WO2011096367A1

WO2011096367A1 - Mobile floor reaction force measuring device

Info

Publication number: WO2011096367A1
Application number: PCT/JP2011/051944
Authority: WO
Inventors: 喜雄井上; 京子芝田; 涛劉; 伸好辻内; 和美纐纈; 陽太郎土屋
Original assignee: 公立大学法人高知工科大学; 学校法人同志社; 株式会社テック技販
Priority date: 2010-02-02
Filing date: 2011-01-31
Publication date: 2011-08-11
Also published as: JP2011158404A; JP4912477B2

Abstract

In order to enable the accurate measurement of reaction force from the floor surface and moment without using a camera and enable the measurement of the orientation of a foot within a horizontal plane, reaction force sensors (10) are attached in three positions to each of a sensor unit (101) provided on the heel side of a foot of a subject and a sensor unit (102) provided on the toe side of the foot to find forces in the directions of three axes orthogonal to each other and moments around the axes. The sensor units (101, 102) are each provided with a posture detection sensor (107) for detecting the angle thereof from the horizontal plane and a geomagnetic sensor (108) for detecting the orientation in the horizontal direction of the foot of the subject, the angle formed with the floor surface is corrected using the posture detection sensor (107), and the change of the orientation within the floor surface is corrected using the geomagnetic sensor (108).

Description

Mobile floor reaction force measuring device

The present invention relates to a mobile floor reaction force measuring device that measures the force in the XYZ-axis direction applied to the sole of the foot and the moment around the XYZ-axis, and can also detect the moving direction of the foot. More specifically, the present invention relates to a mobile floor reaction force measuring apparatus that can estimate a joint moment and muscle force applied to a human lower limb based on a reaction force from the floor.

In recent years, in fields such as rehabilitation, welfare, and sports, footwear that can estimate the walking state of human beings, moments applied to lower limb joints, muscle strength applied to lower limbs, and reaction force measurement devices attached to the footwear have been proposed. (Patent Document 1).

Among such reaction force measuring devices, Japanese Patent Application Laid-Open No. 2007-108079 discloses a reaction force measuring device attached to the floor surface side of the footwear 5 as shown in FIG.

This reaction force measuring device is configured by attaching a plurality of reaction force sensors 70 between two upper and lower upper plates 6u and 6d on which an external force acts. XYZ direction force is output based on the above, and moments about the X axis, the Y axis, and the Z axis can be measured based on the distance and force difference from each reaction force sensor 70.

Further, in Patent Document 1, in order to improve the stability during walking, a sensor unit 71 and a sensor unit 72 are separately provided at two locations of a heel portion and a tip portion of the foot, and the sensor unit 71, The position of the marker 80 provided at 72 is imaged with a camera so that the reaction force and moment from the floor can be measured.

Japanese Unexamined Patent Publication No. 2007-108079 (FIGS. 17, 22, etc.)

However, the method for measuring the reaction force from the floor using the reaction force measuring device as described above has the following problems.

In other words, when the sensor unit is attached to the heel part and the tip part of the foot as described above, the relative angle of each sensor unit changes during walking, so the reaction force and moment are accurately measured. There is a problem that it becomes impossible to do. In detail, when a human walks, as shown in FIGS. 7 (a) to (c), first, the heel portion comes first to contact with the floor (FIG. 7 (a)). In this case, the sensor unit 101 at the heel portion is substantially parallel to the floor surface, while the sensor unit 102 at the distal end side is inclined with respect to the floor surface. When the reaction force from the floor surface is obtained in each of the

sensor units

101 and 102 in such a state, since the angle between the heel side sensor unit 101 and the tip side sensor unit 102 is different, forces and moments in different directions are obtained. Will be measured. Similarly, in the case of taking the next step, as shown in FIG. 7C, the sensor unit 102 on the front end side is substantially parallel to the floor surface, while the sensor unit 101 in the heel portion is on the floor surface. Therefore, the force and moment at different angles will be measured.

Also, when measuring forces and moments in this way, it may be preferable to measure forces and moments in an absolute coordinate system rather than determining coordinates based on the sensor unit. For example, when walking in the inner crotch state where the toe side is rotated inward after grounding the heel during walking (the state of FIG. 8), or when switching between the accelerator and brake of a car, the absolute coordinate system It is preferable to be able to detect what force is applied in which direction.

