JPS6122805B2 - - 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 type 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. is moved parallel to the recording medium and 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 supported on the rotary printing wheel are brought close to the recording medium. The printer is positioned so that it remains stationary at the printed position.

In a device that drives a movable member such as a carriage of a serial printer to a target position using a motor or the like, a signal corresponding to the positional error to the target is applied to the motor, and the motor is operated so that the positional error becomes zero. is moved to move the parts. This type of control includes a speed control mode in which the speed of the motor is made to follow a variable reference speed that accommodates position errors until a certain distance before the target position, as described in U.S. Patent No. 3,954,163, and a 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 position to 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 standard 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, productivity is hindered due to the need for level adjustment for the offset of the analog circuit for position detection, etc., and maintenance requires a large amount of man-hours. This results in an increase in the number of parts and, in turn, an increase in cost due to an increase in the size of the device.

For this reason, in order to solve the above-mentioned drawbacks, patent application no.
No. 70074 and No. 137495 propose positioning control devices in which the control system is digitalized. However, in these digital control devices, in order to ensure the necessary printing accuracy, that is, positioning accuracy, the number of output pulses of the position detector, that is, the incremental encoder, is extremely large, making it necessary to increase the precision of the position detector. , the disadvantage is that the cost is high.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a positioning control device having a novel digital servo system configuration that allows highly accurate positioning even with a relatively small number of output pulses from an incremental encoder.

The device of the present invention is a positioning control device that positions a movable member at a target position, and includes a motor for driving the movable member, and a motor that is mechanically connected to the motor and that rotates each of the movable members each time the motor rotates by a certain angle. a position signal generating means for generating a pair of incremental position signals with reversed polarities and different phases; and a rotation signal for generating a digital rotation signal indicating the rotation and rotation direction of the motor in response to the pair of incremental position signals. a generating means, and a position from the current position to a certain distance before the target position in response to the digital rotation signal based on a movement information signal from the outside indicating the movement distance and movement direction of the movable member from the current position to the target position. The reference speed signal that changes according to the error signal is
A position error signal is output as a first control signal from a certain distance before the target position to the target position, and a mode signal indicating that the position is a certain distance before the target position is output. a first control means that receives the first control signal and the mode signal and integrates the position error signal after a predetermined time has elapsed after the movable member reaches a predetermined distance before the target position; an integrating means for generating an integral signal, and receiving the first control signal and the mode signal so that the first control signal is 0 for a predetermined period of time after the movable member reaches a predetermined distance before the target position. In this case, 1 is added to the first control signal and outputted as a second control signal. a second control means that outputs the second control signal as it is; and a third control means that receives the second control signal, the integral signal, and the digital rotation signal and outputs the signal as a second control signal; a third control means for outputting a control signal;
and a drive means for outputting a drive signal for driving the motor in response to a control signal, and after the movable member reaches a certain distance before the target position by the second control means, When the position error signal is greater than or equal to 0 for a time period, 1 is added to the position error signal, and when it is less than 0, it is output as is;
Further, after the certain period of time has elapsed, the position error signal is integrated by the integrating means, and the movable member is accurately positioned at the target position by adding the integrated signal to the position error signal. shall be.

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

Note that in the following description, a signal line and a signal may be expressed using the same term without distinction.

In one embodiment of the present invention shown in FIG. 1, a moving distance signal 1 is transmitted from an external control device 1 such as a computer
0 and a direction designation signal 9 are initially set in the positioning control circuit 2, and the motor 4 is controlled according to these signals 9 and 10. At this time, the rotational movement of the motor 4 is detected by the incremental encoder 3 and fed back to the positioning control circuit 2 via signal lines 11 and 12. The rotational motion of the motor 4 is transmitted to the carriage 6 via the drive pulley 5, wire 7, and pulley 8, and drives the carriage 6 to a desired position. The incremental encoder 3 is configured using optical or magnetic components, and is an encoder that outputs two incremental position signals whose polarity is inverted every time the motor 4 rotates at a constant rotation angle and whose phase is different from each other. It is. Details of the configuration will be described later with reference to FIG.

