JPS6380309A - Positioning motor driver - Google Patents

Abstract

PURPOSE:To stop a motor correctly at an origin by providing a reset circuit to the titled positioning motor driver, and using an external signal to reset a synchronizing circuit and a deviation counter. CONSTITUTION:In applying a reset input to the deviation counter 7 while it is operated with a command pulse supplied at a frequency always causing a steady-state deviation, a reset circuit 11 stops the output of an operation pulse by the command pulse from a synchronizing circuit 6 and the counter 7 is reset at the leading edge of the input of reset. Since the counter 7 is zero regardless of the steady-state deviation existing before resetting, the state of servo lock is attained at a position supplied with the reset signal and the motor is stopped momentarily. In constituting the control circuit to input the reset signal to the circuit 11 when an origin signal is detected, the motor M is stopped at the origin accurately even when home position restoration is applied at a speed to a degree that the steady-state deviation exists in the counter 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a positioning motor driver in which command pulses are applied from the outside, and the number of command pulses indicates the rotation angle, and the frequency of the command pulses indicates the rotation speed.

[Conventional technology 1 A conventional device of this type is shown in FIG.

In the figure, 1 is a synchronization circuit that synchronizes external command pulses and encoder signals to generate addition and subtraction pulses; 2 is an AT counter that counts up and counts down the addition and subtraction pulses output from the synchronization circuit 1; 3 is a D/A converter that converts the value of width difference counter 2 into an analog voltage, 4 is an F/V converter that generates a speed signal from the signal of encoder E, and 5 is a converter between the output of D/A converter 3 and F/V converter. This is an error amplifier that compares the outputs of the V converter 4 and amplifies the difference.

Next, the operation will be explained. When a positive direction command pulse is input from the outside, an addition pulse is generated by the synchronization circuit 1 and added to the width difference counter 2.

The deviation counter 2 counts up by the number of addition pulses and increases the output value. The output of deviation counter 2 is D/A
The converter 3 converts the voltage into an analog voltage, and the error amplifier 5 amplifies the voltage to a power sufficient to drive the motor M, thereby causing the motor M to rotate. When the motor M rotates, an encoder E connected coaxially generates a pulse, which is converted into a voltage proportional to the rotation speed of the motor M by the F/V converter 4 and then sent to the error amplifier 5.
added to. Since the error amplifier 5 amplifies and outputs the difference between the two inputs, the output of the F/V converter 4 is transferred to the D/A converter 3.
Motor M rotates at a speed equal to the output of . Furthermore, the pulse of the encoder E becomes a subtraction pulse in the synchronization circuit 1 and is added to the deviation counter 2, so that the output of the [1 counter] decreases. When a command pulse in your direction is input from the outside, the operation is the same, but the direction of the signal is reversed.

[Problems to be solved by the invention] Since the conventional positioning motor driver is configured as described above, when a command pulse of a constant frequency is input to rotate the motor at a constant speed, the command pulse is sent to the deviation counter 2. The steady-state deviation is proportional to the frequency of n. Furthermore, when the command pulse disappears, the motor rotates by the amount of steady-state deviation and then stops.

When performing a home return operation to stop the motor M at the home position, either give a command pulse with a low frequency such that the steady-state deviation is always O, and then stop supplying the command pulse when the home signal is detected, or use a command pulse with a relatively high frequency. It was necessary to apply a command pulse of , stop the supply of the command pulse when the origin signal is detected, and at the same time detect how long the motor M continued to rotate due to the steady-state deviation using the control circuit. Therefore, there are drawbacks such as slow return to origin speed and complicated control circuit.

Means for Solving the L Problem] This invention was made to eliminate the drawbacks of the conventional ones as described above, and provides a reset circuit that resets a synchronization circuit and a deviation counter in response to an external reset signal. It is an object of the present invention to provide a positioning motor driver that can correctly stop at the home position even if the home return operation is performed at such a speed that a steady deviation always exists.

[Embodiment of the Invention] An embodiment of the invention will be described below based on the drawings. In Fig. 1, 6 is a synchronization circuit that synchronizes the command pulse and the encoder E signal to generate addition and subtraction pulses, and 7 is a difference counter that counts up and counts down the addition and subtraction pulses output from the synchronization circuit 6. , 8 is a D/A converter that converts the value of the deviation counter 7 into an analog voltage; 9
1 is an F/V converter that generates a speed signal from the signal of encoder E; 10 is an error amplifier that compares the output of D/A converter 8 and the output of F/V converter 9 and amplifies the difference; 11 is an external This reset circuit receives the reset signal and stops the output of addition and subtraction pulses by the command pulses of the synchronization circuit 6, and also resets the deviation counter 7 at the rising edge of the reset signal to set the output to O.

Next, the operation of this invention will be explained. Deviation counter 7
If a reset input is applied from the outside while the command pulse is applied at such a frequency that a steady-state error always exists in the operation, the reset circuit 11 will control the output of the addition and subtraction pulses by the command pulse of the synchronization circuit 6. At the same time as stopping, the width difference counter 7 is also reset at the rising edge of the reset signal.

When the deviation counter 7 is reset, the value of the deviation counter 7 becomes 0 regardless of the steady deviation value that existed before the reset signal was input, so the servo lock state occurs at the position where the reset signal is applied, and the motor stops instantly. . 13? By configuring the control circuit so that a reset signal is input to the reset circuit 11 when a point signal is detected (even if the return-to-home operation is performed at such a speed that a steady deviation exists in the deviation counter 7, the home position can be accurately maintained). The rotation of motor M stops.

In the above embodiment, an F/V converter is provided to generate the speed signal, but a speed generator coaxial with the motor may be provided to obtain the speed signal.

Further, in the above embodiment, each block was constructed using hardware, but it may also be constructed using software, and the same effects as in the above embodiments can be obtained.

[Effects of the Invention] As described above, according to the present invention, the positioning motor driver is equipped with a reset circuit, and is configured to accept external signals to reset the synchronization circuit and deviation counter. Even if the control circuit performs a return-to-home operation at a speed that causes a steady-state deviation, it can be stopped correctly at the home point.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a positioning motor driver according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional positioning motor driver. 6... Synchronous circuit 7... Deviation counter 8... D/A converter 9... F/V converter 1o... Error amplifier 11...Reset circuit M...Motor E...Encoder

Claims (1)

[Claims] A synchronization circuit that synchronizes command pulses and encoder pulses, an F/V converter that generates a speed signal from the encoder pulses, a deviation counter, a D/A converter that converts the value of the deviation counter into an analog voltage, and D The positioning system is equipped with an error amplifier that amplifies the error between the output of the /A converter and the output of the F/V converter, and the number of command pulses indicates the rotation angle of the motor, and the frequency of the command pulses indicates the rotation speed of the motor. A positioning motor driver characterized in that the motor driver is provided with a reset circuit that supplies a reset signal to a synchronization circuit and a deviation counter.