JP3266391B2 - 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 a stabilizing feedback control device, and more particularly to a control device for performing operation control of a soft shaft torsion structure in which a small torque fluctuation is prevented.

[0002]

2. Description of the Related Art An example of a general motor speed control system will be described with reference to FIG. FIG. 6 shows a conventional example of a stabilizing feedback control device, wherein 1 is a PI control device, 2 is a control target, and in this example, a motor. Here, R and Y are set inputs and state quantities, respectively. Therefore, in the speed control system, R is a speed command and Y is a speed detection output. Kt is a torque generation coefficient.

That is, the deviation e of the setting input R and the state quantity Y
Is applied to the control target through the PI compensation element to stabilize the speed control system. The general stabilization adjustment is achieved by increasing the proportional gain Kp as the inertia J increases, and increasing the integral gain Ki accordingly. Thus, as shown in the figure, usually PI
Stabilization is achieved by inserting a compensation element in series and adjusting the proportional gain Kp and the integral gain Ki according to the control target.

[0004]

However, if the proportional gain Kp is increased, it becomes easy to become unstable in a steady state due to the influence of noise and detection ripples, and the integral gain Ki is increased.
Is undesirably increased when the setting input is changed stepwise because an overshoot occurs in the speed. Proportional gain K
Although it is necessary to change p and integral gain Ki according to the operating state of the electric motor and the like, generally, the proportional gain Kp and integral gain Ki are manually adjusted with a variable resistor or the like.
It is not possible to adjust instantaneously, for example, according to the state of the motor.

Further, there is a method of automatically changing the integral gain Ki according to the change of the deviation e.
Although the performance is higher than when i is fixed, it cannot sufficiently cope with the fluctuation of the inertia J and the viscosity coefficient D. In order to achieve a faster response, it is necessary to add a differential compensation element separately, but this is easily affected by noise and the like,
I always struggled with stabilization. As described above, at present, there is no device for optimally adjusting the proportional gain Kp and the integral gain Ki according to the operation state. Therefore, at present, the test run coordinator goes to the site and adjusts each time with difficulty. is there.

In order to solve such a problem, the present inventors have devised a multi-function control device.
It is disclosed in Japanese Patent Publication No. 5505 and the like. Although the high performance of this device is described in detail in the above-mentioned publication, a brief description is given below. That is, P (proportional) or P (proportional), I (integral), and the like, a centralized stabilizing feedback control device, a feedforward unit that improves command followability, and parameters and load fluctuation of a load fluctuation control target FIG. 7 shows a basic diagram of the equivalent disturbance compensating unit and the like which hardly receives the influence of the above.

FIG. 7 is similar to FIG. 6, wherein 4 is a feedforward section, 5 is an equivalent disturbance compensating section, and TL is a load disturbance. 6 that are the same as those in FIG. 6 indicate portions having the same functions. The basic control block of FIG. 7 will be described with reference to FIG. In the drawings, the same reference numerals as those in FIGS. 6 and 7 indicate those having the same functions. The transfer function between the command output r and the output state quantity Y is expressed by the following equation.

(Y / r) = (F1 · G · Kt + F2 · G · Kt) / (F1 · G · Kt + 1) (1) where F2 = 1 / G · kt (2) Equation (1) becomes {(Y / r) = 1}. Therefore, at this time, the deviation is (e = 0).

That is, the output always operates following the input, and the deviation therebetween is always kept at zero. However, for this purpose, the feedforward compensator F2 must be in the form of an inverse function (1 / GKt) of the controlled object G. For example, if the inertia J or the viscosity coefficient D of the controlled object fluctuates, the equation (2)
May not be maintained and may become unstable in control.

Next, the equivalent disturbance compensator 5 will be described. This equivalent disturbance compensator 5 receives the command T as shown in FIG.
It is configured by calculating an equivalent disturbance using information on * (torque command in the case of speed control) and output Y (rotation output or rotation speed in the case of speed control) and adding this to command T *. . Further, the function of the equivalent disturbance compensator 5 will be described with reference to FIG. 9 which is a block diagram. In the figure, the same reference numerals as those in FIG. 7 indicate parts having the same functions. The case where the equivalent disturbance portion 5 is not added in FIG. 9 is shown as follows.

T * (S) · Kt (S) −TL (S) = (JS + D) · ω (S) (3) where TL (S) is a load disturbance and ω (S) is a rotation. Speed.

