JPH01228404A - Controller for position of ground working machine - Google Patents

Abstract

PURPOSE:To accurately reach a working machine to a target set value even if a feed pressure of a hydraulic oil is low by actuating a lifting valve of a hydraulic actuator in the direction to eliminate lifting deviation according to the ON period of the first and second tables of calculated values. CONSTITUTION:Either of the first and second tables (24a) and (24b) of calculated values is selected according to the lifting speed of a working machine within a region with a smaller extent of lifting than the cut set value. Control is performed so as to lift a working machine at the ON period according to the selected table of calculated values. As a result, a lifting valve is turned ON or OFF at the ON period determined according to the second table (24b) of calculated values in which the maximum ON period is set if lifting speed of the working machine is lower than speed lower limit value, such as the case in which the pressure of the hydraulic oil fed to the hydraulic actuator 7 is low.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a ground-based work machine (hereinafter simply referred to as a vehicle) such as a rotary tiller that is attached to the rear of a traveling vehicle such as a tractor (hereinafter simply referred to as a vehicle). It is related to the position control device of a working machine (referred to as a machine), and is particularly effective even when the hydraulic pressure of the hydraulic actuator that drives the working machine up and down is low.
The present invention also relates to a ground work machine position control device that enables accurate positioning.

(Prior Art) Generally, in a traveling work vehicle in which a work equipment is attached to a vehicle such as a tractor, the work equipment can be moved up and down between a work position and a non-work position, and can also be tilted left and right. It is connected to the tractor side via a connecting mechanism.

In the work equipment lifting device of such a traveling work vehicle, for example, a means for mitigating the impact caused by changes in hydraulic pressure when the hydraulic actuator for driving the lift stops, and measures against overshoot of the work equipment are required. There are many things.

In particular, play is provided in the connection between the work machine and the lift arm that suspends the work machine, and the connection between the lift arm and the hydraulic actuator, taking into consideration flexibility during assembly. However, there is a problem in that the end of the working machine has a large play, and the effects of impact and overshoot when the actuator stops are also large.

To solve the above problem, for example, by adjusting the on-time of the control valve for driving the hydraulic actuator within a predetermined cycle, that is, adjusting the on-time duty ratio, the lifting speed of the work machine can be controlled. When the detected value of the detection means that detects the height position of the hydraulic actuator approaches the target setting value, the on-time duty ratio of the control valve for driving the hydraulic actuator is reduced to reduce the lifting speed of the work equipment, thereby preventing overshoot. Techniques have been proposed to prevent and reduce impact (Japanese Unexamined Patent Publication No. 57-97103).
.

(Problems to be Solved by the Invention) However, the above-described conventional technology still has the following problems.

The driving speed of the hydraulic actuator used as a driving means for the working machine varies greatly depending on the pressure of oil supplied to the actuator.

That is, in the traveling work vehicle, since the hydraulic pump that supplies hydraulic oil to the hydraulic actuator is driven by the engine of the traveling work vehicle, there is a large difference in the operating pressure during work operation and during idling operation. It arises.

Therefore, when the supply pressure of hydraulic oil is low, such as during idling operation, if speed control is performed to reduce the on-time duty ratio, the working machine may not be able to rise due to insufficient power. Therefore, there was a problem that the working machine did not reach the target setting position.

The present invention has been made to solve the above-mentioned problems.

(Means and effects for solving the problem) In order to solve the above problems, the present invention provides a hydraulic actuator for raising and lowering a working machine to a target value, a sensor for detecting the current position of the working machine, and a sensor for detecting the current position of the working machine. a first calculated value table that reduces the on-time duty ratio of the control valve of the hydraulic actuator when the deviation between the target value and the current position is small, and increases the on-time duty ratio when the deviation is large; a storage unit storing a second calculated value table in which an on-time duty ratio corresponding to the same deviation is set larger than an on-time duty ratio of the first calculated value table, regardless of the size; A cut setting value setting means is set to a value that is the maximum value of the on-time duty ratio in the calculated value table and corresponds to a deviation near a change point at which the on-time duty ratio transitions from the maximum value to a smaller value. a means for detecting a rising speed of the working machine near the cut setting value and comparing it with a preset value; and a means for selecting the second calculation table when the rising speed is smaller than the predetermined value. It is characterized by having the following.

In the present invention having the above configuration, when the rising speed is smaller than the planned value near the cut setting value, the calculated value table in which the on-time duty ratio becomes smaller according to the deviation is not used, and the on-time duty ratio is larger. The work equipment can now be raised using the control valve on time determined using a calculated value table. Therefore, even when the supply pressure of hydraulic oil is low, the working machine can accurately reach the target setting value.

(Example) The present invention will be described in detail below with reference to the drawings. 9th
FIG. 10 is a side view of the traveling working vehicle of the present invention, and FIG. 10 is a perspective view showing the main parts of the working machine and the coupling mechanism section connected to the rear part of the traveling working vehicle.

