JPH09154900A - Control unit for limb drive - Google Patents

Abstract

(57) [Abstract] [Problem] It is possible to move a human limb while observing it so that it can be dealt with before the joint is overloaded, and the movable range can be easily set in consideration of the limit of the limb. It is an object of the present invention to provide a control device for a drive device that can perform treatment while applying safety to the device itself without applying a heavy load. A load estimating unit 115a that constantly monitors a load on a limb attached to the device by a sensing function.
And an impedance constant conversion unit 116 whose impedance constant can be changed in the vicinity of an overload on the limb, and at the time of entering the overload setting region on the limb, among all the degrees of freedom of the operation of the limb drive device, The impedance constant conversion unit 116 in a certain degree of freedom direction is changed according to an increase in load on the limb, and the movement in the direction of the degree of freedom is virtually freed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a limb orbit for the purpose of eliminating the overload on a human joint or other treatment target in a drive device in consideration of limb movement and improving the safety of the device. The present invention relates to a control device for a limb drive device in consideration.

[0002]

2. Description of the Related Art A device for moving a human limb includes a continuous passive exercise device (CPM device) used in the medical field, a training device used in the rehabilitation field, a sports training device, and the like. In the above device, when the joint is overloaded or when the limb is about to go out of the operating range, the general coping method is that it has no coping function (for example, see JP-A-60-179062). ), Those having a stop function (see, for example, JP-A-61-170464),
It can be divided into three types, one having a drive reversing function (for example, see Japanese Patent Publication No. 4-14028). The "function recovery training device for the wrist joint" does not have a coping function even if the joint is overloaded. In the "passive exercise training device" of the above, in the drive control circuit, in response to a sensed malfunction, a failure to change the angular displacement of the drive shaft or the direction of the angular displacement exceeding a predetermined limit is detected, and an excessive speed or an excessive speed is detected. Equipped with a malfunction detecting means for stopping the movement of the drive shaft when a low speed is detected. In "a device for moving a human joint" in combination with a reversible motor means for driving a reciprocating traveler means on an elongated support, in response to a load sensed through said traveler means, said reversible motor means. A load response means for reversing the rotation of the means is provided. In addition, in Japanese Patent Laid-Open No. 60-232158 “Drive device”, when a resistance larger than the drive force of the drive motor attached to the limb is received, the drive arm temporarily stops and then starts moving in the opposite direction from that position. It has a function and its operation method is controlled by the current flowing through the motor.

[0003]

However, these conventional means cannot operate while constantly monitoring the operating position of the limbs or the joint load. Therefore, measures are taken after the load is actually applied, and the movement range of the limbs is considered only by the operation of the device, and there is no function considering the operation limit of the limbs. Also,
Some devices do not have these safety features. Therefore, when the limb to which the drive device is attached is about to move out of the operating range or when the joint is overloaded, the response is slow and the limb is adversely affected or the joint is considerably loaded. Therefore, in order to improve the safety of the device, it is an object of the present invention to provide a control device suitable for operating a drive device in consideration of a human limb orbit and not applying an excessive load to joints. .

[0004]