On the other hand, in Patent Document 1, the

sensor units

71 and 72 are attached with markers and photographed with a camera. With this method using a camera, the measurable location is the field of view of the camera. There is a problem that it is limited within the range of corners. For this reason, the inspection using the camera cannot be performed in a narrow place where the camera cannot be set up or in a wide place where walking for a very long distance is required.

Therefore, in order to solve the above problems, the present invention makes it possible to accurately measure the reaction force and moment from the floor without using a camera, and to move the foot in the horizontal plane. An object of the present invention is to provide a mold reaction force detection device.

That is, in order to solve the above-mentioned problems, the present invention is a movable floor reaction that is attached to a subject's foot and measures a force in three orthogonal directions and a moment around each axis based on a reaction force from the floor surface. In the force measuring device, a plurality of sensor units that are provided separately on the heel side of the foot and the tip side of the foot and measure the reaction force in the three orthogonal directions and the moment about each axis, and each of the sensors A posture detection sensor for detecting the posture of the unit and an azimuth sensor for detecting the direction of the subject's foot with respect to the horizontal direction are provided.

In this way, the angle between the foot heel side sensor unit and the tip side sensor unit can be detected by the posture detection sensor, so even if the ground contact state of the foot changes during walking, the floor can be accurately detected. The reaction force and moment received from the surface can be measured. In addition, the direction sensor can detect which direction the sensor unit is facing, so it is not limited to the viewing angle of the camera. It becomes possible to measure the force and moment based on it.

In such an invention, when the reaction force sensor is provided in the sensor unit, the reaction force sensor is provided so as to form a triangular shape having the arch side of the foot as a vertex.

In this way, since many reaction force sensors are provided on the heel portion where the body weight is most applied and the tip portion of the foot, the force applied to each reaction force sensor is dispersed to reduce the load resistance of the reaction force sensor. Can do. Thereby, even when the reaction force sensor is attached to a shoe sole or the like, it is possible to reduce the thickness and eliminate the uncomfortable feeling.

According to the present invention, in a mobile floor reaction force measuring device that is attached to a subject's foot and measures a force in three axial directions orthogonal to each other based on a reaction force from the floor and a moment around each axis, A plurality of sensor units that are provided separately on the heel side and the tip end side of the foot, and measure the reaction force in the three orthogonal directions and the moments around the respective axes, and the postures for detecting the postures of the respective sensor units A detection sensor and an azimuth sensor for detecting the direction of the subject's foot in the horizontal direction are provided, and even when the ground contact state of the foot changes during walking, Moment can be measured. In addition, the direction sensor can detect which direction the sensor unit is facing, so it is not limited to the viewing angle of the camera. It becomes possible to measure the force and moment based on it.

Schematic of a mobile floor reaction force measuring device according to an embodiment of the present invention Schematic cross section of mobile floor reaction force measuring device External perspective view of reaction force sensor used in sensor unit of same form Functional block diagram of mobile floor reaction force measuring device in the same form The figure which shows the strain gauge attached to the leg part of the reaction force sensor of the same form (a), and the figure which shows the strain gauge in the back surface side (b) The figure which shows the bridge circuit of the same form Diagram showing human walking state The figure which shows the state and coordinate system which changed the angle by raising a foot to the floor which is a horizontal plane Reaction force measuring device in the conventional example

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The mobile floor reaction force measuring device 100 in this embodiment is used by being attached to the back surface of footwear 5 such as shoes or sandals, and as shown in FIG. 1, on the heel side of the foot and the tip side of the foot. Two independent sets of

sensor units

101 and 102 are provided so that each

sensor unit

101 and 102 can output a reaction force from the floor and a moment about its three axes in the absolute coordinate system XYZ. Then, using the output value and the output value of the posture sensor (not shown) provided on the lower leg and thigh other than this, it is possible to measure the load on the muscles and joints of the human lower limb that performs rehabilitation etc. It is a thing. Hereinafter, the configuration of the movable floor reaction force measuring apparatus 100 according to the present embodiment will be described in detail. In the present embodiment, X′Y′Z ′ is described as a coordinate system based on the

sensor units

101 and 102, and XYZ is described as an absolute coordinate system.

