JPS5829283Y2 - Hydraulic actuator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a direct-acting or rotary hydraulic actuator used in a hydraulic steering device for a ship, a hydraulic crane device, or the like.

Various hydraulic devices using high-output hydraulic actuators,
For example, in a hydraulic steering system for ships, when an electromagnetic hydraulic switching valve for controlling a hydraulic actuator is operated with 0N-OFF control, a fairly large shock is generated when switching, and in some cases, the controlled object may be destroyed. There is also.

Therefore, recently, in order to eliminate such shocks, multiple electromagnetic hydraulic switching valves are used, and the output circuits are connected in parallel and selectively operated to gradually change the displacement speed of the hydraulic actuator. Control devices are now being used to control

FIG. 1 shows an example of this type of control device commonly used in the past. In this case, two electromagnetic hydraulic switching valves 15 and 16 are used to control one straight hydraulic actuator. 26
This figure shows the pattern when controlling.

To explain the operation procedure, the command signal from the command potentiometer 2 in the multistage controller 1 and the hydraulic actuator 26
The difference signal between the feedback signal from the feedback potentiometer 3 which is interlocked with the rod 27 is amplified by a servo amplifier 6 and applied to an on/off controller comprising relay amplifiers 7 and 8 and switch circuits 9 and 10.

Relay amplifiers 7 and 8 have gains set to different values, and output different output signals depending on the value of the input signal.

That is, as shown in FIG. 2A, the relay amplifier 7 outputs an output voltage of +Vo when the input signal is +E1 or more, and -
When the voltage is less than E1, an output voltage of 10 is generated.

As shown in Figure 2, the relay amplifier 8 receives the input signal +
When E 2 (E 1 < E 2 ) or more, the output voltage is +■o, and when it is less than -E2, the output voltage is +■o.

generates an output voltage of

Therefore, the output voltage of the servo amplifier 6 is ±E'(El<
When E'<E2), only the output of the relay amplifier 7 is generated, and when ±E'(E2≦E'), outputs are generated from both relay amplifiers.

Therefore, when the output of the servo amplifier 6 gradually increases from zero, only the output of the relay amplifier 7 is generated, and then both relay amplifiers 7 and 8 generate outputs.

The outputs of relay amplifiers 7 and 8 are applied to switch circuits 9 and 10, which actuate electromagnetic hydraulic switching valves 15 and 16.

At this time, the switch circuit 9 operates the coil 17 of the electromagnetic hydraulic switching valve 15 when the output of the relay amplifier 7 is positive, and operates the coil 18 when the output is negative.

The output of the switch circuit 10 operates in exactly the same manner, operating the coil 19 when the output of the relay amplifier 8 is positive, and operating the coil 20 when the output is negative.

The P ports of the electromagnetic hydraulic switching valves 15 and 16 are connected to the hydraulic pressure source 21 via the check valve 22, the R ports 14j are connected to the hydraulic tank 23, and the A and B ports are connected to a pilot check valve. They are connected in parallel via valves 24 and 25, respectively, to operate a hydraulic actuator 26.

1. When hydraulic pressure is applied to the pilot check valve 25, it is supplied to the actuator 26 via the pilot check valve 25, and at the same time, the hydraulic pressure is applied to the pilot check valve 25.
Pilot pressure is applied to the valve 4 as well, and the pilot check valve 24 starts to flow liquid in the opposite direction, and the liquid pushed out from the actuator 26 passes through the switching valve 15 and returns to the hydraulic tank 23, causing the hydraulic actuator 26 to flow. make it work.

Therefore, when the output of the servo amplifier 6 gradually increases from zero, first the electromagnetic hydraulic switching valve 15 operates to start the rod 27 of the hydraulic actuator 26 at low speed, and then both electromagnetic hydraulic switching valves operate. to displace the rod 27 at high speed.

When the output of the servo amplifier 6 decreases, the operation is reversed,
The rod 27 is decelerated from high speed to low speed and then stopped.

