JPH0220849B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an operation reproducing device for a working machine, which is installed in a working machine such as a hydraulic construction machine, stores the operation of an actuator of the working machine, and automatically operates the actuator based on this memory. Regarding.

FIG. 1 is a schematic diagram showing an example of a conventional motion reproducing device of this type. In this figure, A is an actuator, such as a hydraulic cylinder, B is an electro-hydraulic valve that operates this hydraulic cylinder A, C is a control device that controls the operation of electro-hydraulic valve B, and D is an operation signal that operates electro-hydraulic valve B. A manual controller E is connected to the control device C and is transmitted to the control device C.
This is a storage device that stores the operation signals of.

In this conventional motion regeneration device, when the manual controller D is operated, the operation signal is output to the control device C, and the control device C operates the electrohydraulic valve B in response to the operation signal. This connects the hydraulic cylinder A and the hydraulic source, and the hydraulic cylinder A is operated by the pressure oil supplied from the hydraulic source.
On the other hand, the operation signal output to the control device C is stored in the storage device E.

When carrying out a regeneration operation of the hydraulic cylinder A, a predetermined regeneration instruction signal may be given to the control device C, and this regeneration instruction signal causes the storage device E to
The operation signal stored in is called to the control device C, and the control device C operates the electro-hydraulic valve B in response to the operation signal. In this way, by operating the manual controller D only once, the same operation as that of the hydraulic cylinder A when operating the manual controller D can be performed any number of times without requiring any subsequent operation of the manual controller D. is possible,
Hydraulic cylinder A can be operated automatically.

By the way, in recent years, there has been a demand for automatic operation of actuators in construction machinery such as hydraulic excavators and cranes, but the conventional motion regeneration device described above is configured to operate hydraulic cylinder A via electro-hydraulic valve B. Therefore, hydraulic machines, such as the above-mentioned construction machines, are generally equipped with a manually operated valve that is operated by the hand of the worker, and the actuator is actuated via this manually operated valve. Therefore, this conventional motion reproducing device cannot be applied as is.

In addition, in this conventional operation regeneration device, the entire connection system of the control device C, the storage device E, and the electrohydraulic valve B is configured by an electric system.
If a failure occurs in this electrical system, the hydraulic cylinder A cannot be operated, resulting in an inability to work.

Therefore, various means have been studied to apply the motion regeneration device to hydraulic machines that operate actuators via manually operated valves. One of these methods
One is shown in Figure 2.

FIG. 2 is a system diagram of the motion reproducing device. In the figure,
A is the same hydraulic cylinder as shown in FIG. 1, 1 is a hydraulic pressure source, and 2 is a tank. 3 is a manually operated valve interposed between the hydraulic source 1 and the hydraulic cylinder A to control the drive of the hydraulic cylinder A, and 3a is an operating lever for operating the manually operated valve. 4 is a hydraulic cylinder used when automatically operating the manually operated valve 3;
5 is a servo valve that controls the drive of the hydraulic cylinder 4 in accordance with a control signal; 6 is a hydraulic cylinder so that the hydraulic cylinder 4 does not act as resistance and hinder the movement of the manual operation valve 3 during manual operation using the operation lever 3a; This is a switching valve that opens both end circuits of 4. 7 is a potentiometer that is linked to the movement of the spool of the manually operated valve 3 and generates a voltage according to its position. 8 is a storage device that stores the output signal of the potentiometer 7, that is, the position signal of the spool of the manually operated valve 3; 9 is a servo for automatically operating the manually operated valve 3 based on the information stored in the storage device 8; A control device 10 controls the valve 5, and a command device 10 gives a regeneration operation command to the control device 9.

Workers with advanced skills (skilled workers)
Assume that a person operates the operating lever 3a to drive the hydraulic cylinder A, thereby performing a predetermined work.
In this case, the predetermined work is performed appropriately and accurately. During this work, the control device 9 sets the switching valve 6 to the illustrated position so that the movement of the manually operated valve 3 is not hindered. When the manually operated valve 3 is operated, the movement of the spool is detected by the potentiometer 7 and stored in the storage device 8. That is, appropriate and accurate operation for the predetermined task is performed by the storage device 8.
It will be remembered.

Next, in order to automatically reproduce this work, first, the command device 10 gives a reproduction operation command to the control device 9. As a result, the control device 9 switches the switching valve 6 to the right position, then takes out the signal stored in the storage device 8 and inputs it to the servo valve 5. The servo valve 5 operates in response to this signal, controls the hydraulic cylinder 4, and operates the manually operated valve 3. Therefore, the manually operated valve 3 is operated in the same manner as previously operated by a skilled worker, supplies the same flow rate of oil to the hydraulic cylinder A, and operates it in the same manner. In the end, the movements performed by a skilled worker are reproduced, and the work is performed properly and accurately.

