JPS58141688A - Digital servo device - Google Patents

Abstract

PURPOSE:To alleviate the load of an arithmetic controller by composing all circuits as a rule in all of digital circuits and performing the calculation and signal processing processed by program partly by the digital circuits. CONSTITUTION:Moving information of an article is detected by a moving information detector 10, and information for driving and controlling a DC motor 1 is formed by an arithmetic controller 10 from the moving information and reference position information. A pulse width modulator 30 pulse-width-modulates on the basis of the driving and controlling information of the motor 1. A motor drive circuit 40 supplies a drive power to the motor 1 in accordance with the pulse signal outputted from the modulator 30. The drive power of the motor 1 is detected as the current value by a current detecting resistor 51, converted by an A/D converter 52 to a digital signal, and supplied through a feedback circuit 50 to an arithmetic controller 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a digital chip that drives and controls a device for positioning a semiconductor at high speed and with precision, for example, in a semiconductor manufacturing process.

[Technical background of the invention and its problems]

Conventionally, this type of servo device detects rotation information of a DC motor 1 for moving an object and current position information of a multi-object using an encoder 2 and a direction determining circuit 3, as shown in FIG. The comparison calculation circuit 4 compares the information with the information on the position where the object should be located and the reference position information to determine the difference, and the deviation counter 5 generates control information to reduce the difference in ζ to zero. There is a system in which the signal is converted into an analog note by a D/▲ converter 6, and then applied to a drive circuit 7, which drives and controls the DC motor 1 to position the object.

However, in a device with such a configuration, since the driver circuit 7 is configured with an analog circuit, it is easily affected by offset, drift, noise, etc., and therefore the operational stability of the gear system is affected. This has the disadvantage that the adjustment of the circuit is extremely complicated. In addition, conventional, sir, equipment generally
Electromagnetic tachometer to improve control characteristics -8
is provided to obtain the speed signal of the DC motor 1, and this signal is transmitted to the first
As shown in the figure, a feed path to the output side of the D/A converter 6,
It's happening. However, such a conventional configuration has disadvantages in that the electromagnetic tachometer 8 is used, making the configuration large and expensive.

1'. On the other hand, as another configuration of the digital circuit and i device, part of the analog (ro) circuit part was converted to digital circuits, and most of the control system was processed by micro-combiner and -ta programs. something is proposed. With such a device, the effects of offset, drift, and noise are extremely reduced, but since all control is performed by program execution, there is the problem of not being able to speed up the control response. .

[Purpose of the invention]

Main departure 8A, offset, drift and shadow of noise II! This invention aims to improve the stability of control operation by reducing E, and to increase control response speed by making efficient use of a microcomputer, and to provide a digital serge device with excellent operational performance and a simple configuration.

[Summary of the invention]

In order to achieve the above object, the present invention configures a motor drive circuit system with a digital circuit, and transmits current position detection information in a digital differential signal format suitable for a program-controlled arithmetic control circuit (for example, a microcomputer). A counter is used to convert the resultant red, and the arithmetic control circuit outputs the calculated red in the form of a signal as it is.This is then processed by a digital circuit consisting of a counter, etc. to perform pulse width modulation. In this way, the drive power of the motor is detected by a resistor circuit, and this is used to correct motor drive control information in an arithmetic control circuit.

In other words, the present invention configures all circuits as digital circuits in principle, and also uses digital circuits (partially for arithmetic operations and signal processing that were conventionally processed in programs).
This is done by hardware) to reduce the burden on the arithmetic control circuit.

[Embodiments of the invention]

FIG. 2 is a schematic diagram showing the configuration of a digital surfing device according to an embodiment of the present invention. This device includes a movement information detection circuit 10 that detects movement information of an object, and a movement information detection circuit 10 that detects movement information of an object. An arithmetic control circuit 2o that creates information for driving and controlling the DC motor 1 from the reference position information, and an arm @ modulation circuit 30 that performs arm rotation 411 control based on the drive control information of the motor. A motor drive circuit 40 which supplies driving power to the DC motor 1 according to the output signal from the pulse width changing circuit 30 and a current detection resistor 51 converting the driving power into a current value. It is comprised of a feedback circuit 50 which detects the signal, converts it into a digital signal by an A7'D converter 52, and then supplies the signal to the arithmetic control circuit 20.