As shown in FIGS. 1 and 2, the

sensor units

101 and 102 constituting the movable floor reaction force measuring device 100 are provided with a reaction force sensor 10 between an upper plate 1 u and a lower plate 1 d, and each reaction force. Based on the output value from the sensor 10, the force in the XYZ directions and the moment about each axis in the absolute coordinate system can be measured. Here, the upper plate 1u and the lower plate 1d are made of a relatively hard material such as a metal plate, hard plastic, or ceramic. In FIG. 1, the upper plate 1u is indicated by a broken line. At this time, if the upper plate 1u and the lower plate 1d are made of a relatively soft material, a large load is applied only to the specific reaction force sensor 10, and the load cannot be endured. On the other hand, if the reaction force sensor 10 is enlarged so as to be able to withstand this load, the size of the reaction force sensor 10 increases the state of the foot as when the boots are worn, making natural walking difficult. Therefore, the upper plate 1u and the lower plate 1d are made of a hard material, so that the load applied to each reaction force sensor 10 can be dispersed and the reaction force sensor 10 itself can be made smaller. Moment can be measured by distance and load. As a method of dispersing the load applied to the reaction force sensor 10, first, as shown in FIG. 1, the sensor unit 101 on the heel side is provided with two reaction force sensors 10 on the heel side of the foot, and on the arch side. One reaction force sensor 10 is provided. As for the sensor unit 102 on the tip side of the foot, two reaction force sensors 10 are provided on the tip side of the foot, and one reaction force sensor 10 is provided on the arch side so as to form an equilateral triangle. In this way, since the plurality of reaction force sensors 10 are arranged at the place where the load is most likely to be applied, the load resistance can be reduced, and the thickness of the shoe sole can be reduced by reducing the upper and lower thickness widths. You can make it smaller.

The upper plate 1u and the lower plate 1d are attached to the footwear 5 in a state of being separated into the heel side and the distal end side of the foot so as to give freedom to the movement of the foot during human walking. Of the upper plate 1u and the lower plate 1d, the upper plate 1u is detachably attached to the back surface of the footwear 5 (see FIG. 7) via a hook-and-loop fastener or the like, or is attached to the shoe sole integrally. In addition, a rubber plate or the like is attached to the lower surface side of the lower plate 1d in order to improve cushioning with the floor surface. The upper plate 1u may be attached to the back surface of the footwear 5 by other methods. On the lower surface side of the lower plate 1d, a non-woven fabric such as felt is attached to provide cushioning properties. Also good.

The reaction force sensor 10 attached between the upper plate 1u and the lower plate 1d is a sensor that can measure forces in three orthogonal directions. Here, the three orthogonal axes indicate the respective axes X′Y′Z ′ of the orthogonal coordinate system with reference to each reaction force sensor 10, and the values in the respective axis directions and the posture detection sensor 107 described later. Then, it is converted into an absolute coordinate system using the geomagnetic sensor 108 and the reaction force in the XYZ directions is measured.

FIG. 3 shows an external perspective view of the reaction force sensor 10 in this embodiment. The reaction force sensor 10 shown in FIG. 3 has a size of about 20 mm × about 20 mm in length and width and a thickness of about 5 mm to 6 mm. From the square frame 11 and the center of the frame 11 Legs 12 to 15 extending radially outward and eight first strains provided on both side surfaces of the legs 12 to 15 so as to detect displacement in the longitudinal direction of the legs 12 to 15 The gauges 21 to 28 and the second strain gauges 31 to 38 attached at an angle of about 45 degrees with respect to the longitudinal direction of the legs 12 to 15 are included. In FIG. 3, the first strain gauges 22, 23, 25, 28 and the second strain gauges 32, 33, 35, 38 are not shown because they are provided on the back side of the leg portions 12-15. In such a configuration, a force is applied to the pin 16 penetrating into the center tap hole so that the forces in the three orthogonal directions can be detected.

These leg portions 12 to 15 are configured in a vertically long plane shape having a slight gap from the bottom surface portion of the frame portion 11, thereby being able to withstand a large load in the thickness direction (Z ′ direction in FIG. 3). ing. The first strain gauges 21 to 28 attached to the eight portions on both sides of the leg portions 12 to 15 are attached in the longitudinal direction, and the first strain gauges 21 to 28 are used in FIG. The bridge circuit 41 shown in FIG. 4 is configured so that the load applied in the X ′ direction and the Y ′ direction can be detected. Further, the second strain gauges 31 to 38 are attached at eight positions so as to form an angle of 45 degrees on each side surface of the leg portions 12 to 15, and detect a load applied in the Z ′ direction or the oblique direction. When the second strain gauges 31 to 38 are attached to the both side surfaces, they are attached so that the direction on the front surface side and the direction on the back surface side are reversed. And a load in the Z ′ direction is detected by a change in the resistance value of the bridge circuit.

