg is set to 0). As a result, at the start of the one-leg support period (time when only one leg is a standing leg), the second joint 12 of the leg link 3 on the free leg side is driven to the bending side, and the leg on the free leg side by the user A is driven. Can assist the lifting operation.

  Similarly, in the second embodiment, a part of the processing of FIG. 15 (processing of the left and right target share determination means 71) is changed as follows, for example. That is, when a negative measurement value FRF_R is obtained in S1307 in FIG. 15, as described above with respect to the first embodiment, the FRF that has become a negative value of the left distribution ratio and the right distribution ratio. Is set to a negative predetermined value (for example, -0.1), and the other distribution ratio is set to a positive predetermined value (for example, 1.1) (preferably left distribution ratio + right distribution ratio = 1). . Then, the processing of S1308 and S1311 is performed using this distribution ratio. Thus, similarly to the case described with respect to the first embodiment, at the start of the one-leg support period (a period when only one leg is a standing leg), the second joint 12 of the leg link 3 on the free leg side is bent. It is possible to assist the user A in lifting the leg on the free leg side.

  Further, in each of the embodiments, the first force sensor is constituted by the MP sensor 38 and the heel sensor 39, and these sensors 38 and 39 are formed on the bottom surface of the foot of the leg of the user A as shown in FIG. The foot mounting portion 15 is provided so as to be interposed between the floor and the floor. However, the installation position of the first force sensor is not limited to this. For example, the first force sensor may be provided in the foot mounting portion as shown in FIG. Hereinafter, this embodiment will be described as a fifth embodiment.

  As shown in FIG. 18, in the fifth embodiment, a foot support member 100 is provided inside the annular member 36 of the foot mounting portion 15. The foot support member 100 has a slipper shape, and has a plate-like sole portion 101 (shoe insole-like member) that contacts almost the entire bottom surface of the foot of the user A, and the sole portion 101. And an arch-like member 102 (a member having a substantially semicircular cross section). The lower end portions of both ends of the arch-shaped member 102 are integrally coupled to both side portions of the sole portion 101. The arched member 102 can be inserted into the toe side portion of the user A's foot. In this inserted state, the foot is supported on the sole 101. These foot support member 101 and arch-shaped member 102 are formed of a material having a predetermined rigidity, such as metal or resin.

  Further, a tensile force sensor 103 constituting a first force sensor is interposed between the outer surface portion of the upper portion of the arch-shaped member 102 and the inner surface portion of the upper portion of the annular member 36. The tensile force sensor 103 is joined to the arched member 102 and the annular member 36. The tensile force sensor 103 is, for example, a tension type load cell. In this case, the foot support member 100 is disposed inside the annular member 36 in a non-contact state with the annular member 36 or the shoe 35. Thus, the foot support member 100 is suspended from the annular member 36 via the tensile force sensor 103 so that the force for supporting the foot support member 100 from below does not act from the annular member 36 or the shoe 35.

  A cushion material for protecting the foot of the user A may be provided on the upper surface of the sole 101 or the inner surface of the arch-shaped member 102.

  The above is the structure of the foot mounting portion 15 in the present embodiment. Note that the foot mounting portion 15 of the present embodiment is not provided with the MP sensor 38, the heel sensor 39, or the insole member 37. When the foot mounting portion 15 of the present embodiment is mounted on each foot of the user A, the toe side portion of the foot is passed through the arched member 102 of the foot support member 100, and The foot may be inserted into the shoe 35 through the mouth of the shoe 35 so that the foot rests on the sole 101.

  In the walking assist device of the present embodiment having the foot mounting portion 15 configured as described above, the pedaling force of the leg of the user A serving as a standing leg is caused by the tensile force sensor 103 as a tensile force acting on the tensile force sensor 103. Will be detected.

  In this embodiment, the output of the tensile force sensor 103 of each of the left and right foot mounting portions 15 is input to each pedal force measurement processing means 60 of the arithmetic processing unit 51 instead of the outputs of the MP sensor 38 and the heel sensor 39. Is done. Each of the treading force measurement processing means 60 passes the detected force value (the tensile force is a positive value) represented by the output of the corresponding tensile force sensor 103 through a low-pass filter to each leg of the user A. Obtained as provisional measurement value FRF_p. Further, each pedal force measurement processing means 60 obtains a pedal force measurement value FRF from the provisional measurement value FRF_p according to the table of FIG. 7 (or the table of FIG. 17).