FIG. 2 is a diagram showing the positioning control circuit 2 of FIG. 1 in detail. In the speed control mode,
A moving distance signal 10 corresponding to the target position and a direction designation signal 9 are input from the external control device 1 to the control circuit 20, and are initially set in a counter therein. Here, if the direction designation signal 9 is positive, a positive reference speed signal corresponding to the position error is output from the control circuit 20 to the signal line 28, and a speed control mode display mode signal is output to the signal line 29. . At this time, the integrating circuit 22 prohibits the integration operation of the input signal, that is, the speed reference signal 28, by the speed control mode display mode signal, and at the same time resets the internal integrator to transfer the zero integral signal to the signal line. Output to 30. Furthermore, the position correction circuit 21 also receives an input signal, that is, the speed reference signal 28, according to the speed control mode display mode signal.
is output as is to the signal line 34. Therefore, the reference speed signal is input to the drive circuit 25 via the addition/subtraction circuit 24, and is further input to the signal lines 13 and 14.
The motor 4 is driven in the forward direction via. motor 4
When starts moving in the positive direction, the incremental encoder 3 mechanically connected to the motor 4
Two incremental position signals whose polarity is reversed every rotation of a certain angle and whose phases are different from each other are sent to signal line 1.
1 and 12, respectively. The phase relationship and polarity reversal of the two incremental position signals are detected in the direction pulse generation circuit 27 by reference clocks 38 and 39 from the clock generation circuit, and a positive direction pulse is applied to the signal line 31. In response to this positive direction pulse and the sample clock 35 from the clock generation circuit 26, the speed detection circuit 23 detects the speed of the motor and outputs a speed signal to the signal line 33. Therefore, by subtracting the speed signal from the speed reference signal in the addition/subtraction circuit 24, speed feedback can be provided, and the speed of the motor can be made to follow the reference speed corresponding to the speed reference signal. can.

On the other hand, the positive direction pulse is input to the control circuit 20 via the signal line 31, and the initially set moving distance signal 10 is subtracted, and as a result, the reference speed signal for comparison with the position error signal is also set in advance. decreases along the curve.

As described above, the speed of the motor 4 is controlled by the speed feedback from the speed detection circuit 23 and the addition/subtraction circuit 24 so that it follows the reference speed that decreases along a preset curve corresponding to the position error. can do. In this way, when the motor reaches a certain distance before the target position, the control circuit 20 outputs a position error signal up to the target position to the signal line 28, and at the same time outputs a mode signal indicating the position control mode to the signal line 29. Output. At this time, the position correction circuit 21 receives the position error signal and the position control mode display mode signal, and if the position error signal is 0 or more for a certain period of time after entering the position control mode, the position correction circuit 21 receives the position error signal and the position control mode display mode signal. 1 is added to the position error signal and output to the signal line 34 as a position correction signal. Furthermore, at this time, the integration circuit 22 is prohibited from performing an integration operation as in the speed control mode, and the integration output becomes 0 and is output to the signal line 30. In this way, motor 4
is driven to the target value by the position correction signal, and is stable with a small amplitude as described later with reference to FIG. It is positioned near the boundary line while vibrating. At this time, similarly to the speed control mode, the speed detection circuit 2
3 and the addition/subtraction circuit 24 perform velocity feedback, which functions as damping in the position control mode.

In this way, after stable vibration with a small amplitude occurs for a certain period of time, the position correction circuit 21
When the addition of 1 to the above position error signal is prohibited and the integration circuit 22 is activated, the position correction circuit 21 outputs a normal position error signal including a dead zone, and the integration circuit 22 , the integral clock 36 from the clock generating circuit 26 is integrated with the input signal, ie, the position error signal 28. That is, when the position error signal 28 deviates from the target position in the positive direction, it is integrated in the positive direction, and when it deviates in the negative direction, it is integrated in the negative direction, and the integrated signal is sent to the signal line 30. Output. The adding/subtracting circuit 24 receives the integral signal and adds it to the position correction signal 34, that is, a normal position error signal, and further subtracts the speed signal 33 from the speed detection circuit 23 from the addition result, and the signal line 37 Output to. In this way, the motor 4 is driven via the drive circuit 25.