The reaction force sensor 10 will be described in detail. The bridge circuit 41 shown in FIG. 6A is formed by the first strain gauges 21, 22, 25, 26 provided on the pair of opposing

legs

12, 14. At the same time, a bridge circuit 41 shown in FIG. 6B is formed by the first strain gauges 23, 24, 27, 28 provided on a pair of

leg portions

13, 15 that are adjacent to each other and are opposed to each other. On the other hand, for the bridge circuit 42 using the second strain gauges 31 to 38, as shown in FIG. 6C, the second strain gauges 31 to 38 provided on the front and back of the same leg portions 12 to 15 are connected in series. The bridge circuit 42 is formed so that the second strain gauges 31 to 38 of the leg portions 12 to 15 facing each other face each other.

Here, a case where force is applied to the pin 16 in the center will be described. When a force F _Z is applied in the Z′-axis direction, the center portion moves in the Z′-axis direction, and the leg portions 12 to 15 are bent. As a result, the first strain gauges 21, 22, 25, 26 and the second strain gauges 31, 32, 35, 36 change so as to extend, and the resistance value increases. On the other hand, the first strain gauges 23, 24, 27, and 28 change in the direction in which the length increases, that is, the direction in which the resistance value increases, and the second strain gauges 33, 34, 37, and 38 have a length in the direction. It changes in the direction of shrinking, and changes in the direction of decreasing the resistance value. Thus, when the length of each strain gauge changes, the bridge circuit 42 formed by the second strain gauges 31 to 38 can detect a change in the Z′-axis direction. On the other hand, no change in the Z ′ direction is detected in the bridge circuit 41 formed by the first strain gauges 21 to 28. That is, when the increase in resistance value of the first strain gauges 21 to 28 is equal, the output voltage does not change, and the output voltage does not change for the first strain gauges 21 to 28 as well.

On the other hand, when a force is applied in the Y′-axis direction, the leg portion 12 is compressed, the leg portion 14 changes so as to extend, and the leg portion 13 and the leg portion 15 change in a bending direction. As a result, the first strain gauges 21, 22 and the second strain gauges 31, 32 change in the direction in which the length contracts, and the resistance value decreases. On the other hand, since the

first strain gauges

25 and 26 and the second strain gauges 25 and 36 change in the direction in which the length increases, the resistance value increases. Further, since the

first strain gauges

24 and 27 and the second strain gauges 34 and 37 change in the direction in which the length increases, the resistance value increases. On the other hand, the

first strain gauges

23 and 28 and the second strain gauges 33 and 38 change in the direction in which the length is reduced, and the resistance value decreases.

When the lengths of the leg portions 12 to 15 are changed in this way, a change in the Y′-axis direction is caused by the bridge circuit 41 (FIG. 6A) formed by the first strain gauges 21, 22, 25, and 26. As a result, the output voltage is changed by increasing the resistance of the

first strain gauges

25 and 26 and decreasing the resistance of the

first strain gauges

21 and 22.

On the other hand, in the bridge circuit 41 (FIG. 6B) formed by the first strain gauges 23, 24, 27, and 28, a change in the Y′-axis direction is not detected. This is because if the magnitude of the resistance decrease of the

first strain gauges

23 and 28 is equal to the magnitude of the resistance increase of the

first strain gauges

24 and 27, the output voltage cannot be changed. As described above, the reaction force sensor 10 can detect the force in the Y′-axis direction, and the force in the X ′ direction can be detected in the same manner in the X ′ direction.

Thus, the reaction force acting in the X′Y′Z ′ direction is detected by the reaction force sensor 10 constituted by the first strain gauges 21 to 28 and the second strain gauges 31 to 38.

