JP2011062474A - Walking assisting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a walking assisting system enhancing walking stability of a mounting person to assist his/her walking. <P>SOLUTION: Vehicles 1a and 1b, each of which is equipped with: a wheel body movable on a traveling surface; an actuator device 7 for producing drive force for driving the wheel body; and a base body having the wheel body and the actuator device 7 attached thereto, are locked to a waist part of the mounting person by a belt 58. A six-axial force sensor 57 detects the force added to the vehicles 1a and 1b, and an inclination sensor 52 and open angle sensors 59a and 59b detect the angle related to postures of the vehicles 1a and 1b. A control unit 50 controls the actuator device 7 on the basis of the force detected by the six-axial force sensor 57 and the angles detected by the inclination sensor 52 and the open angle sensors 59a and 59b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a walking assistance system that assists walking of a pedestrian.

  As the omnidirectional vehicle that can move in all directions (two-dimensional omnidirectional) on the floor surface, for example, those shown in Patent Documents 1 and 2 have been proposed by the present applicant. In the omnidirectional mobile vehicle found in these Patent Documents 1 and 2, a spherical or wheel-like or crawler-like moving operation unit capable of moving in all directions on the floor surface while being in contact with the floor surface; An actuator device having an electric motor or the like for driving the moving operation unit is assembled to a vehicle body. And this vehicle moves on a floor surface by driving a movement operation part with an actuator device.

  Further, as a technique for controlling the moving operation of this type of omnidirectional vehicle, for example, a technique found in Patent Document 3 has been proposed by the present applicant. In this technique, a vehicle base is provided so as to be tiltable in the front-rear and left-right directions with respect to a spherical moving operation unit. Then, the vehicle is moved according to the tilting motion of the base by measuring the tilt angle of the base and controlling the torque of the electric motor that drives the moving operation unit so as to keep the tilt angle at a required angle. I have to.

International Publication No. 08/132778 Pamphlet International Publication No. 08/1327979 Pamphlet Japanese Patent No. 3070015

  By the way, when a person with low balance ability walks, the person may fall while walking. In addition, when a person who is extremely inferior in physical strength walks, walking may be overloaded for the person. In order to solve such a problem, it is conceivable to use the omnidirectional vehicle described above to assist walking. However, if no control is performed on the omnidirectional vehicle, walking cannot be stabilized. .

  The present invention has been made to solve the above-described problems, and the object thereof is to improve walking stability of the wearer and assist walking by using a moving body such as an omnidirectional moving body. It is to provide a walking assistance system.

  In order to solve the above-described problem, the invention described in claim 1 drives a driven mechanism (for example, a wheel body 5) that can move a traveling surface (floor surface, road surface, ground, etc.) and the driven mechanism. An inverted pendulum control type moving body (e.g., a base body (e.g., base body 9) on which the driven mechanism and the drive unit are assembled) Detecting force applied to the movable body of the inverted pendulum control type and a locking tool (for example, belt 58) capable of locking at least two or more omnidirectional vehicles 1, 1a, 1b) to the wearer's waist. A force sensor (for example, a six-axis force sensor 57), an angle sensor (for example, an inclination sensor 52, opening angle sensors 59a and 59b) for detecting an angle related to the posture of the inverted pendulum control type moving body, Locked to the fastener And at least two or more of the inverted pendulum control type moving bodies, and a control device (for example, control unit 50) that controls the drive unit based on the force detected by the force sensor and the angle detected by the angle sensor; , A walking assist system. Thereby, based on the force detected by the force sensor and the angle detected by the angle sensor, the drive unit can be controlled so that the wearer's walk is stabilized.

  3. The control device according to claim 2, wherein the control unit detects an opening angle between the inverted pendulum control type moving bodies with respect to a horizontal direction by the angle sensor, and the driving unit is configured to converge the opening angle uniformly. To control. Thereby, an opening angle can be made to converge uniformly.

  In the invention described in claim 3, the control device detects an inclination angle of the inverted pendulum control type moving body with respect to a vertical direction by the angle sensor at the first time point and the second time point, and the second time point. The drive unit is controlled so that the tilt angle detected at the time point converges to the tilt angle detected at the first time point. Thereby, the tilt angle can be converged to the tilt angle at a desired time.

  According to a fourth aspect of the present invention, the control device controls the drive unit according to a frequency component of force detected by the force sensor. Thereby, walking speed can be controlled according to the frequency component of force.

  According to the first aspect of the present invention, by controlling the drive unit based on the force detected by the force sensor and the angle detected by the angle sensor, the drive unit is controlled so that the wearer's walk is stabilized. Therefore, the walking stability of the wearer can be improved and walking can be assisted.

  According to the second aspect of the present invention, even when the wearer moves in an arbitrary direction by controlling the drive unit so that the opening angle converges uniformly, the wearer and the inverted pendulum control type moving body The positional relationship with can be kept constant.

  According to the third aspect of the present invention, the walking stability of the wearer can be further improved by controlling the drive unit so that the inclination angle converges to the inclination angle at a desired time.

  According to the fourth aspect of the present invention, the walking stability of the wearer can be further improved by controlling the drive unit according to the frequency component of the force.

The front view of the omnidirectional vehicle of embodiment. The side view of the omnidirectional vehicle of embodiment. The figure which expands and shows the lower part of the omnidirectional vehicle of embodiment. The perspective view of the lower part of the omnidirectional mobile vehicle of embodiment. The perspective view of the movement operation part (wheel body) of the omnidirectional vehicle of embodiment. The figure which shows the arrangement | positioning relationship between the movement operation | movement part (wheel body) and free roller of the omnidirectional vehicle of embodiment. The figure which shows the inverted pendulum model expressing the dynamic behavior of the omnidirectional vehicle of embodiment. The side view of the walk assistance system of an embodiment. The top view of the walk assistance system of an embodiment. The block diagram which shows the function structure of the walking assistance system of embodiment. The flowchart which shows the process of the control unit of the omnidirectional vehicle of embodiment. FIG. 12 is a block diagram showing processing functions related to the processing in step S160 in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, with reference to FIGS. 1-6, the structure of the omnidirectional vehicle used for the walking assistance system by this embodiment is demonstrated.

  As shown in FIGS. 1 and 2, an omnidirectional vehicle (hereinafter referred to as a vehicle) 1 in the present embodiment is placed on the floor surface of the occupant (driver) and the riding section 3 while being in contact with the floor surface. A moving operation unit 5 that can move in all directions (two-dimensional all directions including the front-rear direction and the left-right direction), and an actuator device 7 that applies power for driving the moving operation unit 5 to the moving operation unit 5; The boarding unit 3, the moving operation unit 5, and the base 9 on which the actuator device 7 is assembled are provided.

  Here, in the description of the present embodiment, “front-rear direction” and “left-right direction” respectively match or substantially coincide with the front-rear direction and the left-right direction of the upper body of the occupant who has boarded the riding section 3 in a standard posture. Means direction. Note that the “standard posture” is a posture assumed by design with respect to the riding section 3, and the trunk axis of the occupant's upper body is generally directed vertically and the upper body is not twisted. It is posture.

