JPH11181820A - Automatic operation device for hydraulic working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate control and besides to perform high-precise control with excellent reproducibility. SOLUTION: A mode switching means is arranged at a controller 8 to control a control valve 4 for a hydraulic actuator 1 through remote control valves 3L and 3R. An actuator 1 is actually artificially operated in a teach mode, and from current level operation amount (s), a valve inlet pressure PS, and a load pressure PL, an actuator flow rate is determined and stored in time series. The opening of the control valve 4 is controlled such that operation during a teach mode is reproduced, based on operation during a teach mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic driving apparatus for repeatedly performing the same operation in a hydraulic working machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art For example, in a hydraulic excavator, a method of excavating a trench by repeatedly moving a bucket between an excavation position and a discharging position, and a method of repeatedly moving a bucket between an upper portion and a lower portion of a slope. Boom like leveling work,
In some cases, the same operation is repeatedly performed by a work attachment such as an arm or a bucket.

Conventionally, in order to reduce the operation burden on the operator at the time of work by such repetitive operations, Japanese Patent Application Laid-Open No.
As shown in Japanese Patent No. 37339, first, in a teaching mode, a work is actually performed by a manual operation, and data relating to the movement of the attachment during the operation is stored. Thereafter, in an automatic driving mode, based on the stored data, There has been proposed a technology for automatically operating a work attachment by operating a work attachment so as to reproduce the movement in the teaching mode.

In this known technique, the angle of the upper revolving structure with respect to the vehicle body, the angle of the boom with respect to the upper revolving structure, the angle of the arm with respect to the boom, and the angle of the bucket with respect to the arm are detected and stored in time series. Are used as teaching data for automatic driving.

[0005]

However, the above-mentioned known technique has the following disadvantages.

[0006] The load condition such as the hardness of the ground to be excavated is different between the operation in the teaching mode and the automatic operation. Even though the load condition causes a change in the movement of the actuator, the change in the load condition is not changed. Since it does not take into account any control, the reproducibility of the operation deteriorates.

In a control system having only a position control loop as in the known art, the stability of the control system greatly changes depending on the attitude of the attachment, as is well known. , It is necessary to use various control methods such as feed forward.

Accordingly, the control becomes complicated, and it is necessary to use a high-performance and expensive control means (controller), which increases the cost. Alternatively, existing control means mounted on the machine cannot be used for automatic operation.

SUMMARY OF THE INVENTION The present invention provides an automatic operating device for a hydraulic working machine that is easy to control and that can perform highly accurate control with good reproducibility.

[0010]

According to a first aspect of the present invention, there is provided a hydraulic actuator, a hydraulic pump as a hydraulic pressure source for the hydraulic actuator, and an operation of the actuator provided between the hydraulic pump and the hydraulic actuator. Control valve, operating means for commanding the degree of opening of the control valve, inlet pressure detecting means for detecting the inlet pressure of the control valve, and load pressure detecting means for detecting the load pressure that is the outlet pressure Operation amount detection means for detecting the operation amount of the operation means, and control means for controlling the operation of the control valve, this control means (i) operating mode, by operating the operation means Teaching mode in which the actuator is actually operated to obtain data for automatic operation, and data obtained in this teaching mode A mode switching means for switching the hydraulic actuator between an automatic operation mode in which the hydraulic actuator is automatically operated without operation of the operation means based on
In the teaching mode, the supply flow rate to the hydraulic actuator is calculated based on the operation amount of the operation means detected by the operation amount detection means and the pressure value detected by the inlet pressure detection means and the load pressure detection means, and a time series is calculated. (Iii) In the automatic operation mode, the actuator supply flow rate stored in the teaching mode is set as a target value, and the target value is set using the pressure values detected by the inlet pressure detection means and the load pressure detection means. The opening of the control valve for obtaining the value is calculated, and the opening is commanded to the control valve.

According to a second aspect of the present invention, a pressure compensating valve for maintaining a constant difference between an inlet pressure of the control valve and a load pressure is connected to a discharge circuit of the hydraulic pump.

According to the above configuration, the opening of the control valve is controlled so that the same actuator flow rate as in the teaching mode is obtained during the automatic operation. Therefore, even if the load condition during the automatic operation is different from that during the teaching mode, The opening degree of the valve may be adjusted according to the change in the load condition, and high-precision control can be performed.

Further, since the valve opening is merely controlled so as to reproduce the flow rate of the actuator in the teaching mode at the time of automatic operation, it is not necessary to use an extra control method such as variable gain, speed feedback, and feed forward. It is easy to control and does not require high performance as control means.

Therefore, the cost can be reduced, or existing control means mounted on the machine can be used for automatic operation.

According to the second aspect of the present invention, a so-called load sensing control (constant differential pressure control) for maintaining a constant relationship between the lever operation amount and the actuator flow rate while maintaining a constant difference between the inlet pressure of the control valve and the load pressure. Is premised on a circuit configuration that performs the following.

