JPH07121236A - Positioning control unit - Google Patents

Abstract

PURPOSE:To increase a speed loop gain and a position loop gain by complementing discontinuity due to the quantization of a command signal for a position and a feedback signal for the position on an analog basis and supplying a continuous quantity without any jump. CONSTITUTION:This positioning control circuit is equipped with a position command arithmetic circuit 1 which outputs arithmetic command pulses and a position command complementing signal for complementing the arithmetic command pulses, a pulse shaping direction decision circuit 2 which shapes the waveform of the two-phase signal of a 90 deg. phase difference of an encoder and decides the direction, a deviation counter 3 which calculates the deviation quantity between the arithmetic pulses and feedback pulses, a feedback pulse complementing signal circuit 5 which complements the feedback pulses and makes the detection quantity of the position continuous, a 1st speed arithmetic circuit 6, a 2nd speed arithmetic circuit 7, a low-speed/high-speed rotation switching circuit 8, etc. A digital signal is D/A-converted through the operation of them to eliminate staircase-shaped variation in speed command value which is caused by analog quantity conversion, and the speed command value can be made continuous.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse train input type positioning control device, and more particularly to a positioning control device which can shorten the positioning settling time and enable smooth operation at an ultra-low rotational speed.

[0002]

2. Description of the Related Art FIG. 16 shows a typical example of a conventional positioning control device. 100 is a main circuit, 101 is a rectifier unit, 102 is a smoothing capacitor, 103 is an inverter unit, 104 is a DCCT (direct current transformer), 105 is a current detection circuit, 106 is a PWM (pulse width modulation) circuit, 107
Is a base drive circuit, 108 and 109 are multipliers, 110 is a current distribution circuit, 111, 112 and 113 are current amplifiers,
114 and 115 are adders, 116 and 117 are inverting amplifiers, 118 is a synchronous motor, and 119 is an encoder.
As the positioning control signal, an incremental command pulse and a rotation direction command for instructing the rotation direction of the motor are given. The position detection amount is given by a feedback pulse of an incremental encoder connected to the motor shaft. The deviation amount between the command pulse and the feedback pulse becomes the speed command value of the speed amplifier via the D / A converter. The encoder feedback pulse is a two-phase pulse with a 90 ° phase difference.
By performing V conversion, a velocity feedback signal to the velocity amplifier can be obtained.

[0003]

The conventional apparatus has the following problems. (1) When the velocity loop gain and the position loop gain are increased, smooth rotation of the motor is impaired and the motor becomes vibrating. (2) Further, it is unavoidable that a minute vibration of one pulse is generated in the servo lock state. (3) Further, at a low rotation speed, the output signal of the f / V converter has an increased ripple component, so that the speed loop gain cannot be increased. Especially when the encoder resolution is low,
For example, an encoder having a resolution of about 1000 [pulses / rev] or less has a large ripple. Therefore, the present invention eliminates the disadvantages of the f / V converter at a low rotation speed, enables a high gain of the speed loop and the position loop, and allows a slight pulse of 1 pulse even when the motor is stopped (at the servo lock). It is an object of the present invention to provide a highly accurate positioning control device that does not generate vibration, has a high gain, and has a short settling time.

[0004]

In order to solve the above problems, the present invention is directed to a position feedback signal and a position command pulse from an encoder mounted on a motor shaft and outputting a two-phase sine wave having a 90 ° phase difference. In the positioning control device, in which the amount of deviation between the position control pulse and the speed feedback signal from the encoder is used to control the speed of the motor, a pulse cycle for calculating the speed from the pulse cycle of the position command pulse A speed calculation circuit,
An integrating circuit that integrates the output of the pulse cycle speed calculating circuit to obtain a position command complementing signal, a feedback pulse complementing signal circuit that generates an analog complementing signal based on the signal from the encoder, and a signal from the encoder 1st and 2nd which calculates a velocity feedback signal based on
And a switching circuit for selecting the first speed calculation circuit at low speed and the second speed calculation circuit at high speed, and the speed command includes the position command complement signal and the feedback pulse complement circuit. The output signal is added.

