JPS6255161B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positioning control device for a device that moves movable members relative to each other, and more particularly to a positioning control device for a carriage feeding mechanism and a character selection mechanism in an impact-type serial printer or the like.

In such an impact type serial printer device, a carriage as a movable member is equipped with a rotary wheel for printing, a motor for driving the wheel, a hammer for printing, and a ribbon cartridge. The carriage is moved parallel to the recording medium and is stopped and positioned at the printing position. Further, the rotary printing wheel mounted on the carriage is rotated by the wheel driving motor, and the printed characters selected from among the plurality of printed characters carried on the rotary printing wheel are brought close to the recording medium. It is positioned so that it remains stationary at the printing position.

In a device that drives a movable member such as a carriage of the serial printer to a target position by a motor or the like, a signal corresponding to the positional error to the target is applied to the motor to set the positional error to zero. The motor is moved to move the parts.

This type of control includes a speed control mode in which the motor speed follows a variable reference speed that accommodates position errors until a certain distance before the target position, as described in U.S. Pat. No. 3,954,163; The motor is moved to the target position and positioned using a combination of two control modes: a position control mode in which the position is controlled from a certain distance before the target position based on the position error itself. In this case, in the speed control mode, the motor speed is controlled by adding or subtracting the analog speed feedback signal corresponding to the motor rotation speed to the analog reference speed signal, and in the position control mode, the analog position error signal is Motor position control is performed by adding and subtracting analog damping signals corresponding to the motor rotation speed. However, in such an analog control system, there is essentially a need for level adjustment for analog circuit offset and drift, which increases adjustment time and inspection time on the production line, increases production costs, and greatly impedes productivity. do.
Further, maintenance to adjust for environmental changes and aging of the offset and drift described above requires a large amount of man-hours, leading to an increase in maintenance costs. Furthermore, in general, analog circuits currently have many drawbacks, such as the difficulty of achieving high integration, the increased circuit mounting space, and the complexity of production management as the number of components increases.

Therefore, in order to solve the above-mentioned drawbacks, Japanese Patent Application No. 17810 of 1973 filed by the same applicant as the present application,
No. 70074, No. 137495 and Patent Application No. 39168 of 1972
In this specification, a digital positioning control device is proposed in which the control system is digitalized to eliminate the drawbacks of the analog control system.

However, in a control device constructed using such digital signal processing, a photo encoder or the like is used as a position detector that generates a position signal, and in this case, in order to ensure the necessary printing accuracy, that is, positioning accuracy, A drawback has arisen in that the number of incremental output pulses of the detector, ie the photo encoder, must necessarily be very large, which increases the cost of the position detector. For this reason, in order to solve the above-mentioned drawbacks, we have further proposed patent application No. 52694 filed in 1972 by the same applicant as the present application.
In this specification, an incremental type position detector is proposed that uses a small, lightweight, and inexpensive absolute type position detector and has a simple circuit and high resolution, that is, a very large number of incremental position pulses. However, in this case as well, as the resolution, that is, the number of position pulses, increases, the output level of the position detector generally decreases, and the S/N ratio tends to deteriorate. The drawback remained that it was prone to malfunctions.

An object of the present invention is to eliminate the above-mentioned drawbacks in a digital positioning control device using a low-cost, high-resolution incremental position detector as proposed in the above-mentioned Japanese Patent Application No. 52694/1982, and to provide a position error signal. Another object of the present invention is to provide a new digital positioning control device that can perform stable positioning against noise and the like by using an absolute position signal that is proportional to the absolute position of the motor.

According to the present invention, in a positioning control device that receives a movement information signal from the outside indicating the movement distance and movement direction of a movable member from its current position to a target position and positions the movable member to the target position, a plurality of signals having different frequencies are used. A clock generation circuit that outputs a clock signal and a clock signal received from one of the clock generation circuits have equal amplitudes and are located at each other.
a driving means that outputs a pair of sinusoidal drive signals that differ by 90 degrees; and a digital position detection signal that receives the pair of drive signals and has a phase difference between the pair of drive signals that is proportional to the amount of movement of the movable member. a position detection means mechanically connected to the movable member that outputs the
When the digital position detection signal and one clock signal from the clock generation circuit are received, the phase difference between the digital position signal corresponding to the movement of the movable member and a signal obtained by dividing the frequency of the clock signal is 1 of the clock signal. an incremental position signal generation circuit that outputs a positive direction pulse or a negative direction pulse depending on the direction of the phase shift, that is, the moving direction of the movable member every time the period unit changes; A clock signal is received, and the phase difference between the digital position signal corresponding to the movement of the movable member and a signal obtained by dividing the frequency of the clock signal is counted using the clock signal, and one of the signals obtained by dividing the frequency of the digital position signal is calculated using the clock signal. an absolute position signal generating circuit that outputs the counting result as a digital absolute position signal every cycle, and the moving speed of the movable member is controlled by the incremental position signal from the current position to a certain distance before the target position. The digital positioning control device is characterized in that the movable member is controlled to be positioned at the target position from a certain distance before the target position to the target position based on the digital absolute position signal. .

Next, the present invention will be explained in detail with reference to the drawings.

