JPH0367310A - Teaching circuit for pulse motor - Google Patents

Abstract

PURPOSE:To simplify the system of a teaching circuit together with improvement of its reliability by providing a means which detects the voltage generated at the coil of a motor, a means which counts the output of the detecting means, and a means which stores the output of the counter means. CONSTITUTION:The voltage generated by a coil 1 is compared with the reference voltage by a comparator CP1 and therefore detected. Then a pulse signal is outputted. The pulse signals outputted from the CP1 are counted by a counter 3 via an OR circuit 2. hen a switch SW2 is operated when a single teaching action is through. Thus a CPU 4 stores the count value of the counter 3 into a prescribed address of a RAM 5 via an I/O port 6 and then resets the counter 3. In such a way, the information corresponding to the drive value of a motor is stored in the RAM 5 for each action. Then the information is read out of the RAM 5 for each action. Then the information is read out of the RAM 5 when a teaching action is through. Thus an object like a robot, etc., to be moved can move as if they are manually moved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a teaching circuit for a pulse motor used as a drive device for a robot or the like.

[Prior Art] Pulse motors used for various types of drives generally operate at 0N10 depending on input pulse signals, as shown in Fig.
It consists of an FF switching transistor Tr+ and a flywheel diode D connected in parallel with the motor M, and when the transistor Tr+ is ON, the motor M current ■. The motor can be rotated by cutting the .

When a robot or the like is driven by such a pulse motor, information such as the amount of movement of the robot is generally stored in a storage device such as a RAM, and a computer reads it from the storage device and uses it based on the stored information. and controls the pulse motor.

One of the ways to set such pulse motor drive control information in the storage means in advance is to
This is a so-called teaching method in which the robot, etc. is actually moved manually while the robot is stopped, and the rotational speed of the motor associated with the movement is detected using an encoder, tacho generator, etc., and stored in a storage means. The law is known.

However, conventional methods require actuators and detectors such as the encoder and tachogenerator as described above, making the system complicated and expensive. Moreover, since the number of mechanical parts is increased, failures occur frequently, and the service life is short and reliability is poor.

The present invention was proposed as a result of studies to solve these problems, and the object thereof is to provide a simple teaching circuit for a pulse motor that is a simple system and has high reliability. It is.

[Means for Solving the Problems] For the above purpose, the present invention provides a drive circuit for a pulse motor that drives a motor using an input pulse signal. Its basic features include: means for detecting the voltage generated in the coil of the motor when the motor is rotated; means for counting the output of the detecting means; and storage means for storing the output of the counting means. It is something to do. Further, the present invention is characterized in that the detection means includes comparison means for comparing the terminal voltage of the motor coil with a predetermined reference voltage.

Furthermore, the present invention is characterized in that the detection means is means for detecting the output of a diode connected in parallel to the motor coil.

Embodiment 1 FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, and FIG. 2 is an output waveform diagram at positions B and C in FIG. 1.

In FIG. 1, 1 is a coil of a pulse motor, Tr+ is a switching transistor for turning the coil of the pulse motor 0N10FF, and the emitter side of this transistor Tr is grounded. Further, D is a flywheel diode connected in parallel to the coil I, and the diode D1 absorbs the high voltage back electromotive force generated in the coil and prevents the transistor Tr+ from being destroyed.

On the other hand, CP1 is a comparator for comparing the terminal voltage of the motor coil I and the reference voltage VR□ from the reference value setting circuit VR, and a pull-up resistor Ra is provided on the output side of the comparator.

Reference numeral 2 denotes an OR circuit, and this OR circuit 2 receives output signals C,
, C2, C, are input, and the output of each comparator is counted. The CPU 4 includes an operation switch SW+ that is operated for teaching, and a switch SW that is operated when storing the output value of the counter 3 in the RAM.
2 is connected, and the counter 3 and the RAM 5 k: are also connected via a predetermined pass line and the I10 port 6.

In this embodiment, for convenience of explanation, teaching will be performed using one motor.

Next, an example of the operation of this embodiment will be explained with reference to FIG. 2. First, when the switch SW+ is closed, the CPU 4 lowers the power supply side of the pulse motor to the GND level, and the pulse generating means (
(not shown) and enters a teaching standby state.

Next, when teaching is started by an external force such as manual,
The pulse motor rotates, and an electromotive force as shown in FIG. 2 is generated at position B. In addition, V in the figure. I is the voltage corresponding to the forward voltage drop of the flywheel diode D1.

