JPS61106081A - Speed controller of dc motor - Google Patents

Abstract

PURPOSE:To obtain a controller having a high accuracy by setting the period of the edge of a timing signal and a set value to device ON and OFF control signals. CONSTITUTION:The output 107 of a frequency generator 102 mounted on the shaft of a motor 101 is converted by a waveform shaper 108 into a timing signal 109. A differentiator 110 generates a one side edge detection pulse 111 at every rising edge of the signal 109, and a monostable multivibrator 112 inputs the pulse 111 to generates a reference pulse 113 of the set value T of a pulse width. A D-flip-flop 114 outputs to a motor drive circuit 116 L level when the period of the signal 109 is shorter than the set value T and H level when longer. Thus, an accurate controller can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a speed control device for a DC motor [Prior Art] Various methods have been devised as methods for controlling the speed of a motor. A typical example thereof is a PLL control method, for example. This is intended to compare the phases of a reference signal and a timing pulse with a frequency proportional to the motor rotational speed, and to control the rotational speed to a constant level using a controller according to the phase difference. Generally, encoders are used to obtain these timing pulses, but in order to ensure the stability and coordination of the control system, the number of output pulses per revolution must be increased, which increases costs. There were drawbacks.

[Problem that the invention seeks to solve]

In view of the above drawbacks, the present invention has a simple configuration even if a speed sensor with a relatively small number of output pulses per rotation is used.
The purpose is to provide a highly accurate control device.

[Means for solving problems]

In order to achieve this objective, the present invention compares the period of the timing pulse with a reference setting period every predetermined edge section of the timing pulse, and outputs a control signal that energizes the motor if it is longer than the reference setting value, and de-energizes the motor if it is shorter than the reference setting value. It has the characteristic that it is determined for the next edge interval.

〔Example〕

Hereinafter, embodiments of the present invention will be described using FIGS. 1 to 7.

A first embodiment of the present invention will be described using FIGS. 1 and 2. FIG. 1 shows the configuration of the speed control device, and FIG. 2 shows its timing chart. 100 is a carriage drive unit of a serial printer, and a recording head 104 is connected to a motor 101.
is driven by a gear train 103 and a bell) 105. Reference numeral 102 denotes a 7 requency generator (alternating current generator) attached to the shaft of the motor 101, which generates a frequency signal 107 with a frequency proportional to the rotational speed. Frequency signal 107 is supplied to waveform shaping circuit 108 . A waveform shaping circuit 10 generates a timing signal 109 by shaping the frequency signal 107. A differentiation circuit 110 differentiates the timing signal 109 and generates a single edge detection pulse 111 for each rising edge. Single edge detection pulse 1
11 is a monostable multipipulator 112 (hereinafter referred to as monomulti) and a D7 rib 70 tube 114 (
(hereinafter referred to as D-IFF). mono multi 11
2 is triggered by the falling edge of the single edge detection pulse 111, and generates a reference pulse 115 having a pulse width of a set value T. Note that the monomulti 112 is triggerable, and when the period of the timing signal 109 is shorter than the set value, such as +1 outside the interval, the reference pulse 115 does not go to the LOW level.

D-? IF114 has a reference pulse 113 of 1 at the D input terminal.
A single edge detection pulse 111 is supplied to the clock input terminal, and a reference pulse 115 is latched every time the single edge detection pulse 111 rises, and this is output as a control signal 115. The control signal 115 is input to the Tanabata drive circuit 116. The motor drive circuit 116 is configured so that the control signal 115 is H.
A drive signal 117 is supplied to the motor 101 that indicates energization if it is at the 1gh level, and is not energized if it is at the r or ow level.In addition, in the set value, the number of revolutions of the motor to be controlled is converted into the period of the timing signal 109. value.

In this embodiment, the operation of latching the reference pulse 113 to the D-Fll'i 14 every time the single edge detection pulse 111 falls is a function of comparing whether the period of the timing signal 109 is longer or shorter than the set value T. have. (However, the pulse width te of the single edge detection pulse 111 is set to a value as small as possible within the range in which the monomulti 108 can be triggered.) As a result, the timing signal 10
If the period of 9 is longer than the set value, the control signal 116 becomes H1gh level in the next section outside +1, and the motor 101
When the period of the timing signal 109 is shorter than the set value as in the section s+1, the next section s+1 is energized.
At step 2, power to the motor 101 is cut off.

As explained above, in this embodiment, by determining the control signal for each section of the timing signal, even if a speed sensor with a small number of output pulses per rotation is used, the period of each section of the timing signal can be maintained at the set value. It has the effect of being able to be controlled to match.

A second embodiment of the present invention will be described using FIGS. 5 and 4. FIG. 3 shows the configuration of the control device, and FIG. 4 shows a timing chart. 510 is a differentiating circuit which differentiates the timing signal 109 and generates an edge detection pulse 51 for each edge.
Generates 1. D・IF at the rising edge of this edge detection pulse 311? 114 latches the reference pulse 113 and outputs it as a control signal 115.

Note that the set value T is a value obtained by converting the rotational speed of the motor to be controlled into a half period of the timing signal 109.

In this embodiment, the control signal is determined by comparing each edge of the timing signal with a set value. This corresponds to doubling the number of speed detections during one rotation of the motor compared to the first embodiment, and has the effect of realizing a control device with even higher control accuracy.

A third embodiment of the present invention will be described with reference to FIGS. 5 to 7. FIG. 5 is a configuration diagram of the control device.