Note that in the drawings below, signal lines and signals may be expressed using the same term without distinction.

FIG. 1 is a block diagram showing an embodiment of the present invention.
b is the positioning control circuit 1 by the set signal 4a.
and their signals 4c and 4b
The motor 3 is controlled accordingly. At this time, the rotational movement of the motor 3 is detected by the position detector 2 which receives sinusoidal signals whose phases differ by 90 degrees from each other via the signal lines 1a, 1b, 1c, and 1d. and 2b. The rotational motion of the motor 3 is transmitted to the carriage 8 via the drive pulley 5, wire 7, and pulley 6, and drives the carriage 8 to a desired position. After the carriage 8 is thus positioned at the desired position, the positioning control circuit 1 returns a ready signal 1e to the external control device 4 indicating that it can accept the next movement command.

FIG. 2 is a block diagram showing the positioning control circuit 1 of FIG. 1 in detail. In the speed control mode, a moving distance signal 4c and a direction designation signal 4b corresponding to the target position are input from the external control device 4 to the control circuit 100, and the counters and registers therein are initially set by the set signal 4a. . Here, if the direction designation signal 4b is positive,
A positive reference speed signal corresponding to the position error is outputted from the control circuit 100 to the signal line 100c, and a mode signal indicating the speed control mode is outputted to the signal line 100a. At this time, the integration circuit 150 prohibits the integration operation of the input signal, that is, the reference speed signal 100c, by a stop signal 100b that is output after a certain period of time after entering the position control mode, which will be described later, and simultaneously starts the internal integrator. It is reset and an integral signal of 0 is output to the signal line 150a.

Further, the position correction circuit 650 also outputs the input signal, that is, the reference speed signal 100c, to the signal line 650a as it is based on the stop signal 100b and the mode signal 100a indicating the speed control mode. Therefore, the reference speed signal is input to a PWM (pulse width modulation) circuit 250 via an arithmetic circuit 200. Said PWM circuit 2
At 50, the output signal 200 of the arithmetic circuit 200 is
a and a PWM clock 400a from a clock generation circuit 400, the output signal 200a is pulse width modulated, and the output is outputted to signal lines 250a and 250b. These signals drive the motor 3 in the forward direction via the motor drive circuit 300. When the motor 3 starts moving in the forward direction, the position detector mechanically connected to the motor 3 receives first and second detection drive signals of sinusoids, which are 90° out of phase with each other, from the detector drive circuit 450. A position detection signal is received by signal lines 1a, 1b and 1f, 1g, and outputs to signal lines 2a, 2b a position detection signal having a phase difference proportional to the position of the motor 3 with respect to the detector drive signal. Amplification circuit 50
0, the position detection signal is amplified, converted into a digital position detection signal, and output to the signal line 500a. The phase difference of the digital position detection signal 500a, which is proportional to the position of the motor 3, is detected in the incremental pulse generation circuit 550 by the first and second reference clocks 400b and 400c from the clock generation circuit 400. A positive direction pulse is given to the signal line 550a every time the rotation is made by a certain angle. In response to this positive direction pulse and the speed sample clock 400f from the clock generation circuit 400, the speed detection circuit 350 detects the speed of the motor and outputs a speed signal to the signal line 350a. Therefore, the arithmetic circuit 200
In this case, a speed feedback can be provided by subtracting the speed signal from the reference speed signal, and the speed of the motor 3 can be made to follow the reference speed corresponding to the reference speed signal.

On the other hand, the positive direction pulse is input to the control circuit 100 via the signal line 550a, and the movement distance signal that has been initially set is subtracted from it.
As a result, the reference speed signal corresponding to the position error signal also decreases along a preset curve.

As described above, due to the speed feedback by the speed detection circuit 350 and the calculation circuit 200,
The speed of the motor 3 can be controlled so as to follow a reference speed that decreases along a preset curve corresponding to the position error. In this way, when the motor 3 reaches a certain distance before the target position,
The control circuit 100 controls the motor 3 detected by the position signal generation circuit 600 from the digital position detection signal 500 and the reference clock 400b.
A digital absolute position signal proportional to the absolute position of (details will be explained later)
In response, a position error signal up to the target position is output to the signal line 100c, and the motor 3 is driven to the target position by this position error signal. At this time, a mode signal indicating the position control mode is output to the signal line 100a, but a stop signal is output to the signal line 100b because a predetermined period of time has not elapsed since switching to the position control mode. Not done. Therefore, in the integration circuit 150, the integration operation is prohibited as in the speed control mode, and the integration output becomes 0 and is output to the signal line 150a. Also, at this time, speed feedback is performed by the speed detection circuit 350 and the arithmetic circuit 200 as in the speed control mode, but in the position control mode the speed signal 350a acts as damping.

In this way, the incremental position signal generated every time the motor rotates by a certain angle is used for speed detection, and the absolute position signal proportional to the absolute position of the motor is used as the position error signal in position control mode. , compared to the method of using an incremental position signal as a position error signal described in the above-mentioned Japanese Patent Application No. 17810 of 1973, No. 70074, No. 137495 of 1973, and No. 39168 of 1974. , positioning point deviations that tend to occur due to induction noise, etc. are eliminated, and positioning is always performed at an accurate positioning point.