The reaction force sensor 10 is arranged at least in a regular triangular shape so as not to be positioned on a straight line with respect to the upper plate 1u and the lower plate 1d, and as shown in FIG. 2, the frame portion 11 is placed on the lower plate 1d. In addition to fixing, the pin 16 inserted in the center is fixed to the upper plate 1u. Then, a slight space is provided between the upper plate 1u and the lower plate 1d, and the reaction force acting in the X'Y'Z 'direction by a load based on the relative displacement between the upper plate 1u and the lower plate 1d. Is detected. Then, reaction forces acting in the X′Y′Z ′ direction of the three reaction force sensors 10 of the

sensor units

101 and 102 are detected, and reaction forces and moments at the center of gravity positions of the

sensor units

101 and 102 are measured. Between the reaction force sensors 10 provided so as to form an equilateral triangle, a substrate having a calculation unit 103 for measuring force, a posture detection sensor 107 such as a gyro sensor, an acceleration sensor, and the like, A geomagnetic sensor 108 and the like are provided.

The computing unit 103 (see FIG. 4) measures the reaction force and moment at the center of gravity of each

sensor unit

101, 102 based on the output value from each

sensor unit

101, 102. Here, each

sensor unit

101 , 102, the reaction force in the X′Y′Z ′ direction is F _{1X ′} , F _{2X ′} , F _{3X ′} , the reaction force in the Y ′ direction is F _{1Y ′} , F _{2Y ′} , F _{3Y ′} , and the Z ′ direction Where F _{1Z ′} , F _{2Z ′} , and F _{3Z ′} are measured, the reaction forces at the gravity center positions G 1 and G 2 of the

sensor units

101 and 102 are measured according to the following equations. Here, F _11M , F _12M , and F _13M (M = X ′, Y ′, Z ′) are the M-axis directions (M = X ′, Y ′, Z ′) of the reaction force sensors 10 in the sensor unit 101. F _21M , F _22M , F _23M (M = X ′, Y ′, Z ′) are the M-axis directions (M = X ′, Y) of each reaction force sensor 10 in the sensor unit 102. ', Z').
F _{1X '} = F _11X' + F _{12X '} + F _13X'
F _{1Y '} = F _11Y' + F _{12Y '} + F _13Y'
F _{1Z '} = F _11Z' + F _{12Z '} + F _13Z'
F _{2X '} = F _21X' + F _{22X '} + F _23X'
F _{2Y '} = F _21Y' + F _{22Y '} + F _23Y'
F _{2Z '} = F _21Z' + F _{22Z '} + F _23Z _'

Further, moments about the X′Y′Z ′ axis with respect to the gravity center positions G1 and G2 of the

sensor units

101 and 102 are expressed by the following equations. Here, L _11M , L _12M , L _13M (M = X ′, Y ′, Z ′) are from each reaction force sensor 10 in the sensor unit 101 to the M axis (M = X ′, Y ′, Z ′). L _21M , L _22M , L _23M (M = X ′, Y ′, Z ′) are distances from each reaction force sensor 10 in the sensor unit 102 to the M axis (M = X ′, Y ′, Z ').
M _{1X '} = F _11Z' × L _{11X '} + F _12Z' × L _{12X '} + F _13Z' × L _{13X '}
M _{1Y '} = F _11Z' × L _{11Y '} + F _12Z' × L _{12Y '} + F _13Z' × L _{13Y '}
M _{1Z '} = F _11X' × L _{11Z '} + F _12X' × L _{12Z '} + F _13X' × L _{13Z '} + F _11Y' × L _{11Z '} + F _12Y' × L _{12Z '} + F _13Y' × L _{13Z '}
M _{2X '} = F _21Z' × L _{21X '} + F _22Z' × L _{22X '} + F _23Z' × L _{23X '}
M _{2Y '} = F _21Z' × L _{21Y '} + F _22Z' × L _{22Y '} + F _23Z' × L _{23Y '}
M _{2X '} = F _21X' × L _{21Z '} + F _22X' × L _{22Z '} + F _23X' × L _{23Z '} + F _21Y' × L _{21Z '} + F _22Y' × L _{22Z '} + F _23Y' × L _{23Z '}

These values are measured every sampling time by the CPU in the calculation unit 103 and output to the correction unit 104.

The correction unit 104 measures the output reaction forces and moments in the X ′, Y ′, and Z ′ directions of the

output sensor units

101 and 102 as reaction forces and moments in the absolute coordinate system. When performing this correction processing, one common posture detection sensor 107 is provided for each of the

sensor units

101 and 102, and the coordinates and postures of the

sensor units

101 and 102 with respect to the absolute coordinates based on the output value from the posture detection sensor 107. Is output. Here, the attitude detection sensor 107 may be any sensor as long as it can output the relative positional relationship and attitude of the

sensor units

101 and 102, for example, a gyro sensor or an acceleration. A sensor or the like is used. The posture detection sensor 107 is fixedly attached to the upper plate 1u and the lower plate 1d, and an output value thereof is output to the correction unit 104.

