JPS6156130B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital synchronous transfer control method and apparatus used for transferring articles between transfer devices and processing transferred articles by a processing machine that moves parallel to the transferred articles.

For example, when operating two transfer devices synchronously,
Conventionally, the difference between the sinusoidal analog voltages of cellsin, etc. attached to each transfer device was used, so when starting the transfer device, the starting point position of the transfer device was adjusted in advance so that the phases of the analog voltages matched. There is the trouble of having to start them at the same time after matching them.
Furthermore, since there is no freedom to change the speed ratio of both transfer devices, it is not possible, for example, to increase the speed of one of the transfer devices to quickly dispose of temporary cargo accumulation in the transfer line, and then return to normal synchronous operation. However, there were disadvantages such as being practically inconvenient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital synchronous transfer control method and apparatus that eliminates the above-mentioned drawbacks of the conventional technology.

Embodiments of the present invention will be described below with reference to the drawings.

First, to explain the principle of the present invention, in FIG. 1, it is assumed that a main conveyor C1 having a drive motor M1 is operated synchronously with a slave conveyor C2 having a drive motor M2, and a pulse generator S1 is provided for each of the conveyors C1 and C2. , S2. S1,S
2 is the article transfer pitch P1 of the conveyors C1 and C2,
Assume that the same number of N pulses are generated for P2. Therefore, if P1=P2 and both conveyors C1 and C2 have the same speed, the time intervals between the generated pulses of S1 and S2 are equal, and the conveyor transfer capacities are also equal.

Figure 2 shows the generated pulse trains of S1 and S2 when the speed of conveyor C2 is higher than that of conveyor C1.If the number of pulses of both pulse trains is integrated by integrators I1 and I2, respectively, the difference between the two integrated values is negative. Conversely, if the speed of conveyor C2 is smaller than that of conveyor C1, the above-mentioned difference gradually increases in the positive direction.
Therefore, motor M1 is set by voltage setting device E.
If the speed of the motor M2 is controlled by the controller R in the direction in which the difference becomes zero according to the magnitude of the difference and the sign of the difference, the conveyors C1 and C
2 are operated synchronously with a constant speed ratio P1/P2.

However, if the integrated value and therefore the difference are changed by periodically reducing or adding pulses to one of the above pulse trains, the conveyor C2 will have a different speed depending on the number of reduced or added pulses. The conveyor C1 is operated in synchronization with the conveyor C1. The pulse interval or the number of pulses N is appropriately determined depending on the synchronization accuracy and the responsiveness of the motor M2 including the inertia of the conveyor C2.

For example, in the case of a body transfer line in an automobile factory, the synchronization accuracy may be low, so conveyor C
1. Set the allowable value of positional deviation of C2 as body transfer pitch.
200mm per 5500mm, pulse generator S1, S
If the pulse pitch of 2 is 40 mm, the number of pulses generated between 1 transfer pitch is 5500/40≒137, and the number of pulses for the above tolerance value of 200 is 200/40=4,
If the supply voltage of the motor M2 to be increased or decreased for each pulse of the difference in the integrated value is determined, the speed of M2 can be controlled within a desired allowable limit by controlling the speed of M2 in four steps.

In Fig. 2, the pulse pitches of pulse generators S1 and S2 are t1 and t2 (t1>t2), respectively.
Then, the level of the difference between these integrated values is D
Since the pulses increase by 1 pulse, 2 pulses, and 3 pulses as shown in FIG. do it.

FIG. 3 shows a block control circuit when the conveyors C1 and C2 are operated synchronously according to the number of reduced pulses by periodically reducing the pulses generated by the pulse generator S1 or S2 and decelerating or speeding up the motor M2. shows. In the figure, TG is a speed detector such as a tachometer connected to the constant speed motor M1, and A1 and A2 are pulse generators S1 and S, respectively.
This is a pulse reduction device that reduces α pulses for every N number of generated pulses.

For the transfer device C1 that is currently operating at a constant speed,
C2 shall be controlled in synchronous operation, and the transfer device C
1. In order to determine the speed ratio of C2, a speed ratio setting device 1 consisting of a digital switch is used to set the pulse generator S.
When the pulse reduction number α of 2 is set, the number α is set in the memory 3 via the encoder 2 of the pulse reduction device A2. N-ary presetting counter 4
counts the number of pulses generated by the pulse generator S2, and when the count reaches N, outputs 1 and a number α is preset from the memory 3. Therefore, the counter 4 generates an output 1 for each input pulse number N-α and closes the gate 5, and the output of the gate 5 becomes a reduced pulse train P〓 in which one pulse is reduced for every input pulse N-α. .

The pulse train P〓 is input to the subtraction terminal n of the addition/subtraction counter 6, and the pulse train P _N of one pulse generator S1 is inputted to the addition terminal m of the addition/subtraction counter 6 without being reduced.
A signal a indicating the level of the difference in the integral value of the number of pulses _N and P〓 and its sign signal b are output.