The motor 3 is moved by the input target movement distance in this way and positioned at the target position, and when a predetermined period of time has elapsed, a stop signal is output to the signal line 100b, and the integration circuit 15
0 is an integral clock 400e from the clock generation circuit 400 in response to the input signal, that is, the position error signal 100c upon receiving the stop signal 100b.
Integrate. That is, the position error signal 100
When c deviates from the target position in the positive direction by more than a certain value, it is integrated in the positive direction, and when it deviates in the negative direction by more than a certain value, it is integrated in the negative direction, and the integrated signal is used as a signal. Output on line 150a.
On the other hand, the position correction circuit 650 receives the position control mode display mode signal and the stop signal, and
During the predetermined time after switching to the position control mode, a position error signal that does not include a dead zone is output as described later, and after the predetermined time has elapsed, a position error signal that includes a certain dead zone is output. At this time, if the non-integration area of the position error signal in the integration circuit 150 is made equal to the dead zone area of the position error signal output from the position correction circuit 650, the position of the motor 3 will deviate from the dead zone in the integration circuit 150. Then we will perform the integration. In this manner, the arithmetic circuit 200 adds the integral signal 150a and the position error signal 650a including the dead zone, and further calculates the speed signal 350 from the addition result.
a is subtracted, output to the signal line 200a, and the above
PWM circuit 250 and the motor drive circuit 30
0 to drive the motor 3.

By doing this, the above-mentioned patent application filed in 1972
As described in detail in No. 137495 and No. 39168 of 1954, positioning to the target position can be performed more accurately for a certain period of time after switching to the position control mode, and furthermore, after the elapse of the certain period of time, It is possible to suppress so-called limit cycles, which are often a problem in positioning servo systems including digital position detection, and achieve accurate positioning control to the target position. In the above description, an example was shown in which the motor 3 is driven in the positive direction, but when driving in the negative direction, a negative direction signal is output as the direction designation signal 4b, and the direction pulse generation circuit 550 outputs a negative direction signal. By outputting a negative direction pulse to the signal line 550b, positioning to the target position is performed as in the case of the positive direction described above.

3a and 3b are side views and circuit diagrams showing the position detector 2 and motor 3 of FIGS. 1 and 2 in detail.

In the figure, a fixed part 30 of the electromagnetic induction sensing element is shown.
is fixed to the frame of the motor 3, and the rotating part 31 of the electromagnetic induction detection element is connected to the rotating shaft 3 of the motor 3.
2, and performs the same rotational movement as the rotating shaft 32 of the motor 3. As shown in Figure b, the fixed part 30 has a first primary coil 30a and a second primary coil 30b, and the first and second primary coils have the same period in terms of position. , the phases are relatively shifted by 90°. Further, the rotating section 31 has one secondary coil 31a, and the first
An induction signal is generated by electromagnetic induction from the second primary coil. Therefore, the period of the induction signal is the same as that of the first and second primary coils 30a and 30b. In addition, in the same figure b, the first and second primary coils 30a and 3
Further, although the secondary coils 31a are illustrated as being arranged in a straight line, in a rotary type detector, they are arranged in an annular arrangement coaxially with respect to the rotating shaft 32 of the motor 3. Further, if the motor is a linear motor, the motors are arranged in a linear arrangement that coincides with the moving direction of the linear motor, as shown in FIG.

Here, the first primary coil 3 of the fixed part 30
When sinusoidal first and second detector drive signals with a phase shift of 90° and equal amplitude are applied to 0b, the first primary coil 30a and the second primary coil 30a
Due to the positional relationship between the secondary coil 30b and the secondary coil 31a of the rotating section 31, as is well known to those skilled in the art, the secondary coil 31a has a constant amplitude and a period that is equal to that of the first and second detectors. Phase modulation that is the same as that of the drive signal, and in which the phase difference between the first and second detector drive signals is proportional to the rotation angle of the rotating section 31, that is, the rotation angle of the rotation shaft 32 of the motor 3. A signal is induced. and,
The phase modulation signal is output as a position detection signal to the signal lines 2a and 2b by the primary coil 33 and secondary coil 34, which function as a rotary transformer. As described above, the rotation angle of the motor 3, that is,
A position detection signal having a phase difference proportional to the rotational position (amount of movement) can be output to the signal lines 2a and 2b. Note that as an example of the electromagnetic induction type detection element, inductosin shown in US Pat. No. 3,191,010 can be used.

FIG. 4 is a block diagram showing the amplifier circuit 500 of FIG. 2 in detail. The position detection signal output from the position detector 2 is input to the first band pass filter 501 via the signal lines 2a and 2b,
Further, a first differential amplifier 502, a second bandpass filter 503, a second differential amplifier 504, a third
After being sufficiently amplified by the signal component through the bandpass filter 505, it is input to the comparator 506, and is output to the signal line 500a as a digital position detection signal. In this way, the position detection signals 2a, 2 having a phase difference proportional to the rotational position of the motor 3 are
b is converted into a digital position detection signal 500a, but since the position detection signal and the digital position detection signal have the same phase and period, the digital position detection signal also becomes a signal having a phase difference proportional to the rotational position of the motor 3.