As described above, by causing forced vibration without a dead zone (so-called limit cycle) for a certain period of time after entering the position control mode, the third
As will be described later with reference to FIG. The positioning accuracy (printing is performed relatively quickly after entering position control mode due to high-speed printing), that is, type selection accuracy and carriage positioning accuracy, has been improved.
A serial printer with high print quality can be realized. Further, after a certain period of time after entering the position control mode, that is, after the end of the printing timing, the servo system including the normal dead zone is restored, and the integration circuit 23 is activated, thereby obtaining As described in detail in the above publication, 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 4 is driven in the positive direction. However, when driving the motor 4 in the negative direction, a negative direction signal is output as the direction designation signal 9, and the direction pulse generation circuit 27 outputs a negative direction signal. By outputting a negative direction pulse to the signal line 32, positioning to the target position is performed as in the case of the positive direction described above.

FIG. 3 is a diagram for explaining in an easy-to-understand manner the transient positional vibration after entering the position control mode of a normal servo system including a dead zone. That is, when the motor is controlled to be positioned at a certain target position 500,
A digital position error signal 504 approximately proportional to the motor position error 501 is fed back and applied to the motor. However, due to digital position detection, the target position 500 has a certain width 505 (this width is the same as that from the incremental encoder).
It has a dead zone with a value (inversely proportional to the number of pulses output per revolution). Therefore, when the motor is driven to the target position 500, the position error signal 504
becomes 0, no force is applied to the motor from the control system, and the motor coasts in the dead zone 500.
-1, the position error signal outputs a negative signal, and the motor 4 is driven in the negative direction. Then, the motor 4 coasts again in the negative direction between the dead zones 500 and enters the +1 region, outputting a positive position error signal and driving the motor 4 in the positive direction. As described above, the motor 4 causes transient vibrations after entering the position control mode, but the amplitude 502 of the vibrations is approximately 2 pulses when converted to the number of pulses of the incremental encoder. Furthermore, due to the increased printing speed, the printing timing is performed relatively early after entering the position control mode (reference numeral 503), which deteriorates printing accuracy. On the other hand, if the resolution of the position detector is increased in order to improve printing accuracy, there will be a drawback that the cost will increase.

FIG. 4 is a diagram for clearly explaining the position response of the positioning control system according to the present invention after entering the position control mode. During a certain period of time 606 determined by the timing signal 605 after entering the position control mode, when the position error signal is 0 or more, the position correction circuit 21 adds 1, so this system uses a dead zone (see Fig. 3) as the target value. 505), and the motor 4 targets the boundary line between +1 and -1 of the position correction signal, and the position error 600 decreases. In this way, when the motor 4 approaches the boundary line, the position correction signal 604, which is approximately proportional to the position error 600, is fed back to the motor 4, so that the motor 4 remains stable near the boundary line for the certain period of time 606. Causes vibration (so-called limit cycle). At this time, the amplitude of vibration 601 is approximately 1 pulse when converted to the number of pulses of the incremental encoder, and compared to the case of FIG. 3, when the same incremental encoder is used, the positioning accuracy is approximately twice as high. , printing accuracy can be obtained. In this way, when the printing timing 607 ends and the timing signal 605 becomes 0, the system becomes a normal servo system including a dead zone 603, and the integration circuit 22 is activated, which is detailed in the above-mentioned patent application No. 53, No. 137495. As described above, the motor 4 is positioned at rest in the dead zone 603.

