JPH01175603A - Automatic controller - Google Patents

Abstract

PURPOSE:To eliminate the needs for calculating both a speed deviation and a position deviation and to obtain sufficient control responsiveness by providing a forward compensator having a specific characteristic in the transmission system of a signal from a simulation circuit for controlled system. CONSTITUTION:With using a transmission function HiLx(s) from the input iL of a feedback controller 8 in a controller 6 to the position (x) of a table 2 being the output signal for controlled system 4, the transmission function GF(s) of the field forward compensator 10 is set to GF(s)=HiMxM(s)=HiMxM(s)/HiLx(s), whereby the transmission function from a model current iM to the table position (x) in the simulation circuit 11 for controlled system and the transmission function HiMxM(s) from the model current iM to a model position xM can be coincident. Thus, only the amount for the deviation between the table position (x) and the model position xM can be compensated in the feedback controller 8, and position control with satisfactory responsiveness can be executed without detecting the speed of a motor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic control device that controls a servo mechanism or the like, and particularly relates to an automatic control device suitable for controlling an XY plotter or a robot.

[Conventional technology]

When it is required to maintain sufficient accuracy not only for positioning of moving parts but also for the movement trajectory itself, such as in the control of XY plotters and robots, for example, Japanese Patent Publication No. 58-9441 has been used. As disclosed in the above publication, a method has been proposed in which control is performed using signals that command each of the target position, target velocity, and target acceleration necessary to provide desired control characteristics. Accordingly, within the limit values of the controlled object, it is possible to obtain position control characteristics exactly as desired, and to obtain control in which undershoot due to disturbances and the like is sufficiently suppressed.

[Problem that the invention seeks to solve]

The above conventional technology applies a target acceleration to a controlled object, determines the speed deviation of the controlled object with respect to the target speed, and the positional deviation of the controlled object with respect to the target position, and generates a compensation signal necessary to converge these deviations to a minimum value. is further applied to the controlled object, and therefore no consideration is given to the fact that it is necessary to calculate the speed deviation in addition to the position deviation. It is necessary to perform the detection and further calculate the position deviation and speed deviation based on the detection, which poses a problem in that the configuration and processing become complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic control device that does not require calculation of both speed deviation and position deviation for a controlled object and can provide sufficient control responsiveness.

[Means for solving problems]

The above purpose is to provide a feedforward compensator in the signal transmission system from the simulated circuit of the controlled object, and to make the characteristics of this feedforward compensator such that the output signal of the simulated circuit follows the signal representing the control result of the controlled object. This is achieved in such a way that the characteristics are as follows.

[For production]

A feedforward compensator that receives the output signal from a simulated circuit to be controlled can be designed by considering all the internal signals of this simulated circuit, so there is no need to calculate both speed deviation and position deviation. The necessary characteristics can be obtained, and this feedforward compensator can be designed so that the transfer function from the command value to the output of the controlled object matches the transfer function from the command value to the output of the control system simulator. The output of the controlled object can be operated in accordance with the output of the simulated circuit of the controlled object.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The automatic control device according to the present invention will be explained in detail below using illustrated embodiments.

FIG. 1 shows an embodiment in which the present invention is applied to position control of a table by motor drive. In the figure, 4 represents a controlled object, and by driving motor 1, table 2 is positioned. The motor 1 is driven by a current amplifier 3. In a controlled object 4 consisting of the motor 1, table 2, and current amplifier 3, a table position X, which is an output signal thereof, is detected by a position detector 5.

Next, 6 is a control device which receives position commands x and l from the position command generation device 7 as input and outputs a current command i'' so that the table position X becomes the position command xR in a steady state. This current command i'' becomes an input to the current amplifier 3.

The control device 6 is composed of a feedback controller 8 for determining characteristics against disturbances, a control system simulator 9 for obtaining a desired response to the position command It is composed of a controlled object simulation circuit 11 that simulates the control object simulation circuit 11, and a controller simulation circuit 12.

FIG. 2 shows the details of the control system simulating device 9, in which the controlled object simulating circuit 11 uses human power as a model current 19 simulating the current i of the motor 1, the motor speed ω, the table position fix
The model position xM is calculated based on the model speed ω that simulates each of the above. In addition, the controller simulation circuit 12 calculates a speed command (dR) based on the difference between the position commands x and l and the model position xMO.The speed limiter 13 calculates the motor 1 to operate at a maximum allowable speed ωWAX or less. The model current iH is calculated based on the difference between the speed command ω8 and the model speed ωa.The current limiter 14 is used to operate the motor 1 at a maximum current iMAX or less.

By configuring the control system simulation bag W9 in this way, the model positions ff1x, 4 do not need to consider parameter fluctuations, disturbances, etc., so that the desired response to the position command xR can always be obtained.

Next, an example of the configuration of the feedback controller 8 is shown in FIG. Here, by configuring the transfer function Hi''x(S) from the current command i'' to the table position ix in the controlled object 4 as
Transfer function HiLx from input i, to table position ix
(s) can be expressed by the following formula.

ξ Φ (K2S"+, S+K.) Therefore, from this equation (2), the gain ko, +, kg, ki, L for each block in the embodiment of FIG.

It can be seen that the transfer function Hitx(S) can be arbitrarily set by changing k. In addition, in general, the transfer function Hi, 4x(S) in equation (2) is simplified, so...
...(3) Often.

Next, the feedforward compensator 1 which is a feature of the present invention
A method for setting the characteristics of 0 will be explained.

Now, the model current i14 in the controlled object simulation circuit 11
Let us consider the case where the transfer function Hisxg(s) from to the model position Set as follows.

0F(s) = HL+x+(s) / H1tx(s
)kHS”+alS+a.

