JP2974508B2 - Automatic control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic controller for automatically controlling an object to be controlled so that a control amount matches a desired value, and particularly to a high-order vibration mode such as a precision positioning system and a flexible structure system. The present invention relates to an automatic control device that requires removal of residual vibration caused by non-linear friction of a drive unit and a driving unit.

[0002]

2. Description of the Related Art FIGS. 5 and 6 are diagrams for explaining a feedback loop control system in a conventional control device.

In these figures, 1 is a controlled object, 2 is an operation amount for the controlled object 1, and 3 is a control amount, which is subtracted and input to a comparator COM. OBJ is the target value and the comparator C
OM is added and input. 8 is a relay element. 9 is P
The ID calculator executes PID calculation on the position deviation amount 4 and outputs the manipulated variable 2 to the control target 1.

The control system shown in FIG. 5 is a PID (proportional + integral + differential operation, the differential term is omitted for the sake of explanation hereinafter) control system.
Excitation of higher modes was inevitable. Therefore, it has been limited to a field where a slow response performance is required or a field where a natural vibration mode exists in a sufficiently high range from a control frequency range.

The control system shown in FIG. 6 is used to compensate for a jumping element characteristic (which is expressed as a dead zone characteristic in the forward direction) such as Coulomb friction. Since the provided relay element 8 operates only by the position (deviation) signal,
Considering the closed-loop characteristic composed of this element and the control target, it is clear that there is a phase shift, and the expected damping is often not obtained. FIG. 7 shows a typical convergence trajectory showing a closed-loop characteristic including the relay element path on a phase plane. In FIG. 7, the vertical axis represents the speed e1, and the horizontal axis represents the position deviation e2.

As shown in this figure, since the relay operation is performed on the vertical axis, not only high-speed operation cannot be expected, but also a large phase lag, for example, a limit cycle (continuous oscillation) as shown in FIG. ) May occur.

[0007]

As described above, in the conventional control apparatus, for a control object including a vibration component having poor damping or a non-linear oscillation element, it is difficult to set a passive parameter only by linear control operation. Not get
The response was slow.

In addition, when a non-linear compensation element depending only on position information is added, it is difficult to set a relay width for stabilization, and it is not possible to greatly improve damping characteristics, so that there is a high possibility of falling into a limit cycle. .

Further, if the residual vibration compensation is to be performed precisely, enormous cost is required, and furthermore, it is necessary to analyze the characteristics in advance, and even if the result is faithfully adopted to realize a control system, it is extremely complicated. There is a problem that the calculation configuration becomes complicated and the practical application is hindered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an automatic control device capable of removing a residual vibration in an operation amount output to a control target with a simple configuration. .

[0011] The automatic control device according to the present invention comprises a computing means.
In addition, a proportional plus differential operation unit that outputs a phase plane signal by performing a proportional plus differential operation on the deviation signal, and performs an equivalent proportional plus integral operation on the phase plane signal output from the proportional plus differential operation unit An integration operation unit that outputs a first operation amount, a relay element unit that outputs a second operation amount that rises later than the first operation amount from the phase plane signal, and a second element that is output from the relay element unit And an adder for executing the addition of the operation amount and the first operation amount and outputting the addition result as an operation amount to a control target.

[0012]

In the present invention, when a proportional plus differential operation is performed on the deviation signal by the proportional plus differential operation unit and a phase plane signal is output, an equivalent proportional plus integral operation is performed on the phase signal surface by the integration operation unit. And the first manipulated variable is output.
The adding unit adds the first operation amount and the second operation amount output from the relay element unit , and calculates the addition result as an operation amount.
Then, the operation amount is output to the control target, and the operation amount from which the residual signal is removed can be output to the control target.

[0013]

FIG. 1 is a block diagram for explaining the configuration of a control device according to an embodiment of the present invention. The same components as those in FIGS. 5 and 6 are denoted by the same reference numerals.

In the figure, CONT is a controller section, which includes a serial path consisting of a proportional plus differential element operation section 7, a proportional element operation section 6, and an integral element operation section 5 in a forward direction, and a relay element section 8 on a path bypassing the integral element. Is provided. The relay element 8 also has a dead zone corresponding to the tolerance of the position deviation 4 (error tolerance (see FIG. 3). Reference numeral 10 denotes an adder, and a first operation amount 5a and a second operation amount 5a.
The operation amount obtained by the addition processing with the operation amount 8a is output to the control target 1.

The serial path is made up of elements obtained by modifying the PI operation shown in the following equation (1).

Kp (1 + 1 / TiS) = Kp · (1 + TiS) / TiS = (1 + TiS) · (Kp / Ti) · (1 / S) (1) where Kp is a proportional gain. And Ti indicates the reset time. S is a Laplace operator.

According to the present invention, the control operation is executed by focusing on the last term (the rightmost term in the equation) of the above equation (1).
That is, the preceding term and the middle term in the above equation (1) merely represent a general PI operation form, but the last term is a change type to a speed type, and the gist is that the element (1+ TiS) can be interpreted as a phase plane signal captured on a phase plane composed of position information and velocity information, and the element including the PI parameter Ti is expressed by the following equation (2) on the phase plane. Represents a straight line.

E (indicating the differential value of phase deviation e) = − (e / Ti) (2) where E> − (e / Ti), u is C, and in other cases, u is u. Becomes -C. Here, u indicates the manipulated variable output, and c is a positive constant. The reason why the straight line of the above equation (2) is switched under the above condition is that the straight line has a gradient, as is clear from the above equation (2), which has the effect of compensating for the phase delay of the vibration component. This is because this makes it possible to improve the attenuation characteristics.

