JPH038616A - Motor controller - Google Patents

Abstract

PURPOSE:To improve a synchronous travel precision at the above device such as a truck or the like, by detecting an outside travel matter speed and a travel matter movement distance by means by an outside encoder, and converting respectively the output data values of an inside encoder, and conducting the synchronous travel control of the travel matter and the truck by means of both data. CONSTITUTION:The output pulse signal of the outside encoder 10 of a work travel portion is counted by means of a counter 22. The signal of the work detection sensor 12 of the travel portion, a data sampling signal and a distance lbetween a sensor 12 installation position and an O position, together with the count value, are supplied to a CPU equivalent portion 21. The CPU equiva lent portion 21 detects the speed and movement distance of the travel portion, and converts them into the output data values of an inside encoder 2, and outputs them as the position command signals of a motor 1 into a motor control portion 13 by adding them. The control portion 13 conducts the position control of the motor 1 by means of the inside encoder 2. As a result, a synchronous precision can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a motor control device for synchronizing running of an external moving object and a truck of an apparatus, for example, and in particular, to control the starting variations of the cart and the speed of the external moving object. This invention relates to a motor control device that is not affected by fluctuations.

[Prior Art] Figure 5 is a block diagram of a conventional motor control device.
1) is an electric motor, (2) is an internal encoder (also called an internal pulse generator), and (3) is an electric motor (in response to a position command).
(1) is a motor control section that controls the position; (4) is a smoothing generating section that includes a position command device.

(5) is generally called an electronic gear, and in order to convert the number of pulses generated by the external encoder to the number of pulses generated by the internal encoder, the product obtained by multiplying the input digital value by the digital number C is further divided by the digital number. This is a calculation unit that outputs the quotient. Therefore, it can be considered that the input value is multiplied by the conversion coefficient C/D and then outputted, and is constituted by, for example, a microprocessor (hereinafter referred to as CPU), and performs the above calculation.

(6) is a counter that counts this pulse train signal, since the input signal from an external encoder is generally a pulse train signal from an incremental encoder;
) is an input interface (hereinafter referred to as input 1/F) for inputting an external signal to start the electric motor (1).

FIG. 6(a) is an explanatory diagram showing an example of application of the motor control device in FIG. 5, in which (1) is the same electric motor as in FIG. 5, (8) is a belt conveyor, and (9) is a belt conveyor (8 ), (10) is an external encoder (also called an external pulse generator), (11) is a trolley that is controlled to run in synchronization with the workpiece (9), and (12) is the workpiece This is a sensor (for example, an optical sensor) that detects passage.

FIG. 6(b) is a speed waveform diagram illustrating the operation of FIG. 6(a).

The operation of FIG. 6(a) will be explained with reference to FIG. 6(b).

In Fig. 6(a), the workpiece (9) on the belt conveyor (8) and the cart (11), which are always running, are assumed to run synchronously in the section from point A to point B in the figure. do.

The cart (11) is stopped at the 0 point, and the workpiece (9) is stopped at the 0 point.
) starts when it passes the position where the sensor (12) is installed, moves at the same speed as the traveling workpiece (9) from point A to point B, and then returns to point 0 again. be. FIG. 6(b) is a speed waveform diagram showing the above operation. That is, the cart speed first linearly accelerates from zero, reaches the conveyor speed, then becomes constant speed, and after passing point B, linearly decelerates to zero. Then accelerate in the opposite direction,
After going through the process of constant speed and deceleration, the cart stops when it reaches the zero point.

A case where the applied operation explained in FIGS. 6(a) and 6(b) is performed by the conventional electric motor control device shown in FIG. 5 will be explained. A pulse train signal output from an external encoder (10) directly connected to an electric motor that drives a belt conveyor (8) is input to a counter (8). The counter (6) counts the input pulse train signals and supplies the counted value to the electronic gear (5). In order to convert the number of pulses generated by the external encoder (lO) into the number of pulses generated by the internal encoder (2), the electronic gear (5) multiplies the input pulse count value by a digital number C and then converts it into a digital number. Output the divided quotient,
It is supplied to the smoothing generator (4).

Also, the detection signal from the sensor (12) is input to 1/F (7).
connected to the input of

The workpiece (9) on the belt conveyor (8) is
2), a detection signal from the sensor (12) is supplied to the smoothing generator (4) via the input 1/F (7). Smoothing generation part (4)
generates a pattern signal determined by the set smoothing time constant, and issues a position command to the motor control section (3).

