JPH0340596B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a rotation speed control signal for a plurality of DC motors, and particularly relates to a control device for a plurality of DC motors suitable for use in a copying machine, etc. .

[Background of the invention]

A block diagram of the prior art is shown in FIG. In figure 1
Encoders E _A , E _B , and _EC are respectively attached as rotation detectors to the DC motors M _A , M _B , and _MC . From the encoder, Fig. 2
As the motor rotates, as shown in E _A ,
A signal with a frequency proportional to the rotation speed is output.
DS is a data selector that selects one signal from among the signals in encoders E _A , E _B , and E _C according to a signal from the control unit CTRL in the MPU, which is a control device, and outputs the interrupt signal in Figure 2. As shown in INT,
A pulse signal periodically generated at the rising edge of the encoder signal is outputted to the CTRL as an interrupt signal INT. The MPU selects the rotation speed value of each motor set in advance and the data selector DS.
The actual rotation speed is determined by comparing the rotation speed converted from the cycle of the encoder signal that comes in through the
The drive devices for each of the motors M _A , M _B , and _MC so that the rotation speed is always the same as the preset rotation speed,
Outputs the time and duty data for energizing the motor to DRIVA, DRIVB, and DRIVC. Said
DRIVA to DRIVC are connected to transistors Q _A , Q _B ,
Turn on Q _C for a certain period of time. In this way, the rotational speed of the motors M _A to _MC is controlled by the ON time of the motors Q _A to Q _C , that is, the duty value. For example, if the rotation speed of motor M _A is lower than the preset rotation speed, the MPU
Outputs a duty data value _that turns on Q _A for a longer time to DRIVA, and
Increase the rotation speed. Here, V is a motor drive power source. A method for detecting the motor rotation speed will be explained with reference to FIG. It is now assumed that the data selector DS has selected the encoder E _A signal. The data selector DS selects the pulse signal INT synchronized with the rise of the signal _EA .
Output as an interrupt signal to the control unit CTRL in the MPU. The CTRL section calculates the time from the first INT signal to the second INT signal by using the oscillation section CK (for example,
The number of pulses from (consisting of crystal X, etc.)
Measure with counter CNTR. This time is inversely proportional to the rotation speed of motor M _A , so
By measuring time, the number of revolutions of motor M _A can be measured. After measuring the rotation speed of motor M _A , the CTRL then outputs a signal to the data selector DS to select encoder E _B , and in the same manner as above, the motor M _B
Measure the rotation speed of the motor, and then
Measure the rotation speed of _MC . The measured rotation speed and the preset rotation speed are compared by the CTRL, and the calculation unit ALU calculates the rotation speed for each motor. On-time data value duty driving circuit DRIVA~
Output to DRIVC.

As described above, by switching the encoder signal to be measured using the data selector DS and sequentially measuring the speed of each motor M _A , M _B , and _MC , one control device can control the speed of three motors. can be controlled in parallel, but it has the drawbacks described below.

That is, as shown in Figure 3, the INT signal is
This is generated by the rising edge of the output signals of encoders E _A , E _B , and E _C , and since these output signals of E _A , E _B , and E _C are not synchronized, for example, the date selector DS is generated by the E _B selection signal. Even if the E _B signal is selected, the INT signal caused by the E _B signal is the worst as shown in the figure.
The time between INT and INT will be delayed. In other words, measuring the rotational speed requires twice the time t between INT and INT. This time becomes a complete waiting time, which deteriorates controllability.

[Purpose of the invention]

An object of the present invention is to provide a device and method for controlling multiple DC motors that eliminates time loss during measurement by performing speed measurements of DC motors in parallel, has higher accuracy, and has good followability. It is in.

[Summary of the invention]

The present invention combines the signals of the rotation detectors of multiple DC motors into one signal, measures the period of this combined signal with a free running counter, distributes these measured values to each DC motor, and calculates the speed in parallel. This eliminates time loss during speed measurement by ensuring that measurement is always performed.

