JP2895352B2 - Force control mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force control mechanism.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional force control mechanism.
FIG. 4 is an external view of the force control mechanism. In the figure, 1 is a motor, 2 is an angle detector (position detector) for detecting the rotation angle of the output shaft of the motor 1, 3 is a coil spring (spring) expanded and contracted by the motor 1, 4 is a force generated by the coil spring 3 , A force generation mechanism including the above elements, 6 is a force control feedback loop that feeds back a detection signal of the force detector 4, and 7 is an angle detector 2.
, A position control feedback loop that feeds back the detection signal, 8 is a power transmission line that sends driving power to the motor 1, 9 is a force compensator that sends a control signal for force control to the motor 1, and 10 is a position control device that sends position control to the motor 1. , A control device, c is a force command value input to the feedback control system, n is a force detection noise mixed into the detection value by the force detector 4, p is a position detection value, f Is a force detection value.

Next, the operation will be described. In the force control device shown in the figure, the motor 1 expands and contracts the coil spring 3 to generate a force at the tip of the coil spring 3. This force is detected by the force detector 4 and fed back to the force compensator 9, which sends a control signal to the motor 1 so that the force compensator 9 eliminates a deviation from the force command value c. The rotation position of the output shaft of the motor 1 is detected by the angle detector 2. This position detection value p is fed back to the position compensator 10 and
A control signal is sent to the motor 1 so as to eliminate the deviation from the input value.

[0004]

Since the conventional force control mechanism is configured as described above, the force detection noise n directly deteriorates the force control accuracy, and high accuracy cannot be achieved. In addition, if a low-pass filter is inserted in the middle of the force control feedback loop 6 for feeding back the force detection value f, the force detection noise n can be removed and high-precision force control can be realized. Because it is cut,
The bandwidth of the control system must be set narrow, and the responsiveness deteriorates. In any case, the conventional configuration has a problem that it is impossible to achieve both accuracy and quick response.

[0005] The present invention has been made to solve the above problems, and has as its object to obtain a force control mechanism capable of achieving both accuracy and quick response.

[0006]

According to a first aspect of the present invention, a force control mechanism includes a low-pass filter that cuts a high-frequency component in the middle of a force control feedback loop, and outputs a detection signal of a position detector. A position-force converter for converting into a force signal, and a high-pass filter for passing only the high-frequency component of the force signal from the position-force converter are newly provided, and the signal passing through the low-pass filter and the high-pass The signal passed through the pass filter is added by an adder and input to a force compensator.

A force control mechanism according to a second aspect of the present invention includes a speed control feedback loop instead of the position control feedback loop.

[0008]

[0009]

The force control mechanism according to the first aspect of the present invention cuts high frequency components of the force signal by the low pass filter.
Therefore, the signal that has passed through the low-pass filter is a signal that lacks high-frequency components. On the other hand, the position-force converter
Hook's law Converts the position detection value to a force according to (force) = (spring constant) x (angle or position). The converted force signal is passed through a high-pass filter to become a signal corresponding to the above-described shortage. This signal is added to the signal after passing through the low-pass filter by the adder, becomes a signal covering almost the entire area, and is fed back to the force compensator. Therefore, quick response is ensured by supplementing the high frequency component. Further, since the force detection noise is removed by the low-pass filter, highly accurate force control can be achieved. The position control is performed by a position control feedback loop as usual.

In the force control mechanism according to the second aspect of the present invention, a speed control feedback loop is provided instead of the position control feedback loop, so that speed control is performed with high accuracy.

[0011]

[0012]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a force control mechanism according to an embodiment of the present invention. In the figure, reference numerals 1 to 11 denote the same elements as those in the conventional example of FIG. In the middle of the force control feedback loop 6, a low-pass filter 12 for removing high-frequency components (force detection noise n) is provided. Reference numeral 13 denotes a position-force converter for converting the position detection value P from the angle detector (position detector) 2 into a force signal according to Hooke's law, and 14 passes only high-frequency components of the signal of the position-force converter 13. This is a high-pass filter to be used.

Next, the operation will be described. In the force control mechanism shown in FIG. 1, a high-precision force control value can be obtained over the entire band through the low-pass filter 12 and the high-pass filter 14, so that high-precision force control can be achieved. At the same time, quick response can be ensured.