However, such operation regeneration work is not necessarily performed under the same conditions as work performed by skilled workers; for example, there may be differences in the viscosity of the hydraulic oil depending on the temperature, or there may be differences in the viscosity of the hydraulic oil due to temperature, If A is an actuator that drives the front mechanism of a hydraulic excavator, the excavated soil quality may be different, etc.
Working conditions may vary. As described above, if the working conditions differ, accurate reproduction of the movement becomes impossible.

The present invention has been made in view of these circumstances, and its purpose is to solve the above problems,
An object of the present invention is to provide a motion reproducing device for a working machine that can perform manual operation and perform accurate motion reproduction.

In order to achieve this object, the present invention stores the displacement value of the manually operated valve and also stores the load pressure of the actuator at that time when the manually operated valve is manually operated. The displacement value of the manually operated valve previously stored based on the relevant load pressure and the current load pressure is calculated as the discharge flow rate of the manually operated valve obtained at the stored pressure under the current load pressure. The displacement value is corrected by a predetermined calculation so as to obtain a discharge flow rate equal to , and the manually operated valve is driven and controlled based on the corrected displacement value.

The present invention will be explained below based on the embodiment shown in FIG.

FIG. 3 is a system diagram of a motion reproducing device according to an embodiment of the present invention. In the figure, parts that are the same as those shown in FIG. 2 are given the same reference numerals, and explanations thereof will be omitted. 12
Reference numerals a and 12b denote oil pressure detectors that detect oil pressures in two pipes connecting the manually operated valve 3 and the hydraulic cylinder A, and output electrical signals corresponding to the detected oil pressures. 13 is a differential amplifier which inputs the output signals of the oil pressure detectors 12a and 12b and outputs the difference thereof.
Reference numeral 14 denotes a changeover switch which has contacts 14A and 14B and is operated by a signal from a control device 20, which will be described later. 15 is a storage device that stores the pressure signal from the differential amplifier 13 when the changeover switch 14 is switched to the contact 14A side. 16 is a computing unit connected to the storage devices 8 and 15 and the contact 14B of the changeover switch 14, and converts the displacement value of the manually operated valve 3 stored in the storage device 8 into the pressure signal stored in the storage device 15. Then, it is corrected by a predetermined calculation based on the pressure signal from the differential amplifier 13. This calculation will be described later. 17 is contact 1
7A, 17B, and 17C, and is a changeover switch operated by a signal from a control device 20, which will be described later. A differential amplifier 18 amplifies the difference between the displacement value stored in the storage device 8 and the displacement signal of the potentiometer 7 via the contact 17B of the changeover switch 17. Further, reference numeral 19 indicates the corrected displacement value outputted from the calculator 16 and the contact point 17 of the changeover switch 17.
This is a differential amplifier that amplifies the difference between the displacement signal of the potentiometer 7 and the displacement signal of the potentiometer 7 via C. A control device 20 controls the changeover switches 14 and 17 and drives the servo valve 5 based on signals from the differential amplifiers 18 and 19.

Next, the operation of this embodiment will be explained. First, the operation when manually operating the manual operation valve 3 to drive the hydraulic cylinder A and storing this will be described.
The control device 20 outputs a signal to the switching valve 6 to switch it to the left position as shown, so that the manually operated valve 3 can be operated without resistance. Further, the control device 20 outputs signals to the changeover switches 14 and 17, respectively, to change the changeover switch 14 to the contact 14A and the changeover switch 17 to the contact 17A. In this state, when the manually operated valve 3 is operated, the potentiometer 7 outputs a displacement signal corresponding to the operation. This displacement signal is transmitted to the changeover switch 17.
is stored in the storage device 8 via the contact 17A.
That is, the movement of the manually operated valve 3 is memorized. On the other hand, pressure (load pressure) is generated in the pipeline of the hydraulic cylinder A by operating the manually operated valve 3. The oil pressure detectors 12a, 12b detect this pressure and output a signal according to the pressure. This pressure signal is stored in the storage device 15 via the differential amplifier 13 and the contact 14A of the changeover switch 14. That is, the load pressure generated when the manually operated valve 3 is operated is stored in correspondence with the movement of the manually operated valve 3.
In this way, for example, the operation of a working machine caused by an operation by a skilled worker is stored, and at the same time, the load pressure associated with the operation is also stored.