Here, when the gyro sensor is used, the angular velocity of the

sensor units

101 and 102 to which the gyro sensor is attached can be detected, and the sensor unit 101 to which the gyro sensor is attached by integrating the angular velocity with the sampling time. The posture of 102 can be detected. That is, it is possible to detect a change in angle with respect to the floor surface. However, this integration process may cause an error due to the passage of time, and the error may be accumulated to greatly deviate from the normal posture.

Therefore, an acceleration sensor can be used together. This acceleration sensor measures the sum of the component of gravity acceleration and the component of acceleration generated by movement, and uses a sensor that measures only the gravitational acceleration in a stationary state. At this time, if the acceleration sensor is tilted, the gravitational component changes. Therefore, if the acceleration sensor is known to be stationary, the tilt posture can be measured. Since the acceleration sensor is stationary when the two sets of

sensor units

101 and 102 are in contact with the floor surface, the inclination obtained by integrating the angular velocity by the gyro sensor can be corrected. Whether or not the two sets of

sensor units

101 and 102 are in contact with the floor surface can be determined by the output of the reaction force sensor 10 in the Z ′ direction. In this way, errors that occur when integrating the gyro sensor can be suppressed.

The ground contact state of the two sets of

sensor units

101 and 102 can be grasped from the output of the reaction force sensor 10 in the Z ′ direction and the output of the posture detection sensor 107. Thus, if the ground contact state and posture are known, a floor reaction force and moment with the floor surface as a reference position can be obtained.

When the reaction force or moment from the floor is obtained in this way, as shown in FIG. 8, if the direction in which the foot faces changes along the floor and the horizontal plane, the force and moment in the Z direction change. Although not, the direction of the force in the X direction and the Y direction of the reaction force sensor 10 changes. For this reason, in order to convert the forces and moments in these directions into the forces and moments in the XYZ directions in the absolute coordinate system, it is detected using the geomagnetic sensor 108 which direction the

sensor units

101 and 102 are facing. . In this embodiment, the geomagnetic sensor 108 is provided on both the heel side sensor unit 101 and the tip side sensor unit 102, but it may be provided only on one side. Then, such a geomagnetic sensor 108 is used to detect the direction in which the

sensor units

101 and 102 face in the absolute coordinate system, and the reaction force and moment from the floor surface are corrected using the values.

Then, the reaction force and moment of the XYZ axes corrected in this way are output to the arithmetic unit 106 via the output unit 105, where these output values and other postures such as the lower leg and thigh are separately detected. Thus, the load on the lower limb of the subject and the moment on the joint are measured. At this time, reaction forces and moments from the

sensor units

101 and 102 may be output, or reaction forces applied to the position of the center of gravity of the entire foot may be calculated and output. Moreover, when outputting to the arithmetic device 106 via this output part 105, you may make it output via a communication cable, or you may make it output to the arithmetic device 106 by radio | wireless.

Next, a usage example of the movable floor reaction force measuring apparatus 100 configured as described above will be described.

First, prior to use, the subject wears the footwear 5, and the

sensor units

101 and 102 provided on the back surface of the footwear 5 are in a horizontal state (FIG. 7B), and the acceleration sensor detects only gravitational acceleration. It measures and corrects the inclination by the gyro sensor and detects the directions of the

sensor units

101 and 102 using the geomagnetic sensor. At this time, a human load is applied to each of the

sensor units

101 and 102, and reaction forces and moments in the XYZ directions in the absolute coordinate system are output from the reaction force sensors 10 of the

sensor units

101 and 102.

Next, when the subject starts walking, the heel side of the foot is lifted as shown in FIG. At this time, the sensor unit 101 on the heel side is inclined by θ _1X , θ _1Y , θ _1Z with respect to the floor surface, and when the heel is slightly in contact with the floor surface, the reaction force or moment from the floor surface is Receive. At this time, since the reaction force and moment output from the reaction force sensor 10 on the sensor unit 101 side are inclined with respect to the floor surface, the reaction force and moment are referenced to the floor surface via the correction unit 104. The reaction force and moment are corrected. On the other hand, since the sensor unit 102 on the front end side is in a horizontal state with the floor surface, the output value of the reaction force in the vertical direction does not change even if correction is performed via the correction unit 104.