By setting as shown in equation (5), the transfer function from model current iH to table position
, model rank from 4! Transfer function Hi14xM (
s).

Therefore, the table position X can always be made to coincide with the model position X, including during transition.

FIG. 4 shows the step response to the position command xR at that time. At this time, in the control system simulator 9, the model position WXM is the limit value of the controlled object (that is, the maximum speed ω□
8. Since it can be designed to respond quickly within the maximum current i, 4Ax), a response as shown in FIG. 4 can be obtained from the table position gx. In addition, the control system simulator 9 provides characteristics with ideal responsiveness, and as a result, the feedforward compensator 10 allows the table position X to match the model position xM when there is no parameter variation of the controlled object. Therefore, the feedback controller 8 only needs to compensate for the deviation between the table position X and the model position x, 4 due to parameter fluctuation.

Therefore, the feedback controller 8 can construct a control system focusing on parameter fluctuations, and can perform control (so-called robust control '4B) with little change in characteristics against the influence of parameter fluctuations.

According to this embodiment, without detecting the motor speed ω,
Position control with good responsiveness can be performed within the limit values of the controlled object. Note that the feedback controller 8 has only one input i, and multiple microprocessors are used to input the controller W.
When configuring 6, it has the feature that it can be easily separated by this manual part i.

Furthermore, according to this embodiment, a limiter is provided inside the control system simulator, and even if an attempt is made to make an excessive movement, this limiter will restrict it, so that it will only be within the limit value of the restriction target. Does not work and is highly secure.

Next, FIG. 5 shows another embodiment of the feedforward compensator 10. In the feedforward compensator 10 according to this embodiment, not only the model current iH but also the model current #i, The model position xM obtained based on 4 is also used, and the model current compensator 15 inputs the model current 1.4,
and a model position compensator 16 which receives as input, and the sum of the outputs of these two is supplied as input i to the feedback controller 8.

At this time, the characteristics of the feedforward compensator 10 are determined so that the table position x matches the model position xM. In other words, the transfer function G of the model current compensator 15 and the model position compensator 16 is
rI(S) and GFX(s) are set as follows.

G rx (s) = 1...
(7) As a result, the transfer function Hi,4x(s) from model current i to table position X, and the transfer function Hi,4x(s) from model current i,4 to model position X,
xH(s) can be matched.

Therefore, according to this embodiment, by using not only the model currents i and 4 but also the model position xM, a position control system with good responsiveness can be configured by the feedforward compensator 10 with simple characteristics.

Next, FIG. 6 shows another embodiment of the present invention in the case where a speed control system has already been configured for the controlled object. In this FIG. Based on the command ω" and the motor speed ω fed back from the controlled object 4, a current command i" is calculated, and this current command 1
1 into the controlled object 4, a speed control system 18 is configured.

If such an existing speed control system 18 exists, the feedback controller 8 calculates the speed command ω9 instead of the current command 11 based on the human power i and the table position X. One method of this calculation is shown in FIG. This makes it possible to configure an optimal feedback control system. Note that the characteristics of the feedforward compensator 10 may be selected so that the table position ix always matches the model position XM.

Therefore, according to this embodiment, a position control system with good characteristics can be constructed while using the existing speed control device as is.

By the way, in the above explanation, the present invention was applied to the position control of an XY child table, but the present invention is not limited to this, but can also be applied to the position control of robots, XY plotters, machine tools, etc. Needless to say, the present invention can also be applied to motor speed control devices and plant control devices.

Furthermore, according to the present invention, since the output of the controlled object operates in accordance with the output of the control system simulator, highly accurate trajectory control can be performed by giving the movement path of a robot or the like using the output of the control simulator. can.

〔Effect of the invention〕

According to the present invention, state quantities (velocity, position, etc.) of a controlled object
Since the target output can be obtained without calculating the deviation of the state B quantity of the controlled object simulation circuit corresponding thereto, the control system can be configured without detecting all the state quantities.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment in which the automatic control device according to the present invention is applied to XY child table position control, Fig. 2 is a block diagram showing an embodiment of the control system simulator, and Fig. 3 is a feedback control A block diagram showing one embodiment of the device,
FIG. 4 is a characteristic diagram for explaining the operation, FIG. 5 is a block diagram showing another embodiment of the feedforward compensator, FIG. 6 is a block diagram showing another embodiment of the present invention, and FIG. FIG. 2 is a block diagram showing another configuration example of the feedback control device. 1...Motor, 2......X
Y child table 3...Current amplifier, 4...
......Controlled object, 5...Position detector, 6...Control device, 7...
...Position command generator, 8...Feedback controller, 9...Control system simulator, 10...Feedforward Compensator, 11... Controlled object simulation circuit, 12...
......Controller simulation circuit, 13...
・Speed limiter, 14...Current limiter, 15...Model current compensator, 16...
...Model position compensator, 17...
...Speed controller, 18... Speed control system. Figure 1! ...Motor 2...XY table 3
...Current up 4...Control light house 5...
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・)s F/l"yri II II 2,19... Control mM4 Leverage 1 English纜口路Fig. 2 Fig. 3 Fig. 4 I6: Mochi" + V angle (12 collapse ('t!! Fig. 6 Fig. 7)

Claims (1)

[Scope of Claims] 1. In an automatic control device of a type in which a motion command value for a controlled object is created by a feedforward control device including a simulating circuit of the controlled object, a feedforward control device is provided in the transmission path of the motion command value. A word compensation circuit is provided, and the characteristics of the feedforward compensation circuit are configured such that the output signal of the simulation circuit follows the detection signal representing the control result of the control object. automatic control device. 2. In claim 1, the simulated circuit comprises:
An automatic control device characterized in that the automatic control device is configured to include a restriction function corresponding to the permissible range of operation of the controlled object.