In the figure, a working machine 3 such as a tillage rotor is connected to a vehicle 1 via a connecting mechanism 2. The work machine 3 is connected to the vehicle 1 via a three-point lifting link structure consisting of a top link 4 and a pair of left and right lower links 5 and 6.

Further, a hydraulic actuator 7 and a lift arm 8.9 driven by the cylinder 7 are attached to the vehicle 1 side. Since the lower links 5 and 6 are connected to a lift arm 8.9 via lift rods 10 and 11, respectively, the working machine 3 is raised and lowered by the expansion and contraction operations of the hydraulic actuator tough.

The vehicle 1 is provided with a horizontal sensor 12 composed of an inclination sensor that detects the amount of left and right inclination, and the lift rod 11 is composed of a telescopic hydraulic actuator 13, and further includes a stroke sensor that detects the amount of expansion and contraction of the hydraulic actuator 13. 14 are provided. Then, the stroke sensor 14 monitors the amount of expansion and contraction according to the degree of inclination of the vehicle 1 detected by the horizontal sensor 12 so that the work equipment 3 is held horizontally with respect to the ground even if the vehicle 1 rolls. At the same time, the hydraulic actuator 13 can be driven and controlled. The lift arm 8.9 is provided with a foot sensor 15, which is composed of a rotary potentiometer that detects the lift angle, and the lifting and lowering of the working machine 3 can be controlled according to the output of the sensor. .

On the other hand, on the working machine 3 side, a pillar 16 is provided which traces the ground and whose opening degree θ changes depending on the depth of tillage when the working machine 3 is in the working position. The opening degree θ of the pillar 16 is detected via the rod 16A by a pillar sensor (angle sensor) 16B composed of a rotary potentiometer, and the hydraulic actuator 7 is driven according to the sensor output to control the depth of tillage. hold at the set value,
Plowing depth can be controlled.

The vehicle 1 is provided with an operator's seat 17, and an operation switch 18 for manually controlling the raising and lowering of the working machine 3 is provided next to the seat.

The operation of the working machine 3 according to the position of the operation switch 18 is
This will be explained with reference to FIGS. 5 and 6.

FIG. 5 is a diagram showing the contact configuration of the operation switch 18, FIG. 6(a) is a front view of the conductive slide member, and FIG. 6(b) is a side view of the same. In the figure, the operation switches 18 are 18a, 18b, 18c, 1 indicated by dashed lines.
It is operated to positions 8d and 18n. The contact portion 28 of the operation switch 18 is provided at the lower end of the operation switch 18 with three contact members 30, 31, 32 which are electrically insulated and separated, and an arrow 5 indicates the contact portion 28 on the contact member.
a conductive sliding member that slides linearly in one direction;
29, and a common contact member 33 that is always in contact with the stud portion 29a of the slide member 29.

The slide member 29 is provided on a slide block 52 having electrical insulation properties, and includes conductive stud members 29a and 29 exposed on the surface of the slide block 52.
b, 29c, and is buried in the slide block 52,
The stud members 29a, 29b, and 29c are electrically connected to each other by conductive wires 29d and 29e.

The slide block 52 is configured such that the protrusion 53 of the operation switch 18 is engaged with the concave portion on the back surface thereof, and when the operation switch 18 is tilted around the central axis 34, it is guided by a guide member (not shown), and is guided by an arrow. Slide linearly in the direction of 51.

The dogleg-shaped portion at the bottom of FIG. 5 indicates the position of the slide member 29 corresponding to the operating position of the operating switch 18.

That is, when the operation switch 18 is tilted to the A position,
The first contact member 30 and the common contact member 33 are connected by the slide member 29 . When the operation switch 18 is in the B position, the first contact member 30, the third contact member 32, and the common contact member 33 are connected.

When the operation switch 18 is in the N position, the third contact member 32 and
The common contact member 33 is connected, the second contact member 31 and the third contact member 32 are connected to the common contact member 33 at the C position, and the second contact member 31 and the common contact member 33 are connected at the D position. is connected.

In this way, A
The contact structure of the operation switch is made up of five operation areas: -D and neutral point N.

Further, the operating switch 18 is configured to return to the N position when the operator's hand is released from each of the A, B, C, and D positions.

Depending on the operating position of the operating switch 18, the position of the working machine 3 is controlled as follows. When the operation switch 18 is in the N position, the lifting and lowering of the work equipment 3 is stopped, in the A and B positions, the work equipment 3 is lowered, and in the C and D positions, the work equipment 3 is stopped.
will rise. No matter which position the operation switch 18 is moved to, it returns to the N position when the operator releases his/her hand, but in the A and D positions, the lifting and lowering of the work implement 3 does not stop even if the switch 18 returns to the N position. That is, once the operation switch 18 is operated to the A position, the work implement 3 is lowered to the position set by the lower setting value, and at the D position, the work implement 3 is raised to the position set by the higher set value. Stop. In positions B and C, the work implement is lowered or raised only when the operation switch 18 is in that position.