FIG. 5 is a diagram showing in detail the position correction circuit 21 of FIG. 2 for improving the positioning accuracy. The mode signal 29 is input to a monostable multivibrator (hereinafter referred to as one shot) 213, and after entering the position control mode, a timing signal with a fixed time width is output. On the other hand, at the same time that the reference speed signal or position error signal is input to the adder 210 via the signal line 28, its most significant bit (MSB) is
The signal is input to one input of the gate 212, and the Q (non-inverted) output of the one shot 213 is input to the other input. In the speed control mode, since the mode signal 29 is 0, the timing signal is not output, and the adder 210 does not add it to the reference speed signal 28, but outputs it to the signal line 34 as it is. When the position control mode is entered, the mode signal 29 becomes 1, the one shot 213 is triggered, and the timing signal with a constant time width is output. At this time, if the position error signal 28 is 0 or more, its most significant bit (MSB) is 1 (the position error signal 0 is 10...00, the maximum positive value is 11...11, (maximum negative value is 00...00)
The adder 21 via the AND gate 212
A carry signal is input to 0, 1 is added to the position error signal, and the result is output to the signal line 34. As described above, while the one shot 213 outputs the timing signal, the adder 210 adds 1 only when the position error signal is 0 or more. Then, after a certain period of time defined by one shot 213 has passed, the timing signal is turned off, no addition is performed in adder 210, and a normal position error signal including a dead zone is output to signal line 34. In this way, the positioning accuracy is improved as described above only for a certain period of time after entering the position control mode, that is, during the printing timing. In this method, the motor 4 vibrates for the certain period of time, but since the period is several milliseconds, it does not affect the device at all.

FIG. 6 is a diagram showing in detail a second configuration example of the position correction circuit 21 of FIG. 2. In FIG. The mode signal 29 is input to a one shot 214 which outputs a pulse of a constant time width for a timing signal, and its Q (non-inverted) output is input to a ROM (read only memory) 215 as an address. On the other hand, the reference speed signal or position error signal is input to the ROM 215 as an address via the signal line 28. The one shot 214 is stored in the ROM 215.
When the Q output of is 1 and the position error signal is 0 or more, a signal obtained by adding 1 to the position error signal is stored. Otherwise, the standard speed signal or position error signal as an address is stored as is.
Therefore, in the speed control mode, the reference speed signal is
In the position control mode, when the Q output of the one shot 214 is 1 and the position error signal is 0 or more, the signal obtained by adding 1 to the position error signal is sent to the signal line, and at other times, the position error signal itself is sent to the signal line. 3
4 is output. As a result, positioning accuracy can be increased as in the case of FIG. 5.

FIG. 7 is a diagram showing the control circuit 20 of FIG. 2 in detail. In the speed control mode, a travel distance signal and a direction designation signal are initially set in a counter 201 and a register 200 via signal lines 10 and 9, respectively, and a reference speed signal is output from a memory 204 to which these output signals are given as an address. . Further, the mode signal 29, which is the output signal of the zero detector 205 to which the output signal of the counter 201 is given, outputs a signal indicating the speed control mode since the counter 201 is not 0, and the selector 206 is activated by the mode signal. The standard speed signal is selected and output to the signal line 28. On the other hand, the output signal of the directional pulse generation circuit 27 is applied to the count-up input and count-down input of the counter 203 via signal lines 32 and 31, respectively. That is, a positive direction pulse is applied to the countdown input, and a negative direction pulse is applied to the countup input. Further, the carry down output signal and the carry up output signal of the counter 203 are logically summed (OR)ed by an OR gate 202, and the output signal is given to the countdown input of the counter 201. Here, when the motor 4 moves in the positive direction, the positive direction pulse causes the counter 203 to count down via the signal line 31, and the down-down output signal is sent to the OR gate 202.
The counter 201 is counted down via the .
In this way, the position error signal of counter 2
The output signal of 01 gradually decreases, and the output signal of the memory 204, that is, the reference speed signal also decreases accordingly.Furthermore, the counter 201 counts down, and when the output signal reaches 0, the zero detector 205 A mode signal indicating the position control mode is output to the signal line 29 by the selector 2.
06 selects the output of the counter 203,
It is output to the signal line 28. At this time, counter 2
The output signal 03 indicates a position error signal from a certain distance before the target position to the target position. Conversely, when moving in the negative direction, the movement distance signal and the direction designation signal indicating the negative direction are initially set in the counter 201 and register 200, respectively.
Negative reference speed signals are output from the memory 204 to which these output signals are provided as addresses.
In this way, when the motor moves in the negative direction, the negative direction pulse counts up the counter 203 via the signal line 32, and the carry output signal is sent to the OR gate 2.
The counter 201 is counted down via 02. In this way, the counter 20 which is the position error signal
The output signal of 1 gradually decreases, and the output signal becomes O.The zero detector 205 outputs a mode signal indicating the position control mode to the signal line 29, and the selector 206 changes the output of the counter 203. It is selected and output to the signal line 28. At this time, the output signal of the counter 203 indicates a position error signal a certain distance before the target position in the negative direction, contrary to the above case. In other words, by setting the position error to zero when the most significant bit of the counter 203 is 1 and all other bits are O, the counter 203 can move from the target position to the correct position at the moment the control mode is switched. Alternatively, it indicates a negative position error signal a certain distance before.