At this time, the area of the triangle shown with diagonal lines in FIG.
) The installation position of the sensor (12) is set at a position advanced by a distance Ω from the stop position 0 point. By making the initial adjustment in this way, when the cart (11) reaches the same speed as the belt conveyor, the workpiece (9
) and the cart (11) will be in the same position, so
If the vehicle travels to point B at that speed, the operation described in FIG. 5 becomes possible.

[Problems to be Solved by the Invention] In the conventional electric motor control device as described above, in order to align the positions of the workpiece and the cart that are traveling synchronously, the sensor (12) is moved forward by the time delay during which the cart accelerates. They were making adjustments to the actual equipment and proceeding with the installation.

This adjustment was performed on the assumption that the moving speed of the workpiece was always constant and that there was no variation in starting the cart. However, in reality, various errors exist as shown in FIGS. 7(a) and 7(b).

FIG. 7(a) is a diagram explaining the start-up variation of the bogie, and the figure shows that the delay due to the variation in Δt is added to the processing delay T for the bogie to start starting after receiving the position detection signal of the sensor. This shows that, assuming the speed of the conveyor is V, the position where the workpiece and the cart enter synchronization will deviate by ■·Δt.

FIG. 7(b) is a diagram explaining the variation in conveyor speed, and the figure shows that when the conveyor speed changes from V to V+ΔV, the position where the warp and the cart enter synchronization is Δvat, where the acceleration time is t. It will shift by just that. Therefore, the conventional control device has a problem in that an error occurs every time in the synchronized position of the workpiece and the cart.

The present invention has been made to solve these problems, and an object of the present invention is to provide a motor control device in which the synchronized position of the workpiece and the truck is not affected by speed fluctuations of the conveyor or variations in starting of the truck.

[Means for Solving the Problems] A motor control device according to the present invention includes an electric motor that drives a cart or the like via a drive device, an internal encoder that detects the rotational position of the electric motor, and an external encoder that detects the rotational position of the external motor. speed detection and conversion means for detecting the speed of a running object driven by an external electric motor from an output signal of an external encoder and converting the detected speed into an output data value of the internal encoder; The distance traveled by the running object between the time when the moving object and the subsequent sampling time of the output signal of the external encoder is detected from the difference value between the output signals of the external encoder, and the detected moving distance is detected from the difference value between the output signals of the external encoder. a moving distance detecting and converting means for converting into an output data value of an encoder; A smoothing pattern that generates a smoothing pattern by calculating from three types of signals output from a set distance converting means for converting into a data value, the speed detecting and converting means, the moving distance detecting and converting means, and the set distance converting means. generating means; the sum of the output signal of the smoothing pattern generating means and the output signal of the speed detection and conversion means is used as a position command signal; and the output signal of the internal encoder is used as a feedback signal; and motor position control means for controlling the position of the electric motor so that a positional deviation between the two is zero.

[Function] In the present invention, the electric motor of this device drives a cart or the like via a drive device, an internal encoder detects the rotational position of the electric motor, and a speed detection and conversion means detects the rotational position of the external electric motor. The speed of the moving object driven by the external electric motor is detected from the output signal of the external encoder, the detected speed is converted into the output data value of the internal encoder, and the moving distance detection and conversion means detects the speed of the moving object driven by the external electric motor. The distance traveled by the running object between the time when the moving object and the subsequent sampling time of the output signal of the external encoder is detected from the difference value between the output signals of the external encoder, and the detected moving distance is detected from the difference value between the output signals of the external encoder. A set distance conversion means converts a preset distance between a specific position where the traveling object passes and an initial stop position of the trolley, etc. into an output data value of the internal encoder. The smoothing pattern generating means generates a smoothing pattern by calculating from the three types of signals output from the speed detecting and converting means, the moving distance detecting and converting means, and the set distance converting means, and the motor position controlling means uses the sum of the output signal of the smoothing pattern generation means and the output signal of the speed detection and conversion means as a position command signal, and uses the output signal of the internal encoder as a feedback signal to determine the position between the traveling object and the truck, etc. The position of the electric motor is controlled so that the deviation becomes zero.

[Embodiment] FIG. 1 is a block diagram of a motor control device showing an embodiment of the present invention, and (1) and (2) are completely the same as the conventional device described above. Reference numeral (13) is a motor control unit that controls the position of the electric motor (1) in response to a position command, and performs control so that the droop between the position command and the position of the motor becomes zero. (14) is the smoothing generation part, (15
-1) and (15-2) are electronic gears for converting the number of pulses generated by the external encoder (lO) into the number of pulses generated by the internal encoder (2), and convert the input digital value into a conversion coefficient C/
Multiply by D and output.

