JPH01177604A - Servo device - Google Patents

Abstract

PURPOSE:To execute a satisfactory control by preparing a control system excellent in a quick-responsiveness and a control system excellent in a stability beforehand, and executing a changeover so as to use the former control system when the quick-responsibility is required and to use the latter control system when the stability is required, respectively. CONSTITUTION:When a target value Xr is given from a terminal 1, such a signal is inputted to a changeover instructing part 2, a control system 3 excellent in the quick-responsiveness and a control system 4 excellent in the stability. To the changeover instructing part 2, a response X outputted from a controlled system 5 is also inputted in addition to the target value Xr. A difference between the target value Xr and response X, DELTAX=¦Xr-X¦ is calculated, a changeover signal to select the control system 4 is outputted when the DELTAX is made smaller than a prescribed set value DELTA, the changeover signal to select the control system 3 is outputted at the time of DELTAX>=DELTA, and a switching device 6 is changeover-operated. Thus, the changeovers to the control system 3 and to the control system 4 are executed when errors with the goal value Xr are large and small, respectively, and the quick-responsiveness and stability can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves preparing in advance a control system aimed at quick response (high speed) and a control system aimed at stability (precision), and then controlling these systems in motion. The present invention relates to a servo device that can simultaneously satisfy high responsiveness and stability by optimally switching according to conditions.

[Prior Art] FIG. 4 is a diagram showing a prior art. As shown in the figure, this device is a servo device composed of a position gain Gp for increasing quick response and a speed gain Gv for increasing stability. In this servo device, when the position gain Gp is increased to increase the quick response, it vibrates a little as shown by the curve A shown in FIG. 5, and when the speed gain Gv is increased to increase the stability, the curve B shown in FIG. This time, the damping is too effective and the quick response is sacrificed.

In other words, there was a trade-off relationship between the two, and a compromise was necessary for the adjustment.

[Problems to be Solved by the Invention] The present invention has been made to eliminate the above-mentioned drawbacks of the conventional technology, and it is possible to improve rapid response and stability without sacrificing either of them as in the prior art. It is an object of the present invention to provide a servo device that is excellent in both of these aspects and can perform good control.

[Means for Solving the Problems] In order to solve the above problems and achieve the objects, the present invention takes the following measures. That is, a control system with excellent quick response and a control system with excellent stability are prepared in advance, and these control systems are switched over and used as appropriate depending on the required conditions.

[Action Co. By taking the above measures, the following effects are achieved.

That is, the servo device of the present invention can switch to a control system with excellent quick response when quick response is required, so it can operate quickly without being affected by stability. Furthermore, when positioning accuracy is required, the control system is switched to a more stable control system, so that precise positioning control is performed with damping.

[Example] The present invention will be specifically described based on an example shown in the drawings. FIG. 1 is a block diagram of a servo device of the present invention. When the target value Xr is given from the terminal 1, the signal is input to the switching command unit 2, the control system 3 with excellent quick response, and the control system 4 with excellent stability. The switching command unit 2 receives the target value X.
In addition to r, a response X output from the controlled object 5 is also input. And the difference between the target value Xr and the response X, ΔX=IXr−X
I is calculated, and if this ΔX becomes smaller than a predetermined set value Δ, a switching signal for selecting control system 4 is output, and ΔX
If ≧Δ, a switching signal for selecting the control system 3 is output, and the switching device 6 is operated to switch. Due to this action, the target value
When the error with respect to r is large, control system 3 is used, and when the error is small, control system 4 is used, so that both excellent quick response and stability can be achieved. 7 is an output terminal.

FIG. 2 is a block diagram showing the internal configuration of the control system 3 which has excellent quick response. A comparator 11 obtains the difference between the target value Xr and the response X, and this difference is multiplied by a feedback gain of 12. Further, the target value Xr is multiplied by a feedforward gain of 13. Finally, these two multiplication results are sent to an adder 14
and output from terminal 15 as operation m S 1. Note that the target value Xr and the response X are vectors including position, velocity, and acceleration. Therefore, the feedback gains Ge and Gff of 12 and 13 are also vectors.

FIG. 3 is a block diagram showing the internal configuration of the control system 4, which has excellent stability. The difference between the target value Xr and the response X is determined by the comparator 21.
The difference is multiplied by an integral gain G1 of 22. Further, the response X is multiplied by a feedback gain Gs of 16. Finally, the subtracter 24 subtracts the multiplication result and outputs it from the terminal 25 as the operation m S 2 .

Note that the gains Gi and Gs of 22 and 23 in this case are also vectors.

[Effects of the Invention] In the present invention, a control system with excellent quick response and a control system with excellent stability are prepared in advance, and when quick response is required, the former control system is used when stability is required. When the latter control system is used, the latter control system is switched and used.
It is possible to provide a servo device that has no trade-off between quick response and stability, and that each independently exhibits excellent functions.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing one embodiment of the present invention, with Figure 1 being a block diagram showing the overall configuration of the servo device, and Figure 2 showing the internal configuration of a control system with excellent quick response. Block Diagram FIG. 3 is a block diagram showing the internal configuration of a control system with excellent stability. FIG. 4 is a diagram showing the prior art, and FIG. 5 is a diagram showing a response example of the prior art. 2... Switching command unit, 3... Control system with excellent quick response, 4
... Control system with excellent stability, 5. Controlled object, 6.
...Switcher, 11.21...Comparator, 12,23.
... Feedback gain, 13... Feedforward gain, 22... Integral gain. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] A servo device comprising a control system with excellent quick response, a control system with excellent stability, and switching means for selectively switching and operating each of these control systems according to required conditions.