[0005]

By the above means, the stepwise change of the speed command value that occurs when the digital signal is D / A converted and converted into the analog amount is eliminated, and the speed command value input to the speed amplifier is made continuous. As a result, the movement of the motor becomes smooth. Further, since a speed feedback signal with less ripple can be obtained even at a low rotation speed, f / V
It is possible to eliminate the drawback due to the increase of the ripple at a low rotation speed of the converter, that is, the problem that the gain of the speed amplifier cannot be increased. Therefore, the position loop gain can be significantly increased due to the synergistic effect of analog complementation of the position signal.

[0006]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is a diagram showing a positioning control circuit showing an embodiment of the present invention with respect to a conventional positioning control circuit portion in a portion surrounded by a dashed line in FIG. In the figure, reference numeral 1 denotes a position command calculation circuit which receives a command pulse and a rotation direction command and outputs a calculation command pulse and a position command complementation signal which complements the calculation command pulse, corresponding to a newly generated input command pulse,
2 is a two-phase signal with a 90 ° phase difference of the encoder (here,
SINθe, COSθe sine wave two-phase signal) waveform shaping and a pulse shaping direction determination circuit for determining the rotation direction, 3 is a deviation counter for calculating the deviation amount between the operation command pulse and the feedback pulse, and 4 is a deviation counter The D / A converter 5 for converting the value of A into an analog amount is a feedback pulse complementing signal circuit for complementing the feedback pulse from the encoder and making the position detection amount continuous. 6 is a first speed calculation circuit for detecting a low rotation speed, and 7 is a second speed calculation circuit for detecting a speed at a high rotation speed, which is constituted by a conventionally known f / V converter. Further, 8 is a switch 9 for discriminating between high speed and low speed.
It is a low-speed / high-speed rotation switching circuit for controlling. The main control circuits according to the present invention are the position command calculation circuit 1, the feedback pulse complement signal circuit 5, and the first speed calculation circuit 6. Hereinafter, these detailed configurations will be further described. Figure 2
FIG. 3 is a detailed block diagram of the position command calculation circuit 1. Reference numeral 11 is a pulse code synchronization circuit for synchronizing the command pulse and the rotation direction command. In this circuit, even if only the rotation direction command is changed, it is not accepted as it is, and it is synchronized with the command pulse so that the rotation direction command becomes effective when the command pulse is applied. A pulse shaping circuit 12 shapes the command pulse into a predetermined pulse width. Reference numeral 13 denotes a speed calculation correction signal generation circuit for correcting the tracking delay of the calculation command pulse generated inside the position command calculation circuit with respect to the input command pulse. Reference numeral 14 denotes an integration calculation stop signal generation circuit which gives a signal for stopping the operation of the integration circuit 17 when the input command pulse number and the calculation command pulse number match. 15
Is a preset signal generating circuit for setting an initial value of the integrating circuit 17. Reference numeral 16 is a pulse cycle speed calculation circuit for calculating the speed from the input command pulse cycle. Reference numeral 17 is an integrating circuit for integrating the velocity signal to obtain a position signal. 18
Numerals 20 to 20 are comparators that generate forward and backward rotation operation command pulses, and give the integration stop timing of the integration circuit 17, which is a signal for generating the operation command pulses. FIG. 3 is a more detailed block diagram of the pulse cycle speed calculation circuit 16 of FIG. Reference numeral 21 is an integrating circuit which starts integration with the reference voltage V0 as a starting point when the command pulse is applied.
