JPH0475113A - Controller - Google Patents

Abstract

PURPOSE:To heighten responsiveness without forcing a controlled system and to stably perform the operation control of the control system with high responsiveness by attaching limitation on the energy of inertia of the controlled system by an area control means so as not to force the controlled system as keeping the acceleration of a variable gain means. CONSTITUTION:A command generating means 11 generates command signals (a), (b), and a control means 14 finds deviation quantity between detection signals (e), (f) for the controlled system and the command signals (a), (b), and a signal is outputted to the controlled system so as to make the detection signals (e), (f) follow the command signals (a), (b) corresponding to the deviation quantity. The variable gain means 18 outputs a correction signal in accordance with the deviation quantity to the control means 14, and an area control means 19 outputs a signal to decide whether or not the variable gain means 18 should be operated based on the command signals (a), (b) and the detection signals (e), (f) to the variable gain means 18. Thereby, it is possible to stably perform the operation control of the controlled system with high responsiveness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device that controls the operation of a controlled object such as an industrial robot or an NC machine tool.

[Conventional technology]

Conventionally, this type of control device uses a positioning servo system to control the operation of a controlled object using command signals. In addition, as another control device, there is a system in which a feedforward loop is added to the positioning servo system to compensate for the delay in response to the command signal of the controlled object using a signal corresponding to the command signal. There is a method of reducing (compensating) the response delay of the controlled object to the command signal.

[Problem to be solved by the invention]

In the above positioning servo system, as shown in Figure 4, the response of the controlled object to the command signal (target position command) is exponential, that is, as the position of the controlled object approaches the target position, it changes gradually. It takes a very long time to match the target position, that is, to converge, making it difficult to shorten the takt time. Furthermore, a method in which a feedforward loop is added to the positioning servo system or a method in which the gain of the positioning servo system is increased has the drawback that strain is placed on the controlled object, causing overshoot due to elasticity or the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device that can improve the above drawbacks and control the operation of a controlled object stably and with high responsiveness.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a command generating means for generating a command signal for causing a controlled object to perform a desired operation, and a detection signal and the above command signal for the $Jtll object that actually operates according to the command signal. and control means for determining a deviation amount from the control object and outputting a signal to the controlled object in accordance with the deviation amount so that the detection signal follows the command signal.

variable gain means for outputting a correction signal corresponding to the deviation amount to the control means in order to compensate for the deviation amount;

and area control means for outputting a signal to the variable gain means for determining whether or not to operate the variable gain means based on the command signal and the detection signal.

[For production]

The command generation means generates a command signal, the control means determines the amount of deviation between the detection signal for the controlled object and the said command signal, and applies the control means to the controlled object so that the said detection signal follows the said command signal according to this deviation amount. Output a signal. The variable gain means outputs a correction signal corresponding to the deviation amount to the control means, and the area control means varies a signal for determining whether to operate the variable gain means based on the command signal and the detection signal. Output to gain means.

〔Example〕

FIG. 1 shows an embodiment of the invention.

The command generating means 11 generates command signals a and b (the target position signal C is the same signal as the command signal a) for causing the controlled object 12.13 to execute a desired operation. In this embodiment, the command generating means 11 generates a position command signal a and a speed command signal S in order to cause the arm of the robot constituting the mechanical system 13 to be controlled to execute a desired operation.

The positioning control means 14 receives command signals a and b from the command generation means 11, and a detection signal e from a detection means for detecting the position and speed of a controlled object 12.13 that actually operates based on the command signals a and b. It is a control means that calculates the amount of deviation from f and outputs a signal to the controlled objects 12 and 13 so that the detection signals e and f follow the command signals a and b according to this deviation amount. In this embodiment, the actuator 12 is constituted by a servo motor, and this servo motor is provided with a pulse generator as a detection means, and this pulse generator detects the shaft position and shaft speed of the servo motor and generates an actuator shaft position signal f. and outputs an actuator shaft speed signal e. Note that the position of the mechanical system 13 to be controlled may be detected by a position detection sensor, and the detection signal from this position detection sensor may be used instead of the actuator shaft position signal f. Further, the positioning control means 14 includes feed forward means 15. Position control means 16
and speed control means 17, and each gain F, G of the feedforward means 157, position control means 16 and speed control means 17 is controlled to either normal gain or high gain by variable gain means 18. Ru. The position control means 16 receives the position command signal a from the command generation means 11.
Then, the actuator shaft position signal f from the pulse generator is subtracted, and the deviation amount d is amplified by a gain. The speed # control means 17 subtracts the actuator shaft speed signal e from the pulse generator from the speed command signal given from the command generation means 11 via the feedforward means 15, and calculates the deviation amount and the output signal of the position control means 16. and amplified by gain G to actuator 1.
Output to 2. The feedforward means 15 amplifies the speed command signal S from the command generating means 11 with a gain F so as to eliminate a delay in response of the controlled object 12, 13 to the speed command signal S, and supplies the amplified speed command signal S to the speed control means 17.

