JPS59114606A - Positioning controlling method - Google Patents

Abstract

PURPOSE:To execute a positioning at a high speed by driving a DC motor by executing a linear accelerating operation at the time of start and a linear decelerating operation at the time of deceleration from the highest angular velocity, a command angular velocity, etc. CONSTITUTION:An angular velocity given to a speed loop system is operated by a command pulse and a feedback pulse from a pulse oscillator 14 connected to a DC motor 12 by an operator 9. This result is compared 10 with the angular velocity of the motor 12 detected by a tachogenerator 13, and the motor concerned 12 is driven through an amplifier 11. This operation is derived by an accelerating angular velocity omegau=omegam(thetan/thetau)<1/2>, and a decelerating angular velocity omegad=omegac(thetar/thetad)<1/2>. (Provided that omegam; the highest angular velocity, Wc; a command angular velocity, thetau and thetar; the number of remaining pulses required for a linear acceleration extending from zero to omegam and to the end point, and thetan and thetad; the number of pulses which are moved already and also required for a linear deceleration extending from omegac to zero.) As a result, after omegau=omegac, thetar=thetad, and after thetar=thetad, each command is outputted until the positioning is ended.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a positioning control method using a digital servo using a DC servo.

Conventional configuration and its problems Traditionally, positioning using digital servo has high precision,
It has features such as high speed and has been widely adopted mainly in automatic machines, and its configuration will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a servo configuration diagram, and when a command pulse is input, the motor 6 rotates at a gradually increasing speed in response to the pulse frequency. This situation is shown in FIG. On the other hand, the rotation angle of the motor 6 is converted into a pulse train by a pulse generator 8 directly connected to the counter-load shaft of the motor 6, and then the rotation angle is converted into a pulse train.

This feed) (tsuku pulse and the above command) pulses are synchronously compared by comparator 1, and the deviation is recorded in deviation register 2.
can be stored in Angular velocity ω of motor 6. Directives equivalent to
The starting characteristics of the motor 6 when the pulse frequency is input are G
tω=ω. (1-ε pl) ・・7・・・・
・It becomes ■. Here, ω is the motor angular velocity, and Gp is the position loop.
tl is the start-up time. On the other hand, when the command pulse is stopped, the amount of deviation stored in the deviation register 2 decreases, and the output voltage of the D/A converter 3 and the angular velocity of the rotary motor decrease. In this case as well, the deceleration characteristic is -5°g-Gpt2. , , , , , , ■. Here, t is ω of motor 6. It represents the time it takes from the rotation speed (number of rotations) until it stops. From equations ■ and equations 2, it can be seen that the starting and stopping characteristics of the motor 6 follow an exponential curve.From equations 2 and 2, the positioning time is shortened by increasing the position loop gain G. The maximum value of Gp that can be achieved is determined by the servo characteristics of the load, motor drive device, etc., and when that value is exceeded, the position loop system becomes unstable and causes a vibration phenomenon. Therefore, once the value of Gp is determined, time t1
and t2 are inevitably determined.

It can be seen that a servo system as shown in FIG. 1 in which the motor angular velocity starts and stops according to an exponential curve is disadvantageous for high-speed position Suto.Purpose of the InventionThe present invention solves the above-mentioned conventional drawbacks. This provides a high-speed positioning method.

Structure of the Invention The present invention provides the maximum angular velocity and command angular velocity of a DC motor, the number of pulses required for linear acceleration/deceleration to reach the maximum angular velocity, 2 the number of movement pulses from the positioning start point, 2 the remaining 9 until the positioning end point.
From the number of pulses, linear acceleration calculations are performed when starting the DC motor, and linear deceleration calculations are performed during deceleration, and by linearly driving the angular velocity of the DC motor, point-to-point (
It has the unique effect that positioning using the FTP method can be performed at high speed.

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

FIG. 3 is a servo block diagram showing an embodiment of a digital servo system suitable for the purpose of the present invention. Reference numeral 9 denotes an arithmetic unit that processes command pulses and feedback pulses from a pulse generator 14 directly connected to the DC motor 12. The output of the calculator 9 is sent to the comparator 1 which constitutes the speed loop servo system.
The output of the comparator 12 is connected to the amplifier 11, and the output of the amplifier 11 drives the DC motor 14. Further, the angular velocity of the motor 14 is detected by the tacho generator 13 and becomes one input of the comparator 1o. ω to the digital servo system configured in this way. When the angular velocity command pulse of the DC motor is inputted, the computing unit 9 performs the following computing process. DC motor 1
2 is from zero to ω. The number of pulses θf required to linearly accelerate to the angular velocity command value is ω. is the maximum angular velocity of the DC motor 12, and θ8 is the maximum angular velocity ω of the DC motor 12 from zero.

