JPS60129809A - Positioning control device - Google Patents

Abstract

PURPOSE:To make a high-speed and low-vibration positioning operation possible, by combining two speed patterns produced by dividing a speed pattern by a cam curve into two parts by multiplication. CONSTITUTION:A speed pattern by a cam curve is divided into two parts, one part being the speed pattern at the time of starting and stopping and the other being the speed pattern of the shifting section from acceleration to deceleration, and the divided patterns are set in data tables 2 and 3, respectively. These patterns are respectively outputted to DA converters 4 and 5 by the command of a microprocessor 1 and command voltages E1 and E2 of the converters 4 and 5 are multiplied by another and combined at an analog multiplier 6. A speed command V outputted from the multiplier 6 is supplied to a servomotor 8 through a driving circuit 7 and the motor is accelerated along the cam curve. After reaching a decelerating point, values of the tables 2 and 3 are outputted and deceleration is made along a speed curve symmetrical to the accelerating time about the time axis and the motor is stopped at an aimed point.

Description

[Detailed description of the invention] The present invention relates to a positioning control device.

Conventionally, in positioning control using a servo motor or a pulse motor, a method has been announced in which the speed pattern during acceleration and deceleration is made into a cam curve in order to reduce vibrations that occur when the motor moves from acceleration to deceleration. However, when acceleration and deceleration are carried out in the conventional manner using the Sicum curve, a speed pattern as shown in FIG. 1 is obtained. In the case of Figure 1(a), the absolute values of acceleration and deceleration are the same regardless of the distance traveled, and the acceleration changes discontinuously from positive to negative at the point of transition from acceleration to deceleration. Therefore, the positioning time changes monotonically according to the travel distance, and while the positioning time can be shortened when the travel distance is short, the speed pattern is discontinuous and vibrations occur at the point where the speed changes from acceleration to deceleration. It is not suitable for applications where the rigidity of the machine controlled by the motor is not very high. In the case of (1) in Figure 1, the acceleration is small depending on the distance traveled, and the acceleration changes continuously from positive to negative at the point of transition from acceleration to deceleration, so no vibration occurs, but when positioning Since time is constant, time is consumed when moving short distances, causing problems with high speed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a positioning control device capable of high-speed and low-vibration positioning.

According to the present invention, the first memory function stores the speed pattern at the time of starting and stopping, and the second memory function stores the speed pattern at the transition from acceleration to deceleration. The main configuration includes first and second digital-to-analog conversion functions that output the speed patterns stored in the first and second memory functions as command voltages, and a multiplication function that multiplies and synthesizes both command voltages. A positioning control device is provided that divides two types of speed patterns based on a cam curve into a speed pattern at the time of starting and stopping and a speed pattern at a portion where the transition from acceleration to deceleration occurs, and multiplies these speed patterns. Optimum positioning control is achieved by composing them.

The present invention will be described below with reference to embodiments shown in the drawings.

In FIG. 2 showing the configuration of an embodiment of the present invention, a microprocessor 1 performs calculations and controls of speed patterns, and controls forward and reverse rotation of the motor. Reference numeral 2 denotes a first data table, which is a memory that stores speed patterns when starting and stopping the motor. Reference numeral 3 denotes a second data table, which is a memory that stores the speed pattern of the portion where the motor shifts from acceleration to deceleration. 4 is a first digital-to-analog converter (hereinafter referred to as DA converter), which outputs the speed pattern stored in the first data table 2 as a command voltage El. 5 is a second A converter, which outputs the speed pattern of the second data tape /L/3 as a command voltage E2. Reference numeral 6 denotes an analog multiplier, which multiplies the values of both command voltages Er and E2 and outputs the result as a speed command (■) for the motor 8. 7 is speed command■
This is a type of motor drive circuit that inputs analog voltage. 8 is a servo motor. Reference numeral 9 is an incremental (monotonically increasing type) rotary encoder which generates pulses proportional to the number of revolutions of the motor 8 at 6!0. Lo is a discrimination circuit for discriminating the output of the rotary encoder 9, and divides and outputs two input pulses having a phase difference depending on whether the motor 8 rotates forward or backward. 11 is an up/down counter, which feeds back the rotational position (current position) of the servo motor 8 to the microprocessor 1 to notify it.

The operation of one embodiment of the present invention having the above configuration will be explained based on FIGS. 2 and 3. Equation v(1) representing the acceleration portion of the speed pattern based on the conventional cam curve is divided into two parts at its inflection point t1, and the following two speed patterns are created based on it.