When the output of the servo amplifier 6 is negative, it operates in exactly the same way, but in this case the movement of the rod 27 is reversed.

In this case, the biggest problem occurs when setting the command potentiometer 2, and at this time, the feedback potentiometers 3, 1, and 11 are stopped, so a large voltage is applied to the input terminal of the servo amplifier 6, and this Therefore, the output voltage of the servo amplifier 6 immediately saturates.

Therefore, in this case, both electromagnetic hydraulic switching valves 15 and 16 operate simultaneously with the setting of the command potentiometer 2.
If the rod 27 of the hydraulic actuator 26 is suddenly displaced at high speed, it becomes difficult to obtain smooth starting characteristics in stages.

The second problem is the operating characteristics when stopping.

Generally, in order to improve positioning accuracy when stopping, it is necessary to set the gain of the servo amplifier 6 to a high value, but if this is done, the output of the servo amplifier 6 will rapidly decrease when stopping, and this Relay amplifiers 7 and 8
The outputs are cut off almost simultaneously.

That is, the relay amplifier 8 is first turned off, and after a certain period of time, the relay amplifier 7 is also turned off, making it impossible to obtain smooth stopping characteristics.

The present invention is applied to a conventional hydraulic actuator control device that uses a high-output hydraulic actuator, such as a hydraulic steering system for ships, and controls an electromagnetic hydraulic switching valve for controlling the actuator on and off to control the hydraulic actuator. It is an object of the present invention to provide a hydraulic actuator control device that eliminates large shocks when switching displacement speeds and performs smooth stepwise control.

Therefore, in the conventional hydraulic actuator control device, the present invention includes a servo amplifier that amplifies the difference signal between the command signal from the command potentiometer and the feedback signal from the hydraulic actuator, and a servo amplifier that generates an output of a predetermined constant voltage. A limiting amplifier, an integrator that integrates the output of the limiting amplifier with a preset integration time constant, and a negative feedback amplifier that negatively feeds the output of the integrator back to the input of the limiting amplifier, the output signal of the servo amplifier being The receiver is equipped with a signal converter that converts and outputs a signal that rises or falls at a set time gradient constant with the integration time constant and the output voltage of the limiting amplifier, and the conversion output signal controls the on/off controller. Smooth starting and stopping can be achieved by selecting the number of parallel connected electromagnetic hydraulic switching valves and operating time.

Therefore, one of the electromagnetic hydraulic switching valves is operated by a command signal to slowly displace the hydraulic actuator, and then the other electromagnetic hydraulic switching valves are operated in parallel to displace the hydraulic actuator at high speed. Then, before further stopping, the electromagnetic hydraulic switching valve is operated independently again to slowly displace the hydraulic actuator, and when the hydraulic actuator matches the command value, the electromagnetic hydraulic switching valve is disconnected and stopped. .

Next, the present invention will be explained with reference to one embodiment shown in the drawings.

FIG. 3 shows a block diagram of the multi-stage controller 28 according to the present invention. In the conventional multi-stage controller, there is a A signal converter 29 having the configuration as described is provided.

The respective outputs of the switch circuits 9 and 10 are connected to the respective coils of the electromagnetic hydraulic switching valves 15 and 16 shown in FIG. 1, so as to control them ON-OFF.

Note that in this figure, devices used for the same purpose as in FIG. 1 are given the same reference numerals, so a detailed explanation thereof will be omitted.

The signal converter 29 is 1. A negative feedback resistor 33 is connected to both ends of the amplifier 31, and a bidirectional voltage regulator diode 32 has two regulator diodes connected in series as a limiter.
A so-called series limiting amplifier connected to both ends of the amplifier 34, an integrator consisting of an amplifier 34, a resistor 38, and a capacitor 35 are connected in series, and the output terminal of this integrator is connected to a phase inverting circuit consisting of a negative feedback amplifier 36. and is connected in feedback to the input of a series limiting amplifier via a resistor 37.

