JPS6264296A - Step-out detector for motor - Google Patents

Abstract

PURPOSE:To immediately shift to next process by detecting the step-out of a motor immediately after the step-out by detecting the step-out of the motor by the inversion of its rotating direction. CONSTITUTION:A rotating direction pulse generator 8 generates reverse and normal rotation pulse signals C, D in response to the rotating direction of a stepping motor 3 by signals A, B from a pulse generator 6. A rotating direction inversion detector 9 monitors the signals C, D to detect that the rotating direction of the motor 3 reverses fro normal to reverse or vice versa, and outputs a direction inversion detection signal H. This signal H is applied to a pulse distributor 1, which stops command pulses FP, BP by notifying the fact that the rotation of the motor is inverted by the signal H.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a motor step-out detection device, and more particularly to a motor step-out detection device suitable for detecting a motor step-out immediately after the motor step-out.

[Background of the invention]

As a method of positioning a driven object such as a table driven by a motor at the origin, a fixed object is placed at the origin position.
There is a method in which when a driven object comes into contact with this fixed object, this condition is detected by the step-out of the motor and the motor is stopped. In addition, as a method of inserting the tip of a dry drive driven by a motor into the screw groove and rotating the driver to ensure that there is no play in the engagement between the driver and the screw, a driver that rotates at low torque is used to engage the screw. There is a method of detecting that the motor has stopped due to a motor step-out.

As an example of such a motor step-out detection device,
2. Description of the Related Art A stepping motor step-out detection device described in Japanese Patent No. 5-83497 is known.

This conventional step-out detection device applies a command pulse to the count input terminal of the counter, and a feedback pulse generated by the rotation of the stepping motor to the preset terminal of the counter. This is a method that counts pulses.

In this method, when the stepping motor is rotating normally, the counter is preset to the initial value by the next feedback pulse before the counter overflows. However, when the stepping motor goes out of step and the next feedback pulse is delayed or does not arrive, the counter overflows due to the command pulse. Therefore, step-out of the stepping motor can be detected by detecting the overflow of the counter. Such conventional devices do not require feedback pulses to have the same resolution as command pulses, and only need a detector that generates one to several pulses of feedback pulses per rotation of the stepping motor, and do not require an expensive position coder. It is advantageous in that it does not.

However, since tens to hundreds of command pulses are input between feedback pulses, step-out of the stepping motor cannot be detected until after the command pulses have been counted in tens to hundreds of pulses. This is disadvantageous in that it takes time to detect step-out, considering that it is not possible to increase the rotational speed of the stepping motor when determining the origin of the table or engaging the screw with the driver as described above. .

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor step-out detection device with a simple configuration that can detect motor step-out immediately after step-out.

[Summary of the invention]

In order to achieve the above object, the present invention utilizes the fact that when a driven body driven by a motor comes into contact with another object, the motor rotates in the opposite direction due to the reaction force received by the driven body, and Motor step-out is detected when the motor reverses. Therefore, the motor step-out detection device of the present invention includes a rotational direction pulse generator that generates pulses according to the rotational direction of the motor, and a reversal of the motor rotational direction using the pulses generated from the rotational direction pulse generator. It consists of a rotation direction reversal detector and a rotation direction reversal detector.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a stepping motor drive control device, FIG. 2 is a detailed circuit diagram of the step-out detection device shown in FIG. 1, and FIG. 3 is a timing chart.

In FIG. 1, a pulse distributor 1 that generates a forward rotation command pulse FP for forward rotation of a stepping motor 3 and a reverse rotation command pulse BP for reverse rotation of a stepping motor 3 is connected to a stepping motor drive device 2. The stepping motor 3 is rotated according to command pulses FP and BP. This stepping motor 3 drives a feed table 4 via a feed screw 5. stepping motor 3
A pulse generator 6 is connected to the pulse generator 6.
is a signal A whose phase changes depending on the direction of rotation.

Generate B. The signal A leads the signal B in phase when the stepping motor 3 rotates in the normal direction, and the signal B leads the signal A in phase when the stepping motor 3 rotates in the reverse direction.

The origin fixing plate 7 is fixed at the origin position, and stops the feed table 4 at the origin position when the feed table 4 comes into contact with it.

The step-out detection device in this embodiment is composed of a rotation direction pulse generation circuit 8 and a rotation direction reversal detection circuit 9. The rotation direction pulse generation circuit 8 detects the rotation direction of the stepping motor 3 from signals A and B from the pulse generator 6. The rotation direction reversal detection circuit 9 monitors the signals C and D and determines whether the rotation direction of the stepping motor 3 is from normal to reverse or from reverse to normal. Detecting that the direction has been reversed, a direction reversal detection signal H is output.