In order to solve the above problems, the present invention also includes sensing information from a force sensor or a position / angle sensor attached to a device for the purpose of moving the limb by the operation of the device attached to the limb. In addition, in the control device of the limb control device that controls the operation of the device by force control or position control, a load estimation unit that constantly monitors the load on the limb attached to the device during operation of the drive device, and [or load A limb position calculation unit that replaces the estimation unit and constantly monitors the limbs by means of sensors attached to the limbs], an impedance constant conversion unit that can change each parameter constant of the target impedance near the overload on the limbs, and the load estimation unit The load on the limb obtained by is smaller than the set overload value Flimit [or range of motion limit value Llimit] on the limb. At the time when the specified value Fstart [or the value Lstart of the position installed in front of it] is reached, the impedance constant in a certain degree of freedom among all the degrees of freedom of the operation of the drive device is set to Flimit [or Llimit]. ] A control device for a limb drive device, characterized in that the limb drive device is provided with a control means for changing the limb load value to a value as the limb load value approaches and virtually freeing the motion in the direction of the degree of freedom. is there. According to the present invention, in order to improve the safety of the device, a control device suitable for operating the drive device in consideration of a human limb orbit and not applying an excessive load to the joint can be obtained.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention also includes sensing information of a force sensor or a position / angle sensor attached to a device for the purpose of moving the limb by the operation of the device attached to the limb. In addition, in the control device of the limb control device that controls the operation of the device by force control or position control, the load estimation unit that constantly monitors the load on the limb attached to the device while the drive device is operating, and the limb The impedance constant conversion unit that can change each parameter constant of the target impedance depending on the vicinity of the overload and the load on the limb obtained by the load estimation unit are set to be smaller than the set overload value Flimit on the limb. Value F
At the time point when start is reached, the impedance constant in a certain degree of freedom of all the degrees of freedom of the operation of the drive device is changed according to the approach load value Flimit to the overload value Flimit. A control device for a limb drive device, comprising: a control means for virtually freeing an operation. According to the invention of claim 1, while constantly monitoring the load on the limb, the value Fstart set before the position from the overload value Flimit on the limb in which the load value on the limb is set to the movable limit. If it is inside, normal impedance control is performed, but
As the joint load reaches the Fstart value and approaches Flimit, the impedance constant in a certain degree of freedom among all the degrees of freedom possessed by the drive device is changed, and the axis is virtually freed. As a result, the load on the limbs increases. When trying to do so, it is possible to operate without imposing an unreasonable load and with safety in the device itself. Furthermore, in order to avoid overload, the impedance constant should be kept small during operation of the device. There is no need to solve the problem that the target trajectory set for treatment cannot be achieved because the impedance constant is small, and the impedance constant can be easily set. The invention according to claim 2 of the present invention is the control device for the limb drive device according to claim 1, which is provided with means for making the monitored object a joint load or a muscle force load. The invention has a function of easily grasping the force change of the load, because the invention has a means for setting the joint load or the muscle load as the monitoring target.

According to a third aspect of the present invention, the present load on the limb obtained by the load estimating unit is the F
If it is in the region between limit and Fstart, in all the degrees of freedom of the operation of the drive device, in a certain degree of freedom direction,
The virtual spring constant or virtual viscosity constant, which is the impedance constant, is gradually reduced from the Fstart to the Flimit as the joint load increases, and means for virtually freeing the motion in the direction of the degree of freedom is provided. Claim 1
This is a control device for the limb drive device described. The invention described in claim 3 has an effect that the impedance constant conversion unit can be configured by a change of only the virtual spring constant, a change of only the virtual viscosity constant, and a change due to a combination of the virtual spring constant and the virtual viscosity constant. In the invention according to claim 4 of the present invention, when the current load on the limb obtained by the load estimating unit is in the region between the Flimit and the Fstart, the maximum load direction in the load measuring means of the device is obtained. On the other hand, the control device for the limb drive device according to claim 1, further comprising means for virtually freeing the motion in the direction of the degree of freedom. According to the fourth aspect of the present invention, when the limbs are about to be overloaded, the operation in the direction of the degree of freedom is virtually freed with respect to the maximum load direction in the load measuring means of the device. It has the effect that The invention according to claim 5 of the present invention is a limb drive device according to claim 1, which has a load estimation unit that calculates a load on the limb by kinematics using the force sensor attached to the limb and the parameters of the limb. The invention according to claim 5 is a control device having a load estimation unit for calculating a load on a limb by kinematics using a force sensor attached to the control device and a limb parameter. It has the effect that means are obtained.

The invention according to claim 6 of the present invention is a load estimating unit for calculating the load on the limb by using a measuring means for measuring the load applied to the mounting portion of the limb drive device on the limb. According to the invention of claim 6, the load on the limb is estimated by kinematics using the force sensor and the limb parameter. This has the effect of providing a control means having a load estimation unit that can be simply calculated by the measurement means attached to the device, without performing it. The invention according to claim 7 of the present invention is the control device for the limb drive device according to claim 1, further comprising a load estimating unit for measuring and calculating joint load estimation calculation by a measuring unit attached to a limb. Yes,
The invention according to claim 7 has an effect that a control means having a load estimating unit for measuring and calculating a load on the limb can be obtained by a torque sensor, a pressure sensor, a tactile sensor, etc. attached to the limb.