Here, C and D are both digital values. (IB) is an electronic gear for converting the distance g between the installation position of the sensor (12) and the zero point position in Fig. 5 (a) into the number of pulses generated by the internal encoder (2). The value is multiplied by the conversion coefficient A/B and output. Here, A and B are both digital values. (17) is a frequency detector which detects the frequency of the input pulse train signal from the number of pulses input during a fixed period of data sampling time (ie, the increase in the count value of the counter (22)). (18) is a difference value detection value, which detects the difference between two data values when the next data is input after a certain period of time after the first data is input. Normally, the difference value can be calculated by subtracting the previous data value from the subsequent data value. (1
9) is an adder that adds two pieces of data, and (20) is a switch. Each of the devices (14) to (20) above can be configured as independent hardware, but it is also possible to configure them collectively with a CPU, and the CPU can perform all the functions of each device above. Since it is possible, (
21) is a portion corresponding to this CPU. (22) is a counter that counts this pulse train signal, since the input signal from the external encoder (10) is generally a pulse train signal from an incremental encoder in many cases, and (23) inputs the count value of the counter (22). This is a latch circuit that latches the signal, and the latch operation is performed when a detection signal from the sensor (12) is input and when a subsequent data sampling signal is input. (24
) is a data manual 1/F for inputting data of distance g from an external keyboard or the like.

FIG. 2 is a waveform diagram for explaining the operation of FIG. 1.

The operation of FIG. 1 will be explained with reference to FIG. Figure 5(a)
A pulse train signal output from an external encoder (lO) directly connected to the electric motor that drives the belt conveyor (8) is always input to the counter (22).

The counter (22) constantly counts the input pulse train signals, and the counted value is transferred to the frequency detector (17) and the latch circuit (
23). In order to read the count value of the counter (22), the frequency detector (17) is supplied with a data sampling signal of a constant period from the outside, so that the count value of the counter (22) is read every time this data sampling signal is input. is read, and the frequency of the input pulse train signal is detected from the increase in the count value of the counter (22) during this data sampling period. The frequency just detected is f, and this f. The data is supplied to the electronic gear (15-1).

Generally, the data sampling signal and the detection signal from the sensor (12) are asynchronous, so the latch circuit (23) uses the detection signal input from the sensor (12) first.
The first count value is latched by the counter (22), and the count value is supplied to the difference value detection device (18). Next, a second count value is latched from the counter (22) by the data sampling signal immediately following the detection signal from the sensor (12), and the count value is supplied to the difference detector (18,). The difference detector (18) detects the difference value between the first and second input count values.

In other words, by detecting the number of pulses input from the external encoder (lO) during the time from input of the detection signal from the sensor (12) until input of the subsequent data sampling signal, The distance traveled by the traveling workpiece (9) during the above time is detected.

The detected difference value is supplied to the electronic gear (15-2).

In addition, the data of the distance g between the installation position of the sensor (12) and the zero point position in Figure 5 (a) is data
F (24). This data input■／F
The data value of the distance g input in (24) can be set arbitrarily. For example, by providing a dedicated variable setting device, inputting arbitrary data from the keyboard, etc.
A data value of an arbitrary distance Ω can be input by receiving arbitrary data from an external device using a data communication method such as H.232C. Therefore, during the initial adjustment of this device, there is no need to precisely adjust the zero point position and the installation position of the sensor (12) using the mechanical system; only the data value of the distance g is changed to match the actual installation position. do it.

The distance g data input to the data input 1/F (24) is supplied to the electronic gear (1B).

The electronic gear (15-1) receives the frequency f of the pulse train signal generated by the external encoder (10) and is supplied from the frequency detector (17). is multiplied by the conversion coefficient C/D, and the multiplication result is f. C/D is output and supplied to the input side of the switch (20). f is the output signal of the electronic gear (15-1).

C/D is called signal a, and signal a is a moving object (workpiece).
9), and it will be explained below that this can be used as the command speed.

Now, the workpiece (9) per pulse of the external encoder (lO) is
) is the distance g. Traveling forward, the frequency of the pulse train signal at this time is f 1 The traveling speed of work (9) is vII117se
If c, the following equation (1) is obtained.

V-gofo (mm/5ec)...(
1) From this formula (1), the frequency f of the pulse train signal. If this is known, the traveling speed V can be determined.

In addition, the pitch of the ball screw directly connected to the electric motor (1) of the control device that runs in synchronization with this work (9) is set to Smm/r.
ev, the resolution of the internal encoder (2) is P.