Below, in response to both the control operation instruction signal from the operation switch 18 and the detection signal from the lift sensor 15, the on/off operation of the valve that gives commands to the hydraulic actuator 7 and the on-operation time of the valve will be described. An example of a control device that performs appropriate control is shown below. FIG. 1 is a block diagram of such a control device.

In the figure, the current height position (current lift value) of the working machine 3 is detected by a lift sensor 15.

The lift current value and the target lift position (rise set value) of the work equipment 3 set in the lift position setter 20 are compared in the lift deviation calculation unit 21, and the deviation between the two values (rise deviation) is compared.
is calculated.

On the other hand, the current lift value and the lowering target position (lowering set value) set in the lowering position setter 37 are compared in the lowering deviation calculating section 38, and the deviation between the two values (lowering deviation) is calculated. .

When the operation switch 18 is operated to the upward side, the upward deviation is set as the lift change amount by the lift change amount setting means 36.
, and when the operation switch 18 is operated to the lowering side, the lowering deviation is set in the lift change amount setting means 36 as the lift change amount.

A fixed deviation (cut setting value) from the rising setting value is set in the cut setting value setting means 19. The cut setting value is such that the control valve on-time duty ratio (hereinafter simply referred to as on-time), which corresponds to the lift change amount stored in the first calculated value table 24a, which will be described later, transitions from a maximum value to a lower value. It is determined to correspond to the lift change amount corresponding to the maximum value near the point.

In the area comparing means 35, the lift deviation stored in the lift change amount setting means 36 as the lift change amount;
It is compared with the cut setting value.

The rising speed detecting means 23 detects the current lift value at regular intervals, and detects the rising speed of the work implement 3 based on the amount of movement at each fixed time. The speed lower limit setting means 22 includes:
A lower limit value of the ascending speed is set for determining whether the ascending speed of the working machine 3 is small or large. Speed comparison means 2
At step 6, the rising speed of the working machine 3 detected by the rising speed detection means 23 is compared with the lower limit value of the rising speed.

The storage means 24 stores a calculated value table of the on-times of the ascending valve 27 and the descending valve 39, which give an operation command to the hydraulic actuator tough to raise the working machine 3. Specifically, when the lift change amount is large, a large on time is set, and when the lift change amount is close to the rise set value, a small on time is set. A second calculated value table 24b is stored in which the maximum on-time is set regardless of the amount of change.

Normally, the valve is opened and closed according to the on-time set in the first calculated value table 24a, and the working machine 3 moves up and down.

When the work equipment 3 is raised, when the work equipment 3 is raised and reaches an area where the amount of change in lift is smaller than the cut setting value, a signal is output from the area comparison means 35, and the speed comparison means 26 performs the comparison. According to the results, if the rising speed is smaller than the lower limit value, the on time calculated in the second calculated value table 24b is used. In this way, in a region smaller than the cut setting value, the on-time corresponding to any of the calculated value tables is input to the valve selection drive unit 25, the ascending valve 27 is opened and closed according to the on-time, and the hydraulic actuator 7 is driven.

Here, the on-time will be explained with reference to FIG. 7. As shown in the figure, the rising valve 27 and the descending valve 39 are turned on and off at preset intervals f, and when the on time is short (on time < f), they become intermittent and turn on. The shorter the on time, the slower the average lifting speed of the work equipment 3, the longer the on time, the faster the average lifting speed, and when the on time reaches the maximum (on time - f), continuous lifting and lowering operation will occur, and the work The lifting speed of machine 3 becomes maximum.

An example of the on-time calculation value table stored in the storage section 24 is shown in FIG. In the figure, (a) shows a first calculated value table 24a, and (b) shows a second calculated value table 24b. In the figure, the horizontal axis is the lift change amount, and the vertical axis is the on-time.

In the first calculated value table 24a shown in FIG.
If the amount of change in lift is larger than the above, the lift valve is turned on and off according to the on time that is in the relationship of the curve S corresponding to the amount of lift change. The lift change amount is the dead zone P
From the point exceeding M to M, the on time is 1/2 and the lift valve is intermittently lifted and lowered, and when the lift change amount is greater than M, the lift valve's on time is 1 and the lift valve is operated continuously, that is, at the maximum speed. It will be done.

The cut setting value is set to a value near the transition point M of the first calculated value table 24a and corresponding to the lift change ff1R corresponding to the maximum value of the on time.

In the second calculated value table 24b shown in FIG. 8(b),
The on time is set to the maximum value regardless of the amount of lift change.

When the operation switch 18 is operated to C or D (rise side), the rise deviation calculated by the rise deviation calculating section 21 is selected, and the valve driving section 25 is operated so that the deviation is reduced.
A drive signal is output to the rising valve 27 from the rising valve 27, and in response to the ON operation of the rising valve 27, the hydraulic actuator 7 is driven.

On the other hand, when the operation switch 18 is operated to A or B (descending side), the descending deviation calculated by the descending deviation calculation section 38 is selected, and the descending valve is sent from the valve driving section 25 so that the deviation is reduced. A drive signal is output to 39, and in response to the ON operation of the lowering valve 39, the hydraulic actuator 7 is driven.

The lifting speed of the working machine 3 is determined as follows.

Depending on the magnitude of the lift change amount, when the lift change amount is large, the on time is large, and when the lift change amount is small, the on time is short, from the first calculated value table 24a of the storage unit 24 in the valve drive unit. 25. That is, when the amount of lift change is large, the proportion of time during which the hydraulic actuator 7 is driven is increased to increase the rising speed of the work equipment 3, and when the amount of lift change is small, the time period during which the hydraulic actuator 7 is driven is increased. The ratio is made small so that the rising speed of the working machine 3 becomes slow.

Therefore, as the lift change amount becomes smaller and the position of the work equipment 3 approaches the set value for raising, the raising speed of the work equipment 3 becomes slower (in the calculation table, the ON time is reduced to 1/2 at point M). 2, the average rising speed is, for example, about 1/2), thereby preventing impact and overrun when the working machine 3 is stopped.

When the speed comparison means 26 determines that the rising speed of the working machine 3 is lower than the lower limit value, the second calculation table 24b is used to calculate the on time.

Note that when the operating switch 18 is operated to the B or C position, that is, when the lifting or lowering operation is performed only while the operating switch 18 is operated to this position, the speed is as described above. The on-time may be determined and controlled according to the amount of change, or the value (see FIG. 8) may be set to the fixed lift change data corresponding to the small on-time in the first calculated value table 24a. You may also use it as

By using the upward change data as the lift change amount, when the operation switch 18 is operated to B or C, the hydraulic actuator 7 is driven with a short ON time, so the work implement 3 is intermittently raised and lowered. Ru.

To summarize the above, in this embodiment, in a region where the lift change amount is smaller than the cut setting value, depending on the rising speed of the work equipment 3, either the first calculated value table 24a or the second calculated value table 24b is selected. is selected, and the work implement 3 is controlled to be raised at an on-time according to the selected calculated value table.

As a result, if the rising speed of the work equipment 3 is smaller than the lower speed limit value, such as when the pressure of the hydraulic oil supplied to the hydraulic actuator tough is low, the second calculated value table 24b in which the maximum on-time is set is determined. The rising valve 27 is turned on and off at the determined on time.

Next, the control flow of this embodiment will be explained in detail with reference to the flowchart of FIG. In the figure, the operation switch 18 is assembled so that no matter which switch position the operation switch 18 is operated, the flow corresponding to the case where the switch 18 is in the neutral position N is first executed, and then the operation corresponding to each switch position is performed. ing.

The control power source is also interlocked so that it cannot be turned on unless the switch 18 is in the N position, or the control flow will not run until the switch 18 is operated to the N position. Note that each flag in the flowchart is reset to "O" when the power is turned on.

First, the ascent setting value of the work equipment 3 set in the ascent position setting device 20 and the 'descending setting value set in the descent position setting device 37 are converted into values corresponding to the lift sensor 15 (step S
l). An increase deviation between the increase set value and the current lift value of the working machine 3 detected by the lift sensor 15 is calculated (step S2).

Similarly, in step S3, a descending deviation between the descending set value and the current lift value is calculated.

In step S4, it is determined whether the rise set value is greater than the current lift value. If the determination in step S4 is affirmative, the raised position flag is set to "1" (step S5), and if the determination in step S4 is negative, the raised position flag is set to "θ" (step S6).

In step S7, it is determined whether the lowering set value is larger than the current lift value. If the determination in step S7 is affirmative, the lowering position flag is set to "1" (step S8), and if the determination in step S7 is negative, the lowering position flag is set to "0" (step S9).

In the above steps, the position of the work equipment 3 is set by the flag '1'.
” or “Om”.

In other words, when the work equipment 3 is positioned above the raised setting value, both the raised position flag and the lowered position flag are "O".
When the working machine 3 is positioned below the lowering set value, both the ascending position flag and the descending position flag are "1". Further, when the working machine 3 is located between the ascending setting value and the descending setting value, the ascending position flag is "1" and the descending position flag is "0".

Next, a description will be given of how the control flow is executed depending on the position of the operation switch 18.

First, if the work equipment 3 is not moving up or down and is in a stopped state and the switch 18 is in the neutral position N, the determination as to whether the switch 18 is in the C position (step 510) is negative, and the process proceeds to step Sll. move on.

In step Sll, it is determined whether or not the operation switch 18 is operated to B. Since the operation switch 18 is in the neutral position, the judgment of the relevant step Sll is negative.
Proceed to step S12.

In step S12, it is determined whether the work implement 3 is ascending or descending, but since the work implement 3 is not ascending or descending, the determination in step S12 is negative, and the stop flag is reset (step 513).