A sample / hold circuit 22 holds the output signal INTEG of the integration circuit 21 in synchronization with the command pulse, and the hold value SAMP is proportional to the length of the pulse cycle. 23 is a division circuit, whose output DI
Since V is the reciprocal of the pulse period, it is a signal corresponding to the speed at that time. Reference numeral 24 is a signal polarity switching circuit that switches the signal polarity according to the rotation direction and specifies the forward rotation side and the reverse rotation side of the speed signal. The position signal is obtained by integrating this velocity signal. When the payout rate of the input command pulse increases, the integration calculation may be delayed due to the incompatibility of the gain of the speed signal, which may cause a delay in following the calculation command pulse. In order to compensate for such a problem, the gain correction circuit 25 increases the gain of the speed signal,
The input of the integrating circuit 17 of FIG. 2 following the next stage is increased to increase the position calculation speed. FIG. 4 is a detailed block diagram of the feedback pulse complementing signal circuit 5. This circuit includes signal polarity switching circuits 26 and 27 and a bias voltage setting device 2.
8, adders 29 and 30, switches 31 and 32, an inverting amplifier 33, and inverters 34 and 65. FIG. 5 is a detailed block diagram of the first speed calculation circuit 6 of FIG. This circuit is differentiating circuits 35-38, signal polarity switching circuit 3
9 to 42, absolute value circuits 43 and 44, a comparator 45, switches 46 to 50, and inverters 51 to 53. FIG. 6 is a block diagram of a circuit for generating encoder signals and various control signals. Reference numerals 54 and 55 are addition circuits, 56 is an inverting amplifier, 57 and 58 are coefficient multipliers, and 59 to 62 are waveform shaping circuits that shape the sine wave signals a to d into square waves A to D.
Further, 63 and 64 are EX-OR (exclusive OR) circuits. FIG. 7 shows the output signal waveform of each part shown in FIG. In FIG. 7, a and b are output signals of the encoder, which are two-phase sine wave signals SINθe and COSθe. c is a signal obtained by adding the signals a and b and dividing the result by 2 ^1/2, which has a phase lead or lag of 45 ° with respect to the signal a.
d adds the signal a through the inverting amplifier to the signal b to obtain 2
It is divided by ^1/2 . The phase is advanced or delayed by 45 ° with respect to the signal b. The signals A to D are waveforms of the signals a to d respectively. Also, the signal E is the signal A
And the EX-OR of B and signal F is signal C
And the EX-OR output of D. FIG. 8 is a signal time chart of each part of the feedback pulse complementing signal circuit. In FIG. 4, when the input signal a is switched to the L level of the signal B so that the input signal polarity is inverted, the output signal of the signal polarity switching circuit 26 becomes as shown by a1 in FIG. Similarly, when the input signal b is switched when the signal A is at the H level, the signal polarity switching circuit 27 inverts the polarity of the input signal with the control signal L, so that the signal b1 is obtained. Further, by the control signal E, a voltage of 2 ^−1/2 of the amplitude voltage of SINθe is added to the signal a1 when E is at H level, and a voltage of −2 ^−1/2 is added when E is at L level. Then, the output signal of the adder 29 becomes the signal a2. On the other hand, when the signal b1 is E of H, it adds -2 ^-1/2 becomes the voltage, when E is L, and adding 2 ^-1/2 becomes the voltage, the signal b2 is obtained. Further, when the signals a2 and b2 are alternately selected by the control signal F and combined, the output Y1 of the switch 32 is obtained. Here, when F is at H level,
The b2 signal is selected, and when F is at the L level, the a2 signal is selected. Y1 is a feedback pulse complementary signal for suppressing the occurrence of discrete operation due to the feedback pulse. Hereinafter, the operation of the feedback pulse complement signal will be described in more detail with reference to FIGS. 9 and 10. The D / A signal in FIG. 9 is an output waveform obtained from the output of the deviation counter 3 via the D / A converter 4. Here, in order to simplify the explanation, consider a case where only the feedback pulse is input to the deviation counter. A and B are feedback signals, fb-pls is the rising edge of A and B signals,
Indicates the situation where falling edges are being counted. That is, the feedback pulse is counted by 4 times. Y1 is a complementary signal of the feedback pulse. When the deviation counter has 1 droop pulse, D /
