JP2614613B2 - Motor control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device, and more particularly to a motor control device that stably controls a movement time from a start to a stop of driving of a motor.

[Prior art] Conventionally, this type of motor control device is synchronized with a signal pulse of an encoder that generates a signal in accordance with rotation of a motor,
I want to stop the motor by generating a signal that turns off the power supply to the motor for a certain period of time among the drive signals of the motor, and turning off the motor drive signal and applying a field brake to the motor for a certain period of time. Motor control is performed in the order of high-speed control, brake control, and low-speed control of the motor up to the position.

However, in such a conventional device, in both the speed control and the brake control, the signal time for turning off the power supply to the motor and the signal time for applying the field brake among the drive signals are constant. If the connected load fluctuates or the power supply voltage fluctuates,
There has been a problem that the rotation speed of the motor fluctuates or the brake amount fluctuates, and the total movement time required from the start of rotation of the motor to the desired stop position is not stable.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems and to provide a motor control device capable of obtaining a stable motor moving time even when a power supply voltage fluctuates or a load fluctuates. To provide.

[Means for Solving the Problems] To achieve the above object, the present invention provides a motor,
A rotator driven in accordance with the rotation of the motor, a detection unit for generating a detection signal in accordance with the rotation of the motor, and a first unit based on a detection signal generated from the detection unit in accordance with the rotation of the motor. Motor drive control means for controlling the speed of the motor to a high first speed and a low speed second speed in accordance with the second drive signal, and the detection means generated by the rotation of the motor. Brake control means for performing brake control of the motor by a field brake signal based on the detection signal of the above, and generating the first drive signal by the input motor drive start signal to bring the motor to the first speed. Drive, when the rotating body reaches the first angular position, generates the field brake signal to brake control the motor, and when the rotating body reaches the second angular position, Control means for generating a second drive signal that is corrected according to the time from the start of driving of the motor to the time when the rotating body reaches the second angular position to drive the motor to the second speed; It is characterized by having.

[Operation] According to the present invention, the time required for the high-speed first speed control by the motor drive control means from the start of driving of the motor required the arrival of the rotating body at the first angle and the brake control. The time is detected by the arrival of the rotating body at the second angular position, and the second drive signal is corrected according to the time from the start of driving of the motor to the arrival of the rotating body at the second angular position. Are driven at a low second speed. Therefore, stable movement time control of the motor can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a circuit diagram showing one embodiment of a motor control device used in a copying machine or the like according to the present invention, where 10 is a microcomputer as a control unit, 20 is a DC motor, and 22 is driven by the motor 20. Rotating body 22A, ... is this rotating body 22
The lock lever is driven by an actuator (not shown) via a driver 23 with engagement grooves provided at 90 ° intervals on the
The projection at the tip of 24 can be engaged, and the lock lever
When the engagement of 24 occurs, the rotating body 22 is locked. 26 is a rotating body
A home position sensor for detecting 22 home positions is connected to the microcomputer 10.

Reference numeral 28 denotes an encoder of the motor 20, and a pulse signal is supplied to the microcomputer 10.

Reference numeral 30 denotes a drive circuit of the motor 20, which includes a buffer 32, a series resistor 34, a power transistor 36, and a resistor 38 connected between the emitter and the base of the power transistor 36. Reference numeral 40 denotes a brake circuit for applying a field brake to the motor, and includes a buffer 42, a series resistor 44, and a transistor 46.
Reference numerals 50 and 51 denote divided resistors for lowering the power supply voltage and supplying the reduced voltage to the microcomputer 10.
The stepped down voltage is 4V, compared to 24V. As is well known, the microcomputer 10 has a CPU 12, a ROM 14, and a RAM 16, and the ROM 14 stores a control program for controlling the entire motor control device and a control program according to a flowchart of FIG. Has an area,
The RAM 16 has an area for temporarily storing detected data and the like. Reference numeral 18 denotes a start signal input of the motor 20.

Next, the operation of each part of the above embodiment will be described with reference to the timing chart shown in FIG.

ED is an output waveform generated from the encoder 28 with the rotation of the motor 20, DV is a drive signal waveform of the motor drive circuit 30, BK is a brake signal waveform of the brake circuit 40, and LK is a lock lever 24.
7 is a driving signal waveform of a driver 23 for driving the driving.