In step S14, a value "θ" is stored in the lift change amount setting means 36 that stores the upward deviation or downward deviation.

The rising flag indicating that the work equipment 3 is in the rising operation is
The determination as to whether the switch 18 is '1' or 'O#' (step 515) is '0', and the process proceeds to the next step 816, where it is determined whether the switch 18 is in position D or not. Since the switch 18 is in the N position, the determination in step S16 is negative, and the process proceeds to step S.
Proceed to step 17. In step S17, it is determined whether the lowering flag indicating that the working machine 3 is in the lowering operation is "1" or "θ", and the result is "0", and the process proceeds to step S18. The determination in step 818 as to whether the switch 18 is in position A is negative, and the process proceeds to step S19, where the ON time of the lift valve is calculated (detailed flow will be described later).

In this case, since the lift change amount is set to "0" in step S14, the valve-on time is calculated as 0 from the calculated value table of FIG. 8, and the work implement 3 does not rise or fall.

With the above, execution of one cycle of the program when the switch position is N is completed, and the program returns to the beginning. As explained above, when the work equipment 3 is in the lifting/lowering stopped state and the switch position is N, the stop flag is reset and the lift change amount is set to "θ", the lift valve is not turned on, and the work equipment 3
is held at its current height.

However, even if the switch 18 is in the N position, if the switch position immediately before being switched to the position is C or D and the lifting/lowering operation is continuing, the determination in step S12 will be affirmative and the process will proceed to step 828. Proceed to. Furthermore, the states of each flag are different, but the flow in this case will be described later.

When the switch 18 is switched from the N position to the A position (downward side), in the first cycle, steps 810 to
The determination and operation in step S17 are performed in the same manner as when the switch 18 is in the N position, and in step 318 it is determined whether the switch 18 is in the A position. Since the switch 18 is in position A, the determination in step 318 is affirmative, and the process proceeds to step S20, where the lower flag is set and the higher flag is cleared.

In step S21, the descending deviation value is stored in the lift change amount used as data for calculating the on-time of the ascending/descending valve.

In step S22, in order to determine the position of the work machine 3,
The state of the descending position flag can be seen.

When the judgment in step S22 is “1°,” in step S23
The process proceeds to step S24, and sets a determination flag (hereinafter referred to as a rise valve flag) to "1" for calculating the on-time of either the rise valve or the fall valve, and when the judgment in step S22 is "θ", the process proceeds to step S24. Proceed and set the rising valve flag to “0”.

In other words, in the case of the descending position flag 1'', it is determined that the work equipment 3 is below the descending set value, so the ascending valve flag is set to "1#" to prepare for ascending operation, and the descending position flag θ is set. In this case, it is determined that the working machine 3 has not reached the position indicated by the lowering set value, so the ascending valve flag is set to "0" to prepare for the descending operation.

The calculation of the valve on time in step S19 follows the flowchart shown in FIG.
), if the rise valve flag is "1", the rise on time is calculated (step 5193). The calculation of the downward ON time is performed by making the lift change amount correspond to the first calculated value table 24a in FIG. The lift change amount is calculated from the first calculated value table 2 in Fig. 8.
4a and the second calculated value table 24b.

The rising ON time and the falling ON time are repeatedly read at a preset period f, and the rising valve 27 and the falling valve 39 are turned on for the ON time at each period f.

The two-cycle flow when the switch 18 is in the A position and the flow when the switch 18 is returned from the A position to the N position are executed in the same manner as described above up to step S12. If work equipment 3 is still descending,
The judgment in step S12 is affirmative, and step 328
Then, it is determined whether the rising flag or the falling flag is set. Since the descending flag remains set in step S20, the judgment in step 328 is affirmative, and the process proceeds to step S29, where the stop 1: flag is set, and the following steps are performed in the same manner as in the flow of the first cycle. Proceed to S19 and return to the beginning of the program.

In this way, once the switch 18 is selected to A,
Even if it returns to N, the descending operation of the work implement 3 does not stop until the lift change amount reaches "O" or reaches the dead zone.

If the switch 18 is in the position D (upper row side), the same steps as in the case where the switch 18 is in the A position are executed up to step S15, and the judgment in step 316 is affirmative, and the process advances to step S30. A flag is set and a falling flag is cleared. In step S31, the lift change amount setting means 36 stores the lift deviation value calculated in step S2. In step S32, the state of the lift position flag for determining the position of the work equipment 3 is checked, and if the flag is "1", the rise valve flag is set to "1" (
Step 533), if the flag is "0", the descending valve flag is set to "0°" (step 534).

In other words, "lift position flag 1" means that the work equipment 3 is below the position indicated by the raise setting value, and the raise valve flag is set to "11" to prepare for the raise operation, and "raise position flag 0" is set. means that the working machine 3 has reached the position indicated by the ascending set value, so the ascending valve flag is set to "0" to prepare for the descending operation.