[Embodiments of the invention]

An embodiment of the present invention will be described below using an example of three DC motors. FIG. 4 shows an outline of an apparatus according to an embodiment of the present invention. M _A , M _B , M _C , E _A , E _B ,
E _C , Q _A , Q _B , Q _C , DRIVA, DRIVB, DRIVC,
CK and ALU are the same as in Figure 1. Also
CTRL1 is a control unit corresponding to CTRL in FIG. OSA captures the rising edge of the signal from E _A ,
This is a one-shot circuit that converts into an interrupt signal. Similarly, OSB is a one-shot circuit that uses signals from _EB , and OSC uses signals from _EC . NOR is OSA,
This is a NOR circuit that combines the signals from OSB and OSC into one and inverts them. Also, FFA is the signal from E _A , FFB is the signal from E _B , and FFC is E _C
This is a latch circuit that stores the rising edge of a signal from. The movement of signals in the apparatus shown in FIG. 4 will be explained with reference to FIG.

In Figure 5, φ _A is the signal from E _A , φ _B is the signal from E _B
The signal φ _C from is the signal from E _C , and respectively,
It has a frequency that corresponds to the rotational speed of the above-mentioned M _A , M _B , and _MC . These φ _A , φ _B , and φ _C are the OSA,
Input to OSB, OSC, OSA, OSB, OSC are
Taking the rising edges of φ _A , φ _B , and φ _C , respectively,
Outputs output signals OUTA, OUTB, and OUTC.

These OUTA, OUTB, OUTC are the NOR
It is input to the circuit, combined into one line, inverted and output, and sent to the control device as an interrupt signal INT.
It is input to the control unit CTRL1 in the MPU1. on the other hand,
The φ _A , φ _B , and φ _C are also input to the FFA, FFB, and FFC, and the signals PA0, PA1, and PA2 that capture and store the rises of these φ _A , φ _B , and φ _C are output, respectively. After these PA0, PA1, PA2 signals are read into CTRL1 of the MPU1,
Reset signals RA, RB, output from CTRL1
Each is reset by RC. This CTRL
1 is the above when the interrupt signal INT is input.
Take in the value of CTRL1, and with this CTRL1,
Based on the PA0, PA1, and PA2 signals, it is determined which encoder the INT signal is from, and the calculation unit ALU calculates the difference between the previously captured value and the motor speed.Furthermore, based on this speed, the
The ALU calculates the energization time data and duty, and controls the motor rotation speed. The procedure for controlling the rotational speed of the motor is shown in the flowchart of FIG. 6, and the procedure for interrupt processing using the interrupt signal ITN is shown in the flowchart of FIG. Moreover, the procedure of speed calculation is shown in FIG. As shown in Fig. 6, first it is determined whether or not to start the A motor M _A , and if it is not to be started, the control shifts to the B motor M _B. If it is to be started, then the A motor M B is controlled.
It is determined whether the speed measurement update flag and the flag indicating whether duty calculation has not been performed for the speed measured by M _A are set. If this speed measurement update flag is not set, control of B motor M _B is started. If this speed measurement update flag is set, the speed is calculated according to the procedure shown in Fig. 8, and based on the value. Calculate energization time data and duty. During this duty calculation, the speed measurement update flag is reset. The data on the energization time and duty of A motor M _A calculated as above are output to the DRIVA, and
Rotate M _A. Similarly, speed calculation of B motor M _B , duty calculation, speed calculation of C motor M _C , and duty calculation are performed in sequence. A motor
The speed calculation of M _A is shown in Figure 8.
This is done by subtracting the value AM1 of CNTR1 taken into the previous CTRL1 from the value AM of CNTR1 taken into CTRL1. Similarly, when calculating the speed of B and C motors M _B and M _C , use the current value of CNTR1.
The previous CNTR1 value BM1 from BM and the current value
From CNTR1 value CM to previous CNTR1 value CM1
This is done by subtracting each. On the other hand, in the interrupt processing shown in FIG. 7, multiple interrupts are first enabled to prepare for overlapping interrupt signals. That is,
It is possible to process even if the rising edges of φ _A , φ _B , and φ _C occur almost simultaneously.