Assuming that the output voltage of the A converter is 1, addition is performed at the input part of the speed amplifier 10 so that the output voltage of Y1 becomes +0.5 and -0.5.
It becomes continuous like fb. If you do not complement,
It is a stepwise signal like a dotted line. Further, FIG. 10 shows a state where the value of the deviation counter is near zero. When the deviation counter value is zero, 1 / of the feedback pulse
The motor is stopped at the center point of the four cycles, and the microvibration of ± 1 pulse, which is seen in the case of the normal deviation counter only configuration, does not occur. FIG. 11 is a signal time chart of each part of the first speed calculation circuit. In FIG. 5, when the signal a (= SINθe) is differentiated, a sine wave signal having a 90 ° advance phase whose amplitude is proportional to the rotation speed is obtained. When the polarity of this signal is inverted at the L level of the control signal B, it is shown in FIG. The signal a3 is obtained. Similarly,
Signals b to d are differentiated to differentiate each circuit 36 shown in FIG.
When the polarity is inverted and the synchronous rectification is performed with the control signal corresponding to the output signal of No. 38, the signals b3, c3, and d3 of FIG. 11 are obtained. In addition, the signals a3 and b3 are set to b at the H level of the control signal F.
If you select 3 and select a3 at the L level, switch 4
The output signal of 8 is Y2. Further, when the signals c3 and d3 are selected at the H level and d3 at the L level of the control signal E, the output signal of the switch 49 becomes Y3. The switches 46 and 47, the absolute value circuits 43 and 44, and the comparator 45 in FIG. 5 are circuits for producing a control signal for further switching and selecting the signals Y2 and Y3. In FIG. 5, when the signals a and b are selected at the H level of the control signal F and the signal a is selected at the L level, the output signal of the absolute value circuit 43 becomes the signal X1 shown in FIG. Similarly,
When the signals c and d are at the H level of the control signal E, the signal c is selected, and when the signal is at the L level, the signal d is selected to obtain the signal X2 in FIG. If the outputs of the signals X1 and X2 passed through the comparator 45 are at the H level when the value of X2 is larger than the value of X1, the control signal X3 is obtained. The signals Y2 and Y3 are controlled by the control signal X3.
When Y2 is selected when X3 is at the H level and Y3 is selected when X3 is at the L level, the output signal of the switch 50 becomes Y4. A low-ripple speed calculation signal can be obtained by the selection logic of the differential signals a to d as described above. Since the linearity of the differentiating circuit is limited to the low rotation speed range, the output signal of the conventional f / v converter is used as the speed feedback signal in the high rotation speed range. Next, the operation of the position command calculation circuit 1 shown in FIGS. 1 and 2 will be described. Time charts of this circuit are shown in FIGS. In FIG. 2, the command pulse PULSE is input to the pulse shaping circuit 12 and shaped into a pulse having a constant pulse width like the PLS of FIG. The pulse PLS is guided to the speed calculation correction signal generation circuit 13 and the pulse cycle speed calculation circuit 16. Signals INTEG, SAMP, and DIV shown in FIG. 12 indicate the operation of the pulse period speed calculation circuit 16 shown in FIG. In FIG. 3, when the pulse PLS is input, the integrating circuit 21 is cleared. Further, the sample / hold circuit 22 holds the value of the integrating circuit 21 immediately before being cleared. This held value passes through the division circuit 23,
Obtain the signal DIV. If the output signal SN of the pulse code synchronization circuit 11 and the signal ACC from the speed calculation correction signal generation circuit 13 in FIG. 2 do not change, this DIV signal is directly input to the integration circuit 17 to integrate the DIV signal. DI
The V signal has a larger voltage value as the cycle of the input command pulse is shorter. That is, the value is proportional to the input command pulse rate. Therefore, the integrated value corresponds to the position and is a signal in which the distance between the pulses of the input command pulse is complemented by calculation. The POS signal in FIG. 12 is this position command complementing signal. The operation of the integrating circuit 17 will be described in more detail.