In this embodiment, a series type limiting amplifier is shown as a specific example of the limiting amplifier, but it goes without saying that a general limiting amplifier may also be used, and will hereinafter be referred to as a limiting amplifier.

That is, the output signal C of the servo amplifier and the output F of the negative feedback amplifier 36 having the opposite polarity are algebraically added by the resistors 30 and 37 and input to the limiting amplifier.

Since the value of the resistor 33 is sufficiently large compared to the resistor 30, the amplification degree of the amplifier 31 is sufficiently large, and therefore, this output signal is sufficiently limited and becomes the Zener voltage of the bidirectional voltage regulator diode 32, and is transmitted to the resistor 38 of the next integrator. added,
The integrator integrates this input signal and sends out an integrated output signal E.

This signal is phase inverted by the negative feedback amplifier 36 to become the feedback signal F, which is fed back to the input side of the limiting amplifier as described above.

This feedback signal F and the output signal C of the servo amplifier
When these become equal, that is, when C-F=0 at time T3 in Figure 4, the input of the limiting amplifier becomes zero, and at the same time the output becomes zero, so the integration operation ends.
Next, the input signal C-F of the limiting amplifier (Fig. 4) becomes the opposite polarity to the current one, the integral characteristic decreases as shown in Fig. 4, and the output signal E of the signal converter 29 becomes as shown in the figure. As explained above in FIG. 1, the coils of the electromagnetic hydraulic switching valves 15 and 16 are operated via switch circuits 9 and 10.

When the device configured as described above is pressed, the command potentiometer 2 is turned on at the time t-O as shown by line A in Figure 4A.
When the feedback potentiometer 3 is moved in a stepwise manner, the feedback potentiometer 3 changes the time to 20 T, as shown by the broken line B in the figure.

It moves linearly from T1, which is a little later than that.

That is, as will be described later, between time T1 and T2, the rod 27 of the hydraulic actuator 26 moves at low speed toward the command value A by the output signal G of the relay amplifier T, and then at time T2.
The rod 27 moves at high speed at T41, and then at time T41, the rod 27 moves at high speed.
4 to T51, the rod 27 operates at low speed and matches the command value A, so the potentiometer 3 outputs a feedback signal as indicated by the broken line B in Figure A.

Therefore, the output of the servo amplifier 6 becomes an output signal C as shown in the diagram, which is obtained by amplifying the difference signal AB.

This signal and the output signal F of the negative feedback amplifier 36 (Fig. be done.

At this time, the maximum output voltage is limited to ±Do by the bidirectional voltage regulator diode 32, and the output waveform becomes as shown in the diagram.

That is, at time T3, +Do is sent out, but since the negative feedback amplification is set so that the input signal (C-F) becomes zero at time T3, it becomes zero at this time T3, and at the same time the input signal C- F is inverted, and after this, the output signal is inverted and becomes -Do.

At time T6, (C-F) becomes O again, and the output signal of the limiting amplifier becomes O.

The output signal of this limiting amplifier is integrated by the next integrator 34 to become an output signal E as shown in Figure 2, which rises or falls at a predetermined time gradient ±θ.

The signal will be limited to Output signal E is relay amplifier 7
and 8.

On the other hand, this signal E has its polarity inverted by the negative feedback amplifier 36 and is applied as the feedback signal F to the input circuit of the limiting amplifier.

As mentioned above, the relay amplifier 7 has ±E1 human power.
The relay amplifier 8 generates an output voltage Vo, and the relay amplifier 8 outputs ±E2(
El<E2) vs. input.

Therefore, among the output signals, the positive direction components Ji- and lj are as shown in the diagram.

The negative direction components -J and - are similar to this, but in this case the voltage direction is reversed.

Since the rond 27 of the hydraulic actuator 26 is operated by these composite signals, the feedback potentiometer 3 which is interlocked therewith will send out an output signal as shown by the broken line B in FIG.