The load sensing control circuit generally includes pressure detecting means for detecting the pressure difference between the inlet and the load of the control valve in order to detect the differential pressure. The obtained pressure value can be used as it is for calculating the flow rate and the valve opening for automatic operation.

That is, since the detecting means only for the automatic operation is not required, the equipment cost can be reduced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

In this embodiment, only one hydraulic actuator (hydraulic cylinder in the figure) 1 is shown as an object of automatic operation and the above-mentioned load sensing control is performed in order to simplify the configuration and make the description easy to understand. It has a circuit configuration.

Between the hydraulic actuator 1 and the hydraulic pump 2 as a hydraulic pressure source, there is provided a hydraulic pilot switching type control valve 4 having a throttle 4a controlled by remote control valves 3L and 3R. The operation direction and speed of the actuator 1 are controlled. Reference numeral 5 denotes a hydraulic pressure source for the remote control valves 3L and 3R.

Reference numeral 6 denotes an operation lever as an operation means for instructing the opening degree of the control valve 4. The operation amount of the operation lever 6 is converted into an electric signal by a lever operation amount sensor (operation amount detecting means) 7 such as a potentiometer. The controller 8 controls the position and opening of the control valve 4 through the remote control valves 3L and 3R.

FIG. 2 shows the relationship between the operation amount s of the lever 6 and the opening Ai of the control valve 4. The control valve opening Ai increases as the lever operation amount s increases. The supply flow increases.

An electromagnetic proportional pressure compensating valve (flow control valve) 9 for load sensing control controlled by a controller 8 is provided between the discharge circuit of the pump 2 and the tank T. Inlet pressure sensor 1 for detecting the inlet pressure 4 (the inlet pressure of the throttle 4a) PS
0 and a load pressure sensor 11 for detecting the outlet pressure (outlet pressure of the throttle 4a = load pressure) PL.

The pressure signals from the two sensors 10 and 11 are sent to the controller 8 and the valve inlet pressure PS and the load pressure PL are sent.
The opening degree of the pressure compensating valve 9 is controlled in accordance with the difference (PS−PL = ΔP) to control the return flow rate to the tank T, that is, the supply flow rate to the control valve 4.

Thus, the differential pressure ΔP is kept constant irrespective of the variation of the load pressure PL. Q: Flow rate through the control valve 4 (actuator flow rate) A: Opening degree (opening area) of the control valve 4 ΔP: Differential pressure c: Flow coefficient

[0026]

## EQU1 ## By the relationship of Q = cAｓΔP, the relationship between the lever operation amount s and the actuator flow rate Q is kept constant.

The internal configuration of the controller 8 will be described with reference to FIG.

It should be noted that in FIG.
Only the control system for the automatic operation of FIG. 1 is shown, and the control system of the pressure compensating valve 9 is not shown.

The controller 8 includes a mode switching means 1
2, an opening degree calculation means 13, a control signal output unit 14, a flow rate calculation means 15, and a storage means 16 are provided.

The operation of this device including the operation of each part of the controller 8 will be described below.

The mode switching means 12 is obtained by a selection execution means such as a changeover switch (not shown). The operation mode is obtained in a teaching mode for obtaining teaching data by performing a work as a model by operating a lever by an operator, and in the teaching mode. Is switched to the automatic operation mode in which the operation in the teaching mode is reproduced by using the data.

A. Teaching mode The actuator 1 is operated by lever operation in a state where the operation mode is set to the teaching mode by the mode switching means 12.

At this time, the lever operation amount s (= opening command value) detected by the lever operation amount sensor 7 is input to the opening calculating means 13, and the opening Ai of the control valve 4 is calculated from the lever operation amount s. ,

[0034]

## EQU2 ## Ai = f (s) f is obtained by a coefficient.

The valve opening Ai is controlled by the control signal output unit 14.
To the remote control valve 3L or 3R, and the control valve 4 is controlled to the command opening Ai.

The flow rate Qi to the actuator 1 at this time is calculated by the flow rate calculating means 15 as the valve opening A
i, the difference between the valve inlet pressure PS and the load pressure PL (PL-PS =?
P) and the flow coefficient c as described above,

[0037]

## EQU3 ## Qi = cAi√ΔP

The thus calculated actuator flow rate Q
i changes with time, and the actuator flow rate Qi that changes in a time series is stored in the storage means 16 as teaching data (time series data) QiT during automatic operation.

At this time, the relationship between the flow rate Qi of the actuator 1 and the operating speed dx is as follows in the case of a hydraulic cylinder.
Equation 4 is obtained.

[0040]

Qi = Ac · dx Ac is the cylinder pressure receiving area. Automatic operation mode After storing the data, the operation mode is switched to the automatic operation mode by the mode switching means 12 to start the automatic operation.

At the time of automatic operation, the valve inlet pressure PS and the load pressure PL differ from those at the time of operation in the teaching mode depending on the load condition such as the hardness of the ground to be excavated, and are PS 'and PL', respectively.

In order to make the actuator operation during the automatic operation equal to the operation during the teaching mode, the opening degree calculating means 13 calculates the flow rate QiT during the teaching mode from the equation (3).
And the flow rate QiP during automatic operation may be made equal.