During the rotation of the motor 20, in synchronization with the falling of the output waveform of the encoder 28, a drive signal for the first speed control for a predetermined time T ₁ off the driving output of the motor drive circuit 30 is output. Also, after the motor 20 has rotated a predetermined angle, the motor drive output is turned off to stop the motor,
It activates the brake circuit 40 applies a field brakes, but also in synchronism with the falling of the output waveform of the encoder 28 to output a brake signal for a predetermined time T _2.

Finally, the lock lever 24 is operated at a predetermined angle before the desired stop position of the motor 20, and thereafter, in order to rotate the motor 20 at a low speed, the drive of the motor drive circuit 30 is synchronized with the fall of the output waveform of the encoder 28. to output a driving signal for the second speed control for ₃ off a predetermined time T to output.

Then, the protrusion at the distal end of the lock lever 24 is engaged with the engagement groove 22A of the rotating body 22, and the motor 20 is completely stopped and is locked at the same time.

Hereinafter, an example of the control procedure of the present embodiment having the above-described configuration will be described with reference to the flowchart shown in FIG.

When the control starts, it is first determined in step S1 whether a start signal 18 of the motor 20 has been input. When the signal is input, in step S2, for example, the movement counter counts the number of pulses 360 of the encoder 28 corresponding to 90 ° rotation of the rotating body 22.
Is set.

Next, the lock lever 24 is turned off in step S3, and the power supply voltage is read in step S4. Then step S5
In determining the predetermined time T ₁ corresponding to the read power supply voltage by table look-up. Shows one example of the table in FIG. 5 (a), for example when the power supply voltage is 25V is T ₁ = 700μsec, become as the T ₁ = 750μsec in the case of 25.5V.

Thus, the program proceeds to step S6, sends a signal to the motor drive circuit 30, thereby setting the signal output for driving the motor 20, sets a one-shot timer for a predetermined time T ₁ the motor 20 described above is turned off. This is what automatically output is inverted after ₁ hour T. In step S6A, a measurement timer described later is cleared. When the motor 20 starts rotating, the falling edge of the pulse of the encoder 28 is detected in step S7.

When the falling edge of the pulse is detected in step S7, the value of the movement counter is decremented by one in step S8, and
In S9, it is determined whether the subtraction value is 160 or less. That is, whether the motor has rotated 50 ° from the start of rotation or
It is a judgment of whether or not it reached 40 ゜ ago. If it does not reach this value, proceed to step S10, read the power supply voltage again,
In step S11 Figure 5 reads the value of T ₁ performs a table lookup of the table exemplified in (a).

Then, while continuing the motor driving in step S12, instead of the value of T ₁ set last time when there is voltage fluctuation, setting the read new value of T _1. Thus, returning to step S7, the count value of the movement counter is
Until 160, the motor 20 is driven at a first speed serving fast off-time T _1. Thus, to reduce the value of T ₁ when the power supply voltage becomes lower, that is, to shorten the off-time to suppress the speed fluctuation of the motor 20.

As the rotation of the motor 20 advances, the count value of the movement counter becomes
When the count value is 160 or less, the process proceeds to step S13, where the count value is further equal to or less than 80, that is, 3
9.75 ゜ (count value = 159) to 20 ゜ (count value = 8
0) is determined, and if so, the pulse cycle of the encoder 28 up to this immediately before is read in step S14.
The routine for measuring the period is 50 as shown in FIG.
This is performed by an internal interrupt every μsec. When the timer operates, it is determined in step S23 whether or not the pulse of the encoder 28 has risen. If so, the pulse counter is cleared in step S24. If it has not risen, the process proceeds to step S25, where it is determined whether or not the pulse of the encoder 28 is at the high level.
At 6, the clock pulse counter is incremented by one. Thus, the pulse cycle of the encoder and, consequently, the rotation speed of the motor 20 are detected by the number of clock pulses of a predetermined cycle counted during the high level of the pulse of the encoder 28.

Then, a predetermined time T ₂ is on time of the braking signal corresponding to the period value immediately before this to read in the step S15 is obtained by table look-up. An example of this table is shown in FIG.
/ 2 is as a T ₂ = 900μsec when T ₂ = 950μsec, following 250μsec when below 200 .mu.sec. In short, the period is short, that is, when the rotational speed of the motor 20 is high is the predetermined time T ₂ so braked longer are predetermined.