As described above, the output signal of the memory 204, that is, the reference speed signal, is used as the signal line from a certain distance before the target position, and the output signal of the counter 203, that is, the position error signal, is used as the signal line from the certain distance before the target position. 28 respectively.

FIG. 8 is a diagram showing the integration circuit 22 of FIG. 2 in detail. Mode signal 29 is input to one shot 220 and simultaneously input to one input of AND gate 221. The (inverted) output of the one shot 220 is input to the other input of the AND gate 221, and the output of the AND gate 221 is sent to the integral counter 2 via an inverter 223.
At the same time as input to the reset input of 24,
1 of each of AND gates 225 and 226
input into two inputs. On the other hand, the position error signal or the reference speed signal is input to the +1 or more detector 227 and the -1 or less detector 228 via the signal line 28, respectively, and the outputs of the two detectors are
It is input to another input of AND gates 225 and 226, respectively. Also, the integral clock 3
6 is input to the third input of the AND gates 225 and 226, and the outputs of the two AND gates are input to the count-up and count-down inputs of the integral counter 224, respectively. In speed control mode mode signal 29
Since the output of the AND gate 221 becomes low level, the integral counter 224 is reset via the inverter 223, and at the same time, the outputs of the AND gates 225 and 226 are inhibited, and the integral counter 224 counts up or down. No operation is performed and 0 is output to the signal line 30 as an integral output. When the position control mode is entered, the mode signal 29 becomes high level, but the one shot 220 operates for a certain period of time, that is, the Q of one shot 213 and one shot 214 in FIGS.
Until the output becomes low level, in other words, until the print timing ends, the one shot 2
The output of 20 becomes low level, and the integration counter 224 does not perform an integration operation as in the speed control mode. After a certain period of time after entering the position control mode, that is, the output of the one shot 220 becomes high level, and the one shot 213 and one shot 2 in FIGS. 5 and 6
After the Q output of No. 14 becomes low level, the above
The output of AND gate 221 becomes high level,
At the same time as the reset operation of the integral counter is released, the AND gates 225 and 226 are also opened. Here, if the motor causes a positional shift in the positive direction with respect to the target position due to a so-called limit cycle, the position error signal is detected by the +1 or more detector 227, and the integrating clock 36 is output from the AND The integral clock 224 is counted up via the gate 225. Conversely, if the motor causes a positional shift in the negative direction, the position error signal is detected by the -1 or less detector 228, and the integral clock counts down the integral counter 224 via the AND gate 226. do.

After the motor is positioned at the target position as described above, the integral counter 224 outputs an integral output to the signal line 30 in accordance with the position error signal.

As shown in FIG. 8, the detection operation by the +1 or higher detector 227 is such that when the most significant bit (MSB) of the position error signal 28 is at a high level, the logic of the other bits excluding the most significant bit is OR the sum
This is performed by using the AND gate 227C to AND the output signal of the OR gate taken by the gate 227A and the most significant bit indicating the high level. In addition, the -1 or less detector 22
8 detects the position error signal 28.
This is done by detecting the low level of the MSB via the inverter 228A.