If it is pulse/rev, the ball screw moves by S/Pomm/pulse per pulse. Therefore, the conversion coefficient C/D of the electronic gear (15-1) is set to satisfy the following equation (2).

D　S/P.

The traveling speed of the workpiece (9) is VIIltI/seC, and the frequency f of the pulse train signal of the external encoder (10). When input to the electronic gear (15-1), the output signal a becomes the following equation (3).

a-f　o　C/　D S/P S/P.

Therefore, (3) can be obtained from the output of electronic gear (15-1).
If signal a in the equation is taken as a speed command signal, then the electric motor (1) is given a speed command signal with a speed vI1 m/sec.

The signal a output from the electronic gear (15-1) is transmitted through the switch (
20). When the detection signal from the sensor (12) is input, the switch (20) immediately closes the circuit, outputs the signal a, and supplies it to the adder (19) and the smoothing generator (14). In FIG. 2, waveform (1) shows the speed V of the conveyor, waveform (2) shows the detection signal of the sensor (12), and waveform (3) shows the signal a. The amplitude of signal a of waveform (3) is f. It is C/D.

The electronic gear (15-2) multiplies the difference value data input from the difference value detector (18) by the conversion coefficient C/D, outputs the multiplication result as a signal C, and outputs the multiplication result to the smoothing generator (14). supply Electronic gear (tS) is data human power 1
/F In order to convert the distance Ω data input from (24) into the number of pulses of the internal encoder (2), the human data is multiplied by the conversion coefficient A/B, and the multiplication result is converted into the signal d.
The smoothing generator (14) is outputted as a smoothing generator (14). The smoothing generator (14) is connected to the input signal aSC.
and d, a smoothing pattern called a signal shown in waveform (4) in FIG. 2 is generated and supplied to an adder (19). This signal S has a signal amplitude f which is the same as that of the signal a. It is generated in such a way that the sign of C/D is opposite polarity, and the area indicated by diagonal lines in waveform (4) is equal to the signal (d-C) corresponding to the physical distance Ω. be.

FIG. 3 is a detailed diagram of the waveform of FIG. 2. The method of generating the signal S using waveform (1) in FIG. 3 will now be explained in detail. In the following description, for example, the unit of distance will be expressed as a dragon, and the unit of distance data will be omitted.

The difference value detector 18) is output as information on the distance traveled by the workpiece (9) after the workpiece (9〉) passes the installation position of the sensor (12) until the data sampling signal is input. The differential value data to be output is transferred to the electronic gear (15
-2), the value of the signal C converted through the electronic gear (16) is 15, the value of the signal d, which is converted from the distance Ω data output by the data human power 1/F (24) through the electronic gear (16), is 75, and the moving speed. Assume that the value of signal a is 10 mm/5ees and the acceleration/deceleration rate is 2 mm/5ee2. In this case, the remaining distance at the time the data sampling signal is input is d−c
= 75-15-80. In the waveform <1) in Fig. 3, by moving by lO at a constant speed from time t1 to t4, by moving by 8 at time t, by 6 at time t, by 4 at time t7, and by 2 at time t8, Remaining distance 8
0 movement can be completed. In this way, signal a
, C, and d and by setting the acceleration/deceleration rate, the smoothing generator (14) can generate a signal pattern. The adder (19) in FIG. 1 adds the positive polarity signal a and the negative polarity signal S, outputs a signal (a+b) as shown in the waveform (5) in FIG. 13). The motor control unit (13) controls the motor (1) so that droop does not occur between the input command signals (a and b) and the position of the trolley (11).
) and the trolley (11) will travel in perfect alignment after synchronization.

This will be explained in detail with reference to FIG. The waveform in the same figure (2
), the value of the traveling speed V of the workpiece (9) is set to 10
Since it is mm/sec, the workpiece (9) is time 1
Move a distance of 90 by -19. -Blade cart (11)
The movement is shown as the signal (a-b) of waveform (3) in FIG.
+ 8 + 10-30 travels, speed is V-10m
m/sec. However, when the trolley (11) passes the sensor installation position and the data sampling signal is input, it is located a distance [80] in front of the workpiece (11), so it is 30+60-90 from the sensor installation position, 9) and the cart (11) are at the same position and have the same speed v = 10 mm/see.

