JPS6319145A - Control method for rehabilitation support equipment - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a control system for a rehabilitation support device used to restore the functions of limbs such as upper or lower limbs that have decreased muscle strength. BACKGROUND TECHNOLOGY Typical prior art involves uniform velocity control of the rocking motion of an angularly displaceable arm to which a limb is attached. To achieve this, a one-way clutch equipped with a ratchet mechanism is interposed between the electric motor and the base end of the arm, and the electric motor is driven to rotate at a preset constant speed.

When the speed of the angular displacement of the arm is smaller than the rotational speed of the electric motor, the one-way clutch does not transmit the torque acting on the arm by the limb to the motor side, and the speed of the angular displacement of the arm is larger than the rotational speed of the electric motor. Sometimes, torque is transmitted from the arm to the electric motor via a one-way clutch, and the output torque of the electric motor is rotated in the opposite direction to serve as a load, thus performing constant velocity control.

Problems to be Solved by the Invention In such prior art, there is a problem in that the one-way clutch has a relatively complicated structure and is large in size.

An object of the present invention is to provide a control method for a rehabilitation support device that has a simple configuration and can be implemented using commercially available components.

Means for Solving the Problems The present invention provides a control method for a rehabilitation support device for restoring the functions of limbs with decreased muscle strength by attaching a limb to an arm capable of angular displacement. A servo motor, a power amplifier that drives the servo motor, a rotation speed detector that detects the rotation speed of the servo motor, a force or torque detector that detects the force or torque applied to the arm from the limb, and the force or torque. A limiter that responds to the output of a rotational speed detector and derives an output at a certain level when the force or torque exceeds a predetermined value, and a limiter that calculates the difference between the output of the rotation speed detector and the output of the limiter. , and a subtractor that supplies a signal representing the difference to a power amplifier.

The present invention also provides a control method for a rehabilitation support device for restoring the function of a limb with reduced muscle strength by attaching a limb to an arm capable of angular displacement, which includes a servo motor for driving the arm through angular displacement, and a servo motor. A driving power amplifier, a rotation speed detector that detects the rotation speed of the servo motor, an angle detector that detects the angle of the arm, and a sensor that responds to the output of the angle detector and detects when the arm exceeds a predetermined range of motion. and a subtracter that calculates the difference between the output of the rotation speed detector and the output of the dead band element and supplies a signal representing the difference to the power amplifier. This is a control method for a rehabilitation support device characterized by:

According to the present invention, when the output of the force or torque detector, that is, the force acting on the arm by the limb, is equal to or greater than a predetermined value set in the limiter, the limiter outputs a predetermined constant value. You can get level output. The subtracter derives a signal representing the difference between the output of the rotational speed detector and the output of the limiter and provides it to the power amplifier. This achieves constant speed control of the servo motor.

Furthermore, according to the present invention, when the amount of angular displacement of the arm exceeds the movable range, that is, when the arm exceeds the upper limit or lower limit of angular displacement, the dead band element outputs an output having a predetermined large level. Derive. The output from this dead zone element is applied to a subtracter to calculate the difference between it and the output of the rotational speed detector, and a signal representing the difference is applied to a power amplifier. In this manner, when the arm exceeds its movable range, the output of the subtractor increases, and the servo motor therefore generates a torque in the opposite direction of rotation to the torque due to the force acting on the arm by the limb. The arm is thus prevented from being angularly displaced beyond the range of movement set by the deadband element.

Embodiment FIG. 1 is a block diagram of an embodiment of the present invention. In order to restore the function of a limb whose muscle strength has decreased, a control method for a rehabilitation support device according to the present invention is implemented.

The upper or lower limb is attached to the end 2 of the arm 1. The base end 3 of this arm 1 is fixed to a rotating shaft 4 having a horizontal axis. The output shaft 6 of the servo motor 5 is connected to a speed reducer 7, and the rotational speed of the output shaft 6 of the servo motor 5 is reduced and transmitted to the rotating shaft 4. servo electric 8
! The rotational speed of the output shaft 6 of No. 5 is detected by a rotational speed detector 8. This rotational speed detector 8 has a characteristic that as the rotational speed of the output shaft 6 increases, the level of the output delivered to the line 9 increases as shown in FIG.

The servo motor 8!5 is driven by a power amplifier 10.

A force detector 11 is attached to the arm 1 and can detect the force acting on the arm 1. This force detector 11
is the output corresponding to the force acting on arm 1 on line 12
The characteristics are shown in FIG.

The force detector 11 is realized by, for example, strainage.

The output signal of force detector 11 is input to limiter 14 via line 12.

When the level of the input signal applied via the line 12 is in a small value range To to -To as shown in FIG. 4, the limiter 14 outputs an output having a level proportional to the input level to the line 15. When the input level of the limiter 14 is equal to or higher than the value 10To, the output level becomes a constant value such as a predetermined value θL. Further, when the input level is below -To, the output level is kept at a constant value of -θ, which is a predetermined value.

The output of the limiter 14 is applied from a line 15 to a subtracter 17 and then to a subtracter 19 via a line 18. Subtractor 1
9 subtracts the level of the signal from the rotational speed detector 8 via line 9 from the level of the signal on line 18;
A signal representative of the difference is provided on line 20 to power amplifier 10.