FIG. 5 is a circuit diagram showing the detector drive circuit 450 of FIG. 2 in detail. First reference clock 400 output from clock generation circuit 400 in FIG.
b is input to the counter 451 and the counter 451
count up. The most significant bit (hereinafter referred to as MSB) of the counter 451 is the first and second exclusive OR (hereinafter referred to as EX/OR) 4
52 and 453, and the bit below the MSB of counter 451 is the first bit.
The next lower bit is input to the other input of the EX/OR, and the bit one bit lower is input to the other input of the second EX/OR. and the first and second
The output of EX/OR is transistor 457 and 45
8 bases respectively, and the first
Resistors 461 and 462 are connected to the collectors of second transistors 457 and 458, respectively, and the other terminals of the two resistors are connected together to signal line 1a. Further, a +5V power supply is connected to the signal line 1b, and a capacitor 470 is connected to the signal lines 1a and 1b. Here, the transistors 457, 4
When the counter 451 is counted up by the first reference clock 400b, the transistor 457 is counted up by the first reference clock 400b. ,458 is・→・b→a・→
Turning on and off is repeated in the order of a・b→a・b→a・→・b→・→. At this time, if the value of the resistor 461 is selected to be approximately 1/3 of that of the resistor 462, the first detector drive current flowing to the first primary coil of the position detector 2 due to the high-pass effect of the capacitor 470. The current is approximately sinusoidal.

On the other hand, the MSB signal of the up counter becomes a signal of the same period delayed by 90 degrees by the flip-flop 465, and is input to one input of the third and fourth EX/OR gates. Furthermore, the signal one level below the MSB of the up counter is transferred to an inverter 456.
is inverted and input to the other input of the third EX/OR gate. In this way, the sinusoidal second detector drive current flows through the signal lines 1f and 1g as in the above case, but the first and second detector drive currents flow through the flip-flop 465.
Then, an inverter 456 generates a signal whose phase is shifted by 90 degrees. As described above, the position detector of FIG. 2 is driven by two sinusoidal detector drive currents that have the same period and amplitude as the MSB of the counter 451, and are 90° out of phase with each other. be done.

FIG. 6 is a block diagram schematically showing the operation of the incremental pulse generation circuit 550 of FIG. 2. The first reference clock 400b output from the clock generation circuit 400 is output from the reference counter 572.
count up. At this time, if the number of bits of the reference counter 572 is made equal to that of the up counter 451 shown in FIG. That is, it becomes equal to the period of the first and second detector drive currents.

On the other hand, the digital position detection signal 500a is phase-modulated depending on the rotational position of the motor 3.
is input to a phase comparator 570 and compared in phase with the MSB signal of the reference counter 572. When the phase of the digital position detection signal 500a deviates by a certain value or more, a phase lead signal,
Alternatively, the phase-delayed signals are output to the signal lines 570a and 570b, respectively, and the pulse generator 571
Enter.

The pulse generator 571 receives the phase lead signal or the phase lag signal, and outputs a positive direction pulse to the signal line 550a in the case of a phase lead signal, and counts up the reference counter 572, and in the case of a phase lag signal, outputs a positive direction pulse to the signal line 550a. Then, a negative direction pulse is output to the signal line 550b, and the reference counter 572 is counted down. As described above, when the motor 3 is stationary, the phase of the MSB of the reference counter 572 always matches that of the digital position detection signal, and when the motor 3 rotates, it moves in that direction every fixed rotation angle. Therefore, a positive direction pulse or a negative direction pulse can be output.

FIG. 7 is a block diagram showing the incremental pulse generation circuit 550 of FIG. 2 in more detail.

Figures 8a, b, and c are waveform diagrams showing examples of signals from each part in Figure 7. Figure 8a is when the motor 3 is stationary, and Figure 8b is when the motor 3 is rotating in the forward direction. If so, c indicates that the motor 3 is rotating in the negative direction. FIG. 7 will be explained below with reference to FIG. 8b.

The first reference clock 400b is an AND gate 5
63 is logically ORed and a reference counter 564 is counted up. Here, when the motor 3 rotates in the positive direction, the MSB of the reference counter 564
From the signal 582, the digital position detection signal 500
The phase of a is advanced. The digital position detection signal 500a is sampled by the second reference clock 400c in flip-flops 551 and 552, and the AND gate 555 outputs a first sample signal 586, and the AND gate 556 outputs a second sample signal 585. . On the other hand, MSB signal 582 of reference counter 564 is sampled by second reference clock 400c in flip-flops 553 and 554, and gate signal 584 is output from AND gate 562. Therefore, AND gate 557 and NAND gate 55
9, the first sample signal 586 is ANDed with the gate signal 584 and the inverted signal of the second reference clock, and a positive direction pulse is output on the signal line 550a. At this time, the positive direction pulse passes through an AND gate 563 and causes the reference counter to count up one more time than the first reference clock. That is, the phase of the MSB signal 582 of the reference counter 564 is made equal to the digital position detection signal 500a. In this way, the state of the direction pulse generation circuit 550 is set to the eighth state.
The state shown in Figure a is reached, and neither positive nor negative direction pulses are output, but the motor 3
rotates in the positive direction, and the digital position detection signal 5
00a and the MSB signal 5 of the reference counter 564
When the phase difference with respect to 82 is a certain value, that is, when the second reference clock 400b advances by one cycle or more,
The state shown in FIG. 8b again occurs, and the positive direction pulse 55
0a is output. Conversely, when the motor 3 rotates in the negative direction and the phase difference lags behind the second reference clock 400c by one cycle or more, the state shown in FIG. 8c occurs and a negative direction pulse 550b is output.