As described above, the actuator 12 is composed of a servo motor and a pulse generator, and the servo motor is driven by the output signal of the position control means I6 to move the mechanical system 13 to be controlled to the target position.

The drive system 13 is composed of a decelerator and a robot arm,
The output of the actuator 12 is decelerated by a decelerator and transmitted to the arm of the robot.

The variable gain means 18 adjusts the deviation amount to the positioning control means 14 in order to compensate for the deviation amount, that is, to make the controlled object 12.13 follow the command signals a and b without delay in control response. Outputs a correction signal corresponding to.

In this embodiment, the variable gain means 18 outputs a signal for changing each gain of the feedforward means 152, position control means 16, and speed control means 17 in the positioning control means 14 from a normal gain to a high gain as a correction signal. Here, the normal gain is a gain that allows the control system to respond stably when the target of the controlled object changes. The gain is such that the arm stably stops at the target position, that is, without causing vibration. With this normal gain, the response of the controlled object is delayed. A high gain is a gain that can improve the response delay of the controlled object, and a high gain causes the problem of vibration of the robot arm, resulting in unstable control.

The area limiting means 19 is configured to control the variable gain means 18 based on the command signal C, the actuator shaft position signal f and the actuator shaft speed signal e from the pulse generator.
A signal determining whether or not to operate is outputted to the variable gain means 18. In this embodiment, the area limiting means 19 receives the area limiting signal g in advance.

A value E indicating an allowable range regarding the speed limit signal and position is set. Then, the area limiting means 19 determines the absolute value 1c of the difference between the target position signal C from the command generating means 11 and the actuator shaft position signal f from the pulse generator.
−fl, and convert this absolute value c−fl into the area limit signal g.
Also, the absolute value let of the actuator shaft speed signal e from the pulse generator is compared with the speed limit signal.

As will be described later, when the conditions shown in the flowchart of FIG. 2 are satisfied, the area limiting means 19
8, i.e. the feedforward means 1
5. A signal is output to the variable gain means 18 that enables each gain of the position control means I6 and the speed control means 17 to be changed from a normal gain to a high gain. The output signal of this area limiting means 19 is transmitted to the feedforward means 15.
2. Instead of a signal for changing each gain of the position control means 16 and speed control means 17 from a normal gain to a high gain, a signal for changing each gain of the feed forward means 152 and a position control means 16 and speed control means 17 from a normal gain to a high gain is used. is determined by the variable gain means 18. Furthermore, after changing the gains of the feedforward means 152, position control means 16, and speed control means 17 from the normal gain to the high gain, the area limiting means 19 determines the absolute difference between the target position signal C and the actuator shaft position signal f. The value 1 cmfl is compared with a value E smaller than the area limit signal g, and the absolute value of the difference between the target position signal C and the actuator shaft position signal f is determined.
If f l is smaller than ε, a signal is output to the area limiting means 19 and the feedforward means 15. The gains of the position control means 1 and speed control means 17 are changed to normal gains.

Although not shown, an arithmetic control device is provided which instructs the start and stop of the operation of each means and the flow of signals.

This embodiment has a command generating means 119, a positioning control means 14. Actuator 12
In addition, the device is characterized by having a variable gain means 18 and further provided with an area limiting means 19, and its operation will be explained next.

The command generating means 11 generates command signals a and b, and the positioning control means 14 generates a control signal based on the command signals a and b, and this control signal is input to the actuator 12 to perform a positioning operation of the arm of the robot. . At this time,
The area limiting means 19 receives the target position signal C from the command generating means 11, the actuator shaft position signal f and the actuator shaft speed signal e from the pulse generator, and as shown in FIG. The absolute value 1c-fl of the difference with the actuator shaft position signal f from
-fl>g, a stop signal is output to the variable gain means] 8 to change the gains of the feedforward means 15, the position control means I6, and the speed control means 17 to normal gains. Typically, the variable gain means 18 includes a feed forward means 159, a position control means 16 and a speed control means 17.
Since each gain is set to the normal gain, the positioning control means 14 performs the control operation as is. Further, the area limiting means 19 compares the absolute value +e+ of the actuator shaft speed signal e from the pulse generator with the speed limit signal ri, and if e l ) h, outputs a stop signal to the variable gain means I8 to feed Forward means 15. Each gain of the position control means 16 and speed control means 17 is changed to a normal gain. Here, the speed limit signal is a value for determining whether the inertial energy of the controlled object 12.13 has become sufficiently small, and the speed limit signal
If tel>h, it is determined that the inertial energy of the controlled object 12.13 has become sufficiently lJX, and the feedforward means 159, position control means 16, and speed control means 17
This means that each gain of is changed to the normal gain. The area limiting means 19 is IC-115g, and if lel≦h, cancels the stop signal to the variable gain means 18 and turns on the variable gain means 18. At this time, the variable gain means 18 differentiates the actuator shaft speed signal e from the pulse generator and calculates the product d-cl' of the differential signal d' and the position deviation signal d from the positioning control means 14. Then, the variable gain means 18 determines whether this dd' is O or not, and if dd'≧O, the feed forward means 15. The gains of the position control means 16 and the speed control means 17 are changed to normal gains, and if cl-d'<O, the gains of the feedforward means 151, the position control means 16 and the speed control means 17 are changed to high gains higher than the normal gains. change to Furthermore, if dd'<O, the controlled object 12.13 has entered the deceleration region.

