JPH05134707A - Servo controller - Google Patents

Abstract

PURPOSE:To remove the influence of resonance frequency in a controlled system and to set a band high for improving the estimation performance of a disturbance observer by additionally arranging a notch filter to a torque disturbance observer, which removes the resonance frequency component of a disturbance estimated value which is outputted from the observer. CONSTITUTION:The disturbance torque estimated value(d)obtained in the disturbance observer 15 is inputted to the notch filter 16. The notch filter 16 removes a burden(load) 11 and the resonance frequency component omegac of a motor 12 from the disturbance torque estimated value (d) so as to obtain the new disturbance torque estimated value df and transmits it to an adder 19. A servo control part 14 is constituted of the notch filter 16 and the disturbance observer 15. Thus, a servo controller is obtained, where the influence of the resonance frequency in the controlled system is removed and the estimation performance of the disturbance observer 15 is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo controller for suppressing vibration of a mechanical system having low rigidity.

[0002]

2. Description of the Related Art Conventionally, a servo controller having a structure shown in FIG. 6 has been used as a servo controller for suppressing vibration of a low-rigidity mechanical system. In the figure, 11 is a load, 12 is a motor to be controlled, 13 is a gain setter (shown as "Gv" in the figure), and 15 is a disturbance observer for feedback controlling the motor 12 to suppress vibration of the motor 12. , 17,
Reference numeral 18 is a subtractor, and 19 is an adder.

The speed ω m detected by the motor 12 is sent to the subtractor 17 and the disturbance observer 15.
The subtracter 17 subtracts the speed ωm from the motor 12 from the given target speed ωr of the motor, and gives the difference to the gain setter 13. The gain setter 13 calculates the motor drive torque command value τ ^* from the given speed value ^. Generate and adder 1
Send to 9. In the adder 19, this motor drive torque command value τ ^* And the disturbance torque estimated value d from the disturbance observer 15
^ Is added, and the sum is supplied to the motor 12 as the motor drive torque τ and is also sent to the disturbance observer 15. Therefore, the generation of the disturbance torque estimated value d ^ in the disturbance observer 15 will be described. The equation of motion of the machine in the motor 12 is represented by Jω ^· m = τ−d (1) (where J: moment of inertia of the motor 12, d: disturbance). When this is modified, d = τ−Jω ^· m (2), which is Laplace transformed into d = τ−Jω ^· m s (3), so if the estimated time constant is T ₀ , The estimated disturbance torque value d ^ is: d ^ = (τ-Jωm s) / (T ₀ s + 1) = τ / (T ₀ s + 1) -Jωm s / (T ₀ s + 1) (4)

Is indicated by Therefore, disturbance observer 15
If the motor speed ω m and the motor drive torque τ are input to, the disturbance torque estimated value d̂ can be obtained from the above equation (1).

Therefore, the disturbance torque d is estimated in real time by the disturbance observer 15, and its output d ^ is added by the adder 19 to the torque command value τ ^*. Was added to obtain the motor drive torque τ, and control was performed to cancel the influence of the disturbance torque d.

[0006]

However, in the conventional disturbance observer 15 described above, if the band is set high in order to improve the estimation performance, the resonance frequency of the mechanical system is set within the set band for the mechanical system having low rigidity. Therefore, the estimation performance cannot be improved because the controllability is limited.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a servo control device capable of setting a high band in order to improve the estimation performance of a disturbance observer. Especially.

[0008]

That is, according to the present invention, a notch filter for removing the resonance frequency component of the estimated disturbance value output from the torque disturbance observer is additionally provided to the torque disturbance observer. , It becomes possible to set the band high in order to remove the influence of the resonance frequency of the controlled object and improve the estimation performance of the disturbance observer.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 exemplifies the configuration when applied to a speed control system, and since it is basically the same as that shown in FIG. 6, the same parts are designated by the same reference numerals and their description is omitted. Is omitted.

The estimated disturbance torque value d ^ obtained by the disturbance observer 15 is input to the notch filter 16. This notch filter 16 has a disturbance torque estimated value d ^.
The resonance frequency component ωc of the load 11 and the motor 12 is removed from the inside to obtain a new disturbance torque estimated value d ^ f, which is sent to the adder 19. The servo control unit 14 includes the notch filter 16 and the disturbance observer 15.
Make up.

In the above-described configuration, the disturbance observer 15 inputs the motor speed ωm and the motor torque τ to obtain the disturbance torque estimated value d ^. The motor 12 includes a resonance frequency component ωc which the motor 12 has because it has a low rigidity. FIG. 2 exemplifies the estimated disturbance torque value d ^ output from the disturbance observer 15, and includes a resonance frequency component having a peak at the frequency ωc as shown in the figure.

On the other hand, as shown in FIG.
Notch filter 1 having the characteristic of removing only the component of c
6 is arranged in the latter stage of the disturbance observer 15, and the resonance frequency component ωc is removed from the disturbance torque estimated value d ^ output by the disturbance observer 15. As a result, a new disturbance torque estimated value d ^ f output from the notch filter 16
4 completely suppresses the influence of the resonance frequency as shown in FIG. 4, and this is sent to the adder 19.

Further, in the above embodiment, the one applied to the speed control system of the motor 12 is illustrated, but the configuration of the one applied to the position control system is illustrated in FIG. 5 instead. Also in this figure, the angle θm detected by the motor 12 is subtracted from the given target angle θr by the subtractor 20, and the difference is converted into the motor speed by the gain setter (indicated as “Gp” in the figure) 21. Is the same as that shown in FIG. 1, and the process of obtaining the disturbance torque estimated value d ^ f is the same as that in FIG. 1, so it is obvious that the same result is obtained.

[0015]

As described above, according to the present invention, the torque disturbance observer is additionally provided with the notch filter for removing the resonance frequency component of the disturbance estimation value output from the observer. It is possible to provide a servo control device capable of setting a high band in order to remove the influence of the resonance frequency of the controlled object and improve the estimation performance of the disturbance observer.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of a speed control system according to an embodiment of the present invention.

FIG. 2 is a diagram showing frequency characteristics obtained by the disturbance observer of FIG.

FIG. 3 is a diagram showing frequency characteristics set in the notch filter of FIG.

FIG. 4 is a diagram showing frequency characteristics obtained by the notch filter of FIG.

FIG. 5 is a block diagram showing a system configuration of a position control system according to an embodiment of the present invention.

FIG. 6 is a block diagram showing a system configuration of a conventional servo control device.

[Explanation of symbols]

11 ... Load, 12 ... Motor, 13 ... Gain setter (G
v), 14 ... Servo control unit, 15 ... Disturbance observer, 1
6 ... Notch filter, 17, 18, 20 ... Subtractor, 19
... adder, 21 ... gain setting device (Gp).

Claims (1)

[Claims] 1. A servo controller, wherein a notch filter for removing a resonance frequency component of a disturbance estimated value output from the observer is additionally provided to the torque disturbance observer.