According to an eighth aspect of the present invention, the limb drive according to the first aspect further comprises means for executing a virtual free function of the drive device in a direction of two or more degrees of freedom and less than or equal to all degrees of freedom. This is a device control device. In the invention according to claim 8, when the limb enters the virtual spring conversion region, by changing the virtual spring constant of the drive device having two degrees of freedom or more and all degrees of freedom or less, when the limb is outside the limb movement region. In, the device can be operated more smoothly, and the safety is improved.

According to a ninth aspect of the present invention, in order to move the limb by the operation of the device attached to the limb, the force is detected based on the sensing information of the force sensor or the position / angle sensor attached to the device. In the control device of the limb drive device for controlling the operation of the device by control or position control, during the operation of the control device, a limb position calculation unit that constantly monitors the operating position of the limb by a sensor attached to the limb, and The impedance constant conversion unit that can change each parameter constant of the target impedance in the vicinity of the movable range limit of the limb movement position and the current position obtained by the limb position calculation unit are the set limb movement limit position Llimi.
Of all the degrees of freedom of the operation of the drive device at the time of entering the position Lstart set before that position with respect to t,
The impedance constant in the direction of a certain degree of freedom is set to Lstart
To L limit according to the distance the limb position is headed, and the limb drive control device is provided with control means for virtually freeing the motion in the direction of the degree of freedom. The invention according to claim 9 constantly monitors the limb movement position of a human, and when the limb approaches the movable limit range, creates a virtual degree of freedom of movement, thereby imposing an unreasonable load on the human joint. It is possible to operate the drive device smoothly without giving the effect, and further, the safety of the device itself is improved.

According to a tenth aspect of the present invention, the present position obtained by the limb position calculating section is the Llimi.
If it is in the region between t and Lstart, the virtual spring constant or virtual viscosity constant, which is the impedance constant in a certain degree of freedom direction, out of all the degrees of freedom of the operation of the drive device, is changed from the Lstart to the Llimit to the limb position. 10. The control device for a limb control device according to claim 9, further comprising means for gradually reducing the movement in the direction of the degree of freedom according to the distance to which the limb travels. According to the tenth aspect of the present invention, there is an effect that the impedance constant converter can be configured by changing only the virtual spring constant, changing only the virtual viscosity constant, and changing by combining the virtual spring constant and the virtual viscosity constant.

The invention according to claim 11 of the present invention has a limb position calculating section for estimating and calculating limb body calculation by kinematics of the limb drive device and kinematics based on parameters of the limb body. It was used as a control device for the drive device, and the sensing function was not used in the limb position calculation unit, the tip position of the device was obtained using forward kinematics from the angle of each axis of the device, and it was attached to the limb from that position. Sprint position, that is, a means for performing coordinate conversion to the absolute position of the limb and estimating the limb position based on the absolute position of the limb, or the parameter of the limb from the absolute position of the limb and the reference point of the limb position (fixed point ), The joint kinematics of the limb is obtained by using the inverse kinematics of the limb, and the position of the limb can be estimated.

According to a twelfth aspect of the present invention, among the ninth to eleventh aspects, the virtual free function of the limb exercising device is executed in a direction of two or more degrees of freedom and less than or equal to all degrees of freedom. The limb drive device according to any one of the items is used as a control device, and when a limb enters the virtual spring conversion region, the virtual spring constant of the drive device having two or more degrees of freedom and not more than all degrees of freedom is changed. By doing so, the device can operate more smoothly when outside the limb movement area,
It also has the effect of improving safety. Next, an embodiment of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals denote the same or corresponding members.

