KR870001209B1 - Position control apparatus using sine curve - Google Patents

Abstract

This invention relates to a position control device for machine tools and robots in which several kinds of servo motor and step motor are used. And this device can control motors precisely in a desired position by connecting with an external computer and a data input- output device. Also, regardless of step motor and servo motor, this device can be applied simply to all control systems as it can control their positions on the input-output bus of the same control signal and it be drived ideally by generating control signal in sine curve to not only eliminate a mechanical load but also decrease chattering in acceleration or deceleration.

Description

Position controller using sine curve

1 is an overall block diagram of the present invention.

2 and 3 are exemplary views of the present invention, and FIG. 2 is an exemplary view when the servo motor is used.

3 is an exemplary view of the case used for the step motor.

4 is an exemplary composite configuration of the present invention.

(A) and (b) of FIG. 5 are control signal output waveform diagrams of a motor controller according to a conventional method.

6 is a control signal output waveform diagram of the present invention.

7 is a relationship between time and speed for generating a sine curve.

The present invention relates to a position control device for a machine tool and a robot using various servo motors and step motors. The present invention relates to an external computer and a device capable of inputting / outputting data so that the motor can be precisely controlled at a desired position. will be.

In general, the control device of the motor includes an analog position control device and a digital logic position control device only for hardware (Hard Ware), but in the former analog position control device, an analog such as a drift phenomenon is observed. Due to the weakness that can occur in the system, it is impossible to obtain the precise and high performance position, and the logic is not suitable for the position control system that requires the intelligence such as the positioning in the logic-only controller that does not have the latter intelligence. There was this.

Accordingly, the present invention can provide a position control device capable of intelligentizing the generation and change of data input / output, acceleration / deceleration form, and position closed loop system using a microprocessor. It is an object of the present invention to achieve a sine curve so that control is not overwhelming.

In addition, unlike the general servo motor, the step motor has an open loop type, and when controlling the step motor, there are many differences from the servo motor. Difficulties have been followed, but the present invention has another object to provide a control device that can be fully controlled to such a control system, such as a step motor.

The position control device of the present invention is a combination of a set of control devices in one motor to form a complete control system can be easily made a plurality of motor control, it is possible to control the continuous position according to the change of software.

In general, in the method for controlling the motor, when the motor is accelerated or decelerated, an operation command of a waveform such as a trapezoid or a modified trapezoid as shown in FIG. 5 (a) (b) is used. The method using the operation command of the waveform causes the motor to be shocked at the discontinuous point of the curve, causing the motor to be unreasonable and causing vibration during the acceleration and deceleration of the motor.

However, in the present invention, by outputting the acceleration / deceleration command in the form of a curve as shown in FIG. 6, it is possible not only to minimize the overcurrent occurring at the initial stage of the operation of the motor, but also to avoid excessive mechanical stress. By doing so, the most ideal motor can be driven without the phenomenon of vibration of acceleration and deceleration.

Therefore, the present invention is characterized in that the drive and position control of the motor in the form of a sine curve using a microprocessor, the following in more detail based on the accompanying drawings a specific embodiment of the present invention.

FIG. 1 is a block diagram of the present invention, wherein the position control device A of the present invention is constructed with the CPU 1, the frequency converter 2, the error counter 3, the DAC 4, and the amplifying circuit 5. The down selection circuit 6 is composed roughly.

The CPU 1 manages the input and output of various data to and from the outside, determines the various drive types based on the information received from the outside, calculates the position data and time received from the external computer 7, and calculates the necessary time. The speed is calculated and the data stored in the ROM (8) and the timer (9) are used to output the speed data corresponding to the sine curve to the frequency converter (2).

The frequency converter 2 has a maximum capacity of 18 bits, but the data actually has a capacity of 16 bits, so that the frequency converter 2 can have a pulp string having a frequency corresponding to the following equation.

Where D: data

fin: reference clock frequency

fout: command pulse string

After the pulse train CPU 1 generated in the processor of the present invention calculates and recognizes, the present position can be identified by equating the total number of pulses outputted with the position value.

The serial pulse generated by the processor of the present invention is input to an error counter 3 by an up / down selection circuit 6, which is always required by the processor. The pulses appearing from the frequency converter 2 are input to the error counter 3 in the direction of The output pulse and the encoder signal of the frequency converter 2 have opposite signs and are compared with each other to form a substantially negative position loop so that the output of the error counter 3 is determined to be a speed command. Will be.

