JP2000020104A - Method and device for speed control gain adjustment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain tolerance to disturbance and to improve the response to a target value by adjusting the gain of a speed control system according to variation in the inertia of controlled system when a difference of outputs enters in a specific range. SOLUTION: A computer 6 inputs the output difference between controlled system and a controller model and outputs the inertia of the current controlled model when the output difference is not within the specific range and the inertia of the last controlled model when the output difference is within the specific range. In this case, a 1st inertia value converting device 7 calculates the inertia of the controlled model corresponding to inertia variation of the current controlled system when the output difference is not within the specific range. Then a 2nd inertia value converting device 8 calculates the inertia of the controlled model corresponding to the inertia variation of the last controlled system when the output difference is within the specific range and the speed control gain of a speed controller 2 is adjusted with the output value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a variable load inertia such as a motor and adjusting a speed control gain in a servo apparatus control apparatus such as a robot and a machine tool.

[0002]

2. Description of the Related Art Conventionally, the inertia is identified by performing a trial operation before actual operation and obtaining the inertia from the relationship between torque and position, and it is difficult to identify the inertia during actual operation. For example, in Japanese Patent Application Laid-Open No. 61-88780, "Method for Setting Control Constants of Speed Control Device", the moment of inertia of a mechanical system is calculated based on the integral of a signal proportional to torque and the width of change in rotational speed. The gain of the speed controller is set automatically before actual operation. Also,
The present applicant has proposed a method for identifying inertia in real time. For example, Japanese Patent Application Laid-Open No. 10-75591
The “motor control device” includes an identification unit that identifies inertia by taking a ratio of a value obtained by time-integrating the speed deviation of the speed control unit in a predetermined section and a value obtained by time-integrating the speed deviation of the estimation unit in the same section. This enables the identification of inertia during actual operation.

[0003]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. 61-8878
0 When the inertia is identified off-line, as in the method of setting the control constant of the speed control device, there is a problem in control performance such as inability to cope with the occurrence of inertia fluctuation and shortening of the settling time. JP-A-10-75
In the method of 591 "motor control device", it is necessary to perform time integration in a certain section, and although it is real time, it takes time and the PI control and the current control are modeled, so that the motor enters the motor. Since the torque corresponding to the disturbance cannot be generated and is weak against the disturbance, there is a problem that the inertia identification is difficult. SUMMARY OF THE INVENTION It is an object of the present invention to solve such a problem and to provide a device for identifying load inertia online and adjusting a speed control gain.

[0004]