That is,

[0044]

## EQU5 ## QiT = cAi√ΔP

[0045]

## EQU6 ## Since QiP = cAi′√ΔP ′ (ΔP = PS′−PL ′),

[0046]

## EQU7 ## The valve opening Ai 'is obtained by Ai' = Ai√ΔP / ΔP ', and control is performed by the control signal from the control signal output unit 14 through the remote control valve 3L or 3R so that the opening Ai' is obtained. The valve 4 may be controlled.

As described above, since the opening of the control valve 4 is controlled so that the same actuator flow rate QiT as in the teaching mode is obtained during the automatic operation, even if the load condition during the automatic operation is different from that in the teaching mode. Thus, the teaching operation can be faithfully reproduced by taking in the change in the load condition.

In order to apply the present invention to a circuit for performing load sensing control for detecting the valve inlet pressure PS and the load pressure PL and keeping the difference between them, the pressure sensors 10 and 11 originally provided in the circuit are automatically used as they are. It can be used for pressure detection for operation.

In the above embodiment, the flow coefficient c is a fixed value, but the flow coefficient c changes due to a change in oil temperature or the like. The relationship between the flow coefficient c and the change factor (oil temperature) can be determined in advance.

Therefore, in order to further improve the control accuracy, the flow coefficient data is tabulated and stored in the storage means 16, and the same coefficient c is obtained from the measured value of the oil temperature and the like, and is used in the flow rate calculation. You may.

In the above embodiment, only a single actuator 1 is described as an object of automatic operation. However, in an actual hydraulic machine, a plurality of hydraulic actuators (a turning motor, a boom hoist cylinder, an arm cylinder, an arm cylinder, a bucket, etc. Cylinder) is controlled in the same manner as described above.

[0052]

As described above, according to the present invention, during automatic operation, the operation in the teaching mode is reproduced by controlling the opening of the control valve so as to obtain the same actuator flow rate as in the teaching mode. Therefore, even if the load condition during the automatic operation is different from that in the teaching mode, the opening degree control according to the change in the load condition can be performed to accurately reproduce the operation in the teaching mode.

Further, since the control is merely performed so that the flow rate of the actuator in the teaching mode is reproduced during the automatic operation, there is no need to use an extra control method such as variable gain, speed feedback, feed forward, etc., and control is easy. Therefore, high performance is not required for the control means.

According to the second aspect of the present invention, a circuit configuration for performing load sensing control for maintaining a constant relationship between the lever operation amount and the actuator flow rate while maintaining a constant difference between the inlet pressure of the control valve and the load pressure is assumed. The detection value of the pressure detection means originally provided in the circuit can be used as it is for calculating the flow rate and the valve opening for automatic operation.

[0055] Therefore, the detection means only for the automatic operation is not required, so that the equipment cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit configuration diagram of an automatic operation device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a lever operation amount and an opening degree of a control valve in the same device.

FIG. 3 is a block diagram showing an internal configuration of a controller in the device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic actuator 2 Hydraulic pump 9 Pressure compensation valve for performing load sensing control 4 Control valve 3L, 3R Remote control valve for controlling control valve 6 Operating lever as operating means 7 Lever operating amount sensor as operating amount detecting means 8 Controller (Control means) 10 Valve inlet pressure sensor 11 Load pressure sensor 12 Controller mode switching means 13 Openness calculating means 14 Control signal output unit 15 Flow rate calculating means 16 Storage means

Claims (2)

[Claims] 1. A hydraulic actuator, a hydraulic pump as a hydraulic pressure source for the hydraulic actuator, a control valve provided between the hydraulic pump and the hydraulic actuator for controlling the operation of the actuator, Operating means for instructing the opening degree, inlet pressure detecting means for detecting an inlet pressure of the control valve, load pressure detecting means for detecting a load pressure as the outlet pressure, and an operation for detecting an operation amount of the operating means Quantity detecting means, and control means for controlling the operation of the control valve, the control means comprising: (i) changing the operation mode during automatic operation by actually operating the hydraulic actuator by operating the operation means; And a hydraulic actuator based on the data obtained in this teaching mode. (Ii) in the teaching mode, the operation amount of the operation means detected by the operation amount detection means and the operation amount of the operation means. The supply flow rate to the hydraulic actuator is calculated from the pressure values detected by the inlet pressure detection means and the load pressure detection means and stored in time series. (Iii) In the automatic operation mode, the flow rate is stored in the teaching mode The opening degree of the control valve for obtaining the target value is calculated using the pressure value detected by the inlet pressure detection means and the load pressure detection means, with the actuator supply flow rate as a target value, and the opening degree is controlled. An automatic operation device for a hydraulic work machine, wherein the automatic operation device is configured to instruct a valve. 2. The automatic operation device for a hydraulic working machine according to claim 1, wherein a pressure compensating valve for maintaining a constant difference between an inlet pressure of the control valve and a load pressure is connected to a discharge circuit of the hydraulic pump. Automatic operation device of hydraulic working machine.