  In this case, in FIG. 1, the “front-rear direction” and the “left-right direction” are the direction perpendicular to the paper surface and the left-right direction of the paper surface, respectively. In FIG. It is the left-right direction of the paper surface and the direction perpendicular to the paper surface. In the description of the present embodiment, the suffixes “R” and “L” attached to the reference numerals are used to mean the right side and the left side of the vehicle 1, respectively.

  The base 9 includes a lower frame 11 in which the moving operation unit 5 and the actuator device 7 are assembled, and a support frame 13 extending upward from the upper end of the lower frame 11. A seat frame 15 projecting forward from the column frame 13 is fixed to the upper portion of the column frame 13. A seat 3 on which an occupant sits is mounted on the seat frame 15. In this embodiment, this seat 3 is a passenger's boarding part. Therefore, the omnidirectional vehicle 1 (hereinafter simply referred to as the vehicle 1) in the present embodiment moves on the floor surface while the occupant is seated on the seat 3. Further, on the left and right sides of the seat 3, grips 17R and 17L are disposed for the passengers seated on the seat 3 to grip as necessary. These grips 17R and 17L are respectively provided to the support frame 13 (or the seat frame 15). It is being fixed to the front-end | tip part of bracket 19R, 19L extended from.

  The lower frame 11 includes a pair of cover members 21R and 21L arranged so as to face each other in a bifurcated manner with a space in the left-right direction. The upper end portions (bifurcated branch portions) of these cover members 21R and 21L are connected via a hinge shaft 23 having a longitudinal axis, and one of the cover members 21R and 21L is hinged relative to the other. It can swing around the shaft 23. In this case, the cover members 21R and 21L are urged by a spring (not shown) in a direction in which the lower end side (the bifurcated tip side) of the cover members 21R and 21L is narrowed. Further, on each outer surface portion of the cover members 21R and 21L, a step 25R for placing the right foot of the occupant seated on the seat 3 and a step 25L for placing the left foot are respectively projected so as to protrude rightward and leftward. Yes.

  The moving operation unit 5 and the actuator device 7 are disposed between the cover members 21R and 21L of the lower frame 11. The structures of the moving operation unit 5 and the actuator device 7 will be described with reference to FIGS. The moving operation unit 5 and the actuator device 7 exemplified in the present embodiment have the same structure as that disclosed in FIG. Therefore, in the description of the present embodiment, the matters described in Patent Document 2 regarding the configurations of the moving operation unit 5 and the actuator device 7 are simply described.

  In the present embodiment, the moving operation unit 5 is a wheel body formed in an annular shape from a rubber-like elastic material, and has a substantially circular cross-sectional shape. Due to its elastic deformation, the moving operation unit 5 (hereinafter referred to as the wheel body 5) has a circular cross section center C1 (more specifically, a circular cross section center C1 as shown by an arrow Y1 in FIGS. 5 and 6). And can be rotated around a circumferential line that is concentric with the axis of the wheel body 5.

  The wheel body 5 is disposed between the cover members 21R and 21L with its axis C2 (axis C2 orthogonal to the diameter direction of the entire wheel body 5) directed in the left-right direction. Ground to the floor at the lower end of the outer peripheral surface.

  The wheel body 5 rotates around the axis C2 of the wheel body 5 as shown by an arrow Y2 in FIG. 5 (operation to rotate on the floor surface) by driving by the actuator device 7 (details will be described later). And an operation of rotating around the cross-sectional center C1 of the wheel body 5 can be performed. As a result, the wheel body 5 can move in all directions on the floor surface by a combined operation of these rotational operations.

  The actuator device 7 includes a rotating member 27R and a free roller 29R interposed between the wheel body 5 and the right cover member 21R, and a rotating member interposed between the wheel body 5 and the left cover member 17L. 27L and a free roller 29L, an electric motor 31R as an actuator disposed above the rotating member 27R and the free roller 29R, and an electric motor 31L as an actuator disposed above the rotating member 27L and the free roller 29L. .

  The electric motors 31R and 31L have their respective housings attached to the cover members 21R and 21L. Although illustration is omitted, the power sources (capacitors) of the electric motors 31 </ b> R and 31 </ b> L are mounted at appropriate positions on the base 9 such as the support frame 13.

  The rotating member 27R is rotatably supported by the cover member 21R via a support shaft 33R having a horizontal axis. Similarly, the rotation member 27L is rotatably supported by the cover member 21L via a support shaft 33L having a horizontal axis. In this case, the rotation axis of the rotation member 27R (axis of the support shaft 33R) and the rotation axis of the rotation member 27L (axis of the support shaft 33L) are coaxial.

  The rotating members 27R and 27L are connected to the output shafts of the electric motors 31R and 31L via power transmission mechanisms including functions as speed reducers, respectively, and the power (torque) transmitted from the electric motors 31R and 31L, respectively. It is rotationally driven by. Each power transmission mechanism is of a pulley-belt type, for example. That is, as shown in FIG. 3, the rotating member 27R is connected to the output shaft of the electric motor 31R via the pulley 35R and the belt 37R. Similarly, the rotating member 27L is connected to the output shaft of the electric motor 31L via a pulley 35L and a belt 37L.

  The power transmission mechanism may be constituted by, for example, a sprocket and a link chain, or may be constituted by a plurality of gears. In addition, for example, the electric motors 31R and 31L are arranged to face the rotating members 27R and 27L so that the respective output shafts are coaxial with the rotating members 27R and 27L, and the electric motors 31R and 31L are respectively arranged. The output shaft may be connected to each of the rotating members 27R and 27L via a speed reducer (such as a planetary gear device).

  Each rotating member 27R, 27L is formed in the same shape as a truncated cone that decreases in diameter toward the wheel body 5, and its outer peripheral surface is a tapered outer peripheral surface 39R, 39L. A plurality of free rollers 29R are arranged around the tapered outer peripheral surface 39R of the rotating member 27R so as to be arranged at equal intervals on a circumference concentric with the rotating member 27R. Each of these free rollers 29R is attached to the tapered outer peripheral surface 39R via a bracket 41R and is rotatably supported by the bracket 41R.

  Similarly, a plurality (the same number as the free rollers 29R) of free rollers 29L are arranged around the tapered outer peripheral surface 39L of the rotating member 27L so as to be arranged at equal intervals on a circumference concentric with the rotating member 27L. Yes. Each of these free rollers 29L is attached to the tapered outer peripheral surface 39L via a bracket 41L and is rotatably supported by the bracket 41L.

  The wheel body 5 is disposed coaxially with the rotating members 27R and 27L so as to be sandwiched between the free roller 29R on the rotating member 27R side and the free roller 29L on the rotating member 27L side. In this case, as shown in FIGS. 1 and 6, each of the free rollers 29 </ b> R and 29 </ b> L has the axis C <b> 3 inclined with respect to the axis C <b> 2 of the wheel body 5 and the diameter direction of the wheel body 5 (the wheel body 5. When viewed in the direction of the axis C2, it is arranged in a posture inclined with respect to the radial direction connecting the axis C2 and the free rollers 29R and 29L. In such a posture, the outer peripheral surfaces of the free rollers 29R and 29L are in pressure contact with the inner peripheral surface of the wheel body 5 in an oblique direction.