These two speed patterns correspond to the first data tape /I/
According to instructions from the microprocessor 1, the first D-A converter 4 and the second D-A converter are The command voltages El and E2 of both converters 4 and 5 are multiplied and synthesized by an analog multiplier 6, and the speed command V output from the multiplier 6 is sent to a servo motor 8 via a drive circuit 7. added,
The motor 8 is accelerated along the cam curve. The rotation of the motor 8 is continuously fed back to the microprocessor 1 by a rotary encoder 9, a discrimination circuit 1O, and an up/down counter 11. After reaching the deceleration point, depending on the deviation between the target point and the current position, the values of the first data tape #2 and the second data table 3 are output, and the speed curve is symmetrical with respect to the time axis during acceleration. , stop at the target point.

When the moving distance is small (short), the command voltage E1 based on the first data tape) v2 is set to a speed pattern that shifts to deceleration in the middle of acceleration, as shown in FIG. 3 is synthesized. This 9-y bond amount is determined by calculation in advance by the microprocessor l.Generally, the deceleration point is selected at the midpoint of the travel distance, but if the acceleration time and deceleration time are set to independent values, the ratio It will be decided. Furthermore, even when an acceleration data table and a deceleration data table are provided independently and the speed patterns during acceleration and deceleration are changed, the deceleration point is set at a point corresponding to those values. If the moving distance is long, insert an equal section in the middle.

In addition to the above-described operation, according to the device which is an embodiment of the present invention, even when the moving distance is short, positioning can be performed with small changes in acceleration A and little vibration, as shown in Fig. 3). It is. Furthermore, as shown in FIG. 1 (Q), the positioning time t also decreases according to the moving distance, allowing high-speed positioning. Furthermore, since the maximum value of k decreases in accordance with the moving distance, it is possible to avoid resonance points in the mechanical system with less vibration caused by the motor 8.

In addition, although the above embodiment describes the case where the servo motor 8 is controlled by a voltage command, it is also possible to connect a voltage-frequency converter (V-F converter) to the output of the analog multiplier 6,
By using the output as a command pulse and feeding it to the up/down counter 11 at the same time, it can be applied to the servo motor drive of the Varne motor and the pulse train command.

- Further, the analog multiplication 'iM6 can be omitted if the microprocessor 1 performs the multiplication or if the second DA converter 5 is a Tosan type DA converter.

As stated above, since the device of the present invention has the above configuration, the speed pattern based on the cam curve is divided into two.
By multiplying and composing two speed patterns, there is an excellent effect that a positioning control device that can perform high-speed positioning with low vibration can be provided.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram showing the speed pattern in a conventional positioning control device, Fig. 2 is a block diagram showing the configuration of the positioning control device which is an example of the present invention, and Fig. 3 is a characteristic diagram showing its characteristics and operation. It is a diagram. ■・・・Microprocessor, 2.3・1st and 2nd
data table, 4.5...first and second D-
A converter, 6... Multiplier, 7... Drive circuit, 8
... Servo motor, 9... Rotary encoder, i
o...Figure 1 (a) (b) Figure 2

Claims (2)

[Claims] (1) The first part that memorizes the speed pattern at the time of starting and stopping
a first digital-to-analog conversion function that outputs the speed pattern stored by the first storage function as a command voltage; and a second storage function that stores the speed pattern of the transition from acceleration to deceleration. , a second digital-to-analog conversion function that outputs the speed pattern stored by the second storage function as a command voltage, a multiplication function that multiplies and synthesizes both command voltages, and an output based on the multiplication function. A servo motor that is accelerated and decelerated by a speed command, a pulse generating means that generates pulses proportional to the number of rotations of this servo motor, and a discrimination device that distributes and outputs the pulses generated by this means according to the phase difference. function, and a counting function that counts the pulses generated by this discrimination function and reports the current location.
During acceleration, the speed pattern stored in the first memory function and the second memory function is stored based on the deviation between the movement start point and the current location, and after reaching the deceleration point, the deviation between the target point and the current location is determined. The first digital/analog 2 conversion [1
and an output command function for instructing the second digital-to-analog conversion function to be output. (2) The first part that memorizes the speed pattern at the time of starting and stopping
a first digital-to-analog conversion function that outputs the speed pattern stored by the first storage function as a command voltage; and a second storage function that stores the speed pattern of the transition from acceleration to deceleration. , a second digital-to-analog conversion function that outputs the speed pattern stored by the second storage function as a command voltage, a multiplication function that multiplies and synthesizes both command voltages, and an output based on the multiplication function. A pulse motor or a pulse train command servo motor that is accelerated and decelerated by command pulses, a counting function that counts the command pulses and informs the current location, and detects the deviation between the movement start point and the current location during acceleration, and the deceleration point. After reaching the target point, the deviation between the target point and the current position and the speed pattern stored in the first storage function and the second storage function are transferred to the first digital-to-analog conversion function and the second digital conversion function, respectively. A positioning control device comprising an output command function for commanding an analog conversion function to output.