On the other hand, equation (4) is set in consideration of parameter fluctuation. Kt = Kt N + ΔKt J = JN + ΔJ D = DN + ΔD (4) where N is a nominal value and Δ is a variation.

Here, when the equation (4) is substituted into the equation (3), the equivalent disturbance Te (S) is as follows. Te (S) = T * (S) · Kt N − (JN · S + DN) · ω (S) (5)

The physical content of this equation (5) is the equivalent disturbance T
e (S) includes all of the load disturbance TL (S) and the variation from the nominal value of the constant, and by considering them collectively as equivalent disturbances, each constant is calculated as shown on the right side of Equation (5). It can be described only by the nominal value of. By adding the equivalent disturbance Te (S) to the command T * through a low-pass filter for removing noise, equivalent disturbance compensation is performed. In equation (5), even if the nominal value of the viscosity coefficient D on the right side is set to zero, the function of equivalent disturbance compensation is not impaired. Since the time constant of the low-pass filter can generally be made sufficiently smaller than the time constant of the control target, FIG. 9 can be rewritten as shown in FIG.

Therefore, as shown in FIG. 10, it is possible to describe only the nominal value irrelevant to the load disturbance and the variation of each constant.
Since it is not affected by load disturbance or constant fluctuation, robust and stable operation can be secured. The block of the equivalent disturbance compensator 5 shown in FIG. 9 can be converted on various control blocks based on this diagram, and is used in a more suitable form in practical use. is there.

Further, this method is as follows: (a) By performing equivalent disturbance compensation, the control target 2 shown in FIGS. 7 and 8 has a relation of only a nominal value, as shown in the block diagram of FIG. Since the control target GKt in the equation (2) is the product of the nominal values of G and Kt, the relationship of the equation (2) can be always maintained, and the feedforward compensation works effectively. Become. (B) The combination of the feedforward compensator and the equivalent disturbance compensator of the above two devices eliminates the drawbacks of each device and exerts its features.

As described above, the multi-function control device can realize high-speed, high-performance, and robust control with a simple algorithm. However, in the above-described example, it is necessary to detect the motor speed as a detection signal. The motor speed can be detected relatively easily with a tachometer, pulse generator, etc., so there is no problem with setting changes, load fluctuations or parameter fluctuations. For example, if the mechanical coupling between the motor and load is flexible, Generates axial torsional vibration. Normally, this method can also be used for vibration damping, but in the case of small torsional vibrations, since the change in motor speed during vibration is very small, this method uses an expensive speed detector with a large number of pulses. It is necessary to increase the resolution by increasing the number of bits in the speed calculation, and both hardware and software become complicated and expensive, and in some cases, image stabilization cannot be performed.

[0018]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned points, and a torque meter is inserted between a motor and a load, and a small torsional vibration is generated by using a detection signal of the torque meter. Is configured to be able to prevent vibration.

First, a block diagram of the torsion shaft system is as shown in FIG. Where Kc is the spring constant of the torsion shaft,
JL is load side inertia, DL is load side viscosity coefficient, ωL
(S) is the load side speed, and TTM (S) corresponds to the torque meter output.

Next, FIG. 1 shows a general block diagram of the means for suppressing the shaft torsional vibration by utilizing the output of the torque meter. 6 is an estimator of the load side speed ωL (S), 7 is a high-pass filter, T and Tc are filter constants,
a is a constant. Here, load-side speed sensor information may be used instead of the estimator 6, but as described above, shaft torque meter information is used to suppress minute torque fluctuations.

That is, the estimated value of ωL (S) is converted into a control signal obtained by cutting the DC component through the high-pass filter 7, and is added to the motor speed ω (S) negative feedback section, thereby preventing vibrations. It is effective. FIG. 3 shows a block diagram of a high-speed response vibration suppression control using the present invention in combination with equivalent disturbance compensation. In FIG. 3, by adding the output of the equivalent disturbance compensator shown in FIG. 7 to T * (S),
By adding the above-described multi-function control device, an even higher-speed vibration damping effect can be obtained. Where 5
Is an equivalent disturbance compensator.

[0022]

According to such a solution, in the example shown in FIG. 1, the output of the load speed estimator is added to the feedback through the high-pass filter using the drive side speed ω (S) and the shaft torque meter TTM (S) information. , Can be damped. Further, in the example of FIG. 3, the vibration suppression operation can be made to respond more quickly by further canceling with the equivalent disturbance compensation output in the example of FIG. Next, the present invention will be described in detail with reference to examples.