  Configurations and processes other than those described above are the same as those in the first embodiment (or the second embodiment).

The side view (figure seen by sagittal plane) of the walk auxiliary device of a 1st embodiment of the present invention. FIG. 2 is a view taken along line II in FIG. III-III sectional view taken on the line of FIG. The block diagram which shows schematically the structure (hardware structure) of the control apparatus of the walking assistance apparatus of 1st Embodiment of FIG. The block diagram which shows the functional structure of the arithmetic processing part with which the control apparatus in 1st Embodiment was equipped. The block diagram which shows the flow of a process of the treading force measurement process means of FIG. The graph which shows the table used by the process of S104 of FIG. The block diagram which shows the flow of the process of the knee angle measurement process means of FIG. 5, and the process of a support force measurement process means. The figure for demonstrating the process of S201 and S203 of FIG. The block diagram which shows the flow of a process of the right-and-left target share determination means of FIG. The block diagram which shows the flow of a process of the feedback operation amount determination means of FIG. The block diagram which shows the flow of a process of the feedforward manipulated variable determination means of FIG. The figure for demonstrating the process of S502 of FIG. The block diagram which shows the functional structure of the arithmetic processing part with which the control apparatus in the walking assistance apparatus of 2nd Embodiment of this invention was equipped. The block diagram which shows the flow of a process of the right-and-left target share determination means of FIG. The figure for demonstrating the structural example of the receiving part in 3rd Embodiment of this invention. The graph which shows the example of the table used by the process of S104 of FIG. 6 in 4th Embodiment of this invention. The figure which shows the structure of the foot mounting part in 5th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Walking assistance apparatus, 2 ... Seating part (receiving part), 3 ... Leg link, 10 ... 1st joint, 11 ... Thigh frame, 12 ... 2nd joint, 13 ... Lower leg frame, 14 ... 3rd joint, 15 ... Foot mounting portion, 27 ... electric motor (actuator), 38, 39 ... first force sensor, 30 ... second force sensor, 50 ... control device, 53 ... lifting force setting key switch (target lifting force setting means), 60 ... pedal force measurement processing means (pedal force measurement means), 62 ... support force measurement processing means (control target force measurement means), 63 ... left and right target share determination means (total target lifting force determination means, distribution means), 64, 65, 66 ... Actuator control means, 70 ... Key switch for assist ratio setting (target assist ratio setting means), 71 ... Left / right target share determination means (target lift share determination means, distribution means, control target force) Value determining means), 101R, L ... flexible member (receiving portion), 102R, 102L ... first joint.

Claims (6)