The amount of angular displacement of arm 1 is detected by angle detector 21 . The output from the angle detector 21 is input to the dead zone element 23 via the line 22. As shown in FIG. 6, the dead zone element 23 is such that when the level of the input applied via the line 22 is within a predetermined meta value θNAX to θWIN, the level of the output derived to the line 24 is zero. and the input level is the upper limit value θl'lA
When it is greater than or equal to X and less than or equal to the lower limit value θMIN, an output of the slope kp is derived. When the input level is greater than or equal to the value θ^X and less than the value θMIN, the amount of change in the output level corresponding to the amount of change in the input level, that is, the slope kp, is extremely large, and the angle α shown in FIG. is a value close to 90 degrees. Dead band element 23
The output derived from line 24 is given to a coefficient multiplier 25, multiplied by a constant kE, and inputted to a subtracter 17. The subtracter 17 subtracts the output of the coefficient unit 25 from the output of the limiter 14, and outputs a signal having a level corresponding to the difference to the line 1b-8.

It is assumed that the angular displacement position of the arm 1 is within a movable range corresponding to preset values θMAX to θMIN in the dead band element 23. When a force is applied to the arm 1 by the limb, the force is detected by the force detector 11.

Servo motor 5, rotation speed detector 8, and power amplifier 1
0 and the subtractor 19 constitute a speed feedback loop, and the actual rotational speed θ of the output shaft 6 detected by the rotational speed detector 8 is the rotational speed product input from the line 18 to the subtractor 19. Assume that the deviation is sufficiently small.

In the limiter 14 to which the output from the force detector 11 is applied, when the input level T is in the range of +TO to -TO, the slope D is expressed by the first equation.

From the feedback law, θ=D−T (−TO≦T≦To) ・・・(
2) θ=θL (To<T)
...(3) θ=-〇 (T < -T o
)...(4) holds true.

In other words, when the force is small, arm 1
rotates at a speed θ according to the second equation. As the force increases, when the speed of arm 1 reaches θ or 10L, even if the blade is increased further, the arm rotates at a constant speed (θ or 10L), thus achieving constant speed control. will be carried out.

The setting of the movable range of the arm 1 will be explained. The level of the signal given from the limiter 14 to the subtracter 17 is set to A
When a signal is given to the dead zone element 23 from the angle detector 21, the following equations 5 to 7 hold true.

θ=A (θKIN≦θ≦θWAX) ・
...(5) θ = A-kp-kE (θ-θ ＾X) (θ
i^χkuθ) ...(6)θ=A
kp-kE (θ-θWIN) (θkuθWIN)
(7) When the level θ of the signal input to the dead band element 23 is in the range of values θMAX to θMIN, the arm 1 moves at a constant speed as described above except for the limiter 140 seconds to θMIN. controlled.

When the 6th or 7th equation holds, that is, arm 1
When the angle exceeds 0Mex or is less than θN, a position feedback operation is performed, and the arm 1 is prevented from greatly exceeding the movable range of vertical positions θMAX to θH,N. In the dead zone element 23, when the output of the angle detector 21 inputted from the line 22 is greater than or equal to θWAX and less than or equal to θWIN, the output changes greatly in response to a change in the input. It has a slope α. Therefore, when constant velocity control is performed by applying force to the arm position using the limbs, does the arm position change to the value θ? An abrupt stop is prevented at the angular displacement position corresponding to IkX90K0. Therefore, impact force can be prevented from being applied to the limbs.

In another embodiment of the invention, the limiter 14 has an input level of 10T. ~-T. The output may be configured to be zero when within the range of .

Further, instead of the force detector 11, a detector that detects the torque of the arm 1 may be used.

Effects As described above, according to the present invention, the configuration can be simplified and downsized, and can be realized using commercially easily available components. Furthermore, by using the dead zone element, the movable range of the arm can be easily set to a desired value.

[Brief explanation of drawings]

1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram showing the characteristics of the rotational speed detector 8, FIG. 3 is a diagram showing the characteristics of the force detector 11, and FIG. 4 is a diagram showing the characteristics of the limiter 14. FIG. 5 is a diagram showing the characteristics of the angle detector 21, and FIG. 6 is a diagram showing the characteristics of the dead zone element 23. DESCRIPTION OF SYMBOLS 1... Arm, 4... Rotating shaft, 5... Servo motor, 7... Reduction gear, 8... Rotation speed detector, 10...
... Power amplifier, 11... Force detector, 14... Limiter, 25... Coefficient unit, 17.19... Subtractor, 21
...Angle detector, 23...Dead zone element agent Patent attorney Keiichi Saikyo Figure 1 Figure 4 Figure 2 Figure 3/11/ ■ Figure 5

Claims (2)

[Claims] (1) In a control method for a rehabilitation support device that attaches a limb to an arm capable of angular displacement and restores the function of the limb with decreased muscle strength, a servo motor and a servo motor are used to drive the arm through angular displacement. a power amplifier for driving the motor; a rotation speed detector for detecting the rotation speed of the servo motor; a force or torque detector for detecting the force or torque applied to the arm by the limb; and a response to the output of the force or torque detector. and a limiter that derives an output at a certain level when the force or torque is greater than a predetermined value, and a limiter that calculates the difference between the output of the rotation speed detector and the output of the limiter,
1. A control method for a rehabilitation support device, comprising: a subtracter that supplies a signal representing the difference to a power amplifier. (2) In a control method for a rehabilitation support device that attaches a limb to an arm capable of angular displacement and restores the function of the limb whose muscle strength has decreased, a servo motor and a servo motor are used to drive the arm through angular displacement. A power amplifier to drive the motor, a rotation speed detector to detect the rotation speed of the servo motor, an angle detector to detect the angle of the arm, and a sensor that responds to the output of the angle detector to detect when the arm exceeds a predetermined range of motion. and a subtracter that calculates the difference between the output of the rotation speed detector and the output of the dead band element and supplies a signal representing the difference to the power amplifier. A control method for a rehabilitation support device characterized by: