JPH0576208A - Controller for lifting or lowering - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a lifting control device equipped with position control means capable of suppressing a decrease in work efficiency and the occurrence of a drive shock without inviting a complicated structure. [Structure] A lift arm for raising and lowering a connected ground work device is configured to be swingably driven by a hydraulic actuator, and an output value of a potentiometer PM2 for detecting a swing angle of the lift arm and an artificial setting device PM1.
A constant-velocity control device including position control means A for controlling and driving the hydraulic actuator so as to match the set plowing depth by a constant speed state for detecting that the lift arm moves up and down at a constant speed state. A detection means B is provided,
Change rate calculating means C for calculating the change rate of the detected value of the potentiometer PM2 when in the constant speed state detecting means BB detection state is provided, and the control constant of the hydraulic actuator 3 is based on the calculated change rate data. A constant changing means D for changing and resetting is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is constructed such that a lift arm for raising and lowering a connected ground working device is driven to swing by a hydraulic actuator, and an output value of a potentiometer for detecting a swing angle of the lift arm. The present invention relates to an elevating control device provided with position control means for controlling and driving the hydraulic actuator so as to match a set working depth by an artificial setting device.

[0002]

2. Description of the Related Art In the above elevator control device,
Control conditions such as the dead zone width of the output value of the potentiometer and the set plowing depth and the amount of pressure oil supplied to the hydraulic actuator were previously set to be constant based on the data of the working conditions in the most common field (for example, , JP-A-3-
No. 51590].

[0003]

However, in the above-mentioned conventional structure, the hydraulic pump for supplying the pressure oil to the hydraulic actuator is generally driven by the engine, but the output speed of the engine is always constant. Not necessarily, the drive speed of the hydraulic actuator may change depending on the engine speed, and the viscosity of the hydraulic oil changes depending on its temperature. Since the above control conditions are constant even when the oil temperature changes, the drive speed of the hydraulic actuator may change due to the oil temperature change, and the lift arm lifting speed may change unexpectedly. As a result, work efficiency may be reduced, and problems such as shock may occur, and there was room for improvement. Therefore, as a method for solving the above-mentioned problem, it is also possible to provide a sensor for detecting the oil temperature and a sensor for detecting the engine speed and configure the control system so as to change the control constant of the lifting control based on these detected values. However, in this case, it is necessary to provide each of the above sensors, and there is a drawback that the number of parts increases and the structure becomes complicated. The present invention aims to eliminate the above-mentioned problems.

[0004]

The features of the first invention are as follows:
In the lifting control device described at the beginning, a constant speed state detecting means for detecting that the lift arm is moving up and down in a constant speed state is provided, and the potentiometer is detected when the constant speed state detecting means is in the detecting state. A change rate calculating means for calculating the change rate of the value is provided, and a constant changing means for changing and resetting the control constant of the hydraulic actuator based on the calculated change rate data is provided. A characteristic configuration of the second invention is that a speed change state detecting means for detecting that the lift arm is moving up and down in a speed change state is provided.
A change degree calculating means for calculating the change degree of the detected value of the potentiometer when the speed change state detecting means is in the detecting state is provided, and the control constant of the hydraulic actuator is changed based on the calculated change degree data. The point is that a constant changing means for resetting is set.

[0005]

When the set working depth and the output value of the potentiometer are different from each other, the hydraulic actuator is drive-controlled based on the position control means, and the lift arm is vertically moved.
From the output of the potentiometer at that time, calculate the data such as the driving speed of the lift arm in the constant speed driving state or the speed change degree at the time of acceleration driving, and if the calculation result is different from the preset value, By changing and resetting the control constant of the actuator,
The drive condition of the lift arm can be maintained in a predetermined control state.

[0006]

Therefore, from the output information of the potentiometer which detects the swing angle of the conventional lift arm,
It is possible to judge the drive status of the hydraulic actuator and maintain a constant drive control state at all times, without complicating the structure such as providing a temperature sensor for hydraulic oil or a sensor for detecting the engine speed It is possible to prevent changes in the driving status of the hydraulic actuator due to changes in temperature or changes in engine speed, etc., and it is possible to suppress a decrease in work efficiency and the occurrence of drive shock.

[0007]

Embodiments will be described below with reference to the drawings. Figure 2
Shows the hydraulic circuit of the agricultural tractor. This hydraulic circuit drives a working device 2 which is connected to the rear part of the traveling machine body via left and right links 1 and 1 so as to be able to move up and down, and is capable of moving up and down. Shows the hydraulic system for.

A lift arm 6 for suspending and supporting the left and right links 1, 1 via lift rods 5, 5 is configured to be oscillated by a lift cylinder 3, and one lift rod 5 is expanded and contracted by a rolling cylinder 4. It is freely configured and configured to be driven by rolling. A hydraulic pump 7 for the lift cylinder 3
Pressure oil from the flow priority valve 8 is supplied to the rolling cylinder 4 via the electromagnetic proportional flow control valve V, and the control flow of the flow priority valve 8 is supplied to the rolling cylinder 4 via the electromagnetic valve 9. is there. The electromagnetic proportional flow control valve V is a hydraulic pilot-operated first type for rising control.
Valve 10, second valve 1 for pilot control of this first valve 10
1, a hydraulic pilot-operated third valve 12 for lowering control, a fourth valve 13 for pilot control of the third valve 12, and the like. The second valve 11 for pilot control and the fourth valve 13 are electromagnetically driven. The pilot operating pressure of the first valve 10 and the third valve 12, that is, the hydraulic oil flow rate can be controlled based on the current supplied to the solenoids 11a and 13a. Also, the lift cylinder 3 is of a single-acting type,
An artificially operated variable throttle valve 14 for artificially adjusting the flow rate of the oil drained when the lift arm 6 is lowered is interposed in the pressure oil supply passage.