Furthermore, the time width of the output pulse of the one shot 220 is preferably equal to the time width of the one shots 213 and 214 in FIGS. 5 and 6, but the time width of the one shot 220 may be longer. . Further, the one shot 220 and the one shot 213 and 214
If the time widths of the two are equal, it is also possible to use one shot.

FIG. 9 is a diagram showing the addition/subtraction circuit 24 of FIG. 2 in detail. In the speed control mode and the position control mode, the reference speed signal and the position error signal are input to the multiplier 240 through the signal line 34, multiplied by K1, and input to the adder 241. Since the output of the integrating circuit 22 is 0 until a certain period of time has elapsed after entering the position control mode, the output of the adder 24 is
1, no addition is performed and the output is input to the subtracter 243. On the other hand, the speed signal that is the output of the speed detection circuit 23 is input to the multiplier 243 via the signal line 33, multiplied by K2, and input to the subtracter 243.
The signal line 37 is subtracted from the output of the adder 241.
is output to. Then, after a certain period of time after entering the position control mode, the integral signal 30, which is the output of the integrating circuit 22, is converted into a position error signal by an adder 241.
It is added to the value multiplied by K1. That is, the integral signal 30 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 speed signal is subtracted from the position error signal for a certain period of time, and after a certain period of time, the integral signal is added to the position error signal. , the speed signal is further subtracted and the signal line 37
is output to. In the explanation of FIG. 9, the multipliers 240 and 242 are used to set the gains of K1 and K2, but here, instead of using the multipliers, the input bits are shifted. It is also possible to set a gain that is a power of 2,
In that case, the circuit will also be simpler.

FIG. 10 is a diagram showing the speed detection circuit 23 of FIG. 2 in detail. A positive direction pulse 31 and a negative direction pulse 32, which are the outputs of the direction pulse generation circuit, are input to the count up input and count down input of the counter 230, respectively. counter 23
The output of 0 is input to the register 231, and the output is output to the signal line 33 as a speed signal. On the other hand, the sample clock 3 of the clock generation circuit 26
5 is input to the set input of the register and further to the delay circuit 232, and the output of the delay circuit 232 is input to the reset input of the counter 230. If the motor is now moving in the forward direction, the forward direction pulse 31 is counted up by the counter 230. When the sample clock 35 is input, first, the register 231
the current value of the counter 230 is set to
The counter 230 is reset by the sample clock, which is slightly delayed by a delay circuit 232. In this way, a signal proportional to the number of positive-direction pulses or negative-direction pulses generated in a certain period of time defined by the sample clock 35, that is, the speed of the motor, can be output to the signal line 33 as a speed signal. .

FIG. 11 is a diagram showing the drive circuit 25 of FIG. 2 in detail. The digital output signal from the adder/subtractor circuit 24 is input to the digital-to-analog converter 250 via the signal line 37 and converted into an analog signal. The motor 4 is then driven via a current-driven power amplifier 25A composed of a power amplifier 251 and a current detection resistor 252.

FIG. 12 is a diagram showing a second configuration example of the drive circuit 25 in FIG. 2. Although not shown in FIG. 2, a PWM (Pulse Width Modulation) clock 269 from the clock generation circuit 26 is input to the counter 254 to count up the counter 254 at all times. That is, the output of the counter 254 operates in a sawtooth waveform between the negative maximum value and the positive maximum value. The reference input b of the comparator 253 has the counter 2
54 is input, and the output 37 of the addition/subtraction circuit 24 shown in FIG. 2 is input to the signal input a. Then, the comparator 253 compares the output of the counter 254 and the output of the addition/subtraction circuit 24, and when the output of the addition/subtraction circuit 24 is greater than the output of the counter 254, the plus output 253A becomes high level. When it is small, the minus output 253B becomes high level.
That is, during one period of the counter 254, the positive output 253A and the negative output 253B alternately become high level, and when the input 37 is a positive signal, the positive output 253A becomes high level in proportion to the level.
3A high level time is minus output 25
It will be longer than the time it takes to reach the high level of 3B. Conversely, when the input 37 is a negative signal, the above is reversed, and when it is 0, the positive output 25
3A and the time when the negative output 253B reach the high level are equal. Now, when the positive output 253A is at a high level, the negative output 253B is at a low level, and at this time, the positive output 253A turns on (conducts) the transistor 257 via the gate 256, thereby turning on the transistor 258. On the other hand, the negative output 253B is inverted by the gate 258 to turn off the transistor 259 (non-conducting), thereby turning off the transistor 253B.
55 is turned off. As a result, a drive signal having a voltage approximately equal to the power supply voltage +ES is applied to the motor 4 via the signal line 13.