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit block diagram of a control means including the present invention. In order to simplify the explanation here, it is assumed that the limb load is monitored by the knee joint [described in claim 2], and the impedance constant conversion unit changes only the virtual spring constant [described in claim 3], and the load estimation is performed by the limb. This is taken as an example for the case of [kinematics] using the force sensor attached to the and the parameters of the limbs [described in claim 6].

In FIG. 1, 101 is an arm of a drive unit,
102 is an object (human limb), 103 is a splint attached to the hand position of the arm 101 (hand position), 104 is a force sensor attached to the tip of the arm 101 to detect force and moment, and 105 is the arm 101. A driving motor, 106 is a rotation angle detection unit that detects the rotation angle of the drive motor 105, 107 is an analog / digital converter that converts the force and moment signals of the force sensor 104 into digital values, 10
8 is a displacement calculation processing unit that converts the force signal into displacement of the hand position 103, 109 is an inverse kinematics calculation unit that calculates the target angle of the motor 105 from the hand position 103, and 110a is a target that sets the target trajectory of the hand position 103. Orbit setting unit, 111 is rotation angle detection unit 106
Rotation angle conversion circuit for converting the output of the above into a digital value, 112 is a gain integrator, 113 is a digital / analog converter for converting the output of the gain integrator 112 into an analog value, 114 is D /
A servo amplifier for moving the drive motor 105 in accordance with the output of the A converter 113, 115a is a load estimating unit for estimating and calculating the operating load of the limb, and 116 is an impedance constant converting unit for changing the virtual spring constant according to the joint load.

When the device operates according to the target trajectory set to move the limbs, the load estimating unit 115a constantly monitors the joint load of the limbs 102, and the virtual spring constant corresponding to the joint load is converted into the impedance constant converting unit 116. And is always sent to the displacement calculation processing unit 108. In the process, the force signal obtained by the force sensor 104 is converted into a digital value by the A / D conversion circuit 107 and input to the displacement calculation processing unit 108. Inertia and viscosity parameters set by impedance constant converter 116 and load estimator
The displacement of the hand load 103 from the target trajectory is calculated based on the elasticity parameter (virtual spring constant) according to the joint load estimated in 115a.

This displacement is added to the output of the target trajectory setting unit 110a and becomes a position command for the hand position 103, which is converted by the inverse kinematics calculation unit 109 into an angle command for each joint. At that time, the rotation angle of the drive motor detected by the rotation angle detection unit 106 is converted into a digital value by the rotation angle conversion circuit 111 and compared with the angle command. Upon receiving the output, this difference is converted into an analog signal by the D / A converter 113 via the gain integrator 112, and is output to the drive motor 105 by the servo amplifier 114, thereby driving the arm 101 of the drive device. To be done. Taking a drive device with legs attached as an example, the load estimator 115a and the impedance constant converter
I will describe the operation of 116. First, the load estimating unit will be described with reference to FIG.

FIG. 2 is an explanatory view of the load estimating operation in the load estimating section as viewed from the side. In FIG. 2, 201 is a leg (limb), 202 is a drive unit, 203 is a force sensor attached to the drive unit, 204 is a splint of the drive unit, 205 is a leg length, 206 is an upper leg length L1, and 207a is a limb. Reference point, 208
Is the knee joint, 209 is the hip joint angle θ1, 210 is the knee joint angle θ2, and 211 is the load (torque) t1 on the hip joint, 21
2 is the load (torque) t2 on the knee joint, 213 is the knee joint
The length L2 from 208 to the center of the sprint 204 is L2. FIG. 3 is an explanatory diagram showing a flow of a process of estimating and calculating a joint load. First, the leg length 20 which is the leg parameter
5. Determine the upper leg length 206 and leg reference point 207a (position from the origin coordinate of the driving device) [step 1].

Considering the leg as a two-degree-of-freedom manipulator, from the force / moment information obtained by the force sensor 203 attached to the drive unit 202, the Jacobian matrix J is used based on the above parameters to calculate the joint torque (load). ) Is estimated. For example, the joint load of a leg attached to a drive device having three degrees of freedom in a vertical plane with two degrees of freedom for translation and one degree of rotation is calculated [step 2]. It is assumed that the information obtained from the force sensor 203 is only the translational forces (Fx, Fz), and the rotational force (moment My) is not detected. At this time, the hip joint load 211 (t1) and the knee joint load 21
2 (t2) uses the transposed matrix of the Jacobian J [step 3], and joint load estimation is performed [step 4] as a result of the calculation as in [Equation 1] below.

(Equation 1)

Next, the impedance constant converter will be described with reference to FIG. FIG. 4 is an explanatory diagram regarding a virtual spring constant value with respect to a joint load. Joint overload value Fli
mit and a position Fstart to be set in front of it are set in advance according to the affected part state of the joint. If the value obtained by the load estimation unit is F, then F <Fstart, the virtual spring constant is constant at a preset value K0. In the case of Fstart ≦ F <Flimit The virtual spring constant changes monotonously and continuously with a proportional coefficient = −K0 / (Flimit−Fstart) according to the distance of the maximum value F of the joint load coordinates. With this method, the joint load estimated value F and the impedance constant conversion corresponding to the joint load estimated value F are performed, and thereafter the control is performed in the same manner as the normal impedance control.

According to the present invention, the joint overload value F is Fstar.
When the distance is greater than t (that is, F <Fstart), the virtual spring constant, which is an impedance parameter, becomes a preset constant value K0. Therefore, in this case, normal impedance control is performed. When F enters within Fstart (Fstart ≤ F <Flimit), the virtual spring constant is the maximum value F of the joint load coordinates based on the above proportional coefficient for one certain degree of freedom among all the degrees of freedom of the drive device. Gradually becomes smaller as F approaches F limit, and the axis is virtually freed. As a result, the joints of the limbs can be operated safely without applying an excessive load. In addition, other than that degree of freedom, normal impedance control is performed.

In order to operate the virtual free function of the apparatus more smoothly, the width from Fstart to Flimit may be increased and the virtual spring constant changing area may be increased. Further, although the constant change is set proportionally in the virtual spring change region, if it is set exponentially, a smoother operation function can be expected. The means described in claim 2 is the control means according to claim 1, which is operated by setting a joint load or a muscle load as a monitoring target. In the means described in claim 3, the control in which the impedance constant conversion unit is configured by the change of only the virtual spring constant described above, the change of only the virtual viscosity constant, and the change by the combination of the virtual spring constant and the virtual viscosity constant. It is a means.

Further, in the means described in claim 4, when the limb is about to be overloaded, the operation in the direction of the degree of freedom is virtually free from the maximum load direction in the load measuring means of the apparatus. The control means according to claim 1, characterized in that Further, according to the means described in claim 5, as shown in the above-mentioned embodiment, the control means having the load estimation unit for calculating the load on the limb by the kinematics using the force sensor attached to the device and the parameter of the limb. Is. Furthermore, in the means according to claim 6, the load on the limb is not estimated by kinematics using the force sensor and the limb parameter, but the load is simply calculated by the measuring means attached to the device. It is a control means having a section.

The means according to claim 7 is a control means having a load estimating unit for measuring and calculating the load on the limb by a torque sensor, a pressure sensor, a tactile sensor, etc. attached to the limb. Further, the means described in claim 8 is means for changing the virtual spring constant of the drive device having two or more degrees of freedom and not more than all degrees of freedom when the limb enters the virtual spring conversion region. As a result, the device can be operated more smoothly and safety is improved even when it is outside the limb movement region. In addition, it has the function and the use of each combination of claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 7 and claim 8 of the means described above. Control means are also useful and suitable. Claim 1
The means indicated by is also suitable as means for performing an operation as a rehabilitation device or a sports training device.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. In order to simplify the description, this will be taken as an example in the case where the impedance constant conversion unit reduces only the virtual spring constant [described in claim 11]. A block diagram showing the circuit configuration of the control means including the present invention is shown in FIG. In FIG. 5, 110b is a target position setting unit that sets the target position of the hand position 103, 115b is a limb position calculation unit that estimates and calculates the movement position of the limb, and 116 is an impedance constant that changes the virtual spring constant according to the limb position. The conversion unit 117 is a limb position measuring sensor that detects the motion position of the limb.

During operation of the apparatus, the position of the limb 102 is constantly monitored by the limb position calculation unit 115b via the limb position measurement sensor 117, and a virtual spring constant corresponding to the limb position is generated by the impedance constant conversion unit 116 to calculate displacement. In the process of constantly sending the force signal to the processing unit 108, the force signal obtained by the force sensor 104 is converted into a digital value by the A / D conversion circuit 107 and input to the displacement calculation processing unit 108. The hand position 103 based on the inertial and viscous parameters set by the impedance constant conversion unit 116 and the elastic parameter (virtual spring constant) corresponding to the limb position estimated by the limb position calculation unit 115b.
The displacement from the target position of is calculated.

This displacement is added to the output of the target position setting unit 110b and becomes a position command for the hand position 103, which is converted by the inverse kinematics calculation unit 109 into an angle command for each joint. At that time, the rotation angle of the drive motor detected by the rotation angle detection unit 106 is converted into a digital value by the rotation angle conversion circuit 111 and compared with the angle command. Upon receiving the output, this difference is converted into an analog signal by the D / A converter 113 via the gain integrator 112, and is output to the drive motor 105 by the servo amplifier 114, thereby driving the arm 101 of the drive device. To be done.

FIG. 6 is an explanatory view of the limb position relating to the limb position calculation section as viewed from the side. In FIG. 6, 214 is the maximum value of the operating position coordinate of the leg 201 obtained by the limb position measuring sensor, and 215 is the distance width (virtual spring) of the position Lstart set before the movable limit position Llimit of the leg 201 from that position. A constant changing region), 204 is a splint of the driving device, 216 is a hand position coordinate of the driving device, and 207b is a motion fulcrum coordinate of the leg 201. FIG. 7 is an explanatory diagram regarding the virtual spring constant value with respect to the motion position of the limb. Here, operations of the limb position calculation unit 115b and the impedance constant conversion unit 116 will be described with reference to FIGS. 6 and 7. The maximum value 214 of the movement coordinates can be obtained by measuring the movement position of the limb with a goniometer, potentiometer, distance measuring sensor, etc., which are limb position measurement sensors.

Now, for example, if the above-mentioned sensor is used and the device is attached to the limb before the treatment and the limb is moved in advance, the movable region of the limb can be estimated in advance. Therefore,
Range of motion limit value Llimit and position Lst set in front of it
art is defined. At this time, the maximum value of the limb position coordinates is 214
Let X be X: When X <Lstart, the virtual spring constant is constant at a preset value K0. In the case of Lstart ≦ X <Llimit The virtual spring constant changes monotonously and continuously with the proportional coefficient = −K0 / (Llimit−Lstart) according to the distance of the maximum value X of the limb position coordinate. By this method, the limb position calculation and the impedance constant conversion corresponding to the calculation are performed, and thereafter the control is performed in the same manner as the normal impedance control.

By the above means, while constantly monitoring the motion position of the limb, the limb position is set from the movable limit position Llimit set to the movable limit to the position L set in front of the movable limit position Llimit.
If it is inside start, normal impedance control is performed, but limb movement enters Lstart and Llimit
As the distance between and decreases, the impedance constant in the direction of a certain degree of freedom among all the degrees of freedom of the drive device is changed, and the axis is virtually freed. As a result, when the limbs are approaching outside the range of motion, it is possible to operate without imposing an unreasonable load on the joints and with the device itself being safe.

According to the present invention, the maximum value X of the limb position coordinates is
Is greater than Lstart (X <Lstart), the virtual spring constant, which is an impedance parameter, becomes a preset constant value K0. Therefore, in this case, normal impedance control is performed. When X enters Lstart (Lstart ≤ X <Llimit), the virtual spring constant is the maximum value X of the limb position coordinate based on the above example coefficient for one degree of freedom among all the degrees of freedom of the drive device. Is Llimit
It gradually becomes smaller as it approaches, and the axis is virtually freed.