As is clear from the above, the limiting amplifier limits the output voltage of the input signal to a predetermined output voltage ±Do, so when this is integrated by the integrator 34, the output signal E after integration always has a time gradient when rising or falling. is limited to ±θ0, and the time difference T2-T corresponding to the voltage values E1 and E2 shown in FIG.
, or T5-T4 always occurs.

Moreover, the minimum value of this time difference can be arbitrarily determined by appropriately selecting the bidirectional voltage regulator diode 32.
6 operation time intervals can be freely selected, and stepwise speed control of the hydraulic actuator 26 can be easily realized.

In addition, the number of electromagnetic hydraulic switching valves can be increased or decreased as desired, so by appropriately selecting the number of parallel connection valves and operating time, smooth starting and stopping characteristics can be achieved even for high-output hydraulic actuators. You can wander around.

However, in this case, it is necessary to increase or decrease the number of parallel circuits of relay amplifiers and switch circuits in the multi-stage controller 28 in accordance with the number of electromagnetic hydraulic pressure switching valves.

As mentioned above, by using the multi-stage controller 28 to which the present invention is applied, it is possible to always control the plurality of electromagnetic hydraulic switching valves in a stepwise order <0N-OFF, thereby reducing the capacity of the hydraulic actuator. Regardless of the type of control, smooth starting and stopping can be achieved by appropriately increasing or decreasing the number of control electromagnetic hydraulic switching valves and by appropriately selecting the operating time interval using the multi-stage controller 28. It is possible to explore the control device of hydraulic actuators with characteristics.

Moreover, since this device does not use expensive control equipment such as hydraulic servo valves, it is relatively inexpensive and is extremely easy to adjust and maintain.

That is, by implementing the present invention, it is possible to use a control device for a hydraulic actuator that is inexpensive and has good performance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a hydraulic actuator control device conventionally used in a relatively large hydraulic device, and FIG. 2 shows the relay amplifier 7 and 8, in which the figure A shows the operation procedure of the relay amplifier 7, and the figure outside shows the operation procedure of the relay amplifier 8. Furthermore, FIG. 3 is a block diagram showing the configuration of the multi-stage controller 28 of the hydraulic actuator control device to which the present invention is applied, and FIG. 4 is a block diagram showing the configuration of the multi-stage controller 28 shown in FIG. This shows the waveform. 1...Multi-stage controller, 6...Servo amplifier, 7゜8...Relay amplifier, 9, 10...
... switch circuit, 15.16 ... electromagnetic hydraulic switching valve, 21 ... hydraulic pressure source, 26 ... hydraulic actuator, 28 ...... Multi-stage controller, 29
... Signal converter, 31 ... Limiting amplifier, 32 ... Bidirectional voltage regulator diode, 34 ...
...Integrator, 36...Negative feedback amplifier.

Claims (1)

[Scope of utility model registration request] The output circuits of a plurality of electromagnetic hydraulic switching valves are connected in parallel, and in response to a command signal, the electromagnetic hydraulic switching valve is activated by an on/off control signal output from an on/off controller consisting of a plurality of relay amplifiers and a switch circuit. Amplifying the difference signal between the command signal and the feedback signal from the hydraulic actuator for a hydraulic actuator control device in which the displacement speed of the hydraulic actuator is controlled in stages by operating them singly or in parallel. a servo amplifier, a limiting amplifier that produces an output of a predetermined constant voltage, an integrator that integrates the output of the limiting amplifier with a preset integration time constant, and the output of the integrator is connected to the input of the limiting amplifier. A signal converter having a negative feedback amplifier that receives the output signal of the servo amplifier and converts it into a signal that rises or falls at a set time gradient determined by the integration time constant and the output voltage of the limiting amplifier. and by operating the on-off controller in response to the conversion output signal and selecting the number of parallel connected electromagnetic hydraulic switching valves and the operating time, smooth starting and stopping can be performed. Characteristic hydraulic actuator control device.