[0023]

FIG. 4 shows a main hardware configuration for realizing the main blocks shown in FIG. The CPU may be a general-purpose microprocessor, but if higher performance is required, the basic operation of the present invention can be realized in about 50 (μs) by using a digital signal processor (DSP). RO
M and RAM are memory elements, and (DI / 0) is a digital input / output, which handles a start / stop command, a pulse generator signal, and the like. In addition, (Analogue -I / 0)
Is connected to speed command (in case of analog), torque meter output, etc.

In FIG. 1, a deviation e between a speed command input ω * and an output ω (S) which is a part of a state quantity is subjected to a stabilization compensation by a P (I) control device or the like, and the output is set to T *
(S). This ω (S) is added with a vibration suppression compensation signal obtained by passing an output of an estimator 6 for obtaining an output of a shaft torque meter through a high-pass filter 7. The torque command T * (S) is passed through a power actuator to generate a torque generation coefficient K
multiplied by t and applied to the motor 2 which is part of the controlled object. If the power actuator is a vector inverter, the response is fast, and the torque generation coefficient Kt may be treated as a constant. On the other hand, FIG. 3 shows the output of the equivalent disturbance compensator 5 which receives the torque command T * (S) and the motor rotation speed ω (S) as inputs.
Add to the stabilization compensation output. In FIG. 4, these calculations are performed by a CPU, a ROM, a RAM, and the like.

Further, in order to suppress the operation and effect of this embodiment, that is, to suppress the minute shaft torsional vibration that is hardly appearing in the rotational speed, the vibration can be prevented by utilizing the output of the shaft torque meter. It is shown in FIG. Here, in FIG. 5, the actual measurement data (b) according to the present invention is compared and presented with the actual measurement data (a) having no anti-vibration effect.

[0026]

As described above, according to the present invention, it is possible to provide a general-purpose high-performance, simple, robust, and low-cost control device that can be specially damped by using a torque meter.

[Brief description of the drawings]

FIG. 1 is a general block diagram of the present invention.

FIG. 2 is a block diagram including a motor load considering a torsion shaft.

FIG. 3 is a block diagram for obtaining a damping effect by using outputs of an equivalent disturbance compensator in parallel;

FIG. 4 is a hardware configuration diagram for realizing the main blocks shown in FIG. 1;

FIG. 5 is a diagram showing actually measured data representing a vibration isolation effect according to the present invention.

FIG. 6 is a block diagram showing a conventional PI control system.

FIG. 7 is a block diagram of a main configuration of a multi-function control device.

FIG. 8 is a basic block diagram of control by a PI control device with a feedforward unit.

FIG. 9 is a block diagram illustrating an equivalent disturbance compensator;

FIG. 10 is a block diagram showing a motor part after equivalent disturbance compensation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PI controller 2 Control object 4 Feedforward part 5 Equivalent disturbance compensation part 6 Estimator 7 High-pass filter

Claims (3)

(57) [Claims] 1. A stabilization system in which a command input to a controlled object having a torsion axis structure and a deviation amount from a state quantity of the controlled object are applied to the controlled object through a stabilizing compensator comprising a proportional or proportional integral element. In a generalized feedback control device, an amount obtained by differentiating the output of a torque meter mechanically coupled between a driving device to be controlled and its load device is calculated from a speed of the driving device as a part of a state quantity of the control object. This it the loading rate was estimated, which was passed through a high-pass filter for removing the DC component in after passed through the filter for noise removal, and is added to the speed information of the drive unit to subtract
A control device characterized in that the stability of speed is improved with (1) and (2). 2. A stabilization system in which a command input of a controlled object having a torsion axis structure and a deviation amount from a state quantity of the controlled object are applied to the controlled object through a stabilizing compensator comprising a proportional or proportional integral element. In the generalized feedback control device, an equivalent disturbance including a variable element affecting a driving characteristic of the controlled object is calculated from an input amount and a state amount of the controlled object, and the equivalent disturbance is added to an input side of the controlled object. 2. The control device according to claim 1, wherein a multi-function control device including a disturbance compensation unit is configured. 3. A feedforward unit for applying a command input to an output of a stabilization compensator through an element configured in the form of an inverse function of a mathematical model of a controlled object. Item 3. The control device according to Item 2.