The area limiting means 19 determines the absolute value 1 cmfl of the difference between the target position signal C and the actuator shaft position signal f from the pulse generator, and compares this absolute value 1c-f with E. Here, E is a value for determining whether the controlled objects +2 and 13 have reached the target position. Area restriction means 19
If 1c-fl≧, it remains the same, but 1cmfl
<ε, it is determined that the controlled object 12° 13 has reached the target position, and a stop signal is output to the area limiting means 19, thereby changing the gains of the feedforward means 152, position control means 16, and speed control means 17 to normal gains. change to

As described above, in this embodiment, in principle, the feedforward means 15. The gains of the position control means 16 and speed control means 17 are set to normal gains to stably control the controlled object 12.13, and even when the controlled object 12.13 converges to the target position, the feedforward means 152 The respective gains of the position control means 16 and the speed control means 17 are set to normal gains, and the controlled objects 12 and 13 are converged to the target position in a short time. Furthermore, when the inertial energy of the controlled object 12.13 becomes sufficiently small, the gains of the feed forward means 159, the position control means 16, and the speed control means 17 are changed to high gains, so that the inertial energy of the controlled object 12.13 is reduced. There is no need to force the controlled objects 12 and 13 in the thick state, and the response can be improved and the tact can be shortened. That is, while maintaining the high speed of the variable gain means 18, by adding a limit to the inertial energy of the controlled object 12.13 by the area limiting means 19 so as not to put strain on the controlled object,
It is possible to improve the responsiveness and shorten the takt time without putting too much stress on the 13. Additionally, if a detection device detects a two-dimensional or three-dimensional trajectory and moves the controlled object along that trajectory, the responsiveness when correcting deviations from the trajectory will improve. The accuracy of the trajectory of the controlled object is improved.

FIGS. 3(a) and 3(b) show the response characteristics of the above embodiment and the conventional device.

In the conventional positioning servo system, the response of the control position and control speed of the controlled object to the target position signal ■ and target speed signal ■ is poor, as shown in the characteristic curves ■ and ■ in FIG.
In a method in which a feedforward loop is added to the conventional positioning servo system, or in a method in which the gain of the positioning servo system is increased, overshoot occurs due to the inertial energy of the controlled object, as shown in the characteristic curves ("l, (l)" in Figure 3. In contrast, in the above embodiment, by providing the area limiting means 19, the characteristic curve (positive,
), the responsiveness of the control position and control speed of the controlled object to the target position signal (2) and the target position signal range can be reasonably increased, and overshoot can be eliminated.

In the above embodiment, the actuator 12 is provided with a pulse generator as an inspection means, but a detection means other than the pulse generator may be used.

Further, although the above embodiment is an example of controlling the arm of a robot, the present invention may be applied to positioning of an NC machine tool, positioning of a processing tool, etc.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a command generating means for generating a command signal for causing a controlled object to perform a desired operation.

The amount of deviation between the detection signal for the control object that actually operates according to the command signal and the command signal is determined, and a signal is output to the control object so that the detection signal follows the command signal according to the deviation amount. and control means to do so.

In order to compensate for the deviation amount, variable gain means outputs a correction signal corresponding to the deviation amount to the control means, and it is determined whether or not to operate the variable gain means based on the command signal and the detection signal. Since it is equipped with an area control means for outputting a signal to the variable gain means, the inertial energy of the controlled object is limited by the area limiting means so as not to put strain on the controlled object while maintaining the high speed of the variable gain means. By adding this, it is possible to improve the responsiveness without putting any strain on the controlled object, and the operation of the controlled object can be controlled stably and with high responsiveness.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a flowchart showing the processing flow of the variable gain means and area limiting means in the same embodiment, and FIG.
)(b) is a characteristic curve diagram showing the response characteristics of the above embodiment and the conventional device, and FIG. 4 is a characteristic curve diagram for explaining the conventional device. 11... Command generating means, 12.13... Controlled object,
14... Positioning control means, 18... Variable gain means, 19... Area limiting means. Also σ Frequency 4 Figure

Claims (1)

[Scope of Claims] Command generation means for generating a command signal for causing a controlled object to perform a desired operation; a control means for outputting a signal to the controlled object so that the detection signal follows the command signal according to the deviation amount, and a correction signal corresponding to the deviation amount to compensate for the deviation amount. variable gain means for outputting to the control means; and area control means for outputting to the variable gain means a signal for determining whether to operate the variable gain means based on the command signal and the detection signal. Characteristic control device.