The movement information detection circuit 10 has an optical encoder 11, and first, the encoder 1 outputs a triangular wave signal M8, B8 consisting of human phase and B phase representing the rotation direction and amount of rotation of the DC motor 1. And this triangular wave signal S,
The BS is introduced into the direction determining circuit 12, where the rotational direction of the motor 1 is determined from the phase difference thereof, and the amount of rotation is detected from the wave number of the triangular wave unit time tooth. Then, /4 pulse strings CP and DP of the number proportional to this detection aK are outputted from the direction discrimination circuit 12 for each rotation direction (positive direction, negative direction) and asked to counter 1:i#14, respectively. -3 and 14, respectively, and the counted values are output as object movement information co;bG in the form of, for example, an 8-bit parallel signal.

As shown in FIG. 3, the direction determining circuit 12 first inputs the human phase and B phase signals As and BS from the encoder 11 to the comparators 15 and 16, where the signals A8 The average value of BS is converted into υ binarization based on the standard level determined. Then, each of these binary outputs and its inverted binary output are combined and supplied to each r-to-controlled monostable multivibrator 17,
The respective outputs are outputted for each direction of rotation via OR gate circuits 18 and 19. It has become a thing.

The arithmetic control circuit 20 is a CP consisting of a microprocessor.
U 21, a ROM that stores the object movement control program and reference position information, and a RAM that stores information introduced from outside and calculated values.
23, the counter j, 14 and the pulse@modulation circuit 3
The ninth Ilo il inputs and outputs information for 0 etc.
1, 4, and a driving clock/4' pulse generator 25. Then, the arithmetic control circuit 20 performs the arithmetic operation flff111ill according to the following procedure. In other words, after the system has been reset, the CPUJJ receives an interrupt from the clock/4 pulse (for example, 1 kHz) CPI from the clock/4 pulse generator 25. Each time an input is made to the terminal, movement information CG and DG are introduced from the counter xs:x4 of the movement information detection circuit 10, and drive current detection information IQ is introduced from the feedback circuit 50. Then, compare the above movement information with the movement information introduced at the time of inputting the previous Clock Tour CP1 and check the difference between the two.
The movement 1iiv,v while the PI is input is determined. Here, since the moving amounts v and v are moving amounts per unit time p, they can be regarded as moving speed information of the object. Next, cPUz
, 1 is the above movement amount vFv from the previous clock arm CP
The current position information P, D is obtained by adding it to the position information calculated at the time of input, and this P7 is compared with the reference position information P0, which is stored in ROM; Drive control information MG for the motor 1 is generated. This drive control information MG is composed of stone information (for example, 2 bits, g) that determines the rotation direction of the motor 1, and information that determines the amount of rotation (for example, 10 pits). Among these, the information that determines the rotation amount is information that determines the pulse width of the arm pulse signal for motor drive control. This information Pw is not only an element corresponding to the difference between the current position information PFD and the reference position information P, but also a speed feedback element obtained from the object speed information and the drive current detection information IG. The obtained current feedback elements are each corrected and added, for example, by the following equation.

PW"KQ(PI)l PFD- to 1vFD) - to 2'FW K.: Time conversion coefficient, : Speed feedback coefficient 2: Current feedback coefficient IFV "Current detected value.

In this way, the CPUJJ transfers the gain/loss drive control information MG to Ilo.
24 to the Nolles width modulation circuit 30. Note that each calculated jIL value obtained by the above calculation is stored in the RAM 2J.

As shown in FIG. 4, the pulse width modulation circuit 30 includes two sets of counter circuits 1' and 2, each of which performs a side run count operation based on the clock/four pulses CP2 of the clock/four pulse generator S1.
．． It has 13. These counter circuits s2 #
33, the count circuit S2 is for determining the pulse frequency of driving the motor 10, and the time constant register sx
Every time the counter sxb counts by a certain value with mK setting
c7! Repeat the operation of setting JV differential p and gear S4. On the other hand, the counter circuit 33 calculates /l of the drive/arm pulse.
19 Time constant register 33 is used to determine the pulse width.
The information for determining the pulse length introduced into m is first introduced into the KfJ counter ssb every time a set output is generated from the counter circuit 32. Then, when the above information ~ has been counted, a signal is issued to the
Reset. Tsutshi, this 7th grade float! The set output generation period of 34 corresponds to the pulse width.

The output pulse signal OP of this frig flow gate 34 passes through an AND gate circuit 35. It is sent to the motor drive circuit 40 as OP2. Here, these AND gate circuits 35 and 36 reciprocally turn on and off the gates according to the outputs of the Furi, fFlo, and Zo 37 whose states are set by the information that determines the rotational direction of the motor l among the drive control information MG. The direction of rotation of the shimotor 1 is designated by K.