  More generally speaking, the free roller 29R on the right side has a frictional force component in the direction around the axis C2 at the contact surface with the wheel body 5 when the rotating member 27R is driven to rotate around the axis C2. (The frictional force component in the tangential direction of the inner periphery of the wheel body 5) and the frictional force component in the direction around the cross-sectional center C1 of the wheel body 5 (the tangential frictional force component in the circular cross section) The wheel body 5 is pressed against the inner peripheral surface in such a posture that it can act on the wheel body 5. The same applies to the left free roller 29L.

  In this case, as described above, the cover members 21R and 21L are urged in a direction in which the lower end side (the bifurcated tip side) of the cover members 21R and 21L is narrowed by a spring (not shown). Therefore, the wheel body 5 is sandwiched between the right free roller 29R and the left free roller 29L by this urging force, and the free rollers 29R and 29L are in pressure contact with the wheel body 5 (more specifically, free The pressure contact state in which a frictional force can act between the rollers 29R and 29L and the wheel body 5 is maintained.

  In the vehicle 1 having the structure described above, when the rotating members 27R and 27L are driven to rotate at the same speed in the same direction by the electric motors 31R and 31L, the wheel body 5 has the same direction as the rotating members 27R and 27L. Will rotate around the axis C2. Thereby, the wheel body 5 rotates on the floor surface in the front-rear direction, and the entire vehicle 1 moves in the front-rear direction. In this case, the wheel body 5 does not rotate around the center C1 of the cross section.

  Further, for example, when the rotating members 27R and 27L are rotationally driven in opposite directions at the same speed, the wheel body 5 rotates around the center C1 of the cross section. As a result, the wheel body 5 moves in the direction of the axis C2 (that is, the left-right direction), and as a result, the entire vehicle 1 moves in the left-right direction. In this case, the wheel body 5 does not rotate around the axis C2.

  Furthermore, when the rotating members 27R and 27L are rotationally driven at different speeds (speeds including directions) in the same direction or in the opposite direction, the wheel body 5 rotates around its axis C2, It will rotate about the cross-sectional center C1.

  At this time, the wheel body 5 moves in a direction inclined with respect to the front-rear direction and the left-right direction by a combined operation (composite operation) of these rotational operations, and as a result, the entire vehicle 1 moves in the same direction as the wheel body 5. Will be. The moving direction of the wheel body 5 in this case changes depending on the difference in rotational speed (rotational speed vector in which the polarity is defined according to the rotational direction) including the rotational direction of the rotating members 27R and 27L. .

  Since the moving operation of the wheel body 5 is performed as described above, by controlling the respective rotational speeds (including the rotational direction) of the electric motors 31R and 31L, and by controlling the rotational speeds of the rotating members 27R and 27L, The moving speed and moving direction of the vehicle 1 can be controlled.

  Next, the structure for operation control of the vehicle 1 of this embodiment is demonstrated. In the following description, as shown in FIGS. 1 and 2, an XYZ coordinate system is assumed in which the horizontal axis in the front-rear direction is the X axis, the horizontal axis in the left-right direction is the Y axis, and the vertical direction is the Z axis. The direction and the left-right direction may be referred to as the X-axis direction and the Y-axis direction, respectively.

  First, schematic operation control of the vehicle 1 will be described. In the present embodiment, basically, when an occupant seated on the seat 3 tilts its upper body (specifically, the occupant and the vehicle 1 are combined). When the upper body is tilted so as to move the position of the entire center of gravity (the position projected on the horizontal plane), the base body 9 tilts together with the sheet 3 to the side on which the upper body is tilted. At this time, the moving operation of the wheel body 5 is controlled so that the vehicle 1 moves to the side on which the base body 9 is inclined. For example, when the occupant tilts the upper body forward and, as a result, tilts the base body 9 together with the seat 3, the movement operation of the wheel body 5 is controlled so that the vehicle 1 moves forward. That is, in the present embodiment, the operation of the occupant moving the upper body and thus tilting the base body 9 together with the seat 3 is one basic control operation (operation request of the vehicle 1) for the vehicle 1, and the control The moving operation of the wheel body 5 is controlled via the actuator device 7 in accordance with the operation.

  Here, in the vehicle 1 of the present embodiment, the ground contact surface of the wheel body 5 as the entire ground contact surface has an area compared to a region where the entire vehicle 1 and the passengers riding on the vehicle 1 are projected on the floor surface. It becomes a small single local region, and the floor reaction force acts only on the single local region. For this reason, in order to prevent the base body 9 from tilting, it is necessary to move the wheel body 5 so that the center of gravity of the occupant and the vehicle 1 is positioned almost directly above the ground contact surface of the wheel body 5.

  Therefore, in the present embodiment, the center of gravity of the entire occupant and vehicle 1 is positioned almost directly above the center point of the wheel body 5 (center point on the axis C2) (more precisely, the center of gravity point is The posture of the base body 9 in a state (which is located almost directly above the ground contact surface of the wheel body 5) is set as a target posture, and basically, the actual posture of the base body 9 is converged to the target posture. The movement operation is controlled.

  In addition, when starting the vehicle 1 and the like, apart from the propulsive force by the actuator device 7, for example, the occupant kicks the floor with his / her foot as necessary, thereby increasing the moving speed of the vehicle 1 ( When the driving force (the propulsive force generated by the frictional force between the occupant's foot and the floor) is applied to the vehicle 1 as an additional external force, the moving speed of the vehicle 1 (more precisely, the occupant and the entire vehicle) The movement operation of the wheel body 5 is controlled so that the movement speed of the center of gravity of the wheel body increases. In the state where the addition of the propulsive force is stopped, the moving operation of the wheel body 5 is performed so that the moving speed of the vehicle 1 is once held at a constant speed and then attenuated to stop the vehicle 1. Control (braking control of the wheel body 5 is performed).

  Further, in a state where no occupant is on board the vehicle 1, a state where the center of gravity of the single vehicle 1 is located almost directly above the center point of the wheel body 5 (center point on the axis C <b> 2) (more accurately, (The state where the center of gravity is located almost directly above the ground contact surface of the wheel body 5) is the target posture, and the actual posture of the base 9 is converged to the target posture. The movement operation of the wheel body 5 is controlled so that the vehicle 1 can stand on its own without tilting.

  In the present embodiment, in order to control the operation of the vehicle 1 as described above, as shown in FIGS. 1 and 2, it is configured by an electronic circuit unit including a microcomputer and drive circuit units of the electric motors 31R and 31L. An occupant is on board the control unit 50, an inclination sensor 52 for measuring the inclination angle θb of the predetermined portion of the base body 9 with respect to the vertical direction (the direction of gravity) and its changing speed (= dθb / dt), and the vehicle 1. A load sensor 54 for detecting whether or not there is a rotary encoder 56R, 56L as an angle sensor for detecting the rotational angle and rotational angular velocity of the output shafts of the electric motors 31R, 31L, respectively. It is mounted on.