This signal H is applied to the pulse distributor 1, and the pulse distributor 1 stops generating the command pulses FP and BP when it is informed by the signal H that the rotational direction of the motor has been reversed. Therefore,
The feed table 4 stops at the origin position. In addition, a control device (
(not shown) is also sent a signal H, and the process moves on to the next step. still,
Signal E is a signal for starting step-out detection, and is given to rotational direction reversal detection circuit 9 from the control device.

As shown in FIG. 2, the rotational direction pulse generation circuit 8 includes a monostable multivibrator 10 to which the signal A is input.
and an AND gate 12 which performs the logical product of the output of the vibrator 1o and the signal B and outputs a reverse pulse signal C, and a logical product of the signal B obtained by inverting the signal B by the inverter 11 and the output of the vibrator 10 and the result is positive. It consists of an AND gate 13 that outputs a rotational pulse signal.

The rotational direction reversal detection circuit 9 consists of a D-type flip-flop 14.15 and an AND gate 16 which performs the AND of the respective output signals F and G of both flip-flops 14.15 and outputs a direction reversal detection signal H. , the signals C and D are applied to the respective block terminals GK of the flip-flops 14 and 15, respectively.
is supplied, and a step-out detection start signal E is given to the clear terminal CL.

With this configuration, when the reverse rotation command pulse BP is output from the pulse distributor 1, the stepping motor 3 rotates in the opposite direction, and the feed table 4 moves toward the origin (fixed plate 7). At this time, the signal B leads the signal A in phase, and the AND gate 12 outputs a reverse pulse signal C, which is the logical product of the pulse generated from the vibrator 10 every time the signal A rises and the signal B. On the other hand, the output of the AND gate 13 remains at low level. In response to this signal C, the D-type flip-flop 14 fixes the output F at a high level when the pulse signal C rises, but since the signal remains at a low level, the D-type flip-flop 15 outputs G.
also remains at a low level, and the output signal H of the AND gate 16 also remains at a low level.

When the feed table 4 contacts the origin fixing plate 7, the reaction causes the stepping motor 3 to rotate in the opposite direction, in the above embodiment, in the normal rotation direction. Then, the phase of signal B lags behind the phase of signal A, and a normal rotation pulse D is output from the AND gate 13. This pulse D is applied to the D type flip-flop 15.
, the output G of the flip-flop 15 becomes high level at the rising edge of the pulse D. At this moment, the output of the AND gate 16 also becomes high level, and step-out is detected.

Note that the timing chart in FIG. 3 shows the vibration of the stepping motor (vibration caused by repeated collisions between the feed table 4 and the fixed plate 7), so even when the signal H is at a high level, the reverse rotation command pulse BP is This shows what happens when the system is not stopped.

It is easily possible to detect synchronization from the signal H immediately after the synchronization and proceed to the next process immediately, and there is no time delay as in the conventional method.

The above explanation took the stepping motor as an example.

It goes without saying that the present invention can be applied to other motors such as DC motors, AC motors, and induction motors, and in the embodiment, it is used to detect predicted step-out such as JM point return. However, it goes without saying that the present invention can also be used for abnormality monitoring such as unexpected step-out, such as step-out caused by unexpected collision of the drive table with an obstacle.

〔Effect of the invention〕

According to the present invention, since motor step-out can be detected immediately after step-out, the next process can be started immediately, which has the effect of shortening the takt time of an automatic machine. Furthermore, since the configuration is simple and does not require a complicated circuit, the device can be configured at low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a motor drive control device equipped with a step-out detection device according to an embodiment of the present invention, FIG. 2 is a detailed circuit diagram of the step-out detection device shown in FIG. 1, and FIG. 3 is a timing It is a chart. DESCRIPTION OF SYMBOLS 1... Pulse distributor, 2... Stepping motor drive device, 3... Stepping motor, 4... Feeding table, 6... Pulse generator, 7... Origin fixing plate,
8... Rotation direction pulse generation circuit, 9... Direction reversal detection circuit, 10... Monostable multivibrator, 14.15... D type flip-flop.

Claims (1)

[Claims] The motor includes a rotational direction pulse generation means for generating pulses according to the rotational direction of the motor, and a rotational direction reversal detection means for detecting that the rotational direction of the motor is reversed by the pulses generated from the rotational direction pulse generation means. 1. A motor step-out detection device, which detects motor step-out from a reversal of the rotational direction of the motor.