Next, the regeneration operation of the working machine will be described. Prior to this, the calculations of the calculator 16 will be described with reference to FIG. 4.

Figure 4 shows the hydraulic cylinder 4 for each load pressure.
FIG. 3 is a discharge flow rate characteristic diagram of the manually operated valve 3 with respect to displacement. In the figure, the horizontal axis shows the amount of left and right displacement of the hydraulic cylinder 4 about a certain reference position, and the vertical axis shows the discharge flow rate of the manually operated valve 3. Figure 4 above uses a servo valve that has an actuator port, a tank port, and a pump port, and is configured such that the opening area at the tank port is proportional to the stroke of the spool, and a load is applied to the actuator port. This is a characteristic diagram obtained through an experiment in which a variable setting pressure relief valve for realizing the pressure is connected, a large-capacity hydraulic pump with a constant discharge amount is connected to the pump port, and the spool is displaced. The relief valve is set to a certain predetermined pressure,
In this state, when the opening area of the tank port is reduced by displacing the spool (corresponding to the displacement of the hydraulic cylinder 4), the relief valve will relieve at a certain stroke, and thereafter the tank port will open in proportion to the stroke. The flow rate decreases (the flow rate through the relief valve increases), and when a certain stroke (corresponding to the displacement a _o of hydraulic cylinder 4 in the figure) is reached, the tank port is fully closed and the total discharge flow rate of the hydraulic pump (b _o )
will flow through the relief valve. As is clear from FIG. 4 above, below the displacement value _ao , the discharge flow rate changes depending on the load pressure. The figure shows the discharge flow rate characteristics in the case of load pressures P ₁ , P _i , P _j , P _k , and P _o . In addition, each load pressure above is P ₁
The relationship is ＜P _i ＜P _j ＜P _k ＜P _o .

Now, if the manual operation valve 3 is operated manually and this is stored in the storage device 8, the displacement amount is the value a _j ,
Assuming that the load pressure (stored in the storage device 15) at this time is P _j , the storage point by the storage device 8 and the storage device 15 is represented by a point C _j in the figure,
The discharge flow rate at that time is the value b _j . Next, when performing regeneration operation, during repeated regeneration operations, for some reason, for example, if the regeneration work is excavation work with a hydraulic excavator, the soil quality changes and the excavation resistance changes, causing the load to change. Consider a case where the pressure is a hydraulic pressure P _i different from the load pressure P _j in the case of the previous memory. In this case, if the hydraulic cylinder 4 is similarly displaced based on the displacement value a _j stored in the storage device 8, the point C _j will not be obtained but will be a point C _i on the pressure P _i , so the manually operated valve 3 The discharge flow rate of is the value b _i
This does not match the flow rate b _j that should be discharged. As a result, the operation of the hydraulic cylinder 4 during regeneration operation,
Therefore, the operation of the work machine will be different from the operation at the time of storage, and accurate reproduction of the operation will no longer be possible. Therefore, in this example,
By performing a predetermined calculation in the calculator 16, the displacement value a _j is corrected so that the discharge amount during regeneration operation becomes the same as the discharge amount during storage.

The above calculation will be explained below. From the characteristic diagram obtained from the above experiment, it was found that the pressure between the pressure P ₁ and the pressure P _o was almost equally distributed between the angles (θ ₁ −θ _o ). Therefore, for point C _j , the following empirical formula can be obtained.

tan {(θ ₁ −θ _o )/(P _o −P ₁ )(P _o −P _j )+θ _o }=a _o
−a _j /b _o −b _j Also, regarding point C _i , the following empirical formula can be obtained.

tan {(θ ₁ −θ _o )/(P _o −P ₁ )(P _o −P _i )+θ _o }=a _o
−a _i /b _o −b _j However, θ ₁ and θ _o are the angles formed between the perpendicular line at the displacement value a _o and the straight line of the pressures P ₁ and P _o , respectively, and the angles θ ₁ , θ _o , and the pressure P ₁ , P _o , and the displacement value a _o are constants.
Further, a _i is a displacement amount for obtaining the same discharge flow rate as the discharge flow rate b _j at the displacement value a _j at the load pressure P _i .

From both of the above equations, the amount of displacement a _i can be determined as follows.

a _i = a _o − tan {(θ ₁ − θn) / (Pn − P ₁ ) (P _o − P _i ) + θ _o } / ta
n {(θ ₁ − θn) / (Pn − P ₁ ) (P _o − P _j ) + θ _o } (a _o −
a _j ) The displacement amount a _i obtained from the above formula is the displacement amount a _j at the load pressure P _j at the time of storage, and the load pressure P _i at the time of regeneration.
This displacement amount a i is the amount of displacement corrected according to the amount of displacement a _i , and even if the load pressure changes during regeneration, it is possible to obtain the same discharge amount as at the time of storage.

