JPH03292805A - Lifting-controlling device of working machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention connects a working device to a traveling machine so that it can be driven up and down by a hydraulic actuator, and supplies pressure oil to the hydraulic actuator via an electromagnetic proportional control valve. a control means configured to supply pressurized oil and control a drive current to the electromagnetic proportional control valve so that the pressure oil supply has a predetermined pressure increase characteristic; The present invention relates to a lifting control device for a work machine, which is provided with means.

[Conventional technology]

Conventionally, the lift control device has been configured so that the hydraulic pressure increase characteristic by the control means is always in a constant appropriate state (for example, as disclosed in Japanese Patent Application No.
-28988).

(Problems to be Solved by the Invention) The above configuration minimizes wasted time due to delay in operation caused by inertia of the spool, etc. when the hydraulic actuator starts operating, and also reduces the amount of time the work device deviates from the current position to the target position. At the same time, the amount of oil is increased to perform quick operation, and the pressure increase curve is made gentle near the target position to soften the shock.

However, since the change characteristics of the hydraulic oil flow rate with respect to the supply current of the electromagnetic proportional control valve vary depending on individual differences or the high or low oil temperature, the pressure increase characteristic curve may differ depending on differences in these various conditions. Therefore, the pressure increase curve may not be gentle near the target position, resulting in a shock or slow operation.

The present invention aims to solve the above-mentioned problems.

[Means to solve the problem]

A characteristic configuration of the present invention is that, in the lifting control device for a working machine described at the beginning, in the forced raising operation, a measuring means for measuring the time required for the working equipment to rise from a set value 1 in the middle of rising to an upper limit position; current correction means for changing the supply current to the electromagnetic proportional control valve to an increasing side if the measurement time is longer than a predetermined time; and changing the supply current to a decrease side if the measurement time is shorter than the predetermined time; There is a point where it is equipped with.

[For production]

In a forced lift operation where the target lift position is fixed, the time required to reach the raised position from the intermediate setting position should always be controlled to be constant, so measure this time in actual operation and compare the set time. The comparison is made and the current to the electromagnetic proportional control valve is corrected to an appropriate value.

[Effects of the Invention] Therefore, according to the present invention, by effectively utilizing the raising operation of the forced raising means provided as standard in this type of work machine, it is possible to compensate for individual differences in electromagnetic proportional control valves and differences in oil temperature. It has become possible to absorb the resulting variations in characteristics and perform high-precision lifting and lowering control.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 5, an engine (4) is disposed at the front of a vehicle body (3) equipped with front and rear wheels (LL (2)), and a transmission case (5) is disposed at the rear of the vehicle body (3). A pair of left and right lift arms (6) and a lift cylinder (7) (an example of a hydraulic actuator) for driving the lift arms (6) up and down are provided on the upper part of the transmission case (5). A driver's seat (9) is provided between left and right rear fenders (8) at an upper position to constitute an agricultural tractor.

A rotary tiller (11) (an example of a ground work device) is connected to the rear end of this agricultural tractor via a two-point link mechanism (10), and the two-point link mechanism (10) and the lift arm (6) and a pair of left and right lift arms (12)
By supporting the rotary tiller (11) in a suspended state, the rotary tiller (11) is moved up and down by the drive of the lift cylinder (7), and furthermore, one of the pair of lift rods (12) is equipped with a double-acting rolling cylinder. (13), the rotary tiller (11) is configured to roll around the longitudinal axis (X) by driving the rolling cylinder (13).

The hydraulic system for performing this lifting and lowering operation and rolling operation is shown in FIG.
), a flow priority valve (15) for controlling the flow rate, and a controlled flow from the flow priority valve (15) to the rolling cylinder (
13), a solenoid proportional control valve (v ), and this control valve (V) includes a first valve (17) for controlling the rise, and a second valve (17) for controlling the pilot pressure that opens and closes the first valve (17).
18), a third valve (19) for descending control, and a fourth valve (20) for pilot pressure control that opens and closes this third valve (19).
) and a relief valve (21), and when controlling the rotary tiller (11) to the upward side, the second valve (18)
By supplying current to the solenoid (18a) and adjusting this current value, the pilot pressure changes in accordance with this current value, resulting in a valve opening proportional to this current value, and When controlling the rotary tiller (11) to the downward side, the current value of the current supplied to the solenoid (20a) of the fourth valve (20) is adjusted as described above, so that the valve is proportional to this current value. It is configured to provide an opening degree of .

Further, in this agricultural tractor, the rotary tilling device (1
1) to a predetermined level with respect to the ground (G), position control to raise and lower the plow to a predetermined level with the vehicle body (3) as a reference, and longitudinal axis (X).
) three types of automatic control including rolling control that sets the tilting posture around the surroundings, and forced lift control that takes priority over these three types of automatic control and raises the rotary tiller (11) to a predetermined level relative to the vehicle body. A control device is provided to perform the following.

Of this control device, a system that performs automatic plowing depth control, position control, and forced lift control is configured as shown in FIG. 1, and in this configuration, as shown in FIG.
), the first potentiometer (24) detects the setting position of the tilling depth setting dial (23) of the control box (22), and the swing type rear cover (Ila) of the rotary tilling device (11). Rokuri tilling device (1
The second potentiometer (2) detects the ground level of (1)
5) constitutes a setting system and a feedback system for automatic plowing depth control, and a third potentiometer ( 27) and a fourth potentiometer (28) that detects the level of the rotary tiller (11) relative to the vehicle body from the amount of swing of the lift arm (6), and a position control setting system and feedback system are configured. , a lift switch (29) that causes the control box (22) to perform forced lift control is provided.

In addition, in this forced rise control, the fourth potentiometer (
28).

Also, the signals from these four potentiometers are A/D
Via a converter (30), the signal is input to a control mechanism (31) comprising a microprocessor (not shown), and the signal from said lift switch (29) is input directly to the control mechanism (31), which control The mechanism (31) outputs an intermittent pulse signal to drive the power transistors (32), (32), so that the intermittent pulse current flows through the solenoid (18a).
), (20a), and a resistor (I?) that converts the current value of the current supplied to the solenoid (18a), (20a) into a voltage value is connected to the solenoid (18a), (20a).
a), interposed in the route (33) from (20a),
Further, the voltage value thus converted is configured to be fed back to the control mechanism (31) via the foot bank path (34) and the A/D converter (30).

Further, the control device adjusts the current value of the current supplied to the solenoids (18a) and (20a) by adjusting the duty ratio of the intermittent signal.
The main operation is performed according to the flowchart shown in FIG. 2.

In other words, when control starts, along with the initial settings, the current value and
Setting the initial value to the duty characteristic (Ilo) #1
Step), determine the state of the rising switch (29) (
#2 step).

Next, if the rise switch (29) is turned on,
An intermittent pulse current with a predetermined duty ratio is supplied to the electromagnetic proportional control valve (V) to drive the lift cylinder (7) in the upward direction (start of upward movement), and the control mechanism (
31) Start counting the intermittent pulse signal output from 17, and manually adjust the current value (I++) supplied to the solenoid (18a) until the count number reaches "10"(#3 to #6) step).

The input of this current value (+*) is converted into a voltage value by the resistor (R) and converted into a digital signal via the A/D converter (30), and this digital signal is converted into an intermittent pulse signal. This is done by inputting a sampling period that is an integer multiple,
Next, after averaging the input current values, the current value (T)
(17. Step #8).

Next, based on the duty ratio (D) and current value (1) during this forced increase control, the current value/duty characteristic (1/D
) and apply the results to the current value/duty characteristics (
I/D) (Steps #9 and #10).

This characteristic (1/D) is used to determine the current value of the current supplied to the solenoids (18a) and (20a) in accordance with the value of the duty ratio, and is used to determine the current value of the current supplied to the solenoids (18a) and (20a) in response to changes in oil temperature. Based on the electrical resistance values of 18a) and (20a), the above-mentioned selection is made from data of a plurality of types of characteristics measured in advance.

Next, after the lift arm (6) reaches a predetermined level and the operation of this forced lift control stops, the lift switch (
29) tiller tiller 1 until it is turned off! (
11) is maintained at a high level (#11 step)
.

In the lifting operation, the time required for the tilling device (11) to rise from the set position on the way up to the upper limit position (T
) (#12 step). The measurement time (T)
is larger than a predetermined set time (To), a characteristic map of the target flow rate (Qo) determined as described later and the corresponding target current value (Io) is set in advance, and the current is increased based on a certain characteristic. Change to the side ($113. #14 step). Also, if the measurement time (T) is smaller than the set time (To), the characteristic map is changed to the current decreasing side (#
15 steps).

Next, at step #16, the rise switch (29) is turned OFF.
When it is detected that it is in the operating state, and when it is detected that the lift switch (29) has been turned off in step #16, the work mode is determined (the operation system for selecting the work mode is (not detailed), performs one of three types of control: automatic plowing depth control, position control, and rolling control, and repeats the above control until reset (#17~ #21 step).

Furthermore, when controlling each of the automatic plowing depth control and position control among the three types of control, the opening degree of the electromagnetic proportional control valve (V) is adjusted so that the larger the position deviation, the higher the vertical speed of the rotary tiller (11). When performing this setting, the set current value/duty characteristics (T/D)
The duty ratio can be determined based on.

In addition, in the control operation explained above, when performing either automatic plowing depth control or position control,
When the rotary tiller (11) is moved up and down, this control system is configured as an oven loop type in which feedback of the current values supplied to the solenoids (18a) and (20a) is not performed.

Also, the automatic tilling depth side? The outline of the operation of both fl and position control can be expressed as shown in the flowchart in Figure 3 (specifically, it is set in the program in the form of a subroutine). This will be explained below.

In other words, during control, the control target (Xo
) is set to the signal of the setting device, that is, the signal from either the first or third potentiometer (24) or (27), and the current level of the rotary tiller (11) (
X,) are the sensor signals, that is, the second and fourth sensors (25
), (28) is set, and the positional deviation (EX) is determined by subtraction (#
22. #23 step).

Next, the overall value of the positional deviation (EX) is compared with the value (ε) set as the dead zone, and the positional deviation (EX) is
) is larger than 4a(ε) of Fuwazai, the control direction is determined and the control direction is determined (#24 to #
27 Stesop).

Next, the target flow rate (Qo) is determined based on the positional deviation (E8), and the target flow rate (Qo) corrected as described above (steps 1113 to #15) and the control valve (V )
The target current value (Io) is determined based on the characteristics of the target current value (Io) and the current value set as described above.
Based on the duty characteristic (D) and the duty ratio (Do
) (#28. #29. #30 Stemp)
.

In addition, #28. #29. In the processing at the $130 step, a decision is made based on the characteristics represented in the illustrated graph, and this decision is made by map data or calculation.

Next, set the value determined in step #30 for the maximum value (D, %□X), and +13 for the initial value (Or).
Set the value determined in step 0 after dividing it by a constant, and output a pulse signal while increasing from this initial value (D,) to the maximum value (D,...) (#31° #32 step) .

Note that #3 above. #11 Step forced rise means (A)
Configure the measurement means (B) in step #12,
In2.1114. In step #15, the current correction means (C
).

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the lifting control device for a working machine according to the present invention, in which Fig. 1 is a control block diagram, Figs. 2 and 3 are control flow charts, Fig. 4 is a hydraulic circuit diagram, and Fig. 5 is an agricultural equipment. FIG. 2 is an overall side view of the tractor. (7)...Hydraulic actuator, (11)...
... Working device, (31) ... Control means, (
A)...forced rise means, (B)...measurement means, (C)...current correction means, (V)...
...Solenoid proportional control valve.

Claims (1)

[Claims] A working device (11) is connected to the traveling aircraft by a hydraulic actuator (7) so that it can be driven up and down, and pressure oil is supplied to the hydraulic actuator (7) via an electromagnetic proportional control valve (V). , a control means (31) for controlling a drive current to the electromagnetic proportional control valve (V) so that the pressure oil supply has a predetermined pressure increasing characteristic; and a control means (31) for forcibly raising the working device (11) to a predetermined high position. A lifting control device for a working machine, comprising a forced raising means (A), wherein in the forced raising operation, the working equipment (11
) measuring means (B) for measuring the time required for the valve to rise from a set position on the way to the upper limit position; and current correction means (C) for changing the supplied current to a decreasing side if the measured time is shorter than the predetermined time.