Next, when the subject lands from the heel side, the sensor unit 101 on the heel side is substantially horizontal with the floor surface, while the sensor unit 102 on the distal end side is inclined with respect to the floor surface. At this time, the reaction force and moment output from the reaction force sensor 10 on the sensor unit 102 side are inclined with respect to the floor surface. Therefore, coordinate conversion is performed via the correction unit 104 to obtain the reaction force and moment. to correct. On the other hand, since the sensor unit 101 on the heel side is in a horizontal state with the floor surface in this state, even if correction is performed via the correction unit 104, the output values of the reaction force and the moment do not change.

Further, in such walking, as shown in FIG. 8, when the subject changes the direction of the foot along the floor surface, the direction of the

sensor units

101 and 102 is detected using the geomagnetic sensor 108 and already calculated. Corrected reaction force and moment as reaction force and moment in XYZ direction.

Then, the reaction force and moment corrected through the correction unit 104 in this way are output to the arithmetic unit 106 through the output unit 105, and the output value and the posture of the lower leg, thigh, etc. are detected separately. To measure the load on the lower limb of the subject and the moment on the joint.

As described above, according to the embodiment, the sensor unit 101 is provided separately on the heel side of the foot and the tip side of the foot, and measures the reaction force in the three orthogonal directions and the moment around each axis. , 102, a posture detection sensor 107 such as a gyro sensor or an acceleration sensor for detecting the posture of each

sensor unit

101, 102, and a geomagnetic sensor 108 for detecting the orientation of the subject's foot in the horizontal direction. Thus, even when the ground contact state or the direction of the foot changes during walking, the reaction force and moment received from the floor surface can be accurately measured. Moreover, since the geomagnetic sensor 108 detects the direction in which the

sensor units

101 and 102 are facing, the direction and angle of the foot is not limited to the viewing angle of the camera, and under any environment. It becomes possible to measure forces and moments based on.

Note that the present invention is not limited to the above-described embodiment, and can be implemented in various modes.

For example, according to the embodiment described above, the three reaction force sensors 10 are provided between the upper plate 1u and the lower plate 1d, but the number of reaction force sensors 10 is limited to three. Instead, four or more may be provided. At this time, each reaction force sensor 10 may be arranged in a place where a load is easily applied.

In the above embodiment, the

sensor units

101 and 102 are provided on the heel side and the tip side, but may be further divided and provided on the back surface of the footwear 5.

Further, in the above embodiment, the

sensor units

101 and 102 are attached between the back surface and the floor surface of the footwear 5, but the

sensor units

101 and 102 may be provided below the insole of the footwear 5. Good.

In addition, in the above embodiment, a gyro sensor, an acceleration sensor, a geomagnetic sensor 108, or the like is used as the posture detection sensor 107, but the angle, position, and direction between each

sensor unit

101, 102 and the floor surface are measured. Anything that can be used may be used.

DESCRIPTION OF SYMBOLS 100 ... Mobile floor reaction force measuring device 101,102 ... Sensor unit 1u ... Upper plate 1d ... Lower plate 10 ... Reaction force sensor 11 ... Frame parts 12-15 ... Leg 16 ... Pins 21 to 28 ... First strain gauges 31 to 38 ... Second strain gauges 41 and 42 ... Bridge circuit 103 ... Calculation unit 104 ... Correction unit 105 ... Output unit 106 ... Calculating device 107 ... Attitude detection sensor (107a: Gyro sensor, 107b: Acceleration sensor)
108: Geomagnetic sensor 5: Footwear

Claims

In a mobile floor reaction force measuring device that is attached to the subject's foot and measures the forces in the three axial directions orthogonal to each other based on the reaction force from the floor surface and the moment about each axis,
A plurality of sensor units that are separately provided on the heel side of the foot and the tip end side of the foot, and that measure the reaction force in the three orthogonal directions and the moment about each axis;
An attitude detection sensor for detecting the attitude of each sensor unit;
An orientation sensor for detecting the orientation of the subject's foot in the horizontal direction;
A movable floor reaction force measuring device characterized by comprising:
The mobile floor reaction force measuring device according to claim 1, wherein the sensor unit includes a reaction force sensor at a position that forms a triangle with the arch as a vertex.