JPS5922109A - Synchronous controlling method of three cylinders - Google Patents

Abstract

PURPOSE:To facilitate synchronous control over three cylinders without linking them to one another mechanically by operating the pressure control valve of the 2nd cylinder according to the mean value of pressure signals of the 1st and the 3rd cylinders. CONSTITUTION:The amplitudes of the rods 6 and 7 of the 1st and the 3rd cylinders 1 and 3 are detected by position detectors 8 and 9, whose detection position signals are processed together with a command signal to operate the flow- rate servo valve 5 of the 1st cylinder 1 according to an arithmetic value. At the same time, the arithmetic value is compared with the position signals of the 1st and the 3rd cylinders 1 and 3 to operate the flow-rate servo valve 5 of the 3rd cylinder 3, moving the 1st and the 3rd cylinders 1 and 3 synchronously. Further, the pressure control valve 18 of the 2nd cylinder 2 is operated according to the mean value of the pressure signals of the 1st and the 3rd cylinders 1 and 3 to synchronize the 2nd cylinder 2 with the 1st and the 3rd cylinders 1 and 3.

Description

[Detailed description of the invention] The present invention relates to a method for controlling synchronization of 1-45 cylinders.

Conventionally, in order to synchronously control three cylinders, the rods of each cylinder are connected to each other, but the mechanical connection of the connecting parts of each rod tends to act as a disturbance element during control. The disadvantage is that the control becomes complicated.

The object of the present invention is to provide a relatively simple control method that does not have these drawbacks. A Ji-IJ-bo valve is provided, and a position detection device for detecting the amount of protrusion and retraction of the rod and a pressure detection device ftfc for detecting the pressure of the working fluid are provided, and a pressure control valve is provided in the intermediate second cylinder to operate the rod in the protrusion and retraction operation. and a pressure detection device for detecting the pressure of the working fluid, and when the rods of these first to third cylinders come into contact with the workpiece, the position signal from the position detection device of the first cylinder is used as a command signal. The flow rate servo valve of the first nuclear cylinder is operated according to the calculated value, and at the same time the calculated value is applied to the first nuclear cylinder.
The position signals from each position detection device of the third cylinder are compared with a comparison value, and the flow rate servo valve of the third cylinder is operated according to the comparison value. The pressure signal of each pressure detection device of the third cylinder is averaged, the value is compared with the pressure signal from the pressure detection device of the second cylinder, and the pressure control valve is operated according to the comparison value, The second
In addition to this feature, the invention compares the total value of each load signal from each load detection device provided in the first to third cylinders with the set load value signal, and when the difference exceeds the predetermined value, the 11th
The present invention is characterized in that a position command signal to be calculated with a position signal from the position detection device of the first cylinder is controlled in order to move the third cylinder forward or backward.

To explain one example of the "non-explosion" method with reference to the drawing (1++
21 (31+″i, for example, the first, second and third cylinders arranged linearly to lift the upper workpiece a,
(・11 (51 is the 1st and 5th cylinders on both sides (II (
Nozzle flapper type and other flow layer servo valves are shown, and each flow rate servo valve f41 (51 is connected to the first and third cylinders (1) (3) depending on the magnitude of the electric signal input to it. ) The operating direction and operating speed of the rods (6) and (7) are controlled. (81+91 is the position detection that detects the amount of protrusion and retraction of the rods (6) (71) of the first and third cylinders (1) and (3). For example, the devices +81 and +91 output an electric signal as a position signal according to the number of rotations of the vinyl men rotated by a rack provided on each rod (61+71).The electric signal of one position detection device (8) is subtracted. vessel 00
) in 1st. It is subtracted from the command signal from the power circuit side that instructs a predetermined movement of the third cylinder (11 (31), and is compared with the electric signal from the other position detection device (9) in the comparator 0υ. Also, the subtractor 00) according to the calculated value.
The flow rate servo valve (4) that drives the cylinder
The flow servo valve (5) of the cylinder (1) is activated. 0
3) (+4JO5) is each of the first to third cylinders +l1
The first and sixth cylinders (11+31
The pressure signal of the pressure detection device Q31 (1, 5) is
The average value is input to the comparator 07) and the average value is calculated by the pressure detection device Oa of the second cylinder (2).
When the comparison value is negative, the pressure control valve oath operates based on the comparison value to connect the pressure supply circuit α1 of the second cylinder (2) to the tank (A). , when the comparison value is positive, the circuit aIG is connected to the hydraulic power source (21), and when the comparison value is zero, the circuit (19) is closed, and the second nuclear cylinder (
2) is the first. The average value of the working pressure of the sixth cylinder (11 (31) was maintained and operated.