Figure 4 shows examples of pulse trains P _N and P when N is changed to 10 and α is changed to 1, 2, 3, and the difference signal a is one pulse for each pulse number N-α. You can see that it is increasing. In the figure, the pulse phases of both pulse trains are shown to match, but even if the phases do not match, the difference signal a continues to increase. The difference signal a increases faster as α becomes larger.

In the regulating voltage generator B, the speed detector TG
The analog output of is converted into an appropriate voltage e by a smoothing rectifier circuit 7 and a voltage dividing regulator 8, and this is converted by a D/A converter 9 into a correction voltage v which increases together with the difference signal a. The voltage adder/subtractor 10 inputs the set voltage V of the motors M1 and M2 set by the voltage setting device 11, the correction voltage v, and the sign signal b, and α
If is positive, the sum voltage of voltages V and v is supplied to the motor M2 according to the sign signal b to speed it up. When the motor M2 speeds up, the pulse interval of the pulse train P becomes smaller, and its integral value becomes the pulse train P _N
When it matches the integral value of D/A, signal a disappears and D/A
The converter 9 outputs a constant correction voltage v to the motor M.
2 is maintained at a constant speed increase state. Therefore, the transfer capacity of conveyor C2 is increased compared to before.

In contrast to the above, when it is desired to decelerate the motor M2 with respect to the motor M1 operating at a constant speed, the pulse reduction number α set by the speed ratio setting device 1 is given to the pulse reduction device A1. In this case, in the same manner as described above, the addition terminal m of the addition/subtraction counter 6 receives the pulse train P
However, the pulse train P _N is also input to the subtraction terminal n from the gate 5 of the pulse reduction device A2. In this case, the subtraction result of the addition/subtraction counter 6 becomes negative, so the sign signal b is inverted, and the voltage adder/subtractor 10 supplies power to the motor M2 with a voltage equal to the difference between the set voltage V and the correction voltage v to decelerate it. . When the motor M2 decelerates, the pulse interval of the pulse train P _N increases, and when its integral value matches the integral value of the pulse train P〓, the signal a
disappears, and motor M2 is maintained in a constant deceleration state. Therefore, the conveyance capacity of conveyor C2 is reduced compared to before.

The present invention has the above-mentioned configuration, and by periodically adding or subtracting pulses from one of the pulse trains generated in proportion to the moving distance of each of the master and slave transport devices operated synchronously, both the master and slave transport devices can be controlled. Since the synchronous operation of the transfer devices is controlled, there is no need to align the two transfer devices when starting the transfer devices, and therefore, the speed ratio of both transfer devices can be arbitrarily changed regardless of the transfer position. Furthermore, since it is a digital control system, accurate synchronous operation control is possible regardless of the length of the control wiring.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a diagram explaining the basic principle, FIG. 2 is a diagram explaining changes in the integral value of pulses generated by the pulse generator, FIG. 3 is a block control circuit diagram, and FIG. is an explanatory diagram of the action of FIG. 3. A1, A2... Pulse reduction device, B... Adjustment voltage generator, C1... Main transfer device, C2... Slave transfer device, M1... Drive motor of main transfer device, M2...
...Drive motor of the slave transfer device, S1, S2...Pulse generator, TG...Speed detector of the main transfer device, 1
...Speed ratio setter, 6...Addition/subtraction counter, 9...
... Conversion device, 10... Voltage adder/subtractor.

Claims (1)

[Scope of Claims] 1. In a control method for synchronously controlling a slave transfer device with respect to a main transfer device having a set speed, one of two pulse trains whose number of pulses is proportional to the distance traveled by each of the two transfer devices is provided. A digital synchronous transfer control method for periodically reducing the number of pulses in a pulse train to create a difference in the integral value of the number of pulses in both pulse trains, and controlling the speed of a slave transfer device so as to reduce the difference to zero. 2. In a control device that controls the synchronous operation of a slave transfer device with respect to a main transfer device having a set speed, two pulse generators generate a pulse train whose number of pulses is proportional to the distance traveled by each of the two transfer devices; a speed ratio setting device that determines the number of pulses to be periodically reduced with respect to the pulse train; a pulse reduction device that periodically reduces the number of pulses to be periodically reduced from the one pulse train to generate a reduced pulse train; an addition/subtraction counter that outputs a difference signal of the integral value of each pulse number between the other pulse train and the reduced pulse train and a sign signal of the difference, and converts the speed detection voltage of the main transfer device into a correction voltage that increases with the difference. The supply voltage of the drive motor of the secondary transfer device is controlled so that the difference becomes zero by adding or subtracting the correction voltage to the set supply voltage of the drive motor of the converter and the main transfer device according to the sign of the difference. Digital synchronous transfer control device with voltage adder/subtractor.