Therefore, the output of the error counter 3 exhibits a position error, and the digital signal output of the error counter 3 is converted into an analog voltage by the digital-analog converter (DAC) 4 to the amplifying circuit 5. The gain is adjusted to be output to the speed controller 10 and the motors 11 and 15 are driven by this output signal.

In addition, according to the present invention, the speed sensor 12 is separately configured to detect an encoder signal detected from the axes of the motors 11 and 15 and is counted by the counter 13, and the signal is counted by the I / O port 14. The absolute positions of the motors 11 and 15, which are inputted to the external computer 7 and the CPU 1 through the, can be known, and the encoder signal encoded by the speed sensor 12 is converted into an analog signal. After the amplification circuit 5 is amplified by the amplifying circuit 5 to output an analog voltage proportional to the frequency of the encoder, the speed can be sensed, and this output becomes a negative feedback amount and is input to the speed controller 10.

The present invention of the member can be used in both the servo motor control system and the step motor control system, the position control of the present invention when used in the servo motor control system as shown in FIG. 2 and FIG. The device A is installed between the servo motor 11 and the external computer 7, respectively, so that the command signal of the external computer 7 or the data and timer stored in the ROM 8 of the CPU 1 of the present invention. By comparing and detecting the speed data using (9) with the encoder signal detected from the axis of the servo motor 11, it becomes possible to control the drive speed or the absolute position of the servo motor 11.

3 illustrates the use state of the step motor control system. The step motor control system is also used in each step motor 15 in which the position control device A of the present invention is connected to the external computer 7.

In addition, FIG. 4 is a system in which a three-axis servomotor and a single-axis step motor shaft are driven to a system bus of an external computer 7. The operation is connected in parallel with the system bus, respectively. Compared with the axis designation address designated by the computer 7 and the value of the axis selection DIP switch in each position control method A, it is determined whether or not the commanded data is inputted. By adding multiple servo systems in parallel, they can be selectively controlled.

Thus, the circuit block diagram showing the position control apparatus A in FIG. 4 mentioned above concretely is FIG. 1, where the speed control apparatus 10 was made by the position control apparatus A in this invention. It is a device that drives a motor by receiving a speed curve in the form of a sine curve. It is irrelevant to generating a sine curve.

In addition, the step motor control system also connects the position control circuit A of the present invention in parallel to the same system bus Bus so that the absolute position signal of the position control circuit A is displayed so as to step through the step motor driver 12. Position the motor 15 is controlled.

7 shows the relationship between the time and the speed of generating a sine curve during acceleration and deceleration. (A) of FIG. 7 shows that the CPU 1 receives the INTERRUPT from the timer 9 at a predetermined time Δt and converts the corresponding value into a frequency, and then converts the value into a frequency. Send a value corresponding to).

Here, K has a relationship of equation (3) in relation to the constant time Δt during the acceleration time ta.

는 요구시간(T)를 만들기 위한 일정시간(Δt)의 합으로 ta보다 클 수 없다.

Is the sum of the constant time Δt for making the required time T and cannot be greater than ta.

In FIG. 7B, the CPU 1 sends data to the timer 9 to request an interrupt so that a constant speed change Δf is obtained.

At this time, the time variation t 'corresponding to the equation (4) is obtained for each interrupt and sent to the timer 9.

Where K 'is represented by equation (5) in relation to the maximum velocity and the constant velocity Δf.

는 요구속도(f)를 만들기 위해 일정속도(Δf)의 합을 나타내며 fmax를 초과하지 못한다.

Denotes the sum of the constant speed Δf to produce the required speed f and does not exceed fmax.

In FIG. 7 (b), although the equation is relatively complicated, various acceleration / deceleration forms can be produced with the minimum modification of the software.

The position controller A can generate a sine curve by appropriately selecting the degrees (a) and (b) of FIG. 7 according to the structural form of the robot.

The present invention as described above can control its position through the same control signal input / output bus without being concerned with step motor or servo motor, so that it can be easily installed and used universally in all control systems, and the operation is in the form of a sine curve. It outputs a control signal to the motor to minimize the overcurrent generated during the initial operation of the motor, thereby eliminating mechanical overload, and simultaneously driving the motor in an ideal state with little occurrence of vibration during acceleration and deceleration. It has it.

Claims (1)

A microprocessor (1), a frequency converter (2) for generating a parallel-serial pulse train, and a digital-analog cover adapter (4) for converting a frequency into a voltage, wherein the microprocessor ( 1) an up-down selection circuit 6 is connected and the encoder signals from the microprocessor 1 and the motor M are compared between the frequency converter 2 and the digital-analog converter 4. Position control device using a sine curve, characterized in that by connecting the error counter (3).

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