The integration circuit 17 is controlled by each signal of the integration calculation stop signal generation circuit 14 and the preset signal generation circuit 15. In FIG. 12, when the POS signal reaches the comparison level + V of the comparator 18, the comparator 18 generates the signal COMP-1. At the same time, the preset signal generation circuit 15 sets the integration circuit 17 to a value of -V, and starts integration with -V as an initial condition. When the POS signal becomes zero,
The output of the comparator 20 for detecting the zero point and the PLS signal,
When it is detected that the pulse numbers of the FP (or RP) signals match, the integration calculation stop signal generation circuit 14 operates to stop the operation of the integration circuit 17. Here, the FP signal is obtained by shaping the output signal COMP-1 of the comparator 18 and making the pulse width constant. The FP signal is a normal rotation side command pulse, and the RP signal is a calculation command pulse corresponding to the reverse rotation side command pulse, which is guided to the deviation counter 3 in FIG. FIG.
6 is a time chart showing another timing of the position command calculation circuit. Here, the integration calculation stop signal generation circuit 1
4 output signal STOP, the output POS of the integrating circuit 17 and the output CO of the comparator 19 at the switching timing of the rotation direction.
MP-2 and the like are shown. Pulse code synchronization circuit 11
Even if the rotation direction command SIGN is switched at the point of the SN signal portion in FIG. 13, for example, the signal state shown in FIG. 13 is maintained until the next pulse enters. When the SN signal is switched, the signal polarity switching circuit 24 of FIG. 3 operates and the input voltage polarity of the integrating circuit 17 of FIG. 2 is inverted, so that the POS signal shown in FIG. Go in the direction. When the value of -V is reached, the comparator 19 operates to generate the output signal COMP-2. At the same time, the preset signal generating circuit 15 sets the integrating circuit 17 to + V. In addition, at the forward rotation side, it is set to -V. Since the negative input voltage is integrated with + V as the initial condition, the POS signal goes to zero. When it reaches zero, the comparator 20 operates and its outputs COMP-3 and SN
EX-OR with signal and PLS signal with comparator 1
It is detected that the number of pulses of the RP signal obtained by shaping the output COMP-2 of FIG.
4 generates a STOP signal. Comparator 2 while integration is stopped
The output of 0 becomes unstable, but there is no problem if it is latched at the edge of the signal. FIG. 14 shows the operation of the gain correction circuit 25 shown in FIG. If the input command pulse rate becomes faster, the generation of the operation command pulses FP and RP signals may be delayed. In order to increase the tracking speed with respect to the command pulse, the gain correction circuit 25 uses the integration circuit 17
If the input voltage to is corrected to an appropriate value, the integration circuit 1
Since the integration time of 7 becomes faster, the generation of the operation command pulse also becomes faster. PL of the speed calculation correction signal generation circuit 13 of FIG.
The S signal is compared with the FP or RP signal, and when the difference between them becomes large, a signal ACC is generated to control the gain correction circuit shown in FIG. FIG. 14 shows a case where the gain is increased to 1.5 times when the pulse difference becomes 2 pulses. The dotted line of the DIV and POS signals is the operation when the gain is corrected. With respect to the operation command pulse FP when the gain is not corrected, when the gain is corrected, the generation speed increases like the FP-C signal. FIG. 15 shows the operation of the position command supplement signal POS. For simplicity of explanation, it is assumed that only the operation command pulse (here, the FP signal) is input to the deviation counter 3. At this time, the output of the D / A converter has a stepwise waveform like D / A. If the output voltage of the D / A converter is 1 when the accumulated pulse of the deviation counter is 1 pulse, the positive and negative peak voltages of the POS signal are +0.5 and -0.5. Figure 1
The D / A and POS signals are added at the input of the speed amplifier 10 of. This combined voltage has a continuous waveform as shown by the solid line of the P-ref signal.