Further, when the minus output 253B is at a high level, the plus output 253A is at a low level, and in this case, contrary to the operation described above, the transistor 253A is at a low level.
5 is turned on, the transistor 258 is turned off, and a drive signal having a voltage approximately equal to the power supply voltage -ES is applied to the motor 4 via the signal line 13.

As described above, a pulse width modulated output voltage proportional to the level of the input signal 37 is applied to the motor 4. At this time, if the repetition frequency of the counter 254 is selected to be sufficiently higher than the cutoff frequency determined by the electrical time constant of the motor 4, a current proportional to the input signal 37 flows through the motor 4 due to the low-pass effect of the motor 4.

FIG. 13 is a diagram showing the incremental encoder 3 of FIG. 2 in detail. A transparent position information pattern 302 is attached to the light source 3 on an opaque disk 301 that is mechanically attached to the shaft of the motor 4 and responds to its rotation.
As the amount of light irradiated by 00 and transmitted through the slit plate 303 increases or decreases, the photodetectors 304 and 305
Detected by These detection signals are sent to comparator 3.
After comparison with the reference voltage 306 at 07 and 308, the signal is converted and output to signal lines 11 and 12 as a digital incremental position signal. At this time, two photodetectors 304 and 30
5 and the interval between the two slits of the slit plate 303 by 1/4 with respect to the interval between adjacent position information patterns 302, the phases of the slits are different from each other by 1/4 of the slit interval. Two incremental position signals are generated.

FIG. 14 is a diagram showing the directional pulse generating circuit 27 of FIG. 2 in detail. The two phased incremental position signals are transmitted through signal lines 11 and 1.
2 through flip-flops 270 and 271
The outputs of the flip-flops 270 and 271 are input to the data inputs of the memory 27.
It is input to the address input of 2. Furthermore, the two outputs of the memory 272 are connected to a flip-flop 273.
and 274 as data inputs, and the outputs of flip-flops 273 and 274 are provided as addresses of the memory 272. Further, two reference clocks having sufficiently high frequencies and different phases from the clock generating circuit 26 of FIG.
The other reference clock is input to the clock input of flip-flops 273 and 274, respectively. The reference clock 38 then transfers the two incremental position signals to the flip-flops 270 and 27.
The reference clock 39 samples the two outputs of the memory at the flip-flops 273 and 274. Here, the outputs of flip-flops 270 and 271 are assumed to be A and B, and the outputs of flip-flops 273 and 274 are assumed to be X and Y, respectively.
Furthermore, the flip-flops 273 and 27
Let the inputs of 4 be P and Q, respectively, and the positive direction pulse and negative direction pulse, which are the outputs of the memory 272, be F and R, respectively. Therefore, in the memory 272, the logical formula F=A..+.X.
Y・+B・X+・・Y、R=A・・Y+
・X・+B・・＋・X・Y, P=A,
If you memorize the state shown by Q=B, the above 2
At the rising and falling edges of the two incremental position signals, a positive direction pulse or a negative direction pulse can be outputted to the signal line 31 or 32, respectively, depending on the rotational direction of the motor 4. In the above description, the memory 272 is used to construct the logic equation, but it is also possible to construct the logical formula using hard logic.