FIG. 5 shows the configuration of the motor drive circuit 4o.
The motor drive pulse width OPI and pulse width modulation circuit 3o outputted from the pulse width modulation circuit 3o are introduced into comparators 41 and 42 for each rotation direction of the motor 1, respectively. The voltage is converted from, for example, 5V to 8V by the converters 41' and 42, and the polarity is inverted by the inverting amplifiers 43, 44, and then supplied to the FET Ql e Q2 of the switching circuit 45. On the other hand, the output pulse signals OP 1' and OP 2' of the converters 41 and 42 are introduced into switch control circuits 46 and 41, respectively. These switch control paths 4e and 4r are the above-mentioned Takanoculus scar number OPI.
'.

Each of the 7 Otokazora 46*a47* is turned on and off according to the signal level of OP2', and switching signals SPI are sent from the converters 46b and 4'lb, respectively, according to the on/off state.

SF3 and these signals sp1. SP2 is supplied to FETs Q2-Q4K of the switching circuit 46, respectively. Note that these switch control circuits 46 and 47 have the same configuration, so only the configuration of 47 is shown in the figure and 46 is omitted. Now, switching circuit 45Fi, motor 1 drive power supply (+20V and -20V
V), the series circuit of FETs Ql and Q5 and the series circuit of FETs Q4 and Q2 are connected in parallel, and the radio wave detection resistor 51 is connected between the intermediate points of each series circuit. It consists of a DC motor J connected in series. Note that, as each FETQ, Q4, a 9W MO8FgT is generally used, which has excellent frequency characteristics and can simplify the circuit.

Therefore, in such a motor drive circuit 40, when a /4 pulse OP 1 ("H" level 5 V) for rotating the motor 1 in the forward direction arrives from the / pulse width variable sl@ path 30, the comparator 41 and A4 pulse signal for switching by amplifier 43 (for example, ""H#H#
Level 8v has been achieved and FE'r Q.

conducts. Along with that, the switch control circuit 47
switching signal (e.g. @“L” level -8V
) SPI is formed and FMQ becomes conductive. This result F
The DC motor IK power output is supplied via ET Ql and Q, and the DC motor l performs normal rotation operation. At this time, voltage is supplied to the DC motor l in a pulsed manner, but D
The current flowing in the C motor is almost continuous due to the actance.

Also, for example, the arm OP2 for reversing the motor 1.
When FICTQ and q4 are brought into conduction, the DC motor IK power output is supplied and the DC motor I rotates in the reverse direction.

Next, the operation of the nine devices configured as above will be explained.

The ROM K of the arithmetic and control circuit 2o stores in advance a groudram for controlling the movement of the object, and the CPU 2J sequentially creates drive control information for the DC one-by-one according to the groudram and drives the blade. As a result, the DC motor 1 rotates according to the information VC and moves the object.

Now, the moving state of this object is detected by the encoder i'r as the rotation direction and rotation amount of the MFiDC motor J, and the direction determination circuit 12 outputs the Yars column CP,
It is output as DP. And this Nonorus row CP
, DP are counters II, respectively.

14 and converted into a parallel signal of, for example, 8 pins, which is input to the CPU (microprocessor) and supplied to the CPU in a form that is easy to process. CPU2J
From Kuro, Ri4 Luz Generator 25 to Kuro, Ri Δ Lus C
Every time PI is input as an interrupt signal, the output information CG, DQ of each of the counters 13e14 and the drive current detection information IQ detected by the # traceback circuit 5o are respectively introduced. Then, by performing the introductory calculations already mentioned, motor 1
The drive control information is created and output in the same signal format. Therefore, the operation of the CPU 21 at the time of execution is only to create the above-mentioned drive control information, and there is no need for signal processing of each input information or creation of a drive nolus signal, so the program is greatly simplified. The processing time is reduced.

The drive control information output from the arithmetic control circuit 20 is sent to the time constant register 5sa of the pulse width modulation circuit 30.
K is set, and the counter JJlb counts the value specified in the drive control information above to drive the motor. Define the width of the loop OP.

Further, this motor driving rotation arm OF is outputted from the terminal corresponding to the rotation direction specified by the drive control information by the driver f70 37 and the AND gate circuits ss and xi. In this way, the motor driving pulse OP 1 ,
When OP 2 is output, the motor drive circuit 40 transfers the t4 pulses OP 1 and OP 2 to the switching circuit 4.
Switching circuit 46 converted into a companion form suitable for control of 5
selectively conducts FITQ, .