Embodiment 2 FIG. FIG. 2 is a block diagram of a force control mechanism according to an embodiment of the present invention. In FIG. 2, reference numeral 15 denotes a differentiator for differentiating a signal of the angle detector 2 to obtain a rotation speed signal of the output shaft of the motor 1 . (Speed detector), 17 is a speed compensator that sends a control signal for speed control to the motor 1. This signal is input to the speed compensator 17 by the speed control feedback loop 7a. In this mechanism, even when the control system is of the I type with respect to the force command value c, the force compensation only needs to be proportional operation.
There is an advantage that an integration operation, that is, an operation requiring an internal memory is unnecessary.

Embodiment 3 FIG. The force control mechanism according to the third embodiment corresponds to the first or second embodiment.
As the angle detector 2 in this mechanism, the detection delay is ignored
This is one that is as small as possible (detection time is about 1 ms) . As such an angle detector, for example,
Absolute encoder and incremental encoder
and so on. In this mechanism, the smell
The first rising component is so small that the delay is negligible
Feedback control by the position detection value P
Therefore, even if the force detection value f has a detection delay, it does not contribute much.
No. For this reason, transient response characteristics such as step response
Advantages such as elimination of bar chute, detection of force detector 4
Advantage, angle that delay characteristics do not adversely affect performance
Transient response of force control mechanism by detection delay performance of detector 2
There is an advantage that characteristics can be designed.

[0016]

As described above, according to the first aspect of the present invention, since the low frequency component is obtained by the force detector and the high frequency component is obtained by the position detector, both high precision and quick response are achieved. There is an effect that a controlled force control mechanism can be obtained.

According to the second aspect of the present invention, since the speed control feedback loop is provided instead of the position control feedback loop, the speed control can be performed with high accuracy.

[0018]

[Brief description of the drawings]

FIG. 1 is a block diagram of a force control mechanism according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram of a force control mechanism according to Embodiment 2 of the present invention.

FIG. 3 is a block diagram of a conventional force control mechanism.

FIG. 4 is an external view of a conventional force control mechanism.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 motor 2 angle detector (position detector) 3 coil spring (spring) 4 force detector 5 force generation mechanism 6 force control feedback loop 7 position control feedback loop 7 a speed control feedback loop 9 force compensator 10 position compensator 12 Low-pass filter 13 Position-force converter 14 High-pass filter 15 Differentiator (speed detector) 16 Adder 17 Speed compensator

Claims (2)

(57) [Claims] A force generating mechanism as claimed in claim 1] to stretch the spring by a motor to generate a force, a position detector for detecting a rotational position of the output shaft of the motor, the spring tip of the force generating mechanism
A force detector that detects the generated force, a force control feedback loop that feeds back a detection signal of the force detector to a force compensator that sends a control signal to the motor, and a detection signal of the position detector to the motor. A position control feedback loop for feeding back to a position compensator for sending a control signal, a low-pass filter for removing high frequency components inserted in the middle of the force control feedback loop, and a detection signal of the position detector as a force signal. Convert located - pass and high-pass filter which passes only the high frequency component of the force signal from the force conversion device, the signal passed through the low-pass filter and the high pass filter - a force conversion device, the position power control mechanism by adding the signal with the adder being sent to said force compensator. A force generating mechanism wherein to stretch the spring by a motor to generate a force, a position detector for detecting a rotational position of the output shaft of the motor, the spring tip of the force generating mechanism
A force detector for detecting the force generated, the output shaft of the motor
A speed detector that detects the rotation speed of the motor, a force control feedback loop that feeds back a detection signal of the force detector to a force compensator that sends a control signal to the motor, and a detection signal of the speed detector to the motor. A speed control feedback loop that feeds back a control signal to a speed compensator, a low-pass filter for removing high frequency components inserted in the middle of the force control feedback loop, and a detection signal of the position detector as a force signal. Convert located - pass and high-pass filter which passes only the high frequency component of the force signal from the force conversion device, the signal passed through the low-pass filter and the high pass filter - a force conversion device, the position power control mechanism by adding the signal with the adder being sent to said force compensator.