As a result, the joints of the limbs can be operated safely without applying an excessive load. In addition, other than that degree of freedom, normal impedance control is performed. To make the virtual free function of the device operate more smoothly, L
It suffices to increase the width of Llimit from start to increase the virtual spring constant change area. Further, although the constant change is set proportionally in the virtual spring change region, if it is set exponentially, a smoother operation function can be expected.

According to a tenth aspect of the present invention, the impedance constant conversion section is configured by changing only the virtual spring constant described above, changing only the virtual viscosity constant, and changing by combining the virtual spring constant and the virtual viscosity constant. It was done. Further, in the device according to claim 11, the sensing function is not used in the limb position calculation unit 115, and the tip position of the device is obtained using forward kinematics from the angle of each axis of the device,
Sprint position attached to the limb from that position, that is, coordinate conversion is performed from the absolute position of the limb, and the method of estimating the limb position based on the absolute position of the limb, or the parameter of the limb from the absolute position of the limb and Based on the reference point (fixed point) of the limb position, each joint angle of the limb is obtained by using the inverse kinematics of the limb to estimate the limb position.

And, in the apparatus according to claim 12,
When a limb enters the virtual spring conversion region, the virtual spring constant of the drive device having two or more degrees of freedom and not more than all degrees of freedom is changed. As a result, the device can be operated more smoothly and safety is improved even when it is outside the limb movement region. Further, the device having all the means described in the second embodiment and shown in claim 9 has the same function as in claim 1 and is used in the field of rehabilitation, that is, operates as a rehabilitation device or a sports training device. It is also desirable as a means of doing so. The control means having the combination of claims 9 to 12 is also a preferable control device for the limb control device.

[0034]

As described above, according to the present invention, the human limb joint load is constantly monitored, and when the load applied to the joint approaches the overload region, virtually free motion freedom is created. Thus, there is an effect that the drive device can be smoothly operated without imposing an unreasonable load on a human joint, and the safety of the device itself is improved. Also, in order to avoid overload, it is not necessary to keep the impedance constant small during the operation of the device, and the problem that the target trajectory set for treatment cannot be achieved because the impedance constant is small can be solved. Also, the impedance constant can be easily set. Further, according to the present invention, the human limb movement position is constantly monitored, and when the limb approaches the movable limit range, a virtual free movement degree of freedom is created so that an unreasonable load is not applied to the human joint. The drive device can be operated smoothly, and the safety of the device itself is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a control means representing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a load estimating unit according to the first embodiment of the present invention.

FIG. 3 is a flowchart for estimating and calculating a joint load according to the first embodiment of the present invention.

FIG. 4 is a diagram showing conversion of a virtual spring constant value with respect to an operating position of a limb according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a circuit configuration of a control means representing a second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a limb position calculation unit according to the second embodiment of the present invention.

FIG. 7 is a diagram showing conversion of a virtual spring constant value with respect to an operating position of a limb according to the second embodiment of the present invention.

[Explanation of symbols]

 101 Drive device arm 102 Limb 103,204 Sprint (hand position) 104,203 Force sensor 105 Motor 106 Rotation angle detection unit 107 Analog / digital converter 108 Displacement calculation processing unit 109 Inverse kinematics calculation unit 110a Target trajectory setting unit 110b Target position setting unit 111 Rotation angle conversion circuit 112 Gain integrator 113 Digital / analog converter 114 Servo amplifier 115a Load estimation unit 115b Limb position calculation unit 116 Impedance constant conversion unit 117 Joint load measurement sensor 118 Impedance constant conversion unit 119 Limb position measurement sensor 201 Leg 202 Drive unit 205 Lower leg length 206 Upper leg length L1 207a Limb body reference point 207b Movement fulcrum coordinate 208 Knee joint 209 Hip joint angle θ1 210 Knee joint angle θ2 211 Hip joint load t1 212 Knee joint load t2 213 Length from knee joint to center of sprint L2 214 Maximum value of motion position coordinates 215 Virtual spring constant change area 216 Hand position coordinates