Since the descending flag is cleared in step S30,
The determination in step S17 is "0", and step 818
Since the switch 18 is in the D position, the determination is negative, and the process proceeds to step S19, where the valve-on time is calculated according to the flowchart shown in FIG.

When the position of the switch 18 is returned from D to N, the explanation is omitted because it is the same as when the position of the switch 18 is returned from A to N.

Next, if the switch 18 is in position B, the determination in step Sll is affirmative, and the process proceeds to step S35, where the rise flag is cleared. The judgment as to whether the stop flag is "1" or "0" (step 535) is made using the switch 18 as described above.
is always switched to another position via the N position, so the stop flag is set in step S.
It is reset at 13 and is "0". In the next step S37, the downward deviation calculated in step S3 is stored in the lift change amount setting means 36. Step 3
In order to judge the position of the working machine 3 at step 38, it is checked whether the lowering position flag is "1" or "0". If the lowering position flag is "1", the rising valve flag is set to "1" (step 539), and if the lowering position flag is "O", the rising valve flag is set to "0" (step 539). 540).

The initial value of the rising flag is “θ”, and step S
Since the rise flag is cleared at 35, step S
The judgment of No. 15 is “0”.

Since the switch 18 is in the position B, the determination in step S16 is negative, and the process proceeds to step S17. The initial value of the descending flag also becomes "0" like the ascending flag, and the next step 81
Proceed to step 8. The judgment in step S18 is negative because the switch 18 is in B, and the process proceeds to step S19, where the valve-on time is calculated based on the amount of lift change in which the downward deviation was stored in step S37, and the valve-on time is calculated at the beginning of the program. Return to

Next, if the switch 18 is operated to position C, the judgment in step SIO is affirmative, and the process proceeds to step S41.
The falling flag is cleared. The process of clearing the descending flag in step S41 is performed during the descending operation of the working machine 3.
In step S42, which is effective when forced to stop, it is determined whether the stop flag is "1" or "0". Since it is assumed that the switch 18 is always switched to another position via the N position, the stop flag is reset in step S13, the determination in step S42 is "θ", and the process is continued in step S.
The process proceeds from step S42 to step S43.

In step S43, the lift deviation is stored in the lift change amount setting means 36.

In step S, 44, in order to determine the position of the work machine 3,
It is determined whether the raised position flag is "1" or "0".

If the up position flag is “1”, the up valve flag is “1”
If the descending position flag is "θ", the rising valve flag is set to "0" (step 546).

Thereafter, as in the case where the switch is B, step S19
Processed up to

Note that when the work equipment 3 is lowered in switch A position or
If you want to forcibly stop the robot while it is rising at position A, you can stop it by switching the switch from position A to position C, or from position D to position B.

For example, if the switch is lowered at position A and switched to position C, the judgment at step SIO will be affirmative, so
Proceeding to step S41, the descending flag is cleared. Before switching the switch 18 from A to C, step S2
Since the stop flag is set in step S4,
2, the stop flag is determined to be "1", and step S
The process advances to 14, and "01" is stored in the lift change amount.

After step S14, the falling flag in step S17 has already been cleared in step S41, so step S
The process advances to step S18, and since the switch 18 has been switched to the C position, the result of step 818 is also negative, and the process advances to step S19, where the valve-on time is calculated. However, since 0 is stored in the lift change amount in step S14, the valve-on time becomes 0, and the lifting and lowering of the working machine 3 is stopped.

Similarly, the work machine 3 can be stopped by switching the switch 18 to B while the switch 18 is in the D position and rising.

As described above, in this embodiment, the position of the work equipment 3 with respect to the above-mentioned upward setting value and downward setting value is determined by comparing the current lift value and the upward setting value and comparing the current lift value and the downward setting value. and the deviation are detected, and the ascending and descending direction of the working machine 3 is determined from the selected position of the switch 18 and the detected position. Further, based on the deviation, the ON time of the lifting or lowering valve of the working machine 3 is calculated, and the ascending and descending speed of the working machine 3 is controlled.

The deviation is updated every execution cycle of the program and set as the amount of change in lift.

In addition, in steps S37 and S43, the lift change data K is set instead of the upward deviation or downward deviation set in the lift change amount setting means 36, and the operation switch 18 is operated to B or C. In this case, the on-time for the period f may be reduced, and the working machine 3 may be driven intermittently.

In this way, by intermittent driving of the work equipment 3, the lifting speed of the work equipment 3 can be slowed down, making it easier to finely adjust the lifting position.
A clear difference is made in the lifting and lowering speeds when the operation switch 18 is operated to A or D, and when the operation switch 18 is operated to A or D, and the optimum operation is performed depending on the operation purpose for each position of the operation switch 18. You can make it happen.

Next, a control flow for selecting either the first calculated value table 24a or the second calculated value table 24b in the rising on time calculation in step 5193 will be explained with reference to FIG.

First, in step S50, the rising valve flag is "1".
By determining whether the value is "0", it is determined whether the control valve 27 on the ascending side should be opened or the control valve 39 on the descending side should be opened. If the determination result in step S50 is "1", the process proceeds to step S51, and if the result is "O", the process proceeds to step S52.

In step S51, it is determined whether the on-time is "0" or not. If the on-time of the control valve is "O", step S51 is performed.
If the on-time is not "θ", the process advances to step 558.

In step S52, the area comparing means 35 determines whether the lift change amount is larger than the cut setting value. If the lift change amount is larger than the cut set value, the process advances to step S53 and the upward check flag is set to "1°.If the cut set value is greater than the lift change amount, the process proceeds to step S54 and the upward check flag is set to 1°. “0” is set.

That is, in steps S52 to S34, a lift check flag is set which indicates the position of the work implement 3 before the lift is started.

In step S55, the initial check flag is set to "0".

In step S56, the pulse cut flag is set to "0°."

In step S57, the first calculated value table 24a is selected.

In step 358, the rising check flag is “O” or “1”.
If the lift change amount is greater than the cut set value and the rise check flag is "1", that is, the current lift value of the work equipment is far from the set value, the process moves to step S57. Then, the on-time is calculated according to the first calculated value table 24a, and the work implement 3 is raised.

If the lift change amount is smaller than the cut setting value and the upward check flag is "0", that is, the current lift value of the work equipment is close to the set value, the process advances to step S59, and the initial check flag is determined. .

The first check flag is “
Since the flag is set to "0", the determination in step S59 is "O" and the process advances to step S60.

In step S60, the area comparing means 35 determines whether the cut setting value is larger than the lift change amount, and if the cut setting value is larger, the process proceeds to step S61.

In step S61, the speed comparing means 26 compares the lower speed limit set in the lower speed limit setting means 22 and the rising speed detected by the rising speed detecting means 23. As a result of the comparison in step S61, if the speed lower limit value is greater than the rising speed, that is, if the rising speed is slow, the process proceeds to step S62.

In step S62, the operation switch 18 is set to B or C.
In the case where the lift change data K is used as the lift change amount when the operation switch 18 is operated to B or C, it is difficult to determine whether the operation switch 18 is operated to B or C and is intermittently driven. Is the lifting speed of the work equipment 3 intentionally lower than the lower speed limit due to a fine adjustment made by the worker's will, or is the lifting speed of the work equipment 3 lower than the lower speed limit due to low oil pressure? A judgment is made as to whether it has become too low.

As a result of the comparison between the on-off period f and the on-time of the ascending valve in step S62, if the period f and the on-time are equal, the process proceeds to step S63, where "1" is set in the pulse cut flag.

In this way, even though the on time is equal to the cycle f, that is, the rising valve 27 is continuously turned on (the judgment result in step S62), the rising speed of the work implement 3 is slow (the judgment result in step S61). ), it is determined that the rising speed of the working machine 3 is lower than the lower speed limit due to the low oil pressure, and the pulse cut flag is set to "1".

On the other hand, if it is determined in step S62 that the period f and the on time are not equal, the process moves to step S64. The fact that the period f and the on-time are not equal means that the on-time of the ascending valve 27 is short, that is, the working machine 3 is driven intermittently. The fact that the work equipment 3 is intermittently driven means that the operation switch 18 is operated to the C position, the lift change data K is set as the lift change amount, and the lifting speed is intentionally lowered by the operator's will. This indicates that the position has been finely adjusted, and it can be determined that the speed reduction is not due to insufficient hydraulic power.

Therefore, in this case, even if it is determined in step S61 that the rising speed of the work implement 3 is lower than the lower speed limit,
Step S63 of setting "1" to the pulse cut flag
is skipped.

As a result of the comparison in step S61, if the rising speed of the working machine 3 is greater than the speed lower limit value, the determination in step S61 is negative and the process moves to step S64. In this case as well, step S6 sets the pulse cut flag to "1".
3 is skipped.

In step S64, the initial check flag is set to "1". When the initial check flag is set to "BI", steps 360 to 44 are skipped from the next processing.

Also, if the lift change amount is greater than the cut setting value,
The judgment at step 860 is negative, and steps 361~
44 is skipped and the process moves to step S65.

In step S65, the pulse cut flag is determined. In step S63, the pulse cut flag is set to “1”.
” is set, the process advances to step 366 and the second calculated value table 24b is selected from the storage unit 24.

Since the second calculated value table 24b stores the maximum on-time regardless of the amount of change in lift, the work equipment 3 can maintain the maximum hydraulic pressure within the pressure range of the hydraulic fluid supplied to the hydraulic actuator 7. raised by pressure.

When the pulse cut flag is "θ", the process moves from step S66 to step S57, the first calculated value table 24a is selected, and the on time is determined by making the lift change amount correspond to the calculated value table. .

As described above, in this embodiment, the area comparison means 35 compares the lift change amount and the cut setting value,
The position of the working machine 3 with respect to the cut setting value is determined.