FIG. 15 is a diagram showing the clock generation circuit 26 of FIG. 2 in detail. A reference oscillator 260 oscillates an accurate clock with a sufficiently high frequency, which is applied to a signal line 38, and is also applied via an inverter 263 to a signal line 39 as a reference clock with a phase difference of 180°. Further, the reference oscillator 26
A clock output of 0 is provided as the count up input of counter 261. As a result, the frequency of the clock output is divided, and an integrating clock necessary for the integrating circuit 22 in FIG. 2 is outputted to the signal line 35. The integrating clock is further frequency-divided by the counter 261, and as a result, a clock whose frequency is sufficiently lower than the output of the reference oscillator 260 is transmitted to the inverter.
It is applied to a pulsing circuit 262 consisting of a resistor, a capacitor and an AND gate. As a result, a sample clock necessary for the speed detection circuit 23 of FIG. 2 is outputted to the signal line 36.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Fig. 2 is a diagram showing the positioning control circuit 2 of Fig. 1 in detail, Fig. 3 is a diagram illustrating the transient positional vibration after entering the position control mode of a normal servo system including a dead zone, and Fig. 4. is a diagram explaining the position response of the positioning control system after entering the position control mode according to the present invention, FIGS. 5 and 6 are diagrams showing an example of the configuration of the position correction circuit of FIG. Control circuit 20 in the figure
8 is a diagram showing an example of the configuration of the integrating circuit 22 in FIG. 2, FIG. 9 is a diagram showing an example of the configuration of the addition/subtraction circuit 24 in FIG. 2, and FIG. Second
A diagram showing an example of the configuration of the speed detection circuit 23 in FIG.
1 and 12 are diagrams showing an example of the configuration of the drive circuit 25 in FIG. 2, FIG. 13 is a diagram showing an example of the configuration of the incremental encoder in FIG. FIG. 15 is a diagram showing an example of the configuration of the clock generation circuit 27 in FIG. 2. In FIG. In FIG. 2, 1...external control equipment, 20...
... Control circuit, 22 ... Integration circuit, 21 ... Position correction circuit, 23 ... Speed detection circuit, 24 ... Addition and subtraction circuit, 26 ... Clock generation circuit, 25 ... Drive circuit, 27 ... Direction pulse generation circuit , 3...incremental encoder, 4...motor, respectively.

Claims (1)

[Claims] 1. A positioning control device that positions a movable member at a target position, which includes a motor for driving the movable member, and a motor that is mechanically connected to the motor and whose polarities are reversed every time the motor rotates by a certain angle and are out of phase with each other. position signal generating means for generating a pair of incremental position signals with different values; rotation signal generating means for generating a digital rotation signal indicating the rotation and rotation direction of the motor in response to the pair of incremental position signals; Based on an external movement information signal indicating the movement distance and movement direction of the member from the current position to the target position, the digital rotation signal is received and changes from the current position to a certain distance before the target position according to the position error signal. outputs a reference speed signal as a first control signal, and outputs a position error signal as the first control signal from a certain distance before the target position to the target position; a first control means for outputting a mode signal indicating that the movable member has reached the target position a certain distance after the movable member receives the first control signal and the mode signal; an integrating means for integrating the position error signal and generating an integral signal; and an integrating means for receiving the first control signal and the mode signal for a predetermined period of time after the movable member reaches a predetermined distance before the target position. When the first control signal is 0 or more, 1 is added to the first control signal and output, and when the first control signal is less than 0 and until the movable member reaches a certain distance before the target position, the first control signal is output. a second control means for outputting the digital rotation signal as it is as a second control signal; a speed detection means for receiving the digital rotation signal and outputting a speed signal indicating the speed of the motor; and a speed detection means for outputting the integral signal and the second control signal. and a third control signal that receives the speed signal, adds the integral signal to the second control signal, simultaneously subtracts the speed signal, and outputs a third control signal.
and a drive means that receives the third control signal and outputs a drive signal for driving the motor, and the movable member is moved to the target position by the second control means. When the position error signal is 0 or more for a certain period of time after reaching a certain distance, 1 is added to the position error signal, and when it is less than 0, it is output as is, and after the certain period of time has elapsed, the position error signal is added to the position error signal, and after the certain period of time has elapsed, Therefore, the positioning control device is characterized in that the movable member is accurately positioned at the target position by integrating the position error signal and adding the integral signal to the position error signal.