In addition, the first to third cylinders (11t2J (31 are load cells and other load detection devices ft H (23) (24
) 'i is installed to detect the load of each cylinder using the electrical quantity load signal, and after adding each load signal to the adder (c), the total value Wt is calculated using a comparator with a dead band (21ii) to detect the load signal of the set load signal. The comparator 0 (5) subtracts the set load signal W8 from the total value Wt, and the value ΔW is compared with ΔW.
When the insensible value of
7a) (27b) or relays (28a) (28bJ).If the solution of the above subtraction is -Δ or less, the comparator (support) 1 closes the relay (27a)k and activates the relay ( 27b) to open the power source (36) and increase the command signal output to the output circuit (30).
A positive voltage correction signal is sent from a), and if the solution is greater than -Δ, the relay (28a) closes and the relay (28b)
is opened and the command signal is controlled to be small by the negative voltage correction signal from the power supply (36b), and when the solution is within the range concavity to 2, the comparator (26) does not output and the relay (27
b) (28b) is closed and zero voltage is output from the power supply (!l 6 a), and the command signal is maintained as it is. c31+ is an integrator, (b)Q is a switch for changing the integration time constant of the integrator C3+), and - is the first . The power supply 5 (351) is supplied to the integrator (31) to cause the third cylinder (3) to move in and out. When each cylinder contacts the workpiece a, the output circuit (3 (1) This is a relay switch that is operated to connect the relay circuit (@) to the output circuit GO when the output circuit is turned.

To explain its operation, first turn off the relay switch (351, connect the power supply - to the output circuit 0()) via the integrator GO, and turn on the switch (32) of the integrator CI+, then subtract M(IOl A command signal of a relatively large voltage that increases with time is obtained from the output circuit connected to the subtractor (101). -4G is input to the flow rate servo valve (4), causing it to move greatly, and the first cylinder (11) moves upward at a high speed.Also, at this point, the input from comparator 0υ to comparator 0'lI is also small. The output from the comparator (12) into which the calculated value is input is also large, and the flow rate servo valve (5) connected thereto also moves greatly in order to move the third cylinder (3) quickly. 6
As the cylinders (1) and (3) start to operate, pressure is generated in the chambers on the head side, and each pressure is detected as a pressure signal by the LE force detection device 0Q51, and the pressure is output to the O mark of the calculator. The average value of the pressure signal is calculated, and it is compared with the pressure signal from the H1 force sensor NG, l) of the second cylinder (2) in the comparator 07), and the comparison value becomes the pressure, fljl
Input to J valve Oa. Since the pressure in the second cylinder (2) is relatively low, the pressure control valves 0~ are wide open to quickly transfer the fluid from the hydraulic source CD to the second cylinder (2) and to the first cylinder (2).
, the third cylinder (] + (31) is supplied to operate until the average pressure is reached. As the rod of the first cylinder (1) moves, the position signal input from the position detection device +jH8+ to the subtractor GO) gradually increases. Although it increases, the command signal of the output circuit (to) also increases, so positive calculated values continue to flow to the flow rate servo valves (4) and (5), and cylinder (]l+31 and following this, cylinder (2) move. Continue to do so.

When each cylinder (11t2J (31) comes into contact with the workpiece a, switch 03 is switched to switch (c) in order to make the gradient of the integral curve of the integrator θυ gentle, and the voltage of the command signal gradually increases, and accordingly Flow rate servo valve (4
) becomes smaller, so the valve (4) does not move much, and the movement of the flow rate servo valve (5) also becomes smaller due to the decrease in the calculated value that enters the comparator 02 from the subtractor 00). , 1st. The third cylinder (1) (3) slowly moves the workpiece a, and in synchronization with these, the second cylinder (2)
Move it loosely and lift the workpiece L.

When the workpiece a moves to the desired position R, the relay switch 051 is switched to hold the workpiece a at the set load, the relay circuit (c) and the output circuit c30) are connected, and the comparator with dead band (26) is connected in advance. When the actual load of the workpiece a changes by a certain value or more than the set load signal W8, the relay circuit 291 issues a correction signal to change the command signal. The third cylinder (11 (31) and the second cylinder (2) that follows it move to keep the load on the workpiece a constant. To explain this further, when the actual load on the workpiece a decreases, the load detection device ( The total value Wt of the load signals input from 21J(2E(2) to the comparator with dead band (26) decreases, and the difference △W between this and the set load signal W[l is the dead band - Δ
When the comparator (26) is below, the relay (27a)'f
: At the same time, open the relay (27b) and turn on the power (36r).
Since the correction signal from h) is input to the integrator Gυ, the subtractor is 0.
The command signal input to 0) increases, and as a result, the flow rate servo valve (41 (5) moves the first and third cylinders (11+31) forward, and the second cylinder (2) moves forward accordingly, and the workpiece A is pressed with a set load.Also, when the actual load of workpiece a is exceeded, the comparator C31 closes the relay (28) and opens the relay (28b), so that the negative voltage correction signal is applied to the integrator C31. ), the command signal input to the subtractor 00) becomes smaller, and the flow rate servo valve (4++51 is operated to move the first and third cylinders (ll+31) backwards based on the negative calculated value of the subtractor Cl0I). However, in synchronization with this, the second cylinder (2) also retreats.

