Muscle strength evaluation system, apparatus and method

The present invention relates to a muscle strength evaluation system, device and method.

Conventionally, a muscle strength evaluation system using a two-joint link mechanism such as a two-joint arm device has been proposed (see, for example, Patent Document 1). In the muscle strength evaluation system, the muscle output of the subject's antagonistic anti-monoarticular muscle group and antagonistic biarticular muscle group is measured by a pressure sensor. Then, the force is exerted in the limbs of the subject with isometric maximum effort in a plurality of predetermined directions, a hexagonal output distribution characteristic diagram is created based on this, and the execution muscle strength by function is evaluated.

In addition, as an actuator for driving the biarticular link mechanism, we proposed a model of the biarticular muscle that functions to bend the arm in animals including humans, and studied the motion control of the biarticular link mechanism using this model. (See, for example, Non-Patent Document 1). In this study, in order to control the force and rigidity of the arm tip in a two-joint link mechanism equipped with a two-joint simultaneous drive source, an actuator having a contraction element and an elastic element that exert a force in the contraction direction as a drive source. It is said that it is preferable to use the model of.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2000-210272</text></patcit><nplcit num="1"><text>Tomohiko Fujikawa, 3 others, "Cooperative control function by antagonistic muscle group", Japan Society of Mechanical Engineers Proceedings (C), Vol. 63, No. 607 (1997-3), p.769-776, Paper No.96-1040</text></nplcit>

<p> However, in the conventional muscle strength evaluation system, the muscle strength is evaluated based on the hexagonal output distribution characteristic diagram by simulating the limbs of the subject as a link system. However, the hexagonal output distribution at the tip of the link system is used. Since the figure differs depending on the joint angle of the link system, it could not be measured without scale contraction. In addition, if the posture of the subject was different each time the muscle output was measured, it was difficult to make an appropriate comparison.</p><p> The present invention solves the problem of the conventional muscle strength evaluation system and measures the axial torque that can be generated simultaneously in the first joint and the second joint by the cooperation between the antagonistic monoarticular muscle group and the antagonistic biarticular muscle group. However, by creating a hexagonal output distribution characteristic diagram on a plane with the axial torques of the 1st and 2nd joints as the two axes, without specifying the individual muscle strength of the effective muscles for each function, Another object of the present invention is to provide a muscular strength evaluation system, device and method capable of accurately evaluating the muscular strength changed by training even if the posture of the subject changes or the joint angle changes.</p>

<p> Therefore, in the muscle strength evaluation system of the present invention, the first link in which the first joint and the second joint are connected to both ends and the second link in which one end is connected to the second joint and the other end is the tip of the system. And straddle (and also) the antagonistic monoarticular muscle group around the 1st and 2nd joints, which exerts an effect on the movement of the plane including the 1st joint, the 2nd joint and the tip of the system, and the 1st and 2nd joints. It is a muscle strength evaluation system of the biarticular link mechanism of the subject equipped with the antagonistic biarticular muscle group.<u style="single">A saddle on which the subject sits, a robot arm that can be adjusted to the length of the subject's upper limbs or lower limbs, a fitting that fixes the robot arm along the subject's upper limbs or lower limbs, and a first robot arm. The subject has a muscular strength evaluation device including a control device for controlling the axial torques of the joint and the second joint and an angle measuring device for measuring the joint angle of the robot arm, and the force exerted at the tip of the robot arm is applied to the subject. Measure the axial torque of the 1st and 2nd joints when they antagonize the force exerted by the system tip of the 2-joint link mechanism.</u>The axial torque that can be generated simultaneously in the first joint and the second joint is measured by the cooperation between the antagonistic monoarticular muscle group and the antagonistic biarticular muscle group, and the axial torque of the first joint and the axial torque of the second joint are measured. A hexagonal output distribution map is created on a plane with two axes, and the muscle strength of the biarticular link mechanism of the subject is evaluated by the output distribution map.</p><p> In the muscular strength evaluation device of the present invention, a saddle on which the subject sits, a robot arm that can be adjusted to the length of the upper limb or lower limb of the subject, and a fitting that fixes the robot arm along the upper limb or lower limb of the subject. A control device for controlling the axial torques of the first joint and the second joint of the robot arm, and an angle measuring device for measuring the joint angle of the robot arm. The control device has a tip of the robot arm. The direction of the force that the subject should exert in order to measure the muscle strength by having elasticity and controlling the elasticity to change depending on the direction is taught.</p>