  In this case, the control unit 50 and the inclination sensor 52 are attached to the column frame 13 in a state of being accommodated in the column frame 13 of the base body 9, for example. The load sensor 54 is built in the seat 3. The rotary encoders 56R and 56L are provided integrally with the electric motors 31R and 31L, respectively. The rotary encoders 56R and 56L may be attached to the rotating members 27R and 27L, respectively.

  More specifically, the tilt sensor 52 includes an acceleration sensor and a rate sensor (angular velocity sensor) such as a gyro sensor, and outputs detection signals of these sensors to the control unit 50. Then, the control unit 50 performs a predetermined measurement calculation process (this may be a known calculation process) based on the outputs of the acceleration sensor and the rate sensor of the tilt sensor 52, and thereby the part on which the tilt sensor 52 is mounted. The measured value of the inclination angle θb with respect to the vertical direction (the column frame 13 in this embodiment) and the measured value of the inclination angular velocity θbdot, which is the change speed (differential value) thereof, are calculated.

  In this case, the tilt angle θb to be measured (hereinafter also referred to as the base body tilt angle θb) is more specifically, the component θb_x in the Y axis direction (pitch direction) and the X axis direction (roll direction), respectively. It consists of component θb_y. Similarly, the measured tilt angular velocity θbdot (hereinafter also referred to as the base tilt angular velocity θbdot) is also measured in the Y-axis direction (pitch direction) component θbdot_x (= dθb_x / dt) and the X-axis direction (roll direction). Component θbdot_y (= dθb_y / dt).

  In the description of the present embodiment, a variable such as a motion state quantity having a component in each direction of the X axis and the Y axis (or a direction around each axis) such as the base body inclination angle θb, or a relation to the motion state quantity. For a variable such as a coefficient to be processed, a suffix “_x” or “_y” is added to the reference symbol of the variable when each component is expressed separately. In this case, for a variable related to translational motion such as translational speed, a subscript “_x” is added to the component in the X-axis direction, and a subscript “_y” is added to the component in the Y-axis direction.

  On the other hand, for variables related to rotational motion, such as angle, rotational speed (angular velocity), angular acceleration, etc., the subscript “_x” is added to the component around the Y axis for convenience in order to align the subscript with the variable related to translational motion. In addition, the subscript “_y” is added to the component around the X axis.

  Further, when a variable is expressed as a set of a component in the X-axis direction (or a component around the Y-axis) and a component in the Y-axis direction (or a component around the X-axis), the reference numeral of the variable The subscript “_xy” is added. For example, when the base body tilt angle θb is expressed as a set of a component θb_x around the Y axis and a component θb_y around the X axis, it is expressed as “base body tilt angle θb_xy”.

  The load sensor 54 is built in the seat 3 so as to receive a load due to the weight of the occupant when the occupant sits on the seat 3, and outputs a detection signal corresponding to the load to the control unit 50. Then, the control unit 50 determines whether or not an occupant is on the vehicle 1 based on the measured load value indicated by the output of the load sensor 54. Instead of the load sensor 54, for example, a switch type sensor that is turned on when an occupant sits on the seat 3 may be used.

  The rotary encoder 56R generates a pulse signal every time the output shaft of the electric motor 31R rotates by a predetermined angle, and outputs this pulse signal to the control unit 50. Then, the control unit 50 measures the rotational angle of the output shaft of the electric motor 53R based on the pulse signal, and further calculates the temporal change rate (differential value) of the measured value of the rotational angle as the rotational angular velocity of the electric motor 53R. Measure as The same applies to the rotary encoder 56L on the electric motor 31L side.

  The control unit 50 determines a speed command that is a target value of the rotational angular speed of each of the electric motors 31R and 31L by executing a predetermined calculation process using each of the measured values, and the electric motor is operated according to the speed command. The rotational angular velocities of the motors 31R and 31L are feedback controlled. The relationship between the rotational angular velocity of the output shaft of the electric motor 31R and the rotational angular velocity of the rotating member 27R is proportional to the constant reduction ratio between the output shaft and the rotating member 27R. In the description of this embodiment, for the sake of convenience, the rotational angular velocity of the electric motor 31R means the rotational angular velocity of the rotating member 27R. Similarly, the rotational angular velocity of the electric motor 31L means the rotational angular velocity of the rotating member 27L.

  Next, an outline of arithmetic processing performed by the control unit 50 for vehicle control will be described.

  In the following description, when an observed value (measured value or estimated value) of an actual value of a variable (state quantity) such as a measured value θb_xy_s of the base body tilt angle θb is represented by a reference code, the reference code of the variable Is appended with a subscript “_s”.

  In the following description, regarding the value (value to be updated) determined by the control unit 50 in each control processing cycle, the value determined in the current (latest) control processing cycle is the current value, and the control processing immediately before that The value determined by the cycle may be referred to as the previous value. A value not particularly different from the current value and the previous value means the current value.

  Further, regarding the speed and acceleration in the X-axis direction, the forward direction is a positive direction, and regarding the speed and acceleration in the Y-axis direction, the left direction is a positive direction.

  In this embodiment, the dynamic behavior of the center of gravity of the vehicle system (specifically, the behavior seen by projecting from the Y-axis direction onto the plane orthogonal to this (XZ plane) and the plane orthogonal to this from the X-axis direction) (Behavior projected on the (YZ plane)) is approximately expressed by the behavior of the inverted pendulum model (the dynamic behavior of the inverted pendulum) as shown in FIG. The arithmetic processing is performed.

  In FIG. 7, reference numerals without parentheses are reference numerals corresponding to the inverted pendulum model viewed from the Y-axis direction, and reference numerals with parentheses refer to the inverted pendulum model viewed from the X-axis direction. Corresponding reference sign. In this case, the inverted pendulum model expressing the behavior viewed from the Y-axis direction has a mass point 60_x located at the center of gravity of the vehicle and a rotation axis 62a_x parallel to the Y-axis direction, and can be rotated freely on the floor surface. Wheel 62_x (hereinafter referred to as virtual wheel 62_x). The mass point 60_x is supported by the rotation shaft 62a_x of the virtual wheel 62_x via the linear rod 64_x, and can swing around the rotation shaft 62a_x with the rotation shaft 62a_x as a fulcrum.

  In this inverted pendulum model, the motion of the mass point 60_x corresponds to the motion of the vehicle system center of gravity as viewed from the Y-axis direction. Further, the inclination angle θbe_x of the rod 64_x with respect to the vertical direction coincides with the deviation θbe_x_s (= θb_x_s−θb_x_obj) between the measured base body tilt angle value θb_x_s and the base body tilt angle target value θb_x_obj in the direction around the Y axis. Further, the changing speed (= dθbe_x / dt) of the inclination angle θbe_x of the rod 64_x is set to coincide with the measured body inclination angular velocity θbdot_x_s in the direction around the Y axis. Further, the movement speed Vw_x (translation movement speed in the X-axis direction) of the virtual wheel 62_x is the same as the movement speed in the X-axis direction of the wheel body 5 of the vehicle 1.