[0007]

As described above, according to the present invention, the discontinuity due to the quantization of the position command signal and the position feedback signal can be complemented by analog, and can be given in a continuous amount without a jump. . Further, at a low rotation speed, a speed feedback signal with less pulsation can be obtained. Therefore, the velocity loop gain and the position loop gain can be significantly increased, and since one pulse of slight vibration does not occur at the time of servo lock, the positioning control device is highly accurate and highly rigid, and has a short positioning settling time. It is possible to provide.

[Brief description of drawings]

FIG. 1 is a diagram showing a positioning control circuit showing an embodiment of the present invention.

FIG. 2 is a detailed circuit block diagram of a position command calculation circuit.

FIG. 3 is a detailed circuit block diagram of a pulse cycle speed calculation circuit.

FIG. 4 is a detailed block diagram of a feedback pulse complementary signal circuit.

FIG. 5 is a detailed block diagram of a first speed calculation circuit.

FIG. 6 is a block diagram of a generation circuit for an encoder signal and various control signals.

FIG. 7 is a time chart of output signals of various parts in FIG.

FIG. 8 is a signal time chart of each part of the feedback pulse complementary signal circuit.

FIG. 9 is a signal time chart of each part of the feedback pulse complementary signal circuit.

FIG. 10 is a signal time chart of each part of the feedback pulse complementary signal circuit.

FIG. 11 is a signal time chart of each part of the first speed calculation circuit.

FIG. 12 is a signal time chart of each part of the position command calculation circuit.

FIG. 13 is a signal time chart of each part of the position command calculation circuit.

FIG. 14 is a signal time chart of each part of the position command calculation circuit.

FIG. 15 is a signal time chart of each part of the position command calculation circuit

FIG. 16 is a diagram showing a configuration of a conventional positioning control device.

[Explanation of symbols]

1 Position Command Calculation Circuit 2, 67 Pulse Shaping Direction Discrimination Circuit 3 Deviation Counter 4 D / A Converter 5 Feedback Pulse Complementary Signal Circuit 6 First Speed Calculation Circuit 7 Second Speed Calculation Circuit 8 Low Speed / High Speed Rotation Switching Circuit 9 , 31, 32, 46, 47, 48, 49, 50 Switch 10 Speed amplifier 11 Pulse code synchronization circuit 12 Pulse shaping circuit 13 Speed calculation correction signal generation circuit 14 Integration calculation stop signal generation circuit 15 Preset signal generation circuit 16 Pulse period Speed calculation circuit 17,21 Integration circuit 18,19,20,45 Comparator 22 Sample and hold circuit 23 Division circuit 24,26,27,39,40,41,42 Signal polarity switching circuit 25 Gain correction circuit 28 Bias voltage Setting device 29, 30, 54, 55, 114, 115 Adder 33, 56, 116, 17 Inverting amplifier 34, 51, 52, 53, 65 Inverter 35, 36, 37, 38 Differentiating circuit 43, 44 Absolute value circuit 57, 58 Coefficient multiplier 59, 60, 61, 62 Wave shaping circuit 63, 64, 66 EX- OR circuit 68 f / V converter 100 Main circuit 101 Rectifier unit 102 Smoothing capacitor 103 Inverter unit 104 DCCT 105 Current detection circuit 106 PWM circuit 107 Base drive circuit 108, 109 Multiplier 110 Current distribution circuit 111, 112, 113 Current amplifier 118 Synchronous motor 119 Encoder

Claims (1)

[Claims] 1. A speed feedback signal from the encoder, wherein a deviation amount between a position feedback signal from a encoder attached to a motor shaft and outputting a two-phase sine wave having a 90 ° phase difference and a position command pulse is used as a speed command. In a positioning control device configured to control the speed of the motor according to a deviation from the pulse cycle speed calculation circuit for calculating the speed from the pulse cycle of the position command pulse,
An integrating circuit that integrates the output of the pulse cycle speed calculating circuit to obtain a position command complementing signal, a feedback pulse complementing signal circuit that generates an analog complementing signal based on the signal from the encoder, and a signal from the encoder 1st and 2nd which calculates a velocity feedback signal based on
And a switching circuit for selecting the first speed calculation circuit at low speed and the second speed calculation circuit at high speed, and the speed command includes the position command complement signal and the feedback pulse complement circuit. A positioning control device characterized by adding an output signal.