Further, in step S16, the output of the motor drive circuit 30 is turned off and the signal output of the brake circuit 40 is set,
Sets the one-shot timer as a brake signal for a predetermined time T _2. This is what automatically output is inverted after T ₂ hours. Thus, for each falling edge of the pulse of the encoder 28 as described above, it is field brakes applied to the predetermined time T ₂ motor 20.

Further, when the count value of the movement counter becomes 80 or less, the process proceeds to step S17, where it is determined whether the count value is 1 or less, that is, 19.75 ゜ before the desired stop position (count value = 7
It is determined whether it is between 9) and 0.25 ゜ (count value = 1). If so, the measurement timer is latched in step S18A, and it is necessary in step S18 from the start of driving the motor 20 to the end of the brake control. The read time T _A value is read. The T _A value is obtained by counting up the measurement timer one by one in step S27 by an internal timer interrupt every 1 msec according to the flowchart shown in FIG. 4 (C).

Then, in step S19, a table lookup of the table illustrated in FIG. 5C is performed in correspondence with the T _A value, and the T ₃ value is read. For example, T _A value 1540μsec _ternary T when the following 670Msec, when the following 680msec is set to as the 1520Myusec. When the measurement time T _A is short, that is, when the motor 20 rotates rapidly, the motor 20 is driven at a lower speed by increasing T ₃ of the drive signal, which is the time for turning off the supply of the power supply voltage. The movement time is stabilized.

Next, in step S20, the output of the brake circuit 40 is turned off, the driver 23 of the lock lever 24 is turned on, and the drive signal output of the motor drive circuit 30 is set again every time the pulse of the encoder 28 falls, and the motor 20 is turned off. Predetermined time
To set a one-shot timer of T _3. This is also intended to automatically output is inverted after T ₃ hours had passed.

If it is determined in step S17 that the count value = 0, the drive of the motor 20 is turned off and stopped in step S21. In this case, the rotating body 22 is locked by the lock lever 24 as described above.

Finally, in step S22, it is determined whether or not the start signal is off. If the start signal is off, the process returns to the start signal waiting state in step S1.

As described above, in this embodiment, the off-time of the drive pulse at the first speed is controlled according to the fluctuation of the power supply voltage,
The amount of braking is changed according to the rotation speed before applying the brake, and the speed control of the motor 20 is performed accurately. At the same time, the control of the second speed was performed in accordance with the time required from the start of driving the motor to the end of the brake control, and stable movement time control of the motor was achieved.

Incidentally, in the present embodiment, the value of the off-time T ₁ and the braking time T ₂ of the drive pulses of the first speed has been explained an example for changing in accordance with each state, which like the value of constant It may be a value.

[Effects of the Invention] As is apparent from the above description, according to the present invention, even if the movement time from the start of driving of the motor fluctuates due to the fluctuation of the power supply voltage or the fluctuation of the load, the total movement time Is controlled to a predetermined value, and a stable motor moving time can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of the present invention, FIG. 2 is a circuit diagram showing one embodiment of the present invention, FIG. 3 is a timing chart showing operation timing of each part of the embodiment, FIG. 4 is a control procedure of the embodiment FIG. 5 is a diagram showing an example of a table of T ₁ , T ₂ , and T ₃ . 10: microcomputer, 20: motor, 24: lock lever, 28: encoder, 30: motor drive circuit, 40: brake circuit.

Claims (1)

(57) [Claims] 1. A motor, a rotating body driven in accordance with the rotation of the motor, detection means for generating a detection signal in accordance with the rotation of the motor, and the detection means generated in accordance with the rotation of the motor Motor drive control means for controlling the speed of the motor to a first high speed and a low second speed, respectively, by first and second drive signals based on a detection signal from the motor; A brake control unit for performing brake control of the motor based on a field brake signal based on a detection signal generated from the detection unit, and generating the first drive signal based on an input motor drive start signal. Driving the motor to the first speed, generating the field brake signal when the rotator reaches the first angular position to brake-control the motor; When the motor reaches the second angular position, the motor generates a second drive signal that is modified according to the time from the start of driving of the motor to the time when the rotating body reaches the second angular position. And a control means for driving the motor at a speed.