As shown in FIG. 1, an equivalent PI calculation of the proportional gain Kp and the reset constant Ti is executed by the forward main path (the serial path) as shown in FIG. Phase plane control of the vibration component of the position deviation amount 4 is executed by the plus differential element calculation unit 7. According to this embodiment, if the amplitude of the relay element section 8 is set to zero or the dead width is made sufficiently large, a PI control system is obtained, so that the conventional proportional gain Kp and reset time Ti are used as they are. To perform arithmetic processing. Further, since the dead width is directly given from the control use, the only adjustable parameter left is the relay amplitude, but the relay amplitude only needs to correspond to the amplitude of the residual vibration, and adjustment is easy.

In the automatic control device thus configured, when the proportional plus differential operation is performed on the deviation signal by the proportional plus differential operation unit (proportional plus differential element operation unit 7) and the phase plane signal is output, Integral operation units constituting a path (in this embodiment, proportional element operation unit 6, integral element operation unit 5
When an equivalent proportional plus integral operation is performed to output the first manipulated variable 5a, the adding unit 10 outputs the first manipulated variable 5a and the second manipulated variable 5a output from the relay element unit 8. Is added to the operation amount 8a , and the addition result is referred to as the operation amount
As a result, it is possible to output the manipulated variable from which the residual signal has been removed to the control target 1.

FIG. 2 is a characteristic diagram showing a damping characteristic of the residual vibration in the automatic control device shown in FIG. 1. The vertical axis represents the speed e1 as a differential value of the phase deviation e2, and the horizontal axis represents the phase deviation. e2 is shown. The inclination of the switching line is determined by the above equation (2).

FIG. 3 is a diagram showing a step response characteristic in the automatic control device shown in FIG. 1, in which the horizontal axis represents time (mse
c) is shown.

As shown in these figures, the residual vibration due to the relay amplitude can be favorably attenuated.

In the above embodiment, the proportional plus differential element operation unit 7, the proportional element operation unit 6, and the integral element operation unit 5
Of a manipulated variable by adding a series path consisting of
Has been described, but there are various methods for simulating operations such as how to have coefficient elements, differentiation operation, integration operation, and the like, and there is no particular limitation in applying the present invention.

Further, in the above embodiment, the case where the control system calculates and outputs the manipulated variable 2 by a continuous calculation process has been described. For example, as shown in FIG. The configuration may be as follows.

FIG. 4 is a block diagram for explaining the configuration of a control device according to another embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals.

As shown in this figure, the proportional plus differential element calculator 7 calculates the following equation (3) for the position deviation amount 4.

(1 + τ) -τz-1 (3) where z-1 is a delay operator corresponding to the sampling period, τ is a time parameter, and the sampling time is Δ
If t, the relationship with the reset time Ti in the above equation (1) is τ = Ti / Δt.

The proportional element operation unit 6 executes an operation based on the following equation (4) on the operation result of the proportional plus differential element operation unit 7.

Proportional gain Kp / time parameter τ (4) Further, the integral element operation unit 5 executes an operation based on the following expression (5) on the operation result of the proportional element operation unit 6.

1 / 1-z-1 (5) With this configuration, the present invention can be easily applied to a control system that executes a discrete time operation.

In the above embodiment, the control target 1 is not particularly limited, because the present invention can be applied to any control system that needs to consider the residual vibration.

[0033]

As described above, according to the present invention, when the proportional plus differential operation is performed on the deviation signal by the proportional plus differential operation section and the phase plane signal is output, the present invention is equivalent to the integration operation means constituting the serial path. When the first manipulated variable is output after the proportional proportional plus integral operation is performed, the adding unit adds the first manipulated variable and the second manipulated variable output from the relay element unit , and the addition result is obtained. Is output to the control target as an operation amount, so that the vibration component of the control target is directly related to structural flexibility, or whether the vibration component is caused by nonlinearity, Alternatively, even if it is caused by disturbance, the residual signal can be removed with a very simple configuration.

Therefore, measures against vibration factors in the control system can be greatly improved, and the economical burden conventionally required for the measures against vibrations can be greatly reduced, and the design burden on the developer can be reduced. It has excellent effects such as shortening the period.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a control device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a damping characteristic of residual vibration in the automatic control device shown in FIG.

FIG. 3 is a diagram showing a step response characteristic in the automatic control device shown in FIG. 1;

FIG. 4 is a block diagram illustrating a configuration of a control device according to another embodiment of the present invention.

FIG. 5 is a diagram illustrating a feedback loop control system in a conventional control device.

FIG. 6 is a diagram illustrating a feedback loop control system in a conventional control device.

FIG. 7 is a characteristic diagram showing a convergence trajectory showing a closed loop characteristic including a relay element path on a phase plane.

FIG. 8 is a characteristic diagram showing a limit cycle specific to a feedback loop control system in a conventional control device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 control target 2 operation amount 3 control amount 4 position deviation amount 5 integral element operation unit 6 proportional element operation unit 7 proportional plus differential element operation unit 8 relay element unit

Claims (1)

(57) [Claims] 1. A automatic control device with the operation amount to the control target from the deviation signal between the control amount and the target value having an arithmetic means for calculating an output, said calculating means, a proportional plus derivative operation on said deviation signal A proportional plus differential operation unit for executing and outputting a phase plane signal; and an integral for executing an equivalent proportional plus integral operation on the phase plane signal output from the proportional plus differential operation unit and outputting a first manipulated variable. wherein the arithmetic unit, a relay element section for outputting a rising slow second operation amount than the first operation amount from the phase plane signal, and the second manipulated variable output from the relay element portion first An adder for performing addition with the first operation amount and outputting an addition result to the control target as the operation amount.