  Similarly, an inverted pendulum model (refer to the reference numerals in parentheses in FIG. 7) expressing the behavior seen from the X-axis direction includes a mass point 60_y located at the center of gravity of the vehicle system and a rotation axis 62a_y parallel to the X-axis direction. And virtual wheels 62_y (hereinafter referred to as virtual wheels 62_y) that can rotate on the floor surface. The mass point 60_y is supported by the rotation shaft 62a_y of the virtual wheel 62_y via a linear rod 64_y, and can swing around the rotation shaft 62a_y with the rotation shaft 62a_y as a fulcrum.

  In this inverted pendulum model, the motion of the mass point 60_y corresponds to the motion of the vehicle system center-of-gravity point viewed from the X-axis direction. In addition, the inclination angle θbe_y of the rod 64_y with respect to the vertical direction coincides with the deviation θbe_y_s (= θb_y_s−θb_y_obj) between the measured base body tilt angle value θb_y_s and the base body tilt angle target value θb_y_obj in the direction around the X axis. In addition, the change speed (= dθbe_y / dt) of the inclination angle θbe_y of the rod 64_y coincides with the measured base body inclination angular velocity θbdot_y_s in the direction around the X axis. Further, the moving speed Vw_y (translational moving speed in the Y-axis direction) of the virtual wheel 62_y is set to coincide with the moving speed in the Y-axis direction of the wheel body 5 of the vehicle 1.

The virtual wheels 62_x and 62_y have predetermined radii of predetermined values Rw_x and Rw_y, respectively. Further, the rotational angular velocities ωw_x and ωw_y of the virtual wheels 62_x and 62_y and the rotational angular velocities ω_R and ω_L of the electric motors 31R and 31L (more precisely, the rotational angular velocities ω_R and ω_L of the rotating members 27R and 27L), respectively. The relationship of the following formulas 01a and 01b is established.
ωw_x = C · (ω_R−ω_L) / 2 …… Formula 01a
ωw_y = (ω_R + ω_L) / 2 …… Formula 01b

Note that “C” in the expression 01a is a coefficient of a predetermined value depending on the mechanical relationship between the free rollers 29R and 29L and the wheel body 5 and slippage. Here, the dynamics of the inverted pendulum model shown in FIG. 7 is expressed by the following equations 03x and 03y. The expression 03x is an expression expressing the dynamics of the inverted pendulum model viewed from the Y-axis direction, and the expression 03y is an expression expressing the dynamics of the inverted pendulum model viewed from the X-axis direction.
d ² θbe_x / dt ² = α_x · θbe_x + β_x · ωwdot_x ...... Formula 03x
d ² θbe_y / dt ² = α_y · θbe_y + β_y · ωwdot_y ...... Formula 03y

  In equation 03x, ωwdot_x is the rotational angular acceleration of the virtual wheel 62_x (first-order differential value of the rotational angular velocity ωw_x), α_x is a coefficient that depends on the mass and height h_x of the mass 60_x, and β_x is the inertia (moment of inertia of the virtual wheel 62_x ) And the radius Rw_x. The same applies to ωwdot_y, α_y, and β_y in Expression 03y. As can be seen from these equations 03x and 03y, the motions of the mass points 60_x and 60_y of the inverted pendulum (and hence the motion of the center of gravity of the vehicle system) are the rotational angular acceleration ωwdot_x of the virtual wheel 62_x and the rotational angular acceleration ωwdot_y of the virtual wheel 62_y, respectively. It is defined depending on.

  Therefore, in the present embodiment, the rotational angular acceleration ωwdot_x of the virtual wheel 62_x is used as an operation amount (control input) for controlling the motion of the vehicle system center of gravity point viewed from the Y-axis direction, and viewed from the X-axis direction. The rotational angular acceleration ωwdot_y of the virtual wheel 62_y is used as an operation amount (control input) for controlling the motion of the vehicle system center of gravity.

  The calculation processing for vehicle control will be described schematically. The control unit 50 determines that the motion of the mass point 60_x viewed in the X-axis direction and the motion of the mass point 60_y viewed in the Y-axis direction are the vehicle system center of gravity. Virtual wheel rotational angular acceleration commands ωwdot_x_cmd and ωwdot_y_cmd, which are command values (target values) of the rotational angular accelerations ωwdot_x and ωwdot_y as the operation amounts, are determined so as to correspond to the desired motion. Further, the control unit 50 integrates the virtual wheel rotation angular acceleration commands ωwdot_x_cmd and ωwdot_y_cmd, and the virtual wheel rotation that is the command values (target values) of the respective rotation angular velocities ωw_x and ωw_y of the virtual wheels 62_x and 62_y. The angular velocity commands are determined as ωw_x_cmd and ωw_y_cmd.

  Then, the control unit 50 moves the virtual wheel 62_x corresponding to the virtual wheel rotational angular velocity command ωw_x_cmd (= Rw_x · ωw_x_cmd) and the virtual wheel 62_y corresponding to the virtual wheel rotational angular velocity command ωw_y_cmd (= Rw_y · ωw_y_cmd). ) As the target movement speed in the X-axis direction and the target movement speed in the Y-axis direction of the wheel body 5 of the vehicle 1, and the respective speeds of the electric motors 31 </ b> R and 31 </ b> L so as to realize these target movement speeds. The commands ω_R_cmd and ωL_cmd are determined.

  Next, the configuration of the walking assist system using the vehicle 1 will be described. 8 and 9 schematically show the configuration of the walking assist system according to the present embodiment. FIG. 8 is a view of the walking assist system as viewed from the side, and FIG. 9 is a view of the walking assist system as viewed from above.

  The walking assist system according to the present embodiment includes two vehicles 1a and 1b each including a tilt sensor 52 and a six-axis force sensor 57, and a belt 58 on which the two vehicles 1a and 1b are locked. When the user U (wearer) walks while wearing the belt 58 on the waist, the two vehicles 1a and 1b support the user U and assist the walking by pushing the user U from behind. In addition, since a person does not board the vehicles 1a and 1b, the seat 3, the seat frame 15, the grips 17R and 17L, the brackets 19R and 19L, the steps 25R and 25L, and the load sensor 54 described above are not necessary. In the present embodiment, two vehicles are used, but three or more vehicles may be used.

  The belt 58 includes an angle sensor (opening angle sensors 59a and 59b described later) for detecting the opening angle θ1 of the vehicle 1a and the opening angle θ2 of the vehicle 1b with respect to the horizontal direction with respect to the reference axis P direction, and the vertical direction. A button (an inclination angle reset button 61 described later) for resetting a target value θb_x_obj of the base body inclination angle θb corresponding to the inclination angle of each vehicle is incorporated. This angle sensor is disposed at a connection portion of the belt 58 with the vehicles 1a and 1b, and when the vehicles 1a and 1b rotate in a horizontal plane around an axis connecting the vehicles 1a and 1b and the belt 58. The amount of rotation is detected as opening angles θ1 and θ2. In the present embodiment, since the control is performed so that the opening angles θ1 and θ2 converge uniformly, the positional relationship between the user U and the vehicles 1a and 1b is constant even when the user U moves in an arbitrary direction. Can be kept in. That is, the direction of the vehicles 1a and 1b changes according to the change in the direction of the user U, and the opening angle of the vehicles 1a and 1b becomes constant.