As a result, the workpiece a is pressed with the set load.

The difference between the actual load of the workpiece a and the set load is determined by the comparator 12.
If it is within the range of dead band △ set in 6), the normally closed relays (27b) (28b) remain closed and a zero voltage correction signal is output, so the command signal does not change and the cylinder moves. never be done.

In addition, if there are 6 cylinders, divide them into 2 systems of 5 cylinders each,
If a common command signal is given to each system, all cylinders can be controlled synchronously and the load can be controlled to a set value.

As described above, according to the present invention, the first. Detected by the position detection device of the fourth cylinder 4-rod Jlt'fc,
The detected position signal is used as a command signal to operate the flow rate servo valve of the first cylinder according to the calculated value, and the calculated value is compared with the comparison value of the position signal of the first and fifth cylinders. By operating the flow rate servo valves of the three cylinders, the first and third cylinders are moved synchronously, and the first and third cylinders are moved synchronously.
．． The pressure servo valve of the second cylinder is actuated in response to the average value of the pressure signal of the third cylinder. Since the second cylinder is synchronized with the third cylinder, the three cylinders can be synchronously controlled by relatively simple means without mechanically connecting them to each other. In addition to the configuration of the first invention, the second invention compares the total value of the load signals from each cylinder with the set load signal, and if the difference exceeds a predetermined value, outputs a correction signal to change the command signal. When this is used, in addition to synchronous control, the load acting on the workpiece can be made constant, and the structure can be relatively simple and inexpensive.

[Brief explanation of the drawing]

The drawing is a diagram of an embodiment of the method of the present invention.
First cylinder (2)...Second cylinder (3)...
@3 cylinder +41 +51...Flow rate servo valve +6
1 (71 (2...rods (8) (91...
・Position detection device 00)...Subtractor 0υQ21
Q71... Comparator (13) (14) (151
...Pressure detection device (16)...Performance W device Q81
...Pressure control valve (221
Rihito North Likin -do'. 2 other people

Claims (1)

[Claims] 1. Each of the first and third cylinders on both sides is provided with a flow rate servo valve to move the rod in and out, and a position detection device to detect the amount of protrusion and retraction of the rod, and a position detection device to detect the pressure of the working fluid. A pressure detecting device is provided to detect the pressure, and a pressure control valve 'f is provided in the intermediate second cylinder to cause the rod to protrude and retract, and a pressure detecting device is provided to detect the pressure of the working fluid. When the rod contacts the workpiece, the position signal from the position detection device of the first cylinder is calculated with the command signal, and the flow rate servo valve of the first cylinder is operated according to the calculated value.At the same time, the calculated value is is compared with the comparison value of the position signal from each position detection device of the first and sixth cylinders, and the flow rate servo valve of the third cylinder is operated according to the comparison value. The pressure signal of each pressure detection device of the fifth cylinder is averaged, that value is compared with the pressure signal from the pressure detection device of the second cylinder, and the pressure control valve is operated according to the comparison value. Synchronous control method for three cylinders. 2. Each of the first and third cylinders on both sides is provided with a flow rate servo valve to move the rod in and out, and a position detection device to detect the amount of protrusion and retraction of the rod, and a pressure detection device to detect the pressure of the working fluid. A pressure control valve is provided in the intermediate second cylinder to cause the rod to protrude and retract, and a pressure detection device is provided to detect the pressure of the working fluid, and the rods of these first to third cylinders are brought into contact with the workpiece. At this time, the position signal from the position detection device of the first cylinder is calculated with the command signal, and the flow rate servo valve of the first cylinder is operated according to the calculated value, and at the same time, the calculated value is applied to the first cylinder.
The position signals from each position detection device of the fifth cylinder are compared with the comparison value, and the flow rate servo +t of the fifth cylinder is operated according to the comparison value. The pressure signal from the pressure detection device of the sixth cylinder is averaged and the averaged value is compared with the pressure signal from the pressure detection device of the second cylinder, and the pressure control valve is operated according to the comparison value. The sum of each load signal from each load detection device installed in the third cylinder ff1
m is compared with the set load value signal, and if the difference exceeds the predetermined value, the 1st. A method for synchronizing control of three cylinders, characterized in that a position signal from a position detection device for the first cylinder and a position command signal to be calculated are controlled in order to move the third cylinder forward or backward.