FIG. 4 is a waveform diagram illustrating another embodiment of the present invention. In the figure, waveforms (1), (2), and (3) are exactly the same as the waveforms in FIG. Waveform in Figure 2 (4
) and waveform (5) indicate that after the workpiece (9) passes the sensor installation position, the cart (11) is accelerated after a certain period of time and the workpiece (9) and the cart (11) reach the same position. This shows that both have the same speed. However, waveform (4) and waveform (5) in Fig. 4 are different from the workpiece (
9) passes the sensor installation position, immediately accelerate the cart (11), make the speed of the cart (11) faster than the speed of the workpiece (9), and then decelerate to the same speed. There is. The area gs and g of the shaded part in the waveform (4) have a relationship of D-111 with respect to the distance g between the installation position of the sensor (12) and the 0 point position.

In the above description, an example is given in which both the internal and external encoders are incremental encoders that output relative position signals, but this may be replaced by an absolute encoder.

That is, in this case, the angular position signal as an absolute value is sent from the external encoder to the frequency detector (22) without going through the counter (22).
17) and the latch circuit (23), exactly the same operation can be expected.

Furthermore, it is clear that even if each hardware device in the above embodiment is replaced with a CPU and software that perform the same functions, exactly the same operation is possible.

[Effects of the Invention] As described above, according to the present invention, the speed of a traveling object driven by an external motor is detected from the output signal of an external encoder that detects the rotational position of the external motor using a speed detection and conversion means, and The detected speed is converted into an output data value of the internal encoder, and the moving distance detection and conversion means is used to convert the detected speed into an output data value between the time when the traveling object passes a specific position and the subsequent sampling time of the output signal of the external encoder. The distance traveled by the running object is detected from the difference value between the output signals of the external encoder, the detected moving distance is converted to the output data value of the internal encoder, and the running object is calculated by taking the converted moving distance into account. Since the synchronized running of the object and the cart is controlled, even if there is a delay or variation in the starting process of the cart, there will be no variation in the synchronized position, and even if the speed of the moving object varies, the speed of the cart will be maintained. follows this, so highly accurate synchronized running is achieved and the performance of the device is improved.

In addition, since the device according to the present invention has a very small increase in cost compared to conventional devices, it has a high performance-to-cost ratio and is economical.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a motor control device showing an embodiment of the present invention, FIG. 12 is a waveform diagram for explaining the operation of FIG. 1, FIG. 3 is a detailed diagram of the waveforms in FIG. 2, and FIG. The figure is a waveform diagram explaining another embodiment of the present invention, FIG. 5 is a block diagram of a conventional motor control device, and FIG. 6(a) is an explanatory diagram showing an example of application of the motor control device of FIG. Fig. 6(b) is a speed waveform diagram explaining the operation of Fig. 6(a), Fig. 7(a) is a diagram explaining variations in starting of the cart, and Fig. 7(b) is a diagram illustrating variations in conveyor speed. FIG. In the figure, (1) is the electric motor, (2) is the internal encoder, (3) and (13) are the electric motor control unit, and (4) and (1
4) is the smoothing generation part, (5), (15-1),
(15-2), (16) are electronic gears, (6), (22
) is the counter, (7) is the input 1/F, (8) is the belt conveyor, (9) is the workpiece, (10) is the external encoder,
(11) is a trolley, (12) is a sensor, (17) is a frequency detector, (18) is a difference value detector, (19) is an adder,
(20) is the switch, (21) is the CPU equivalent part, (23
) is a latch circuit, and (24) is a data input 1/F. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] An electric motor that drives a cart or the like via a drive device, an internal encoder that detects the rotational position of the electric motor, and an external electric motor driven by an output signal of the external encoder that detects the rotational position of the external motor. speed detection and conversion means for detecting the speed of a running object and converting the detected speed into an output data value of the internal encoder; and a time at which the running object passes a specific position and a subsequent output of the external encoder. A moving distance detection method that detects the distance traveled by the running object between a signal sampling time and a difference value between the output signals of the external encoder, and converts the detected moving distance into an output data value of the internal encoder. a conversion means; a preset distance conversion means for converting a preset distance between a specific position through which the traveling object passes and an initial stop position of the cart or the like into an output data value of the internal encoder; A smoothing pattern generation means that generates a smoothing pattern by calculating from three types of signals output from the detection and conversion means, the moving distance detection and conversion means, and the set distance conversion means, and the output signal of the smoothing pattern generation means. and the output signal of the speed detection and conversion means as a position command signal, and the output signal of the internal encoder as a feedback signal, so that the positional deviation between the traveling object and the truck etc. becomes zero. A motor control device comprising: motor position control means for controlling the position of the motor.