As described in the above-mentioned Japanese Patent Application No. 52694 of 1982, the phase difference between the digital position detection signal and the MSB signal of the reference counter is determined by the advance of one cycle or more of the reference clock. ,
Alternatively, with respect to the rotation of the motor 3 that causes a delay, a positive direction pulse or a negative direction pulse is output depending on the direction.

In other words, one period of the digital position detection signal is interpolated with a short period of the reference clock, and as a result, the rotation angle corresponding to one pitch of the primary or secondary coil of the electromagnetic induction sensing element is Interpolation is performed using fine incremental positive direction pulses or negative direction pulses.

FIG. 9 is a block diagram showing the position signal generating circuit 600 of FIG. 2 in detail. In addition, FIGS. 10a, b, c, and d are waveforms and conceptual diagrams showing examples of signals of each part, and in the figures, a is the reference number 61 of d.
4, b represents the state of point 613 of d, and c represents the state of point 615 of d, respectively. FIG. 9 will be explained below with reference to FIG. 10.

The first reference clock 400b output from the clock generation circuit 400 in FIG.
, and the counter 601 is counted up. Here, if the number of bits of the counter 601 is equal to that of the counter 451 shown in FIG. (waveform 611 in FIG. 10), and the mutual phase difference is as described above, the motor 3
is proportional to the rotational position of Therefore, an EX/OR gate 602 outputs the MSB signal 610 of the counter 601 and the digital position detection signal 500a.
(waveform 611 in FIG. 10) is taken, and a gate signal 612 is output. In the NAND gate 605, the gate signal 612 and the first
The output is logically ANDed with the reference clock, and the output is counted up by a counter 603, and the output is input to a register 604. On the other hand, the MSB signal 610 of the counter 601 is transmitted to the register 604.
At the same time as input to the set input of the delay element 60
6 to the clear input of the counter 603. Therefore, a value proportional to the high level time of the gate signal 612, that is, an absolute value proportional to the absolute rotational position of the motor 3, is set in the register 604, and the signal line 600a
output as a digital position signal. 10th
FIG. d schematically shows the output of the register 604, that is, the digital position signal 600a, as an analog signal as a position signal 616. If 1/2 of the maximum and minimum values of the position signal 616, indicated by reference numeral 614 in the figure, is defined as zero, that is, the positioning point, then the area indicated by reference numeral 617, that is, ±1/2 pitch. The digital position signal 600a accurately represents the absolute rotational position of the motor 3 about the positioning point 614.

In this way, from the position signal generation circuit 600, the motor 3
A digital absolute position signal 600a indicating the absolute rotational position of the motor 3 is output, and in the position control mode, the motor 3 is positioned at a positioning point by this digital absolute position signal 600a. At this time, the problem of position offset due to noise that tends to occur when using incremental position signals is eliminated, and stable positioning is always achieved.

FIG. 11 is a block diagram showing the control circuit 100 of FIG. 2 in detail. In the speed control mode, a travel distance signal and a direction designation signal are initially set from the external control device 4 in FIG. At the same time as the reference speed signal 104b is output from the memory 104 given as an address, the mode switching flip-flop 105 is reset, and a mode signal indicating the speed control mode is sent to the signal line 1.
Output to 00a. In this way, the selector 106 selects the reference speed signal based on the mode signal and outputs it to the signal line 100c, and the mode signal is sent to the external control device 4 via the AND gate 107 as a ready signal indicating a busy state via the signal line 1e. At the same time, a stop signal indicating that it is not in a stopped state is outputted via an AND gate 110 via a signal line 100b. On the other hand, the output signal of the incremental pulse generation circuit 550 is inputted to the AND gate 103 via signal lines 550a and 550b, and the logical sum is essentially taken, and the output thereof is given to the countdown input of the counter 102. Here, when the motor 3 moves in the positive direction, the positive direction pulse causes the counter 102 to count down via the signal line 550a, and its output signal gradually decreases.
The output signal of No. 4, that is, the reference speed signal, also decreases. Furthermore, when the counter 102 counts down and its output signal becomes less than a preset value, the memory 104 outputs a mode switching signal 104a, sets the mode switching flip-flop 105, and transmits the mode signal indicating the position control mode to the signal line 100a. Output to. In this way, in the selector 106, the position signal generation circuit 6
The digital absolute position signal 600a indicating the absolute position of the motor 3 outputted from the signal line 100c is selected and outputted as a position error signal to the signal line 100c. Further, the ready signal 1e indicates a busy state for a certain period of time defined by a monostable multivibrator (hereinafter referred to as one shot) 108 after entering the position control mode. Further, stop signal 100b is also not output for a certain period of time defined by one shot 109. At this time, the digital position signal 600a is transmitted to the positioning point 614 within the area indicated by reference numeral 617 in FIG. 10d.
A point deviated by a certain value from , that is, indicates a position error, and the motor 3 is driven to the positioning point by the position error signal and positioned at the target position.