<p> According to the present invention, the muscle strength evaluation system measures the axial torque that can be simultaneously generated in the first joint and the second joint by the cooperation between the antagonistic monoarticular muscle group and the antagonistic biarticular muscle group, and measures the first joint and the second joint. A hexagonal output distribution characteristic diagram is created on a plane with the axial torque of the joint as two axes. As a result, it is possible to accurately evaluate the muscle strength changed by training even if the posture of the subject changes or the joint angle changes without specifying the individual muscle strength of the effective muscle for each function. ..</p>

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram schematically showing a muscle group of a user's limb in the first embodiment of the present invention, and FIG. 3 is a diagram showing the activity of a user's limb muscle in the first embodiment of the present invention. The graph showing the pattern, FIG. 4, is a diagram showing the output distribution characteristics of the muscles of the limbs of the user in the first embodiment of the present invention.

In FIG. 2, 20 is a user as a subject in the present embodiment, and is a person who evaluates muscle strength using a muscle strength evaluation system. First, the two-joint link mechanism of the human body and limbs, which is the background of the muscular strength evaluation system, will be described to the extent necessary for understanding the present invention.

Biarticular muscles exist in human body limbs, that is, limbs, and the biarticular muscles control the output of the tip in cooperation with the one-joint muscle acting on one joint, and the tip output is It is known to be represented by a hexagonal output distribution as shown in FIG. 4 (see, for example, Non-Patent Document 2). Then, a method of evaluating the execution muscle strength by function based on the output distribution characteristic of the hexagon is also known (see, for example, Patent Document 1).<nplcit num="2"><text>Tomohiko Fujikawa, Toru Oshima, Mizuyori Kumamoto, Tomohisa Yamamoto, "Cooperative activity of antagonistic monoarticular and biarticular muscle groups in the upper limbs and control function analysis by their mechanical model", Biomechanism 13, Biomechanism Society, (1996) 181 ..</text></nplcit>

Next, the tip output characteristics of the limbs described in Non-Patent Document 2 and Patent Document 1 will be described to the extent necessary for understanding the present invention.

In both the upper and lower limbs of humans, the muscle groups that act on the first and second joints in the movement in the two-dimensional plane including the first joint, the second joint, and the tip of the system are shown in Fig. 2 in consideration of their functions. As shown, a pair of antagonistic monoarticular muscle pairs around the 1st joint (f1, e1), a pair of antagonistic monoarticular muscle pairs around the 2nd joint (f2, e2), and the 1st and 2nd joints. It is possible to represent by 3 to 6 muscles of a pair of antagonistic one-joint muscle pairs (f3, e3) straddling and, and this is called a function-specific execution muscle. The example shown in FIG. 2 is a muscle group that acts on the hip (ko) joint and the knee (knee) joint of the lower limbs of the user 20.

The one-joint muscle is a muscle that acts on only one joint. In the upper limbs, it corresponds to the anterior and posterior deltoid muscles of the shoulder joint, the brachialis and triceps lateral heads of the elbow joint, and the hip joint in the lower limbs. Corresponds to the triceps and brachialis muscles, the triceps brachii muscle of the knee joint, and the lateral broad muscle. The biarticular muscle is a muscle that acts across two joints, and corresponds to the biceps brachii muscle and the long head of the triceps brachii muscle in the upper limbs, and the hamstrings and the rectus femoris muscle in the lower limbs.

The force exerted at the tip of the two-joint link of the upper and lower limbs, that is, the carpal joint in the upper limb and the ankle joint in the lower limb, and its output direction are the coordination of the function-specific execution muscles of 3 to 6 muscles. Controlled by activity. When the force is exerted with the maximum effort in each direction at the tip of the system, the function-specific execution muscles of 3 to 6 muscles contract alternately according to the output direction of the force as shown in FIG. In FIG. 3, F represents the force of the joint muscle indicated by the subscript.

In addition, the direction of the force generated at the tip of the limb by the contraction force exerted by the function-specific execution muscles of the 3 to 6 muscles is as shown in Fig. 4, and the coordination according to the alternation pattern as shown in Fig. 3 The maximum output distribution characteristic of the hexagon is shown by the combined force by control.