Now, the regeneration operation of this embodiment shown in FIG. 3 will be explained. First, the operator uses the command device 10
A regeneration operation command is output to the control device 20. In response, the control device 20 outputs a signal to the switching valve 6 to switch it to the right position, shutting off the hydraulic cylinder 4 and the tank 2, and also outputs a signal to the switching switches 14 and 17, so that their contacts are switched to contacts 14B and 17B, respectively. In this state, the control device 20 takes out the stored displacement value a _j from the storage device 8 via the differential amplifier 18,
The servo valve 5 is driven accordingly. Servo valve 5
The manually operated valve 3 is driven via the hydraulic cylinder 4, and the potentiometer 7 outputs a displacement signal in accordance with the movement of the manually operated valve 3. From then on, the displacement amount a _j in the differential amplifier 18 and The difference between
Execution of feedback control is started so that On the other hand, when the manually operated valve 3 is driven, pressure is generated in the pipe line of the hydraulic cylinder A, and this pressure is detected by the oil pressure detectors 12a and 12b (this pressure signal is designated as P _i ). The control device 20 controls the pressure signal P _i , the displacement value a _j stored in the storage device 8 and the pressure value at the time of storage stored in the storage device 15.
P _j is input to the arithmetic unit 16, and the arithmetic unit 16 calculates the modified displacement value a _i according to the arithmetic expression. Next, the control device 20 outputs a signal to the changeover switch 17 and switches it to the contact 17C. Therefore, the corrected displacement position a _i output from the arithmetic unit 16 and the current displacement amount of the manually operated valve 3 are input to the differential amplifier 19, and the difference between the two is input to the control device 2.
Output to 0. The control device 20 drives the servo valve 5 based on this difference signal, and thereafter feedback control is continued using the corrected displacement value.

In this way, in this embodiment, the load pressure is stored together with the displacement amount of the manually operated valve at the time of memorization using the changeover switch, and when the operation is regenerated, the changeover switch is changed and the load pressure at that time is input to the computing unit. The stored displacement amount is corrected based on this load pressure, the stored displacement amount, and the load pressure, and feedback control during regeneration is performed using this corrected displacement amount. In addition to being able to
At the time of operation reproduction, the same discharge flow rate as at the time of storage can be obtained by the corrected displacement amount, and accurate operation reproduction can be performed.

As described above, in the present invention, when storing, the displacement value of the manually operated valve is stored, and the load pressure of the actuator is also stored, and when the operation is regenerated, the load pressure at that time, the stored load pressure, and the stored load pressure are stored. The stored displacement value is corrected based on the displacement value, and the manually operated valve is driven and controlled based on the corrected displacement value.
Manual operation can be performed in the motion reproducing device, and accurate motion reproduction can be performed.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a conventional motion regeneration device, FIG. 2 is a system diagram of a motion regeneration device under consideration, FIG. 3 is a system diagram of a motion regeneration device according to an embodiment of the present invention, and FIG. 4 is a system diagram of a motion regeneration device under consideration. It is a discharge flow characteristic diagram of a manually operated valve under load pressure. 3...Manual operation valve, 4...Hydraulic cylinder, 5...
... Servo valve, 6 ... Switching valve, 7 ... Potentiometer, 8, 15 ... Memory device, 10 ... Command device, 12a, 12b ... Oil pressure detector, 13, 1
8, 19... Differential amplifier, 14, 17... Changeover switch, 16... Arithmetic unit, 20... Control device, A
...Hydraulic cylinder.

Claims (1)

[Claims] 1. In a working machine equipped with an actuator driven by hydraulic pressure and a manually operated valve that controls the drive of the actuator, a pressure detection device that detects the load pressure of the actuator and a pressure detected by the pressure detection device are provided. a first storage means for storing the displacement value of the manually operated valve; and a second storage means for storing the displacement value of the manually operated valve; and a regeneration pressure detected by the pressure detection device and stored in the first storage means at the time of operation regeneration. a displacement stored in the second storage means so as to obtain a discharge flow rate equal to the discharge flow rate of the manually operated valve obtained at the stored pressure under the regeneration pressure based on the stored pressure; 1. An operation regeneration device for a working machine, comprising: a calculation means for correcting a value; and a drive control means for driving the manually operated valve based on a displacement value obtained by the calculation means.