This is the number of pulses required to linearly accelerate up to

Next, the calculator 9 calculates the angular velocity given to the velocity loop system. This angular velocity calculation is ω. If this is the acceleration angular velocity command given by the calculator 9 to the comparator 10, then Here θ. is the number of pulses that have already moved from the positioning starting point, and can be known from the feedback pulse from the pulse generator 14.

From formula (■) and formula (2), we obtain. This calculation of ω1 is performed while the DC motor 12 is being accelerated by the calculator 9. This is done successively using variables. The angular velocity command to the DC motor 12 for the velocity loop by 20 is a linear acceleration as shown in FIG. The acceleration calculation shown in formula ■ is ω. After ω0 = ω0, the arithmetic unit 9 outputs ω to the comparator 10. The DC motor 12 is controlled at the commanded angular velocity by performing calculations so as to give an angular velocity command as follows. Further, the calculator 9 commands the DC motor 12 at an angular velocity ω. In order to decelerate linearly from 0d is the command angular velocity ω. The number of pulses required to linearly decelerate the DC motor 12 from to zero is as follows. Here, θ is the maximum angular velocity ω of the DC motor 12.

This is the number of pulses required to decelerate linearly from to zero.

The calculator 9 constantly checks the number of pulses θ remaining until the positioning end point, and when θd shown in equation (2) becomes equal to 01, performs the following linear deceleration calculation of the DC motor 12. If ωd is the deceleration angular velocity command given to the comparator 10 by the calculation 9, then Obtain 2〇 and 2 from. This calculation ωd is performed by the calculator 9 on the DC motor 12.
While the speed is being decelerated, successiveness is determined using the remaining pulse number θ1 as a variable. The angular velocity command to the DC motor 12 for the velocity loop system according to equation (2) is a linear deceleration as shown in FIG.

As described above, according to this embodiment, when starting the DC motor, the DC motor can be linearly accelerated by performing calculations using the number of pulses moved from the starting point as a variable, and when decelerating, the DC motor can be linearly accelerated until the positioning end point. By performing calculations using the number of pulses as a variable, it is possible to linearly decelerate the DC motor, which has the great effect of enabling high-speed positioning.

Note that the arithmetic unit 9 shown in FIG. 3 can be constructed from a general computer, but it can also be realized by software such as a microcomputer.

It goes without saying that the present invention can be applied to both analog and all-digital speed loop systems.

Effects of the Invention As described above, the present invention performs linear acceleration calculation using as variables the maximum angular velocity of the DC motor, the number of pulses required for linear acceleration to the maximum angular velocity, and the number of pulses moved from the positioning start point, and Performs linear acceleration, and when decelerating, performs linear deceleration calculation using as variables the number of pulses required to linearly decelerate from the commanded angular velocity and maximum angular velocity to zero, and the number of pulses remaining until the positioning end point. High-speed positioning can be achieved by slowing down the speed, which has great practical effects.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional digital servo, Fig. 29 is a characteristic diagram of the time diagonal velocity of the same motor, and Fig. 3 is a block diagram of a digital servo of a positioning control method according to an embodiment of the present invention. , FIG. 4 is a time versus angular velocity characteristic diagram of the motor for explaining FIG. 3. 9... Arithmetic unit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4

Claims (1)

[Claims] In positioning using a digital servo with a velocity loop system and a position loop system, a DC motor constituting the velocity loop system is linearly accelerated from zero to a maximum angular velocity in the position loop system. θU is the number of pulses required to linearly decelerate from the maximum angular velocity to zero. 2 The number of pulses moved from the positioning starting point is θ. 2. The remaining number of pulses up to the positioning end point is θ2. Perform the given DC Luss calculation and obtain the calculation result ω. is the speed command value ω. The calculation result is applied to the velocity loop system until the calculation result ω is equal to the angular velocity command value ω. After the angular velocity command value ω becomes equal to θd, the angular velocity command value ω is applied to the velocity loop system until the θ· becomes equal to θd. , and the above θ1 is the above θd
A positioning control method in which an angular velocity command having the calculation result ωd is given to the speed loop system after the angular velocity becomes equal to ωd until the positioning of the DC motor is completed, and the positioning start/stop control of the DC keyer is performed.