As described above, the output signal of the memory 104, that is, the reference speed signal, is used until a certain distance before the target position, and the output of the position signal generation circuit 600 is used from the certain distance before the target position, which is the absolute position of the motor 3. A digital absolute position signal indicating this is output as a position error signal to the signal line 100c.

After being positioned at the target position in this way, a ready signal 1e is output to the external control device after a certain period of time defined by the one shot 108, allowing the control circuit 100 to accept new data. Also, the stop signal 100b is also one shot 10.
It is output after a certain period of time specified in 9.

FIG. 12 is a block diagram showing the integration circuit 150 of FIG. 2 in detail. Further, FIG. 13 is a waveform diagram for explaining the operation of the integrating circuit 150 of FIG. 12 in an easy-to-understand manner. The integrating circuit 150 shown in FIG. 12 will be explained below with reference to FIG. 13.

Since the stop signal 100b is at a low level during the period specified by the one shot 109 after entering the speed control mode and the position control mode, the integral counter 157 is prohibited from counting up and counting down, and at the same time, the inverter 154
, and outputs 0 to the signal line 150a as an integral signal. Then, after a certain period of time after entering the position control mode, the stop signal 100b becomes high level, so the NAND gates 155 and 15
6, the gate is opened, and the inverter 154
As a result, the reset of the integral counter 157 is released. At this time, the digital position signal 100c is transmitted to the positive detector 152 and the negative detector 153.
and the ply detector 152 indicates that the position 160 of the motor 3 is a dead zone 1.
When it shifts to the positive side from 69, negative detector 1
53 detects when the position error 160 deviates from the dead zone to the minus side, and outputs a plus signal and a minus signal to NAND gates 155 and 156, respectively. Furthermore, the integral clock output from clock generator 400 in FIG.
6 respectively. Here, when the position 160 of the motor 3 deviates to the +1 region 172 due to an external force (caused by the wire system, motor brushes, etc.) indicated by the reference number 162 in FIG. A positive signal 166 is detected and an integral clock counts up an integral counter 157 via a NAND gate 155.
In this way, the outputs 167, 15 of the integral counter 157
0a gradually increases and integrates an integral value of 168, which is enough to counter the external force 162, and
As described in detail in the specification No. 137495 of 2013 and the specification No. 39168 of 1954, the motor 3 has a dead zone 169.
stationary position in the area of .

FIG. 14a is a block diagram showing the position correction circuit 650 of FIG. 2 in detail, and FIGS. 14b and 14c are operational conceptual diagrams for explaining the position correction circuit 650 in an easy-to-understand manner.

In the speed control mode, a reference speed signal is input to the selector 652 via the signal line 100c,
The reference speed signal is selected by the mode signal 100a and output to the signal line 650a. When entering the position control mode, the selector 652 selects the output of the memory 651, but for a certain period of time until the stop signal 100b is input, the memory 651 does not include a dead zone as shown in FIG. 14b. The memory 651 outputs a position correction signal, and when the stop signal 100b is input, the memory 651 outputs a position correction signal including a dead zone 653 as shown in FIG. 14c. By doing this, the position 160 of the motor 3 is positioned toward the boundary line 161 between +1 and -1 by the position correction signals 164 and 650a for a certain period of time shown by the arrow 170 in FIG. At this time, the motor 3 vibrates stably with a small amplitude around the boundary 161 between +1 and -1 as shown in FIG. 13, but this does not pose a problem in terms of positioning accuracy because the amplitude is small. When printing is completed at the time indicated by arrow 163 in FIG. 13, stop signal 10
By inputting 0b, the position correction signals 164, 650a including the dead zone 169 are output, and the motor 3 is positioned at rest in the dead zone 169 as described above.

FIG. 15 is a block diagram showing the speed detection circuit 350 of FIG. 2 in detail. Positive direction pulse 5 which is the output of the incremental pulse generation circuit 550
50a and negative direction pulse 550b are counter 3
51 count-up input and count-down input, respectively. The output of the counter 351 is input to a register 352, and the output is output to a signal line 350a as a speed signal.

On the other hand, the sample clock 400f of the clock generating circuit 400 is input to the set input of the register 352 and at the same time is input to the reset input of the counter 351 via the delay element 353.

If the motor 3 is now moving in the forward direction, the forward direction pulse 550a causes the counter 351 to count up. When the sample clock 400f is input, the current value of the counter 351 is first set in the register 352, and the counter 351 is reset by the sample clock slightly delayed by the delay element 353. In this way, a signal proportional to the number of positive direction pulses or negative direction pulses generated in a certain time width defined by the sample clock 400f, that is, the speed of the motor 3, can be output as a speed signal to the signal line 350a. .

