JPH05252772A - Method for controlling high speed positioning of servo motor - Google Patents

Abstract

PURPOSE:To position a servo motor in a high speed based on only position information by connecting a compensator having disturbance suppressing characteristics and frequency characteristics of noise resistance properties for the motor in series with the motor. CONSTITUTION:In the case of controlling to drive a servo motor P(s) for driving FA, OA devices, a position command theta<ref> is input to a first subtracter 1, butted to an actual position signal theta of the motor P(s) to be controlled to be driven, signals in which its deviation is processed by a transfer function K1/S, K2 are butted by a second subtracter 3. After an output from the subtracter 3 is processed by a transfer function 1/S, it is butted to a position deviation signal by a third subtracter 4, its deviation is input to a compensator K(s) having disturbance suppressing characteristics and frequency characteristics of noise resistance properties for the motor (s), a control signal obtained through the compensator K(s) is input to the motor P(s), and a positioning control at a high speed is conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servomotor high-speed positioning control method, and more particularly to a new improvement for high-speed positioning of a servomotor using only position information without using speed and acceleration information.

[0002]

2. Description of the Related Art Generally, as a conventional method for controlling the position of a servo motor, although no literature name is disclosed here, the actual position and the target of the position are represented by the PID town and the PI control method. Control has been performed by a combination of a P operation for multiplying a deviation from a value by a constant, an I operation for integrating and multiplying by a constant, and a D operation for differentiating and multiplying by a constant.

[0003]

However, in the above-mentioned conventional method, since the velocity deviation and the acceleration deviation are involved, when the high-speed position control is performed, the position phase deviation occurs. Therefore, in order to compensate for this, there has been a method of performing control by adding velocity and acceleration information to the control law for a high-speed position set value. However, in this case, the number of sensors of the servo motor is increased, and the differential term is included in the control law, which is extremely difficult to realize.

The present invention has been made in order to solve the above problems, and in particular, it is a high speed servomotor for driving a servomotor at high speed by using only position information without using speed and acceleration information. An object is to provide a positioning control method.

[0005]

In a servomotor high-speed positioning control method for performing high-speed position control of a servomotor, a compensator having a frequency characteristic of a disturbance suppression characteristic and a noise resistance characteristic with respect to the servomotor which is control symmetric is provided. It is a method in which the servomotor is connected in series to the servomotor and the compensator drives the servomotor at high speed by using only the position information without using the speed and acceleration information.

[0006]

In the servomotor high-speed positioning control method according to the present invention, the compensator satisfying the desired frequency characteristics of the disturbance suppression characteristic and the noise resistance characteristic is provided in series with the servomotor. It is possible to perform high-speed positioning by using only position information without using speed and acceleration information.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a servo motor high speed positioning control method according to the present invention will be described in detail below with reference to the drawings. Note that the present invention realizes high-speed positioning control by constructing a control system equivalent to a control system using only speed information and speed and acceleration information without using a differentiator.

FIG. 1 is an equivalent block diagram of a servomotor for driving general FA and OA equipments. This servomotor has a frictional force T _frc , an interference force _int , a gravity T _g , and
_External force such as load torque T _Load is applied. Therefore, the motor drive voltage e _a is input to the subtractor 1, the torque constant I _a of the drive current is input to the second subtractor 2 to which the external force is applied,
The rotation speed ω is obtained as a rotation angle signal θ via a transfer function I / S from the speed to the angle, and the induced voltage constant Ke from the rotation speed ω is fed back to the first subtractor 1. In addition,
In FIG. 1, R is the DC resistance of the armature, and JS is the inertia of the motor and the load system.

In order to instantly suppress the influence of the external force, it is preferable to drive the controlled object with the acceleration command ω _cmd . The block diagram shown in FIG. 2 is adopted as the method of configuring this acceleration control method. Where acceleration command ω _cmd
Is converted into an input u and input to the first subtractor 1, and the compensator K that makes the frequency characteristic of the acceleration controller a desired characteristic is obtained.
(s), the rotation angle θ is obtained via the servo motor P (s) to be controlled and the first adder 2.