  The target value θb_x_obj of the base body tilt angle θb is set to, for example, the base body tilt angle θb when the user U wears the belt 58. In the present embodiment, control is performed such that the measured value θb_x_s of the base body inclination angle θb of the vehicles 1a and 1b converges to the target value θb_x_obj.

  The vehicles 1a and 1b incorporate a six-axis force sensor 57 that detects the force applied to the vehicles 1a and 1b (force between the vehicles 1a and 1b and the wearer) together with the tilt sensor 52 described above. The six-axis force sensor 57 is disposed in the vicinity of the connection portion with the belt 58 in the vehicles 1a and 1b. In the following, the force in the X-axis direction in the coordinate system of the vehicle 1a detected by the six-axis force sensor 57 of the vehicle 1a is Fx1, and the X-axis in the coordinate system of the vehicle 1b detected by the six-axis force sensor 57 of the vehicle 1b. The direction force is Fx2. In the present embodiment, the speed of the vehicles 1a and 1b is controlled in accordance with the low frequency component of the force detected by the six-axis force sensor 57. Therefore, the walking fluctuation due to the fluctuation of the movement of the vehicles 1a and 1b in the front-rear direction (for example, The meandering in the left-right direction) is suppressed, and the user U can stably travel in a certain direction.

  FIG. 10 shows a functional configuration of the walking assist system according to the present embodiment. In addition, FIG. 10 shows only the configuration of the main part related to the travel control of the vehicles 1a and 1b, and a part of the configuration is omitted.

  The belt 58 includes an opening angle sensor 59a for detecting the opening angle θ1 of the vehicle 1a, an opening angle sensor 59b for detecting the opening angle θ2 of the vehicle 1b, and an inclination angle reset button 61. A signal indicating the opening angle θ1 detected by the opening angle sensor 59a is output to the control unit 50 of the vehicle 1a, and a signal indicating the opening angle θ2 detected by the opening angle sensor 59b is output to the control unit 50 of the vehicle 1b. A signal from the tilt angle reset button 61 is output to the control unit 50 of the vehicles 1a and 1b.

  The vehicles 1a and 1b include an actuator device 7 that generates the driving force of the wheel body 5 shown in FIG. 1 and the like, a control unit 50 that controls the traveling of each vehicle, a base body inclination angle θb, and its change speed (= dθb / An inclination sensor 52 that detects dt) and a six-axis force sensor 57 that detects a force applied to each vehicle (a force between each vehicle and the wearer). As described above, the actuator device 7 includes the rotating member 27R and the free roller 29R, the rotating member 27L and the free roller 29L, the electric motor 31R, and the electric motor 31L illustrated in FIG.

  Next, the control process of the control unit 50 will be described in more detail. The control unit 50 executes the process (main routine process) shown in the flowchart of FIG. 11 at a predetermined control process cycle.

  First, in step S100, the control unit 50 acquires the output of the tilt sensor 52.

  Next, the process proceeds to step S110, and the control unit 50 calculates the measured value θb_xy_s of the base body tilt angle θb and the measured value θbdot_xy_s of the base body tilt angular velocity θbdot based on the acquired output of the tilt sensor 52.

  Next, proceeding to step S120, the control unit 50 obtains the measured value θ1_s of the opening angle θ1 that is the output of the opening angle sensor 59a or the measured value θ2_s of the opening angle θ2 that is the output of the opening angle sensor 59b.

  Next, the process proceeds to step S130, and the control unit 50 acquires the measurement value Fx1_s of the force Fx1 or the measurement value Fx2_s of the force Fx2 that is the output of the six-axis force sensor 57.

  Next, the process proceeds to step S140, and the control unit 50 determines whether or not the tilt angle reset button 61 has been operated. This operation is, for example, an operation of switching the tilt angle reset button 61 from OFF to ON.

  When the tilt angle reset button 61 is operated, the process proceeds to step S150, and the control unit 50 sets the target value θb_x_obj of the base body tilt angle θb to the current base body tilt angle θb. When the initially set target value θb_x_obj does not match the walking characteristics of the user U and the user U feels it is difficult to walk, the target value θb_x_obj is updated to the base body tilt angle θb at one point during walking. Thus, the user's walking can be further stabilized. If the tilt angle reset button 61 is operated, the process proceeds to the next step S160 without executing step S150.

  Next, the process proceeds to step S160, and the control unit 50 determines the respective speed commands of the electric motors 31R and 31L by executing a vehicle control calculation process. Details of this vehicle control calculation processing will be described later.

  Next, the process proceeds to step S170, and the control unit 50 executes an operation control process for the electric motors 31R and 31L in accordance with the speed command determined in step S160. In this operation control process, the control unit 50 determines the difference between the speed command of the electric motor 31R determined in step S160 and the measured value of the rotational speed of the electric motor 31R measured based on the output of the rotary encoder 56R. The target value (target torque) of the output torque of the electric motor 31R is determined so that the deviation converges to “0”. Then, the control unit 50 controls the energization current of the electric motor 31R so that the output torque of the target torque is output to the electric motor 31R. The same applies to the operation control of the left electric motor 31L. The above is the overall control process executed by the control unit 50.

  As described above, the control unit 50 has the function shown in the block diagram of FIG. 12 as a function for executing the vehicle control calculation process in step S160. That is, the control unit 50 includes a filter calculation unit 70 that functions as a low-pass filter with a time constant T for removing a high-frequency component of the force measurement value Fx1_s applied to the vehicle 1a, and a high-frequency of the force measurement value Fx2_s applied to the vehicle 1b. A filter calculation unit 71 that functions as a low-pass filter with a time constant T for removing components, and a center-of-gravity speed calculation unit that calculates a center-of-gravity speed estimated value Vb_xy_s as an observed value of the center-of-gravity speed Vb_xy that is the moving speed of the center of gravity of the vehicle 72. Further, the control unit 50 further outputs the above-described attitude control calculation unit 80 for calculating the virtual wheel rotation angular velocity command ωw_xy_cmd and the virtual wheel rotation angular velocity command ωw_xy_cmd to the speed command ω_R_cmd (rotation angular velocity command) of the right electric motor 31R. Value) and a speed command ω_L_cmd (rotational angular speed command value) of the left electric motor 31L.

  The reference numeral 84 in FIG. 12 indicates a delay element for inputting the virtual wheel rotation angular velocity command ωw_xy_cmd calculated by the attitude control calculation unit 80 for each control processing cycle. The delay element 84 outputs the previous value ωw_xy_cmd_p of the virtual wheel rotation angular velocity command ωw_xy_cmd in each control processing cycle.