FIG. 16 is a block diagram showing the arithmetic circuit 200 of FIG. 2 in detail. Mode signal is signal line 100
Memories 201, 207, 2 input via a
08 has the optimum gain in speed control mode
Optimum gains KP ₁ , KP ₂ , and KP ₃ in the position control mode are set in advance for KS ₁ , KS ₂ , and KS ₃ , respectively. In the speed control mode and the position control mode, the reference speed signal and position error signal are sent to the multiplier 2 through the signal line 650a, respectively.
In the speed control mode, the reference speed signal is _multiplied by KS, and in the position control mode, the position error signal is _multiplied by KP and input into the adder 203. Before the motor 3 is positioned at the target position, that is, before the stop signal is output, the integral signal 150a that is the output of the integrating circuit 150 is 0, so the adder 203 does not add it, and the reference speed signal or The positioning error signal is output as is and input to the subtracter 204. On the other hand, the speed signal that is the output of the speed detection circuit 350 is transmitted through the signal line 350.
It is input to the multiplier 206 via a, _multiplied by KS in the speed control mode, _multiplied by KP in the position control mode, and input into the subtracter 204. In the subtracter 204, the output of the multiplier 206, that is, the speed signal, is subtracted from the output of the adder 203, that is, the reference speed signal or the position error signal, and the result is input to the multiplier 205. In the multiplier 205, KS is multiplied by ₃ in the speed control mode, KP is multiplied by ₃ in the position control mode, and the signal line 20 is multiplied by 3.
A calculation signal is output to 0a. After the stop signal is output, the integral signal 150a is sent to the adder 20.
3, it is added to the position error signal _multiplied by KP. That is, the integral signal is added to the lower bits of the position error signal.

As described above, in the speed control mode, the speed signal is subtracted from the reference speed signal, and in the position control mode, the integral signal is added to the position error signal, and the speed signal is further output to the signal line 200a from which it is subtracted.

FIG. 17 is a block diagram showing the PWM circuit 250 of FIG. 2 in detail. The PWM clock 400a of the clock generating circuit 400 in FIG. 2 is input to the count up input of the counter 252 of the PWM circuit 250, and constantly counts up the counter 252. That is, the output of the counter 252 operates in a sawtooth waveform between the negative maximum value and the positive maximum value. The output of the counter 252 is input to the reference input B of the comparator 251, and the output 200a of the arithmetic circuit 200 is input to the signal input A.
is entered. And comparator 251
Then, the output of the counter 252 and the output of the arithmetic circuit 200 are compared in magnitude, and when the output of the arithmetic circuit 200 is larger than the output of the counter 252,
Positive output 251a is high level (logic “1”)
, and when it is small, the minus output 251b becomes high level. That is, during one cycle of the counter 252, the positive output 251a and the negative output 2
51b are alternately set to high level, and when the signal input 200a is a positive signal, the time for the positive output 251a to be at the high level is longer than the time for the negative output 251b to be at the high level in proportion to the level. In addition, conversely, the signal input 20
When 0a is a negative signal, the above is reversed,
When the signal input 200a is 0, the times at which the plus output 251a and the minus output 251b reach the high level are equal. As described above, a pulse width modulated output proportional to input signal 200a is provided to signal lines 251a and 251b.

FIG. 18 is a circuit diagram showing the motor drive circuit 300 of FIG. 2 in detail. If the motor 3 is demagnetized by excessive current, or if the carriage 8 shown in FIG. 1 has a predetermined acceleration limit, the current flowing through the motor 3 must be limited.

In FIG. 18, when the positive output 250a is at a high level, the negative output 250b is at a low level, and at this time, the positive output 250a is at a low level.
Transistor 303 via AND gate 301
and 304 are turned on (conducting). On the other hand, negative output 250b closes the gate of AND gate 302 and transistors 305, 306 and 307.
is off (non-conducting). As a result, a voltage approximately equal to the positive power supply voltage +ES is output to the signal line 1c as a motor drive output. Also, when the negative output 250b is at a high level, the positive output 250b
a is a low level, and contrary to the operation described above, a voltage approximately equal to the negative power supply voltage - ES is applied to the signal line 1c.
is output to. At this time, the PWM circuit 250
If the repetition frequency of the counter 252 is selected sufficiently higher than the cutoff frequency determined by the electric time constant of the motor 3, a current proportional to the output of the arithmetic circuit 200 flows due to the low-pass effect of the motor 3.

On the other hand, the current flowing through the motor 3 is detected by a current detection resistor 308 and input to comparators 309 and 310, respectively. When the current flowing through the motor 3 exceeds the positive current limit value, the comparator 309 compares it with a positive reference voltage 311 proportional to the positive limit current value, and the gate of the AND gate 301 is detected. Close.
Conversely, when the current flowing through the motor 3 exceeds the negative current limit value, the comparator 310 compares and detects the current with a negative reference voltage 312 proportional to the negative current limit value, and the AND gate 302 Close the gate. As a result, the current flowing through the motor 3 decreases to the set limit value. As described above, a current proportional to the output of the arithmetic circuit 200 can be caused to flow through the motor 3, and an undesirable excessive current can be prevented from flowing through the motor 3.