This rotation angle θ is fed back to the first subtractor 1 via the second adder 4. In FIG. 2, d represents disturbance, W represents observation noise, and the sensitivity function S (s) representing the disturbance suppression characteristic is S (s) = 1/1 + P (s) K (s) (1) The complementary sensitivity function T (s) expressed by the equation and representing the noise resistance characteristic is T
(s) = P (s) K (s) / 1 + P (s) K (s) (2) In order to improve the disturbance suppression characteristic, the sensitivity function S
It is better to make (s) smaller, and in order to improve the noise resistance characteristic, the complementary sensitivity function T (s) may be made smaller.
Since there is a relationship such as S (s) + T (s) = 1 ... (3) between (s) and T (s), it is not possible to reduce both at the same time.

Therefore, the compensator K (s) is adjusted so that the respective functions S (s) and T (s) have appropriate characteristics. Here, the transfer function between the acceleration command ω _cmd and the position θ is given by the following expression (4).

[Equation 1] The transfer function between the disturbance d and the position θ is given by the following equation (5).

[Equation 2] Therefore, the compensator K (s) can be used to configure an acceleration controller as shown in FIG.

The acceleration controller can be realized in the frequency range limited by the complementary sensitivity function. Therefore, since the realized acceleration controller takes into consideration the noise resistance characteristic and the disturbance suppression characteristic, the acceleration controller 10 shown in the block diagram of FIG. 4 has a desired frequency characteristic. Then, a high-speed positioning control system of the servo motor is constructed by using this acceleration controller as shown in FIG. In FIG. 5, the response to each command value is expressed by the following equation (6) in the frequency range where the acceleration controller 10 is established,

[Equation 3] The position command θ, the speed command ω, and the acceleration command ω _a are followed without any delay in position. In FIG. 5, K ₁ ,
K ₂ is a constant, S is the reciprocal of 1 / S, and is a transfer function from an angle to a velocity by differentiation.

In the case of the control system shown in FIG. 5, a high speed positioning control system for the servo motor is realized by using the acceleration information, the speed information and the position information. Therefore, if the cascade connection of the integrators is rearranged in FIG. 5, it becomes as shown in FIG. Also in Fig. 6, the response of the actual position to the position command is described in (6) above.
It becomes like the formula and follows without delay of the phase. Therefore, the high-speed positioning control system of the servomotor can be constructed only by the position information. When the control system of FIG. 6 is used, control can be performed only with position information, so that the system can be simplified and high-speed positioning control of a servo motor can be performed simply and with high precision using only a position sensor such as a rotary encoder. That is, only by inputting the position command θ ^ref , the position is transmitted via the first subtractor 1, the first adder 3, the second adder 4, the compensator K (s) and the servo motor P (s) to be controlled. θ is output and this position θ
Is fed back to the first subtractor 1.

[0014]

Since the servomotor high-speed positioning control method according to the present invention is configured as described above, a compensator satisfying the frequency characteristics of the disturbance suppression characteristic and the noise resistance characteristic is inserted in series with the servomotor. Therefore, this compensator enables high-speed positioning of the servomotor using only position information without using speed and acceleration information.
High-speed positioning can be performed with few sensors and a simple hardware configuration.

[Brief description of drawings]

FIG. 1 is an equivalent block diagram of a general servo motor.

FIG. 2 is a configuration diagram of an acceleration control method.

FIG. 3 is a characteristic diagram showing characteristics of an acceleration controller.

FIG. 4 is a block diagram showing an acceleration controller.

FIG. 5 is a configuration diagram of an equivalent block of a high-speed positioning control system for a servo motor using an acceleration controller.

FIG. 6 is a configuration diagram showing an equivalent block of a servo motor high-speed positioning control system according to the present invention.

[Explanation of symbols]

 P (s) Servo motor K (s) Compensator

Claims (1)

[Claims] 1. A servo motor high-speed positioning control method for performing high-speed position control of a servo motor, wherein a compensator K having a frequency characteristic of a disturbance suppression characteristic and a noise resistance characteristic with respect to the servo motor P (s) having a control symmetry. (s) is connected in series to the servo motor P (s), and the compensator K (s) drives the servo motor P (s) at high speed by using only position information without using speed and acceleration information. Servo motor high-speed positioning control method characterized by.