When the cut setting value becomes larger than the lift change amount, that is, when the work equipment 3 is located at the position just before the on time starts to change from the maximum value to a lower value, the rising speed of the work equipment 3 and the speed lower limit The speed comparison means 26 compares the value with the speed comparison means 26,
When the rising speed is lower than the speed lower limit value, the on-time is determined according to the second revised value table 24b.

The lift deviation is updated every execution cycle of the program and set as the amount of change in lift.

The valve-on time calculation (step 519) is not limited to the timing shown in the flowchart of this embodiment, but can also be processed by interrupting at any period.

In the above embodiment, an example is shown in which one selection is made from the two calculated value tables only when the working machine 3 moves up. This is because when the work equipment 3 moves downward, the weight of the work equipment 3 normally acts in the downward direction, so even if the hydraulic oil supply pressure decreases, the speed remains stable without being affected by it. This is because a descending operation can be performed.

Of course, if a hydraulic system is used that supplies hydraulic oil to a hydraulic actuator to force it to perform a downward movement, the present invention can also be applied to control the downward movement as necessary.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects can be achieved.

(1) If the supply pressure of the hydraulic oil supplied to the hydraulic actuator becomes low, such as when a traveling work vehicle is idling, and the lifting speed of the work equipment decreases due to this, the control valve of the hydraulic actuator Since the working machine is raised by setting the ON time to the maximum value, it is possible to stably raise the working machine even when the supply pressure of the hydraulic oil is low.

(2) When raising the work equipment with normal hydraulic oil pressure, the on time of the control valve is calculated according to the amount of lift change, and when it approaches the rise setting value, the work equipment is raised at a low speed, so it is overloaded. Great for preventing shoots and mitigating shock.

Note that this switching to a low speed is not performed when the rising speed is slow, so that the reduction in work efficiency due to deceleration can be kept to the minimum necessary range.

(3) Since the selection switching between the first calculated value table and the second calculated value table is performed based on the amount of change in lift,
Even if the increase setting value is changed, the effects (1) and (2) above can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control device showing an embodiment of the present invention, FIGS. 2, 3, and 4 are flowcharts showing the operation of the control device, and FIG. 5 is a contact configuration diagram of an operation switch.
FIG. 6(a) is a front view of the conductive slide member, FIG.
b) is a side view of the conductive slide member, Fig. 7 is a time chart of on-time, Fig. 8 is a diagram of the relationship between on-time and lift variation, Fig. 9 is a side view of the traveling work vehicle, and Fig. 10 is a diagram of the relationship between on-time and lift change amount. FIG. 3 is a perspective view of a working machine and a connecting portion connected to the rear of the traveling work vehicle. 1... Traveling vehicle, 3... Ground work equipment, 7... Hydraulic actuator, 8, 9... Lift arm, 10°1
1...Lift rod, 15...Lift sensor, 18
. . . Operation switch, 19 . . . Cut setting value setting means, 20 . . . Ascent position setter, 21 . Detection means, 24... Storage unit, 24a... First calculated value table, 24b... Second calculated value table, 25.
... Valve drive unit, 26... Speed comparison means, 27...
・Rise valve, 35...Area comparison means, 36...Lift change amount setting means Agent Patent attorney Michito Hiraki and one other person Figure 2 (Part 1) Figure 3 Figure 4 (Part 1) 7 Figure 8 Figure 8 (a) Figure 9 Figure 10

Claims (3)

[Claims] (1) An ascent position setting device that sets a target ascent position of the work equipment, a sensor that detects the current position of the work equipment, an ascent deviation calculation unit that calculates a deviation between the target position and the current position, and the deviation is small. A first calculated value table that sometimes reduces the on-time duty ratio of the control valve of the hydraulic actuator and increases the on-time duty ratio when the deviation is large, and corresponds to the same deviation regardless of the size of the deviation. a storage unit storing a second calculated value table in which the on-time duty ratio to be calculated is set to be larger than the on-time duty ratio of the first calculated value table; and the on-time duty ratio in the first calculated value table. setting means for setting a cut setting value that corresponds to a deviation in the vicinity of a change point where the on-time duty ratio transitions from the maximum value to a smaller value, the deviation being smaller than the cut setting value; means for comparing the rising speed of the working machine with a predetermined speed lower limit value and selecting the second calculation table when the rising speed is smaller than the speed lower limit value; and the first and second calculated values. A ground work machine position control device comprising: a valve drive unit that operates a lift valve of a hydraulic actuator in a direction to eliminate the rise deviation according to the on-time of the table. (2) The ground work machine position control device according to claim 1, wherein the storage unit stores a calculated value table in which the on-time duty ratio changes continuously from a maximum value to a minimum value. . (3) The ground work machine position control device according to claim 1, wherein a calculated value table in which the on-time duty ratio changes stepwise from a maximum value to a minimum value is stored in the storage unit. .