SUMMARY OF THE INVENTION According to the present invention, in a speed control system of a servo device, an inertia of a control target model is controlled so that an output difference between a control target inputting a torque command and a control target model falls within a predetermined range. And adjusting the gain of the speed control system according to the amount of change in the inertia of the controlled object when the difference between the outputs falls within the predetermined range. A speed controller that inputs a speed deviation and outputs a torque command, a control target and a control target model that inputs the torque command, and an output difference between the control target and the control target model, and the output difference is a predetermined value. When it is not within the range, the inertia of the current control target model is changed and output. When the output difference is within the predetermined range, the inertia of the previous control target model is changed. An arithmetic unit that outputs an inertia, and a first inertia value conversion device that calculates the inertia of the controlled object model according to the inertia variation of the controlled object this time when the output difference is not within the predetermined range, When the output difference is within the predetermined range, the inertia of the controlled object model is calculated in accordance with a previous inertia variation of the controlled object, and the output value is used to adjust a speed control gain of the speed controller. A speed control gain adjusting device, characterized in that the speed control gain adjusting device is provided with an inertia value converting device, wherein the control target is a motor, and the outputs of the control target and the control target model are position pulses. Is what you do.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a specific embodiment of the present invention. FIG. 1 is a control block diagram for explaining an embodiment of the present invention. In the embodiment, the load is described as a motor, but the present invention is not limited to the motor load, but can be applied to a general load machine.
In the figure, 1 is a speed command, 2 is a speed controller, 3 is a motor, J is the inertia of the motor, and s is a Laplace operator. 4 is a motor model, and 5 is a position deviation pulse Δθ which is a difference between position signal pulses (θ1, θ2) of the motor and the motor model. Numeral 6 denotes an arithmetic unit for calculating a motor inertia coefficient K (i) (hereinafter, referred to as an operator) until the position deviation pulse Δθ enters a certain range, and 7 denotes an operator K (i) obtained by the arithmetic unit 6. ) and multiplying the motor inertia factor beta (i) obtained by adding 1 to the inertia value J9 _M of the motor model which has been stored before the motor inertia is varied first changing the inertia value J9 _M of the motor model J9 _M '
8 is a position deviation pulse Δ
The motor inertia coefficient β (i−1) calculated by the calculator 6 when θ satisfies the condition is multiplied by the stored motor model inertia value J9 _M to obtain the motor model inertia value J9 _M as J9 _M ′. Is a second inertia value conversion device. Reference numeral 9 denotes a difference calculator which inputs a position signal pulse θ1 of the motor 3 and outputs a speed feedback signal. Next, a method of sequentially calculating the operator K (i) in the control device having the above-described configuration will be described. As an initial value, it is assumed that β (i-1) is input as 1, K (i-1) is input as 1, and K (i-2) is input as 0. In the arithmetic unit 6, when the position deviation pulse Δθ is equal to or larger than α (No at the judgment step 10 and Ye at the judgment step 11)
s), the sum of the previous operator K (i-1) and K (i-2) is multiplied by -1/2, and its value K (i) (step 13)
Is output from the computing unit 6 by switching the switch 15 to the point a side. The value β (i) obtained by adding 1 to the output value is passed to the first inertia value converter 7 and the memory 12. First
In the inertia value conversion unit 7 is stored in advance motor inertia coefficient inertia value J9 _M of the motor model have beta (i) the over the next motor model inertia value J9 _M 'is generated. Thereafter, when the position deviation pulse Δθ becomes equal to or smaller than −α (judgment step 1).
1 and No), the operator before and the operator before (K
(I-2), the previous time, the sum of K (i-1)) is multiplied by 1/2, and the value K (i) (step 14) is set to the switch 15
Is switched to the point b and output from the computing unit 6. The value β (i) obtained by adding 1 to the output value is passed to the first inertia value converter 7 and the memory 12. Then, the first inertia value conversion unit 7, and outputs it as previously inertia value J9 _M for the next motor model over the inertia value J9 _M motor inertia coefficient β (i) is a stored have motor model '. By calculating in this manner, the position deviation pulse Δθ becomes smaller, and its absolute value α
At some point, it becomes smaller (decision step 1)
When the result is 0 (Yes), the previous β (i−1) stored in the memory 12 is output from the computing unit 6. Then, in the second inertia value converter 8, the previous β (i−
And outputs as the inertia value J9 _M 'for the next motor model over the inertia value J9 _M of the motor model which has been obtained beforehand 1). The speed controller 2 adjusts a speed control gain Kv obtained by multiplying the inertia value J9 _M ′ of this motor model by a constant K.

[0006]

As described above, according to the present invention, the output of the controlled object and its model are constantly compared with each other,
The inertia is calculated from the difference between the outputs, and the speed gain is adjusted. Since the speed control gain is changed using the calculated value, the speed control gain is strong against disturbance and the response characteristic to the target value is improved. Moreover, since the speed control gain is not changed until the output difference is stabilized, an excellent effect that the entire control system can operate stably is achieved.

[Brief description of the drawings]

FIG. 1 is a control block diagram for explaining an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Speed command 2 Speed controller 3 Motor 4 Motor model 5 Position deviation pulse 6 Calculator 7 First inertia value converter 8 Second inertia value converter 9 Difference calculator 10 Judgment step (-α <Δθ <α) 11 judgment step (Δθ ≧ α) 12 memory 13, 14 Ki calculation step 15 switch

Claims (3)

[Claims] In a speed control system of a servo device, an inertia of the control target model is changed so that an output difference between a control target inputting a torque command and a control target model falls within a predetermined range. A speed control gain adjusting method, comprising: adjusting a gain of the speed control system according to a variation in inertia of the control object when the speed falls within the predetermined range. 2. A speed control system for a servo device, comprising: a speed controller for inputting a speed deviation and outputting a torque command; a control target and a control target model for inputting the torque command; An output difference is input, and when the output difference is not within a predetermined range, the inertia of the current control target model is changed and output. When the output difference is within the predetermined range, the previous control target model is output. And a first inertia value conversion device that calculates the inertia of the controlled object model according to the inertia variation of the controlled object this time when the output difference is not within the predetermined range. When the output difference is within the predetermined range, the inertia of the controlled object model according to the previous inertia variation of the controlled object is calculated, and its output is calculated. A speed control gain adjustment device, comprising: a second inertia value conversion device whose value adjusts a speed control gain of the speed controller. 3. The speed control gain adjusting device according to claim 2, wherein the control target is a motor, and outputs of the control target and the control target model are position pulses.