As described above, in this embodiment, since the motor drive circuit 40 is configured to control the supply of power output to the motor 1 through a switching operation, there is no practical problem of bad engraving due to offset, drift, and noise. It can be reduced to a very small extent. As a result, the operational stability of the control system can be improved and accuracy can be improved. In addition, the movement information detection circuit 1o and the pulse wheel modulation circuit J6 are provided with counters 13.14, count circuits JJ, JJ, etc., so that the input/output information for the j50PUxiK is
Since the form 1IIK is arranged so that UzJ can immediately handle it, the CPUJJ program can be greatly simplified and the processing speed can be improved. In this case, since the circuit for adjusting the signal form can be configured with a relatively simple circuit such as a counter, the configuration does not become complicated. 51 is installed externally to detect the drive current flowing through the motor 1, and the detected value is used for creating drive control information in the CPU 21. Therefore, it is possible to eliminate the nonlinearity of the delta pulse variation circuit, and the power MO
8FgT Q4. ~． It is possible to compensate for variations in conduction resistance between the source and drain of Q4 and for an increase in conduction resistance due to temperature rise, making it possible to construct a highly stable control system. In the case of a tachometer, the configuration is much larger than when using a conventional electromagnetic tachometer.
lAK can be simplified and a compact device can be realized. It is also possible to improve reliability.

Note that the present invention is not limited to the above embodiments.

For example, each counter 13.14 of the movement information detection circuit 10
may be configured with one ag-end counter. In this way, the circuit configuration can be further simplified. Nine C
A moving coil type linear motor may be used instead of the motor. In that case,
- You can use 〆. Furthermore, the switching circuit 45 of the motor drive circuit 40 may be configured using bipolar transistors.

Other CPU 2 JK arithmetic methods, elbow smooth modulation circuits, feedback circuits, and movement information detection (gIWIIO
The configuration and the like can be modified in various ways without departing from the gist of the present invention.

〔Effect of the invention〕

The present invention configures the motor drive circuit system with an f-turn path, uses a counter to convert current position detection information into a signal form suitable for a program-controlled arithmetic control circuit, and sends arithmetic results from the arithmetic control circuit. It is configured so that the signal is output in the same form as it is, and the motor drive power is detected by a resistor circuit and used to correct the motor drive control information in the arithmetic control circuit.

Therefore, according to the present invention, it is possible to improve the stability of control 1 operation by reducing offsets, drifts, and noise artifacts, and to increase the control response speed by making it possible to use microcombinations with good efficiency. It is possible to provide a digital sensor with excellent operating performance and simple configuration.

[Brief explanation of the drawing]

Figure 1 is a block configuration diagram of a conventional digital server device, Figures 2 to 5 show an embodiment of the present invention, and Figure 2 is a block diagram showing the entire digital server device. , FIG. 3 is a circuit diagram showing the configuration of the direction discrimination circuit, and FIG.
This figure is a circuit diagram of the pulse width modulation circuit, and FIG. 5 is a circuit diagram of the motor drive circuit. 1... DC motor, 10... Movement information detection circuit, 2
0... Arithmetic control circuit, 3Q-Norse width modulation circuit, s
2.33...Count circuit, 40...Motor drive circuit, 45...Switching circuit, 46.41--Switch control circuit, 50--Feedback circuit, 51--Current detection resistor.゛□１□″Applicant's agent Patent attorney Takehiko Suzue - Figure 3 Figure 4

Claims (1)

[Claims] A motor for moving an object, a rotation information detection circuit that detects the direction and amount of rotation of the motor, converts the amount of rotation into a pulse train for each direction of rotation, and outputs it, and a rotation information detection circuit that counts the pulse train and outputs it. A movement information counter that outputs the count value as movement information of the object, and a reference position information that is obtained by introducing the movement information from this movement information counter for a certain period of time to obtain the current position information of the object and setting the information in advance. A Glodarum control arithmetic control circuit that generates drive control information for the motor in order to bring the difference closer to zero by comparing it with the drive control information; Then, each pulse width modulation is performed and the nine pulse signals are output separately according to the rotation direction information.
From the Lus width change @ circuit and this No amount Lus width change @ circuit,
a motor drive circuit that controls on/off a drive power supply path to the motor according to a pulse signal and a pulse signal to drive the motor;
This motor drive circuit is characterized by a feedback circuit that detects the drive power, converts it into a digital quantity, and supplies the value to the arithmetic control circuit to correct the motor drive control information. l device.