Claims (12)

[Claims] 1. The operation of the device is controlled by force control or position control based on the sensing information of a force sensor or a position / angle sensor attached to the device for the purpose of moving the limb by the operation of the device attached to the limb. In the control device of the limb drive device, the load on the limb attached to the device is
The load estimation unit that constantly monitors, the impedance constant conversion unit that can change each parameter constant of the target impedance near the overload on the limb, and the load on the limb obtained by the load estimation unit When a value Fstart smaller than the value Flimit is reached, the impedance constant in a certain degree of freedom among all the degrees of freedom of the operation of the driving device is set to the overload value Flimit. A control device for a limb drive device, comprising: a control means for changing the motion in the direction of the degree of freedom virtually as it approaches, and for virtually freeing the motion in the direction of the degree of freedom. 2. The control device for a limb drive apparatus according to claim 1, further comprising means for setting a joint load or a muscle load as a monitored object. 3. If the current load on the limb obtained by the load estimating unit is in the region between the Flimit and the Fstart, in all the degrees of freedom of the motion of the drive device, in a certain degree of freedom direction. A means for gradually reducing the virtual spring constant or virtual viscosity constant, which is the impedance constant, from the Fstart to the Flimit as the joint load increases, and virtually freeing the motion in the direction of the degree of freedom. The control device for the limb drive device according to claim 1, wherein 4. When the current load on the limb obtained by the load estimation unit is in the region between the Flimit and the Fstart, the direction of the degree of freedom with respect to the maximum load direction in the load measuring means of the device. 2. The control device for the limb drive apparatus according to claim 1, further comprising means for virtually freeing the operation of. 5. A load estimation unit for calculating a load on a limb by kinematics using the force sensor attached to the limb and a parameter of the limb.
A control device for the limb drive device described. 6. A load estimating unit for calculating the load on the limb by using a measuring means for measuring a load applied to a mounting portion of the limb drive unit on the limb, the load estimating unit. A control device for the limb drive device described. 7. The control device for a limb drive apparatus according to claim 1, further comprising a load estimating unit that measures and calculates the joint load by a measuring unit attached to the limb. 8. The control device for the limb drive device according to claim 1, further comprising means for executing a virtual free function of the drive device in a direction of two or more degrees of freedom and a total degree of freedom or less. 9. The operation of the device is controlled by force control or position control based on the sensing information of a force sensor or a position / angle sensor attached to the device for the purpose of moving the limb by the operation of the device attached to the limb. In the control device of the limb drive device, a limb position calculation unit that constantly monitors the movement position of the limb with a sensor attached to the limb during operation of the drive device, and a target near the range of motion of the limb movement position. When the current position obtained by the impedance constant conversion unit that can change each parameter constant of impedance and the limb position calculation unit enters the position Lstart set before that position with respect to the set movable limit position Llimit of the limb Then, of all the degrees of freedom of the operation of the driving device, the impedance constant in the direction of a certain degree of freedom is calculated from the Lstart. A control device for a limb drive device, comprising: a control unit that changes the limb position to Llimit according to the distance to which the limb position is headed, and virtually frees the motion in the direction of the degree of freedom. 10. The control unit is configured such that the current position obtained by the limb position calculation unit is the Llimit and the Lstar.
If it is in the region between t, the virtual spring constant or virtual viscosity constant, which is the impedance constant in the direction of a certain degree of freedom, of all the degrees of freedom of the operation of the drive device, is the distance from the Lstart to the Llimit at which the limb position moves. 10. The control device for a limb drive device according to claim 9, further comprising means for gradually reducing the movement in the direction of the degree of freedom to thereby virtually free the movement in the direction of the degree of freedom. 11. The control device for the limb drive device according to claim 9, further comprising a limb position calculation unit that estimates and calculates the position of the limb by kinematics of the limb drive device and kinematics based on the parameters of the limb body. 12. The limb drive device according to claim 9, wherein the virtual free function of the limb movement device is executed in a direction of two or more degrees of freedom and less than or equal to all degrees of freedom. Control device.