FIG. 19 is a block diagram showing the clock generation circuit 400 of FIG. 2 in detail. Reference oscillator 40
1, and use it as a PWM clock to connect the signal line 400a.
and the count-up input of the counter 402. As a result, the frequency of the clock is divided, the integration clock necessary for the integration circuit 150 is output to the signal line 400e, and the frequency is further divided to create a clock whose frequency is sufficiently lower than that of the clock, which is composed of an inverter, a resistor, a capacitor, and an AND gate. A sample clock necessary for the speed detection circuit 350 is connected to the signal line 4 via the pulse circuit 404.
Output to 00f. Further, the reference oscillator 40
1 output is flip-flop 403 and NAND
Gates 405 and 406 connect the first and second reference clocks, which have a phase difference of 180°, to the signal line 400.
b, output to 400c.

As described above, in the present invention, the entire control system is configured with a digital circuit, and moreover, the conventionally used inexpensive analog position detector can be used to generate high-resolution incremental position signals and absolute position signals using a small-scale circuit. For speed detection, an easily detectable incremental position signal is used, and for position control, a digital signal proportional to the absolute position of the motor is used, which eliminates the risk of position offset due to induction noise, etc. By using the absolute position signal, the motor and movable member can be positioned at the target position with high precision. Furthermore, after positioning, so-called limit cycles can also be suppressed, thereby making it possible to accurately reach the target position. A positioning control device that achieves static positioning can be realized.

Note that depending on the control device, the limit cycle after positioning may not be a problem, and in that case, the above-mentioned integration circuit and position correction circuit for limit cycle suppression are not necessary.

Furthermore, by digitizing the entire control system, the device can be made into an LSI, lower cost, and smaller.

In the above explanation, an impact-type serial printer device was used as an example, but there are various other types of devices that require positioning, such as magnetic files and optical disks. The scope of the present invention is not limited to the above examples.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
2 is a block diagram showing the positioning control circuit 1 shown in FIG. 1 in detail, FIGS. 3a and 3b are side views showing the position detector 2 and motor 3 shown in FIG. 2 in detail, and FIG. 4 is a circuit diagram. is a block diagram showing the amplifier circuit 500 in FIG. 2 in detail, FIG. 5 is a circuit diagram showing the detector drive circuit 450 in FIG. 2 in detail, and FIG.
7 is a block diagram showing the details of the incremental pulse generation circuit 550 in FIG. 2, and FIGS. A waveform diagram to be explained; FIG. 9 is a block diagram showing the position signal generation circuit 600 of FIG. 2 in detail;
10a, b, c, and d are waveforms and conceptual diagrams that clearly explain the operation of the position signal generation circuit 600 in FIG. 2, and FIG. 11 is a diagram showing the control circuit 100 in FIG. 2.
12 is a block diagram showing in detail the integrating circuit 150 of FIG.
3 is a waveform diagram that clearly explains the operation of the integrating circuit 150 in FIG. 2, and FIGS.
15 is a block diagram and conceptual diagram showing the position correction circuit in detail, and FIG. 15 is the speed detection circuit 35 of FIG.
16 is a block diagram showing the arithmetic circuit 200 of FIG. 2 in detail, FIG. 17 is a block diagram showing the PWM circuit 250 of FIG. 2 in detail, and FIG. FIG. 19 is a circuit diagram showing the motor drive circuit 300 in detail.
2 is a block diagram showing in detail the clock generation circuit 400 shown in FIG. In the figure, 4...external control equipment, 100...control circuit, 150...integrator circuit, 650...position correction circuit, 200...arithmetic circuit, 250...PWM circuit, 3
00...Motor drive circuit, 350...Speed detection circuit,
400... Clock generation circuit, 450... Detector drive circuit, 500... Incremental pulse generation circuit, 600... Position signal generation circuit, 3... Motor, 2
...The position detectors are shown respectively.

Claims (1)

[Claims] 1. A positioning control device that receives a movement information signal from the outside indicating the distance and direction of movement of a movable member from its current position to a target position and positions the movable member to the target position, outputting a plurality of clock signals having different frequencies. a clock generation circuit that receives one clock signal from the clock generation circuit, and outputs a pair of sinusoidal drive signals having equal amplitude and a phase difference of 90 degrees from each other;
a position detection means mechanically connected to the movable member that receives the pair of drive signals and outputs a digital position detection signal whose phase difference with the pair of drive signals is proportional to the amount of movement of the movable member; 1 from the digital position detection signal and the clock generation circuit.
Each time the phase difference between the digital position signal corresponding to the movement of the movable member and the signal obtained by frequency-dividing the clock signal changes by one cycle of the clock signal, the direction of the phase shift, that is, the an incremental position signal generation circuit that outputs a positive direction pulse or a negative direction pulse depending on the moving direction of the movable member; and an incremental position signal generation circuit that receives the digital position detection signal and one clock signal from the clock generation circuit and controls the movement of the movable member. The phase difference between the corresponding digital position signal and a signal obtained by dividing the frequency of the clock signal is counted using the clock signal, and the counting result is calculated as a digital absolute position for each period of the signal obtained by dividing the frequency of the digital position signal. an absolute position signal generation circuit that outputs a signal as a signal, controls the moving speed of the movable member by the incremental position signal from the current position to a certain distance before the target position, and controls the moving speed of the movable member from a certain distance before the target position. A digital positioning control device, characterized in that the movable member is controlled to be positioned at the target position by the digital absolute position signal until the movable member reaches the target position.