JPS6352683A - Positioning control method for linear motor - Google Patents

Abstract

PURPOSE:To enable a device to be finely controlled, by controlling a linear motor according to the position, speed, and acceleration. CONSTITUTION:The input of present position signal from a position detector 16 together with target position signal from a setting unit 13 to a subtracter 17 is provided. The input of the present position signal to a differential unit 18 is also provided, and the input of differential-processed present speed signal together with target speed signal from a setting unit 14, to a subtractor 19 is provided. Besides, the present speed signal of output generated from the differential unit 18 is directed also to another differential unit 20 for input, and the input of differential-processed present acceleration signal together with target acceleration signal from a setting unit 15, to a subtractor 21 is provided. A position deviation value, a speed deviation value, and an acceleration deviation value obtained as a result are directed to a subtracter 25 for input, and are addition-processed, and are directed to the driving circuit 11 of a linear motor 12 to be inputted.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a positioning control method for a linear motor.

2. Description of the Related Art Conventionally, as a highly accurate positioning control method for this type of linear motor, there is a method as disclosed in Japanese Patent Application Laid-open No. 1793/1983. This method will be explained with reference to FIG. First, the target position signal given by Pl and the current position signal from the position detector 2 for recognizing the current position of the movable element of the linear motor 1 are input to the computing unit 3. A position deviation value is calculated in the second computing unit 3.

Then, the position deviation signal that is the output thereof and the speed feedback signal that is the output signal from the speed detector 4 that detects the current speed of the movable element of the linear motor 1 are input into the computing unit 5. The arithmetic unit 5 calculates the deviation between the two, and the outputs thereof are amplified by 1 and K2 times by amplifiers 6 and 7, respectively. The amplifiers 6 and 7 are controlled by a switch 9 which is controlled by the output of the speed level detector 8.
One of the amplifiers 6 or 7 is selected, and the signal from the selected amplifier 6 or 7 is input to the drive circuit 10 for the linear motor 1. The linear motor 1 is controlled by the output J signal from the drive circuit 10 so as to approach the target value.

Problems to be Solved by the Invention However, in this conventional method, the amplification gain is switched and set simply by detecting the current speed level, which causes sudden changes in the motion of the linear motor 1. can occur. As a result, overshoot may occur and high-speed access may become impossible. Therefore, amplifier 6
, it is necessary to optimize the gain of 7 and the value of 1 for □+, making the adjustment troublesome.

Means for Solving Problems Setting a target value consisting of a target position, target speed and target acceleration of the linear motor, detecting a current value consisting of the current position, current speed and current acceleration of the linear motor, After calculating the deviation values of the position, velocity, and acceleration between the target value and the current value, and amplifying each deviation value, a control command signal obtained by calculating these deviation values is sent to the drive circuit for the linear motor. is input to cause this linear motor to follow the target value. Further, the amplification gain of the amplifier is set according to the detection of each deviation value level.

In other words, control is performed by taking into consideration not only position and velocity data, but also acceleration. According to this method of adding acceleration, the access speed and accuracy of the linear motor are improved compared to a method of controlling only position or a method of controlling position and speed. In other words, the linear motor can follow the target value no matter what state it is in. Further, by adjusting and setting the amplification gain according to the deviation value level, the weight distribution for position, velocity, and acceleration can be changed, and it is not affected by disturbances such as vibrations and rocking.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 and 2. First, a linear motor 12 to be controlled and driven by a drive circuit 11 is provided. On the other hand, setting devices 13, 14, and 15 are provided for setting the target position, target speed, and target acceleration for the linear motor 12, respectively. A position detector 16 for detecting the current position of the linear motor 12 is provided. Here, the position detector 6 can be any one using mechanical means, electric means, magnetic means, optical means, etc., and in short, it can detect the position and convert it into an electric signal. Any means is fine. Most commonly it will be a potentiometer. The current position signal from the position detector 16 is input to the subtracter 17 together with the target position signal from the setter 13.

This subtracter 17 calculates a positional deviation value.

The current position signal is also input to a differentiator 18, and a differentiated current speed signal is output from the differentiator 18. This current speed signal is input to the subtracter 19 together with the target speed signal from the setter 14. This subtractor 1
9, the speed deviation value is calculated. Further, the current speed signal outputted from the differentiator 18 is also input to another differentiator 20 and subjected to differentiation processing to obtain a current acceleration signal.

This current acceleration signal is input to the subtracter 21 together with the target acceleration signal from the setter 15. This subtracter 21 calculates the acceleration deviation value.

In this way, the current value consisting of the current position, current speed, and current acceleration is detected, and each is subjected to arithmetic processing with the target value to calculate the deviation value for one position, speed, and acceleration. The position deviation value, velocity deviation value, and acceleration deviation value obtained in this way are input to amplifiers 22, 23, and 24, respectively,
Each KIIKMTK is amplified three times. Each amplifier 22,
The amplified deviation values from 23 and 24 are input to the arithmetic unit 25 and subjected to addition processing. That is, K, ・(Position deviation value) 2 to 10・(Speed deviation value) to 10, ・
(Acceleration deviation value) The following calculation process is performed. The output signal after the calculation from the calculator 25 is obtained as a control command signal. This control command signal is inputted to an adder 26 together with a bias signal and subjected to addition processing, and the output signal is amplified four times by an amplifier 27. The output J signal from the amplifier 27 after amplification is input to the drive circuit 11, and is also input to the subtracter 28. Here, the bias signal is obtained by calculating the deviation value between the bias amount set by the bias setting device 29 and the input to the drive circuit 11 by a subtracter 28,
This is a feedback signal that is input to the adder 26 after being multiplied by a multiplier 30 of 6 to a coefficient smaller than 1. Based on the control command signal input to the drive circuit 11, the linear motor 12 is drive-controlled to follow the target value. In other words, the linear motor 12 is controlled by the drive circuit 11 so that this control command signal becomes zero.
control.