Each side of the hexagon with this maximum output distribution characteristic is characterized by being parallel to the straight line connecting the first link, the second link, the first joint and the tip of the system. Therefore, the shape of the hexagon depends on the posture of the limbs. Even if the contraction force of the muscle is constant and the torque generated in each joint does not change, the force generated at the tip of the human body limb due to the joint axis torque also changes in that direction depending on the posture of the upper limb or lower limb. The size also changes.

Next, the configuration of the muscle strength evaluation device 10 used in the muscle strength evaluation system according to the present embodiment will be described.

FIG. 1 is a diagram schematically showing the structure of the muscle strength evaluation device according to the first embodiment of the present invention. In FIG. 1, (a) is a view showing a side surface, and (b) is a view showing a front surface.

The muscular strength evaluation device 10 in the present embodiment realizes effective muscular strength evaluation in consideration of the output characteristics at the tip of the human body limb as described above. Then, as shown in FIG. 1, the muscle strength evaluation device 10 controls a saddle 11 on which the user 20 sits, a robot arm 12 mounted along the body limbs of the user 20, and the robot arm 12. It is composed of a control device that is not used, and an input operation device (not shown) in which the user 20 inputs the intention of muscle strength evaluation. For convenience of explanation, only the example of the lower limbs will be described here, but the same applies to the upper limbs.

The robot arm 12 is a two-degree-of-freedom robot arm composed of two links, a first link 14a corresponding to the thigh and a second link 14b corresponding to the lower leg. In addition, the first link 14a and the second link 14b are provided with a slide mechanism capable of adjusting the link length, and when performing muscle strength evaluation, the lengths of the thighs and lower legs of the user 20 are the same, respectively. It is adjusted so as to be fixed to the thigh and lower leg by the first fitting 15a and the second fitting 15b. When the first link 14a and the second link 14b and the first fitting 15a and the second fitting 15b are described in an integrated manner, they will be described as the link 14 and the fitting 15, respectively.

The robot arm 12 is attached to the user 20 with the user 20 seated on the saddle 11. At this time, the first joint axis 16a of the robot arm 12 is aligned with the hip joint of the user 20. , Align the second joint axis 16b of the robot arm 12 with the knee joint axis of the user 20. Further, the first servomotor 17a and the second servomotor 17b are connected to the first joint shaft 16a and the second joint shaft 16b, and an absolute encoder is equipped as an angle detection device for measuring the joint angle. Has been done. When the first joint shaft 16a and the second joint shaft 16b and the first servomotor 17a and the second servomotor 17b are described in an integrated manner, they will be described as the joint shaft 16 and the servomotor 17, respectively. Here, the servomotor 17 functions as a joint drive source and generates torque for rotating the joint shaft. The torque generated by the servomotor 17 is controlled by the control device. Further, the torque generated by the joint shaft of the robot arm 12 can be recorded by the recording device connected to the control device.

Further, an output means such as a CRT (not shown), a display device including a liquid crystal display, a printing device such as a printer, or the like is connected to the control device. The output means creates, displays or prints a hexagonal output distribution map, which will be described later, and teaches the user 20 the direction of the force to be exerted.

Next, the operation of the muscle strength evaluation device 10 having the above configuration will be described.

FIG. 5 is a diagram showing a comparison between the output distribution map of the force at the tip of the link system and the output distribution map of the joint shaft torque in the first embodiment of the present invention, and FIG. 6 is a diagram showing a comparison between the output distribution map of the joint shaft torque and FIG. It is a figure which shows the change of the output distribution map of the joint shaft torque before and after training. In FIG. 5, (a) shows an output distribution map of the force at the tip of the link system, and (b) shows an output distribution map of the joint shaft torque.

The output distribution map of the force exerted at the tip of the link system corresponding to the carpal joint in the upper limb and the ankle joint in the lower limb changes depending on the joint angle of the link system. Therefore, in the present embodiment, as shown in FIG. 5 (b), the axial torque (τ1) of the first joint is taken on the horizontal axis, and the axial torque (τ2) of the second joint is taken on the vertical axis. In the figure, consider an output distribution diagram of joint shaft torque that plots shaft torque that can occur simultaneously in the first joint and the second joint.

According to the theory of effective muscles by function, the joint axis torque output distribution map is also hexagonal, similar to the force output distribution map at the tip of the link system as shown in Fig. 5 (a). In FIG. 5, the output distribution map of the joint shaft torque and the output distribution map of the force at the tip of the link system are shown to correspond to each other.