  In the vehicle control calculation process of step S160, the processes of the above-described respective processing units are executed as described below. That is, the control unit 50 first executes the processing of the filter calculation units 70 and 71 and the processing of the gravity center speed calculation unit 72.

  The force calculation value Fx1_s acquired in step S130 is input to the filter calculation unit 70. Then, the filter calculation unit 70 performs a filter calculation for removing a high frequency component from Fx1_s. Similarly, the force measurement value Fx2_s acquired in step S130 is input to the filter calculation unit 71. Then, the filter calculation unit 71 performs a filter calculation for removing a high frequency component from Fx2_s.

  The center-of-gravity velocity calculation unit 72 receives the current value of the base body tilt angular velocity measurement value θbdot_xy_s (θbdot_x_s and θbdot_y_s) calculated in step S110, and delays the previous value ωw_xy_cmd_p (ωw_x_cmd_p and ωw_y_cmd_p) of the virtual wheel speed command ωw_xy_cmd. Input from element 84. Then, the center-of-gravity speed calculation unit 72 calculates the center-of-gravity speed estimated values Vb_xy_s (Vb_x_s and Vb_y_s) from these input values using a predetermined arithmetic expression based on the inverted pendulum model.

Specifically, the center-of-gravity velocity calculation unit 72 calculates Vb_x_s and Vb_y_s by the following equations 05x and 05y, respectively.
Vb_x_s = Rw_x · ωw_x_cmd_p + h_x · θbdot_x_s ...... 05x
Vb_y_s = Rw_y · ωw_y_cmd_p + h_y · θbdot_y_s …… 05y

  In these expressions 05x and 05y, Rw_x and Rw_y are the respective radii of the virtual wheels 62_x and 62_y as described above, and these values are predetermined values set in advance. H_x and h_y are the heights of the mass points 60_x and 60_y of the inverted pendulum model, respectively. In this case, in the present embodiment, the height of the center of gravity of the vehicle is maintained substantially constant. Therefore, predetermined values set in advance are used as the values of h_x and h_y, respectively.

  The first term on the right side of the formula 05x is the moving speed in the X-axis direction of the virtual wheel 62_x corresponding to the previous value ωw_x_cmd_p of the speed command of the virtual wheel 62_x, and this moving speed is the X-axis direction of the wheel body 5 This corresponds to the current value of the actual movement speed. Further, the second term on the right side of the expression 05x is the movement speed in the X-axis direction of the vehicle system center-of-gravity point caused by the base body 9 tilting at the inclination angular velocity of θbdot_x_s around the Y axis (relative to the wheel body 5). This is equivalent to the current value of the movement speed. The same applies to Formula 05y.

  Note that a set of rotational angular velocity values (current value) of the electric motors 31R and 31L measured based on the outputs of the rotary encoders 56R and 56L is converted into a set of rotational angular velocities of the virtual wheels 62_x and 62_y. These rotational angular velocities may be used instead of ωw_x_cmd_p and ωw_y_cmd_p in the expressions 05x and 05y. However, it is advantageous to use the target values ωw_x_cmd_p and ωw_y_cmd_p in order to eliminate the influence of noise included in the measured value of the rotational angular velocity.

  The control unit 50 executes the processing of the filter control units 70 and 71 and the gravity center speed calculation unit 72 as described above, and then executes the processing of the attitude control calculation unit 80. Processing of the attitude control calculation unit 80 will be described.

  The posture control calculation unit 80 calculates the force measurement values Fx1_s and Fx1_s from which the high frequency components have been removed by the filter calculation units 70 and 71, the opening angle measurement values θ1_s and θ2_s acquired in step S120, and the calculation in step S110. The base body tilt angle measured value θb_xy_s, the base body tilt angular velocity measured value θbdot_xy_s, and the center of gravity speed estimated value Vb_xy_s calculated by the center of gravity speed calculator 72 are input.

  Then, the attitude control calculation unit 80 first calculates virtual wheel rotation angular acceleration commands ωwdot_xy_cmd (ωwdot_x_cmd and ωwdot_y_cmd) by using the following expressions 07x, 07y, 08x, 08y using these input values.

  The expressions 07x and 07y are expressions for the vehicle 1a and are expressions for the expression 08x and 08y vehicle 1b. K1 to K6 and W1 to W3 are gain coefficients, θset is a target value of the opening angles θ1 and θ2, and bias is, for example, a fixed value.

  Therefore, in this embodiment, as an operation amount (control input) for controlling the motion of the mass point 60_x of the inverted pendulum model as viewed from the Y-axis direction (and hence the motion of the center of gravity of the vehicle as viewed from the Y-axis direction). Virtual wheel rotation angular acceleration command ωwdot_x_cmd and the operation amount (control input) for controlling the motion of the mass point 60_y of the inverted pendulum model viewed from the X-axis direction (and the motion of the center of gravity of the vehicle viewed from the X-axis direction) The virtual wheel rotation angular acceleration command ωwdot_y_cmd is determined by adding the five terms on the right side of the expressions 07x, 07y, 08x, and 08y, respectively.

  Here, the first term and the second term on the right side of the expression 07x are the PD law (proportional / differential law) as the feedback control law, which is the difference between the measured base body tilt angle value θb_x_s and the target value θb_x_obj around the X axis. Therefore, it has a meaning as a feedback manipulated variable component for converging to “0” (converging the base body tilt angle measurement value θb_x_s to the target value θb_x_obj). The same applies to the first and second terms on the right side of Expression 08x.

  Also, the first and second terms on the right side of the expression 07y have the meanings as feedback manipulated variable components for converging the base body tilt angle measurement value θb_y_s in the direction around the Y axis to “0” by the proportional / derivative law. Have. The same applies to the first and second terms on the right side of Expression 08y.

  The third term on the right side of the expression 07x has a meaning as a feedback manipulated variable component for converging the center-of-gravity velocity estimated value Vb_x_s to “0” by the proportional law as the feedback control law. The same applies to the third term on the right side of the expressions 07y, 08x, and 08y.

  The fourth term on the right side of the expression 07x has a meaning as a feedback manipulated variable component for converging the low frequency component of the force measurement value Fx1_s to “0” by the proportional law as the feedback control law. Low frequency component in order to prevent the user U from pulling the vehicle 1a, 1b gently rather than suddenly to the speed of the vehicle 1a, 1b so as not to be affected by the back and forth movement of the waist and the left and right shaking due to walking. Only take out. As a result, the back and forth movement of the waist and the shaking of the left and right are suppressed, and walking is stabilized. The same applies to the fourth term on the right side of Expression 08x.

  Further, the fourth and fifth terms on the right side of the expression 07y converge the difference between the measured opening angle value θ1_s and the target value θset to “0” by the PD rule (proportional / differential rule) as a feedback control law ( It has a meaning as a feedback manipulated variable component for converging the measured opening angle value θ1_s to the target value θset). The same applies to the fourth and fifth terms on the right side of Expression 08y.