In this embodiment, the electromotive voltage generated by the coil is detected by comparing it with a reference voltage V□ in a comparator CP, and a pulse signal is output. The output pulse signal from this comparator CP+ is
It is counted by a counter 3 via an R circuit 2. When the SW2 is operated when the teaching of one operation is completed, the CPU 4 stores the count value of the counter 3 in a predetermined address of the RAM via the r10 port, and then resets the counter 3.

In this way, the RAM 5 stores information corresponding to the amount of motor drive for each operation.

After completing the teaching operation described above, when a pulse signal is input to the switching transistor Tr+ and the pulse motor is rotated, a back electromotive voltage is generated in the coil l.

This is detected by the comparator CP+ in the same manner as described above, and is counted by the counter 3 via the OR circuit 2.

In the CPU 4, the count value stored in advance in the RAM 5 is read out via the I10 port 6, and the pulse generating means transmits a pulse signal to the motor until the count value from the counter 3 reaches the set count value. In this way, when one operation is completed, the counter 3
is reset, the next drive information is read from the RAM 5, and the next operation begins. As a result, the object to be moved, such as a robot, moves in the same way as when it is operated manually.

FIG. 3 shows another embodiment of the means for detecting the current generated in the motor coil, in which a differential amplifier OPl is connected in parallel to the flywheel diode D. Note that an input resistor R6 and a feedback resistor Ra are connected to the inverting input terminal of the differential amplifier OP+,
Input resistors R6 and R2 are also connected to the non-inverting input terminal.

Now, if the anode potential of the flywheel diode D is EA and the cathode potential is Ec, the back electromotive force VDI generated in the coil l is V,, =EA-EC If the output of the differential amplifier OPl is Eo, then 7 ,',Eo=Vo+R.

The signal from the differential amplifier OPI is counted by the counter 2 via the OR circuit 2 in the same manner as in the above embodiment.

FIG. 4 shows still another embodiment of the present invention, in which a light emitting diode D3 is connected in place of the flywheel diode D1, and its output is connected to a phototransistor T.
The light is received by a light receiving element such as an rz.

A power supply voltage Vcc is connected to the collector of the phototransistor Trz, and a resistor R9 and a resistor RIG
are connected, and their resistances R,,R,. The reference voltage determined by is input to the inverting input terminal of the comparator CPa. Also, phototransistor Trz
is connected to the emitter of the resistor R8, and the output of the emitter is configured to be input to the non-inverting input terminal of the comparator CP2.

According to this embodiment, when a back electromotive force is generated in the coil 1, the light emitting diode D3 lights up.

When the phototransistor Trz receives the output, the photovoltaic force is input to the non-inverting input terminal of the comparator CP2, and the output is compared with the reference voltage determined by the resistors R9 and R1°. Comparator CP
A signal is output from . The output signal is counted by the counter 3 via the OR circuit 2.

[Effects of the Invention] According to the present invention described above, in the pulse motor drive circuit, when power is not supplied to the motor,
The motor is rotated by an external force, the current generated at that time is detected, and the output of the detection means is counted and stored in the storage means, which eliminates the need for tacho generators, encoders, etc. as in the past, and the system This simplifies the process, reduces failures and improves reliability.
Moreover, the effect is that it can be implemented at low cost.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining its operation, and FIGS. 3 and 4 are circuit configuration diagrams showing other embodiments of the present invention. FIG. 5 is a circuit diagram of a general pulse motor. In the figure, 1 is the pulse motor coil, 2 is the OR circuit, and 3
is a counter, 4 is a CPU, 5 is a RAM, D is a flywheel diode, D2 is a light emitting diode, Tr+ is a switching transistor, Tr2 is a phototransistor, cp, , cp2 is a comparator.

Claims (3)

[Claims] (1) In a pulse motor drive control device that drives the motor using input pulse signals, when the motor is rotated by an external force without power being supplied to the motor, the voltage generated in the motor coil is detected. 1. A teaching circuit for a pulse motor, comprising: means for counting the output of the detecting means; and storage means for storing the output of the counting means. (2) The pulse motor teaching circuit according to claim 1, wherein the detection means includes comparison means for comparing the terminal voltage of the motor coil with a predetermined reference voltage. (3) The pulse motor teaching circuit according to claim 1, wherein the detection means is a detection means for detecting the output of a diode connected in parallel to the motor coil.