Here, the correspondence between the two hexagons shown in FIGS. 5 (a) and 5 (b) will be described.

FIG. 5 (a) corresponds to the output distribution characteristic of Patent Document 1, but in the hexagon shown in FIG. 5 (a), the second joint, that is, the two sides parallel to the second link. Is equivalent to τ2 = constant, that is, a straight line parallel to the τ1 axis in the joint axis torque output distribution map because the moment for the second joint does not change. Similarly, in the hexagon shown in Fig. 5 (a), the two sides parallel to the straight line connecting the first joint and the tip of the link system do not change the moment with respect to the first joint, so the output distribution diagram of the joint axis torque. Then, τ1 = constant, that is, it is equivalent to a straight line parallel to the τ2 axis.

Further, among the hexagonal sides shown in FIG. 5 (a), for the first rod, that is, two sides parallel to the first link, the force of the force from one vertex of the side to the other vertex is obtained. Considering the change, the direction is equal to the direction of the first link, and it is considered that the torque change is equal to that of the first joint and the second joint, so that it is equivalent to a straight line parallel to the straight line of τ1 = τ2.

Then, if the output distribution map of the joint axis torque as shown in FIG. 5 (b) can be measured, it is also possible to obtain the output distribution map of the link tip at an arbitrary joint angle.

Further, in order to evaluate the individual muscle strength of the effective muscles for each function, it can be estimated by specifying the lean body mass of the pair of antagonistic biarticular muscles as shown in Patent Document 1.

In order to obtain the output distribution map of the joint axis torque in the muscle strength evaluation device 10, the user 20 puts out in various directions with the maximum effort while the robot arm 12 is attached to the lower limbs of the user 20. Record the force as joint shaft torque. In this case, the user 20 is made to exert the force while instructing the direction of the force by means such as an illustration. Further, since the robot arm 12 generates a reaction force with respect to the user 20 by controlling the joint axis torque so that the joint angle does not change, the user can determine the joint axis torque when the joint angle does not change. Record as the joint shaft torque exerted by 20.

Then, the recorded joint axis torque is plotted on the τ1-τ2 coordinate plane as shown in FIG. 6 as the torque that can be generated by the two joint axes at the same time. Then, a hexagon that contains the set of the entire plot internally, with two sides parallel to the τ1 axis, two sides parallel to the τ2 axis, and the other two sides parallel to the straight line τ2 = τ1. The smallest hexagon is drawn, and the hexagon is used as an output distribution map of the joint axis torque. Then, a hexagon created by using the muscle strength evaluation device 10 before the user 20 trains and a hexagon created by using the muscle strength evaluation device 10 after the same user 20 trains. As shown in FIG. 6, by showing on the same screen, it is possible to grasp the change in muscle strength before and after training.

Training can also be performed using the muscle strength evaluation device 10. When performing training, the user 20 first operates the input operation device of the muscle strength evaluation device 10 to input the training menu. The input of the training menu is, for example, to input the output direction to be enhanced at the tip of one's own limb and the magnitude of the training load based on the hexagon of the maximum output distribution characteristic as shown in FIG.

For example, if the user 20 wants to increase the tip output in the b direction in a hexagon as shown in FIG. 4 with the intention of increasing the jumping distance of the standing long jump, the user 20 selects the b direction as the output direction for training. Enter the magnitude of the training load. From the 3 to 6 muscle alternation pattern shown in Fig. 3, the muscles that are active when exerting force in the b direction are f1 (hip joint biarticular flexor muscle group) and e2 (knee joint biarticular flexor muscle group). And f3 (hip biarticular flexor muscle group).

In order to increase the tip output in the b direction, the three muscle groups f1, e2, and f3 need to be trained. Therefore, the muscle strength evaluation device 10 corresponds to the hip joint and the knee joint when the three muscle groups are active. The torque generated by the 1 servo motor 17a and the 2nd servo motor 17b is gradually or gradually increased in the opposite direction to the magnitude of the training load input by the user 20. Then, the user 20 can maintain a predetermined state of muscle output and train the muscle strength by exerting a force so as to oppose the torque generated by the muscle strength evaluation device 10.