The control circuit for driving the solenoids 11a and 13a is constructed as shown in FIG. 1, and is a manpower-operated first potentiometer P provided in the control section on the body side.
The output of M1 [an example of an artificial setting device] and the output of the second potentiometer PM2 for detecting the swing angle of the lift arm 6 are converted into digital signals via the A / D converter 15 and the control device 16 including a microcomputer is provided. The solenoids 11a and 13a are input so that the respective input values match.
Position control means A for supplying a pulse current to the control device 16 via the power transistor 17
It is provided in the form of control program. In addition, the resistor 1 interposed in the current supply path for each solenoid 11a, 13a
The detected voltage of 8 is fed back to the control device 16 to control so that the current value is always appropriate. In the position control operation, the first and second potentiometers P
When the deviation between M1 and PM2 is large, that is, when the work device 2 is largely raised from the grounded state, the duty ratio of the pulse current is changed to the lift cylinder 3 immediately after the control is started. After the pressure oil supply is accelerated and increased to a predetermined value, the pressure oil supply amount is kept constant and constant speed driving is performed.After the deviation becomes small, the pressure oil supply is decreased and the rising speed is gradually increased. It is configured to perform speed control based on the deviation for making the speed low.

The control device 16 includes a constant speed state detecting means B for detecting that the lift arm 6 is moving up and down in a constant speed state, and the constant speed state detecting means B when the constant speed state detecting means B is in the detection state. A change rate calculating means C for calculating the change rate of the detected value of the second potentiometer PM2 and a constant changing means D for changing and resetting the control constant of the lift cylinder 3 based on the calculated change rate data. , Each is provided in the form of a control program. Hereinafter, the control procedure of the control device 16 will be described. As shown in FIG. 3, the solenoids 11a, 13
An initial value is set to the peak value gain of the pulse current with respect to a (step S1). Then, the output values Px, Py of the first and second potentiometers PM1, PM2 are read, the deviation ΔP is calculated (steps S2, S3), and when the deviation ΔP exceeds the predetermined dead zone width N, the deviation is detected. The operation direction is determined from the ΔP data, and the position control as described above is executed (steps S4 to S6). Then, when the lift cylinder 3 is in the constant speed drive state, the output Py of the second potentiometer PM2 is read for a predetermined time and the angular change rate ΔV1 per unit time is calculated (steps S7 to S10). The calculated angle change rate ΔV1
Is different from the predetermined value M1, the peak value gain of the pulse current for the solenoids 11a and 13a is corrected and reset so as to return to the predetermined change rate (step S1).
1, S12). Then, such a gain correction control is executed until it is reset (step S13). The position control means A is constituted by the step S6, the constant speed state detection means B is constituted by the step S7, and the step S
The change rate calculating means C is constituted by 10 and step S12
The constant changing means D is constituted by.

[Other Embodiments] Instead of detecting the constant speed driving state of the lift cylinder 3 as described above, as shown in FIG. 4, it is detected that the lift cylinder 3 is in the acceleration driving state. (Step S7), this detected acceleration ΔV
The gain may be modified by determining whether 2 is different from the predetermined value M2 (steps S8 to S11). In this case, the speed change state detecting means E is constructed in step S7, the change degree calculating means F is constructed in step S9, and the constant changing means G is constructed in steps S10 and S11.

It should be noted that reference numerals are added to the claims for facilitating the comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 Control block diagram

[Fig. 2] Hydraulic circuit diagram

FIG. 3 is a control flowchart.

FIG. 4 is a control flowchart of another embodiment.

[Explanation of symbols]

 2 Ground work device 3 Hydraulic actuator 6 Lift arm A Position control means B Constant speed state detection means C Change rate calculation means D Constant change means E Speed change state detection means F Change degree calculation means G Constant change means PM2 Potentiometer

Claims (2)

[Claims] 1. A lift arm (6) for raising and lowering a connected ground working device (2) is swingably driven by a hydraulic actuator (3), and a swing angle of the lift arm (6) is detected. Potentiometer (P
A lift control device comprising position control means (A) for controlling and driving the hydraulic actuator (3) so that the output value of M2) and the set plowing depth set by the artificial setting device (PM1) match. A constant speed state detecting means (B) for detecting that the arm (6) moves up and down in a constant speed state is provided, and the potentiometer (PM2) of the constant speed state detecting means (B) is in the B detecting state. Constant change means (D) is provided for providing a change rate calculating means (C) for calculating the change rate of the detected value, and changing and resetting the control constant of the hydraulic actuator (3) based on the calculated change rate data. Lift control device. 2. A lift arm (6) for raising and lowering a connected ground working device (2) is swingably driven by a hydraulic actuator (3), and a swing angle of the lift arm (6) is detected. Potentiometer (P
A lift control device comprising position control means (A) for controlling and driving the hydraulic actuator (3) so that the output value of M2) and the set plowing depth set by the artificial setting device (PM1) match. A speed change state detecting means (E) for detecting that the arm (6) is moving up and down in a speed change state is provided, and the potentiometer (PM2) when the speed change state detecting means (E) is in the detection state. A change degree calculating means (F) for calculating the change degree of the detected value is provided, and a constant changing means (G) for changing and resetting the control constant of the hydraulic actuator (3) based on the calculated change degree data. ) Is provided for the lifting control device.