Next, set the free running counter to CTRL1.
The value of CNTR1 is taken in, and then it is determined whether the interrupt is due to _φA , that is, it is determined whether the PAO signal is set, and if it is set, it is processed as an interrupt due to _φA . Next, output the reset pulse RA to the FFA, and
Reset the PAO signal. Then, CTRL1
The current value AM taken in is set as the previous value AM1, and the newly imported value of CNTR1 is set as the current value AM. Next, the speed measurement update flag of MA is set, and the process moves on to determining whether or not the interruption is due to _φB .
Thereafter, interrupts caused by φ _B and interrupts caused by φ _C are processed in the same manner. Furthermore, if the interrupt is not caused by φ _A , the process immediately moves on to determining whether the interrupt is caused by φ _B or not. The case of φ _B and φ _C is also the same as the case of φ _A.

By performing speed measurement, speed calculation, and duty calculation in the manner described above, highly accurate control can be performed without causing any time loss in speed measurement.

〔Effect of the invention〕

As described above, in the present invention, the control device includes a counter for measuring the period of the output signal of the rotation detector, takes in the measured value of this counter, performs predetermined processing, and generates and outputs the rotation speed control signal. a control unit;
It is provided with an arithmetic unit that performs arithmetic operations to create this rotation speed control signal, the counter is a free running counter, and a storage means is provided for temporarily storing the signals generated from each of the rotation detectors. create one interrupt signal by ORing each signal from the above, input this interrupt signal to the control device, and read the count value of the counter at the time this interrupt signal is input to the control section. Based on the contents of the storage means in which the signals from the rotation detectors are stored in advance, the control unit determines which rotation detector the signal is from, and the period of the signal obtained from each rotation detector is determined by the count value. Since the speed measurement of the DC motors is performed in parallel by measuring the amount of change in There is an effect that it can be done.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a conventional example, Fig. 2 is a diagram showing a method of measuring rotational speed in a conventional example, Fig. 3 is a detailed explanatory diagram for measuring rotational speed in a conventional example, and Fig. 4 is an apparatus according to an embodiment of the present invention. 5 is a diagram explaining the signals in the device of FIG. 4, FIG. 6 is a flowchart showing the procedure for controlling the motor rotation speed of the present invention, and FIG. 7 is a diagram showing the procedure for interrupt processing. Flowchart FIG. 8 is a flowchart showing the procedure of speed calculation. M _A ... Motor A, M _B ... Motor B, M _C
...Motor C, E _A ...Encoder A, E _B ...
Encoder B, E _C ... Encoder C, Q _A ... Transistor A, Q _B ... Transistor B, Q _C ...
Transistor C, DRIVA...driver A,
DRIVB...Drive device B, DRIVC...Drive device C, DS...Data selector, MPU, MPU1
...Overall control device, CTRL, CTRL1...control unit, CNTR...counter, ALU...calculation unit,
CNTRL1...Free running counter, CK
...Oscillation section, X...Crystal.

Claims (1)

[Claims] 1. A plurality of DC motors, a rotation detector coupled to these DC motors and outputting a signal with a frequency corresponding to the rotation speed of each of the DC motors, and the DC motor for energizing the DC motors. For one motor, one set of drive circuit and the above-mentioned
A control device for multiple DC motors comprising one control device that provides signals for controlling the rotational speed of the DC motors to these drive circuits, and this control device has a control device for measuring the period of the output signal of the rotation detector. counter, import the measured value of this counter,
A control unit that performs predetermined processing to create and output the rotation speed control signal, and a calculation unit that performs calculations to create the rotation speed control signal, the counter is a free running counter, and each of the above A storage means is provided for temporarily storing signals generated from the rotation detectors, and one interrupt signal is created by ORing the respective signals from these rotation detectors, and this interrupt signal is inputted to the control device. Then, the count value of the counter when this interrupt signal is input is read to the control unit, and according to the contents of the storage means in which the signal from the rotation detector is stored in advance,
The control unit determines which rotation detector the signal comes from,
A plurality of DC motors, characterized in that the control device is configured to measure the speed of the DC motors in parallel by measuring the period of the signal of each rotation detector by the amount of change in the count value. Base control device.