Since the muscle strength evaluation device 10 applies a constant torque to the user 20 as a load, the user 20 makes an effort not to change the position of the tip of the limb (in the case of the above example, the ankle). It is also possible to do isometric training. Further, since the load on the muscle does not change even if the posture of the user 20 changes during the training, it is possible to perform isotonic training.

As described above, in the present embodiment, if the user 20 wants to evaluate the changed muscle strength by performing some training, that is, if the purpose is to evaluate the difference in the changed muscle strength, the effective muscle for each function is not necessarily effective. It is possible to evaluate what kind of change has occurred in muscle strength from the change in the hexagon showing the output distribution of joint axis torque without specifying the individual muscle strength of.

For example, if the output distribution map of the joint axis torque changes as shown in Fig. 6 by some kind of training, it is evaluated that the same effect as when the muscle strength of the effective muscle f3 is increased is obtained. can do.

The force output distribution map at the tip of the link system changes depending on the length of each link and the angle of the link, but the joint axis torque output distribution map changes only depending on the output of the effective muscle. Therefore, the posture information of the user 20 is not required for the purpose of obtaining the output distribution map of the joint shaft torque.

In this way, by using the joint axis torque output distribution map, it is possible to compare the effective muscle strength even if the joint angles at the time of measurement are different.

Next, a second embodiment of the present invention will be described. For those having the same structure as that of the first embodiment, the description thereof will be omitted by assigning the same reference numerals. Further, the description of the same operation and the same effect as that of the first embodiment will be omitted.

In the present embodiment, the stiffness characteristic control of the link tip described in Japanese Patent Application No. 2006-205829, which is the prior application of the applicant, is used for the muscle strength evaluation device 10. Since the other configurations are the same as those in the first embodiment, the description thereof will be omitted.

Next, the operation of the muscle strength evaluation device 10 in the present embodiment will be described.

FIG. 7 is a diagram showing a method of matching the load direction and the eigenvector of the stiffness characteristic in the second embodiment of the present invention.

In the muscle strength evaluation device 10, the torque generated by the joint drive source equipped in each joint is calculated by the following equation (1) based on the joint angle measured by the angle detection device arranged in each joint. It is controlled so that the torque becomes the same.

<maths num="1"><img file="JP4946509B2_D0001.tif" /></maths> Thereby, the characteristics equivalent to the tip output characteristics and the stiffness characteristics of the human limbs revealed by Non-Patent Document 2 are reproduced.

In the present embodiment, the tip of the robot arm 12 of the muscle strength evaluation device 10 can be provided with a stiffness characteristic whose characteristic is indicated by an elliptical circle. Then, by displaying the direction of the force being measured to the user 20 by utilizing the stiffness characteristic, the user 20 is guided so that the measurement can be performed appropriately.

Here, the stiffness characteristic is expressed by a matrix as shown in the following equation (2) as the relationship between the joint axis torque and the displacement angle, and can be expressed by an ellipse in the case of a two-joint link.

<maths num="2"><img file="JP4946509B2_D0002.tif" /></maths> The major and minor axes of the ellipse coincide with the direction of the eigenvectors of the matrix and are perpendicular to each other. Then, the elastic modulus in the major axis direction or the minor axis direction of the ellipse corresponds to the eigenvalue with respect to the eigenvector. In the robot arm 12 of the muscle strength evaluation device 10, the eigenvalues and the eigenvectors can be arbitrarily set.

In this case, since the direction of the load is determined by the input measurement menu, the elastic modulus in the direction of the load is set to be smaller than the elastic modulus in the direction perpendicular to the load. Then, the control device controls the robot arm 12 so as to generate the joint axis torque in response to the joint angular displacement from the outside based on the set stiffness characteristic. Further, when the user 20 exerts a force to apply an angular displacement to the robot arm 12, the robot arm 12 generates a load torque according to the angular displacement.

The direction of the force that the user 20 wants to measure is a direction in which the elastic modulus is low with respect to the other directions and the force is easily displaced. Therefore, the user 20 can recognize the direction in which the force should be applied as the direction in which the body limb to be measured, for example, the lower limb, is easily moved.

Next, a method of matching the load direction and the eigenvector of the stiffness characteristic will be described.

As shown in FIG. 7, the directions in the measurement workspace are a vector (a vector starting from the hip joint and ending the ankle joint) and b vector (a vector starting from the knee joint and ending the ankle joint). ) Is represented as a base vector. Then, the direction in which the force is applied in the hexagon as shown in FIG. 4 is the direction shown by the following equation (3).