  Further, the fifth term on the right side of the expression 07x is a bias for the vehicles 1a and 1b to always push the user U slightly. The same applies to the fifth term on the right side of Expression 08x. This bias may be a fixed value or may be adjusted during walking. Due to the presence of this bias, the user U is always pushed and walking is facilitated.

  After calculating the virtual wheel rotation angular acceleration commands ωwdot_x_cmd and ωwdot_y_cmd as described above, the attitude control calculation unit 80 then determines the virtual wheel rotation speed commands ωw_x_cmd and ωw_y_cmd by integrating these ωwdot_x_cmd and ωwdot_y_cmd respectively. To do. The above is the details of the processing of the attitude control calculation unit 80.

  Returning to the description of FIG. 12, the control unit 50 next inputs the virtual wheel rotational speed commands ωw_x_cmd, ωw_y_cmd determined by the attitude control calculation unit 80 as described above to the motor command calculation unit 82, and the motor command calculation unit By executing the process 82, the speed command ω_R_cmd of the electric motor 31R and the speed command ω_L_cmd of the electric motor 31L are determined.

  Specifically, the motor command calculation unit 82 replaces ωw_x, ωw_y, ω_R, and ω_L in the above-described equations 01a and 01b with ωw_x_com, ωw_y_com, ω_R_cmd, and ω_L_cmd, respectively, and ω_R_cmd and ω_L_cmd as unknown numbers. To determine the speed commands ω_R_com and ω_L_com of the electric motors 31R and 31L. Thus, the vehicle control calculation process in step S160 is completed.

  As described above, when the control unit 50 executes the control calculation process, basically, the posture of the base body 9 is such that the difference between the base body tilt angle measurement value θb_x_s and the target value θb_x_obj is “0” and the base body tilt angle measurement is performed. The virtual wheel rotation angular acceleration command ωwdot_xy_cmd as the operation amount (control input) is determined so that the posture where the value θb_y_s is “0” (hereinafter, this posture is referred to as a basic posture).

  Then, the rotational angular velocities of the electric motors 31R and 31L obtained by converting the virtual wheel rotational angular velocity command ωw_xy_cmd obtained by integrating the components of ωwdot_xy_cmd are determined as the speed commands ω_R_cmd and ω_L_cmd of the electric motors 31R and 31L. Further, the rotational speeds of the electric motors 31R and 31L are controlled according to the speed commands ω_R_cmd and ω_L_cmd. As a result, the moving speeds of the wheel body 5 in the X-axis direction and the Y-axis direction are controlled so as to coincide with the moving speed of the virtual wheel 62_x corresponding to ωw_x_cmd and the moving speed of the virtual wheel 62_y corresponding to ωw_y_cmd, respectively. The

  For this reason, for example, when the actual base body tilt angle θb_x deviates from the target value θb_x_obj in the direction around the Y axis, the speed of the wheel body 5 changes to eliminate the deviation. For example, when the actual base body tilt angle θb_y deviates from “0” in the direction around the X axis, the speed of the wheel body 5 changes in order to eliminate the deviation.

  In this way, when the base body 9 is tilted from the basic posture, the speed of the wheel body 5 is changed so as to return the posture toward the tilted side.

  When the user U is about to fall down, control is performed to return the base body tilt angle θb_x to the target value θb_x_obj according to the first term of the expressions 07x and 08x. In addition, the control to try to set the speed to “0” (try to stop toppling) works according to the second term of the expressions 07x and 08x. Alternatively, when the user U is about to fall down suddenly, the influence is mitigated by the fourth term of the expressions 07x and 08x.

  Further, when the control unit 50 executes the control calculation process, the operation amount is set so that the posture of the base body 9 is maintained in a posture where the difference between the opening angle measured values θ1_s, θ2_s and the target value θset is “0”. A virtual wheel rotation angular acceleration command ωwdot_y_cmd as (control input) is determined.

  Note that when the user U moves, for example, diagonally forward right by his / her own intention, the force Fx1 increases, and the vehicle 1a moves faster than the vehicle 1b. Therefore, the user U can move forward diagonally to the right. Similarly, when the user U moves to the left diagonally forward, for example, by his own intention, the user U can move forward diagonally to the left. Further, when the user U wants to turn clockwise or counterclockwise, when the user U moves in this way, the opening angles θ1 and θ2 are controlled to be θset.

  As described above, since a user (wearer) who is walking is supported by two or more omnidirectional vehicles, a wide support base surface formed by the user's legs and omnidirectional vehicles can be obtained. , Increase the stability of walking. In addition, since the vehicle control calculation is performed based on the force detected by the force sensor and the angle detected by the angle sensor, the drive mechanism can be controlled so that the user's walking is stabilized. Can be improved.

  In addition, by carrying out vehicle control calculations to converge the opening angle in the horizontal plane uniformly, even if the user moves in any direction, the positional relationship between the user and the omnidirectional vehicle can be kept constant. it can.

  Further, the vehicle control calculation is performed so that the base body tilt angle in the vertical plane is converged to the tilt angle at a desired time point (for example, when the user wears the belt 58 or one time point during walking). The fluctuation in the vertical direction when the moving vehicle pushes the user can be suppressed, and the walking stability of the wearer can be further improved.

  In addition, by performing vehicle control calculations and controlling the speed of omnidirectional vehicles according to the low-frequency component of force, fluctuations associated with fine movements during walking can be suppressed, and the user's walking stability can be reduced. This can be further improved.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the above-described embodiments, and includes design changes and the like without departing from the gist of the present invention. .

1, 1a, 1b Omnidirectional moving vehicle (moving body)
5 Wheel body (driven mechanism)
7 Actuator device (drive unit)
9 Base 50 Control unit (control device)
52 Tilt sensor (angle sensor)
57 6-axis force sensor (force sensor)
58 Belt (locking tool)
59a, 59b Opening angle sensor (angle sensor)

Claims (4)

Inverted pendulum control type movement having a driven mechanism capable of moving a traveling surface, a driving unit for generating a driving force for driving the driven mechanism, and a base body on which the driven mechanism and the driving unit are assembled. A locking tool capable of locking at least two bodies to the waist of the wearer;
A force sensor for detecting a force applied to the inverted pendulum control type moving body;
An angle sensor for detecting an angle related to the posture of the inverted pendulum control type moving body;
At least two inverted pendulum control type moving bodies locked to the locking tool;
A control device for controlling the drive unit based on the force detected by the force sensor and the angle detected by the angle sensor;
Walking assistance system with   The said control apparatus detects the opening angle between the said inverted pendulum control type moving bodies with respect to a horizontal direction with the said angle sensor, and controls the said drive part so that the said opening angle converges uniformly. Walking assistance system.   The control device detects, at the first time point and the second time point, the tilt angle of the inverted pendulum control type moving body with respect to a vertical direction by the angle sensor, and the tilt angle detected at the second time point is The walking assist system according to claim 1, wherein the drive unit is controlled to converge to the tilt angle detected at the first time point.   The walking assist system according to claim 1, wherein the control device controls the drive unit according to a frequency component of a force detected by the force sensor.

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