FIG. 2 shows temporal changes in each of these position deviation values, speed deviation values, acceleration deviation values, and control command signals. These represent the trajectory from when the linear motor 12 is stationary at a position shifted by ΔX from the target position until it reaches the target position 80 hours later.

Here, time is the time at which the speed deviation value becomes maximum and the acceleration deviation value becomes zero. Further, time t2 is the time when the control command signal becomes zero. Here,
The signal input to the drive circuit 11 for the linear motor 12 is an amplified sum of a control command signal and a bias signal. At this time, since the bias signal has a constant value over time, only the control command signal changes over time, and this control command signal is the amplified position deviation value, speed deviation value, and acceleration deviation value. Since it is calculated by calculating , there is no need to set it in advance using memory or circuit processing.

In this way, according to this embodiment, the position, speed, and acceleration of the linear motor 12 are controlled by taking acceleration into consideration, so that it is possible to control the position, speed, and acceleration of the linear motor 12, so that it is possible to control the position, speed, and acceleration of the linear motor 12. In comparison, fine-grained control becomes possible, improving access speed and accuracy. In other words, there is no sudden change in the motion of the linear motor 12, and no overshoot occurs. Therefore, no matter what state the linear motor 12 is in, it can be controlled to follow the target ξ value.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those explained in the previous embodiment are indicated using the same reference numerals. In this embodiment, each deviation value level is detected and the amplification gain is set according to the detected level. First, each amplifier 22, 2
3.24 is 22a, 22b, 23a, 23b, 24a,
As shown by 24b, each is divided into two pieces. Here, these amplifiers 22 a, 22
b.

The amplification gains of 23a, 23b, 24a, and 24b are each K.
I II I K + 21 K I l l K 2□
I k, , K32.

The position deviation value, velocity deviation value, and acceleration deviation value signals obtained from each subtractor 17, 19.21 are also input to the state control circuit 31. This state control circuit 31 performs level detection from these deviation value signals and outputs respective gain selection signals.

These gain selection signals are sent to decoders 32, 33.3, respectively.
4 is entered. These decoders 32, 33.3
4 is an analog switch 35°3 according to the gain selection signal.
6. Controls the opening and closing state of 37. For example, the decoder 32
closes the analog switch 35a connected to the amplifier 22a or closes the analog switch 35a connected to the amplifier 22a according to the position gain selection signal.
Controls whether to close the analog switch 35b connected to b. Due to this.

One of the amplifiers 22a, 22b is selected and the gain for the position is set to 1□ or K+x. The same applies to velocity and acceleration.

In this way, according to this embodiment, the amplification gains for the position deviation value, velocity deviation value, and acceleration deviation value are selected and set according to the level of the deviation value, so that the amplification gains for the position deviation value, velocity deviation value, and acceleration deviation value are The weight distribution can be controlled while being varied, and it can be made less susceptible to disturbances such as vibrations and rocking.

Note that if the amplifiers 22, 23, and 24 provided on the output side of each subtractor 17, 19, 2 are further provided in multiple stages, control of all conditions becomes possible.

Effects of the Invention As described above, the present invention takes acceleration into account in each of the target value and the current value, and controls the linear motor in a state where the position, velocity, and acceleration are integrated. Compared to control methods and control methods using only position and speed,
Fine-grained control is possible, and sudden changes do not occur in the movement of the linear motor. Therefore, high-speed access is possible, and more accurate positioning can be achieved, and each deviation value level can be adjusted. Since the amplification gain of each deviation value is set according to the deviation value status at that time, it is possible to control the weight distribution of position, velocity, and acceleration while changing it according to the deviation value state at that time, and the influence of external disturbances such as vibration is reduced. The state can be controlled.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG.
The figure is a timing chart, FIG. 3 is a block diagram showing a second embodiment of the present invention, and FIG. 4 is a block diagram showing a conventional example.

Claims (1)

[Claims] 1. Setting a target value consisting of a target position, target speed, and target acceleration of the linear motor, detecting a current value consisting of the current position, current speed, and current acceleration of the linear motor; After calculating the deviation values of the position, velocity, and acceleration between the target value and the current value, and amplifying each deviation value, a control command signal obtained by calculating these deviation values is sent to the drive circuit for the linear motor. A method for controlling positioning of a linear motor, characterized in that the linear motor is made to follow the target value by inputting a value to the target value. 2. Set a target value consisting of a target position, target speed, and target acceleration of the linear motor, detect a current value consisting of the current position, current speed, and current acceleration of the linear motor, and set the target value and the current value. Calculate the deviation values of each position, velocity, and acceleration from , detect the level of these deviation values, set the amplification gain according to the level, amplify each deviation value, and then calculate these deviation values. A method for controlling the positioning of a linear motor, characterized in that the control command signal obtained by the above step is inputted into a drive circuit for the linear motor to cause the linear motor to follow the target value.