<maths num="3"><img file="JP4946509B2_D0003.tif" /></maths> Also, if the Jacobian matrix at the tip of the two-joint arm mechanism is J, then p_sThe direction perpendicular to is expressed by the following equation (4).

<maths num="4"><img file="JP4946509B2_D0004.tif" /></maths> Furthermore, the following equation (5) holds.

<maths num="5"><img file="JP4946509B2_D0005.tif" /></maths> Therefore, the relationship between the joint shaft torque and the displacement of the tip of the two-joint arm mechanism is expressed by the following equation (6).

<maths num="6"><img file="JP4946509B2_D0006.tif" /></maths> Then, using the relationship between the displacement of the tip of the two-joint arm mechanism and the joint angle displacement, the relationship between the joint axis torque and the joint angle displacement is corrected to the following equation (7).

<maths num="7"><img file="JP4946509B2_D0007.tif" /></maths> Since J is a Jacobian matrix, it is a function of the joint angle. Therefore, in order to obtain the components of the matrix of J, the actual joint angle is measured by the joint angle detection device arranged in the joint of the robot arm 12.

Then, according to the above formula, when the robot arm 12 is displaced from the reference point, the joint axis torque that the robot arm 12 should generate is calculated, and the control device uses the calculated joint axis torque as a target value to control the robot arm 12. By controlling the joint shaft torque of the robot, a desired stiffness characteristic can be obtained.

In the above equation (3), if the ratio of the scalar pairs (α, β) related to the a and b vectors is equal, the ratio of the muscle strength generated by each effective muscle of 3 to 6 muscles is equal. And if the ratio of the muscle strength generated by each effective muscle of 3 to 6 muscles is equal, the directions in the τ1-τ2 plane are also the same.

In order to measure the output distribution map of the joint axis torque, the user 20 needs to exert the force with maximum effort in multiple directions so that each side of the hexagon can be determined. Therefore, the stiffness characteristic control is used to teach the direction of the force required for measuring the output distribution map of the joint shaft torque. By lowering the elastic modulus in the direction in which you want the user 20 to exert force and increasing the elastic modulus in the direction perpendicular to it, the reaction force when the user 20 moves with force on the leg The direction is taught by the difference in hardness. Depending on the user 20, it may be taught by reversing the hardness and softness, increasing the elastic modulus in the direction in which the force is desired to be exerted, and decreasing the elastic modulus in the direction perpendicular to it.

As described above, in the present embodiment, since the hexagon in the output distribution map of the joint shaft torque does not depend on the joint angle, the posture of the user 20 may change during the measurement. Therefore, the direction in which the force should be exerted tactilely can be taught in an easy-to-understand manner by the hardness of the reaction force with respect to the force exerted by the user 20.

In the first and second embodiments, the evaluation of the effective muscle strength of the lower limbs has been described, but the human upper limbs have a muscle arrangement structure including one-joint muscles and two-joint muscles, similarly to the lower limbs. Since it has, the muscle strength evaluation device 10 can be used to similarly evaluate the effective muscle strength of the upper limbs.

Further, the present invention is not limited to the above-described embodiment, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention.

<figref num="1">It is a figure which shows typically the structure of the muscle strength evaluation apparatus in 1st Embodiment of this invention.</figref><figref num="2">It is a figure which shows typically the muscle group of the body limbs of the user in 1st Embodiment of this invention.</figref><figref num="3">It is a graph which shows the activity pattern of the muscle of the body limb of the user in the 1st Embodiment of this invention.</figref><figref num="4">It is a figure which shows the output distribution characteristic of the muscle of the body limb of the user in the 1st Embodiment of this invention.</figref><figref num="5">It is a figure which shows the comparison between the output distribution map of the force of the tip of a link system and the output distribution map of a joint shaft torque in the 1st Embodiment of this invention.</figref><figref num="6">It is a figure which shows the change of the output distribution map of the joint shaft torque before and after training in the 1st Embodiment of this invention.</figref><figref num="7">It is a figure which shows the method of matching the direction of a load and the eigenvector of a stiffness characteristic in the 2nd Embodiment of this invention.</figref>

Code description

10 Muscle strength evaluation device 11 saddle 12 robot arm 14a 1st link 14b 2nd link 15a 1st fixture 15b 2nd fixture 20 users