In the figure, 501 is a CPU that controls the present embodiment;
2 is a ROM that stores a control program, and 505 is a RAM that secures areas such as flags and registers required by the control program. 504 and 505 are bidirectional peripheral interface adapters (hereinafter referred to as P-A). P engineering A304 has CPU and waveform shaping circuit 10
The P engineering A305 has an interface with c'pv and the motor drive circuit 116.

506 is a timer, and C! Command tree i from PU
6o 1 (6th fJ(b)) starts counting at the set value, and outputs a timer signal (Fig. 6 (C)) that becomes H1gh when in the counting state and LOW when counting ends.
Send to H. The set value is a value obtained by converting the rotational speed of the motor to be controlled into a half cycle of the timing signal 109.

The speed control performed with the above configuration will be explained using the timing chart shown in FIG. 6 and the flow chart shown in FIG. 7. In FIG. 6, (α) is a timing pulse, (b) is a command trigger force, and (C) is a timer signal.

(d) is a control signal, which energizes the motor when it is at H1gh level, and de-energizes when it is at LOW level. Figure 7
In step 701, first, the control signals are )Ii,
The motor is energized and started at the gh level. In step 702, it is determined whether a certain period of time t5tart has elapsed. The value of t5tart is the time required for the motor speed to reach 60% to 70% of the rotational speed to be controlled, thereby ensuring reliable startup. In step 703, occurrence of an edge in the timing signal is determined. Repeat this step until an edge occurs. When an edge occurs, the process proceeds to step 704, where the CPU sends a command trigger to the timer, and the timer starts counting the set value T. In step 705, it is determined whether an edge of the timing signal occurs. Repeat this step until edges occur. If an edge occurs, step 706
Then, it is determined whether the timer has finished counting the set value T or not. Here, it is assumed that the counting has ended, and the process advances to step 707. Here, the CPU again sends a command trigger to the timer, and the timer starts counting the set value T. In step 708, the control signal is set to H1.
The signal is sent to the drive circuit as the gh level, and the motor is energized. If the timer has not expired in step 706, the process advances to step 709. Here, the CPU sends a command trigger to the timer, and the timer resets the previous count and starts counting the set value T again. In step 710, the control signal is set to LOW level, and power to the drive circuit is turned off. In step 711, it is determined whether or not to continue the control, and if so, step 7
The process returns to step 05 and waits for the edge of the timing signal to occur again. The above is the control procedure.

In steps 705 and 706, whether the period of each edge section is longer or shorter than a set value is measured by determining whether or not the timer has finished counting for each edge of the timing signal. This results in
If the period of the edge section is longer than the set value, as in section 5, the motor is energized in the next section n+1, and if the period of the edge section is shorter than the set value, as in section 5+1, the motor is energized in the next section s+2. (turn off the power to the motor),
The period of each edge section is controlled to match the set value.

Generally, the printing operation sequence of a printer is programmed and controlled by a micro combinator. Since this embodiment can be easily programmed and the processing time is short, it can be incorporated into the print operation sequence program as a speed control routine. Therefore, the first and second
The external connection for speed control as in the embodiment does not require any circuitry, and has the advantage that an inexpensive speed control device can be realized.

〔Effect of the invention〕

As described above, according to the present invention, the cycle of the predetermined edge section and the set value are compared for each predetermined edge of the timing signal, and the ON operation is performed accordingly.

By determining the OFF control signal, even if a speed sensor with a small number of output pulses per revolution is used, it is possible to realize a highly accurate control device that is easy to construct. The third embodiment is particularly effective, and the cost of the printer can be reduced by incorporating the speed control program into the print operation sequence program.

[Brief explanation of the drawing]

FIG. 1 is an h'q diagram of a control device for explaining a first embodiment of the present invention, and FIG. 2 is a timing chart for explaining the first embodiment. FIG. 6 is a configuration diagram of a control device for explaining a second embodiment of the present invention, and FIG. 4 is a timing chart for explaining the second embodiment. FIG. 5 is a configuration diagram of a control device for explaining the third embodiment of the present invention, FIG. 6 is a timing chart for explaining the third embodiment, and No. 75A is a diagram for explaining the fifth embodiment. This is a 70-chart for Written amendment to the above procedure (spontaneous) Patent Original No. 224739 of 1982 2, Title of invention: DC motor speed control device 3, Relationship with the person making the amendment Case: Applicant Representative Director Tsuneya Nakamura 4 Agent Address: 104 Mogami Patent Office 6, Matabe Seiko Co., Ltd., 2-6-21, Kyobashi, Chuo-ku, Tokyo Subject of amendment Amended procedure (voluntary) 1. In the specification, the phrase "triggerable" in the fourth line from the bottom of page 4 is corrected to "retriggerable". λ Same, page 8, line 11 from the top, “Timing no Kurusu”
It's more than just correcting it as a "timing signal"

Claims (1)

[Scope of Claims] In a recording device in which a carriage loaded with a print head is driven by a DC motor and travels in the direction of the printing column to perform printing, the timing of generating a timing pulse with a frequency proportional to the rotational speed of the DC motor. a pulse generating means, and when the predetermined edge sections of the timing pulse are defined as edge section 1, edge section 2, to edge section n in the order of occurrence,
comprising a time interval comparing means for comparing the time interval of the edge section n with a reference setting time; if the time interval of the edge section 1 is longer than the reference setting time, energizing the motor in the edge section n+1; A speed control device for a DC motor, characterized in that when the time interval of the edge section n is shorter than a reference setting time, the rotational speed of the motor is controlled by a control signal that turns off electricity to the motor in the edge section n+1.