A receiving part disposed between the bases of both legs of the user so as to receive a part of the weight of the user from above, and a pair of left and right thigh frames respectively connected to the receiving part via a first joint; A pair of left and right lower leg frames connected to each thigh frame via a second joint, respectively, and each leg frame connected to each foot via a third joint and attached to the foot of each left and right leg of the user A pair of left and right foot mounting portions that come into contact with each leg of the user as a standing leg, and the left side first joint, thigh frame, second joint, lower leg frame, third joint, and foot mounting portion. A left actuator that drives a second joint among the joints of the left leg link, and the first joint on the right side, the thigh frame, the second joint, the lower leg frame, the third joint, and a foot mounting portion. Right A right actuator for driving a second joint of the joints of the leg links, and driving the second joint of each leg link by the actuator so that an upward lifting force is applied to the user from the receiving portion. A walking assist device,
When the line of support force acting on the lower leg frame from the third joint of the leg link corresponding to the leg when each leg of the user becomes a standing leg, when the leg link is viewed in the sagittal plane of the user Further, each leg link is connected to the receiving portion from the third joint so as to pass through a predetermined point located above the receiving portion within the width in the front-rear direction of the contact surface between the receiving portion and the user. And
Means for causing the lifting force to act on the user by controlling each actuator so that the support force is a control target force and the control target force becomes a predetermined target value for each leg link. A featured walking aid.   The first joint of each leg link is a joint that connects the thigh frame of the leg link and the receiving portion so that the leg link can swing at least in the front-rear direction with the predetermined point as a swing center point. The walking assistance device according to claim 1, wherein   The first joint of each leg link is a joint that connects the thigh frame of the leg link and the receiving portion so that the leg link can swing in the front-rear direction and the left-right direction, and at least the leg link 2. The walking assist device according to claim 1, wherein a swing center point in the front-rear direction of the link is arranged above the receiving portion as the predetermined point.   The left actuator and the right actuator are each connected to the thigh frame at a position closer to the receiving part than the second joint, and a pair of left and right powers that transmit the driving force of each actuator to the second joint. The walking assist device according to any one of claims 1 to 3, further comprising a transmission unit. Treading force measuring means for measuring the treading force of each leg of the user based on a force detection value indicated by an output of a first force sensor provided in each foot mounting portion;
A target lifting force setting means for setting a target lifting force that is a target value of an upward lifting force that acts on the user from the receiving portion;
A second force sensor interposed between the lower joint of each leg link and the lower end of the lower leg frame, or between the third joint of each leg link and the foot mounting portion;
Control target force measuring means for measuring, as a control target force, the support force actually acting on the lower leg frame from the third joint of each leg link based on the force detection value indicated by the output of the second force sensor;
The sum of the target lifting force and the supporting force for supporting the weight obtained by subtracting the total weight of the lower part of each second force sensor of the walking assist device from the total weight of the walking assist device, or A total target lifting force determining means for determining a sum of the target lifting force and a supporting force for supporting the entire weight of the walking assist device on the floor as a total target lifting force;
By distributing the total target lifting force to each leg link according to the ratio of the pedaling force of the left leg and the right leg of the user, the burden of the left leg link out of the total target lifting force A distribution means for determining a target share which is a target value of minutes and a target share which is a target value of a share of the right leg link;
Based on the control target force of the left leg link and the target share of the left leg link, the left actuator is controlled so that the difference between the control target force of the left leg link and the target share approaches zero. Based on the control target force of the right leg link and the target share of the right leg link, the right actuator is controlled so that the difference between the control target force of the right leg link and the target share approaches zero. The walking assist device according to any one of claims 1 to 4, further comprising an actuator control means for performing the operation. Treading force measuring means for measuring the treading force of each leg of the user based on a force detection value indicated by an output of a first force sensor provided in each foot mounting portion;
A second force sensor interposed between the lower end portion of the lower leg frame of each leg link and the third joint, or between the third joint of each leg link and the foot mounting portion;
Control target force measuring means for measuring, as a control target force, the support force that actually acts on the lower leg frame from the third joint of each leg link based on the force detection value indicated by the output of the second force sensor;
A target assist ratio setting means for setting a target assist ratio that is a target value of a ratio of the total pedaling force, which is the total pedaling force of each leg of the user, to be supported by the walking assist device with respect to the total pedaling force;
By multiplying the pedal assist force of each leg of the user by the target assist ratio, the target lift that is the target value of the share of the left leg link out of the upward lifting force to be applied to the user from the receiving portion A target lifting share determining means for determining a target lifting share that is a target value of the share and the share of the right leg link;
The supporting force for supporting the weight obtained by subtracting the total weight of the lower part of each second force sensor of the walking assist device from the total weight of the walking assist device, or the entire weight of the walking assist device. Is distributed to each leg link in accordance with the ratio of the pedaling force of the left leg and the right leg of the user, so that the burden on the left leg link of the supporting force is distributed. A distribution means for determining the share of the right leg link and the share of the right leg link as the share of the target device supporting force of each leg link;
The sum of the left leg link target lifting share and the target device supporting force share is determined as a target value of the left leg link control target force, and the right leg link target lifting share and target device supporting force are determined. Control target force target value determining means for determining the sum of the share and the share as a target value of the control target force of the right leg link;
Based on the control target force of the left leg link and the target value of the control force of the left leg link, the left actuator is controlled so that the difference between the control target force of the left leg link and the target value approaches zero. In addition, based on the control target force of the right leg link and the target value of the control target force of the right leg link, the right leg link is controlled so that the difference between the control target force of the right leg link and the target value approaches zero. The control device for the walking assist device according to any one of claims 1 to 4, further comprising an actuator control means for controlling the actuator.

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