JPH0227905A - Apparatus for controlling working mechanism of mobile farm working machine - Google Patents

Abstract

PURPOSE:To prevent the dashing of a lifting apparatus of a working machine and prevent uncomfortable shock in the change-over of the apparatus to a low-speed mode by controlling the lowering of the working machine to effect smooth deceleration. CONSTITUTION:A working machine is vertically displaced by a hydraulic actuator energized by a signal transmitted to a lifting or lowering solenoid by the operation of a position lever. The above lifting apparatus is provided with a real speed calculation means to calculate the real lowering speed of the working part and with a deceleration means to decelerate the hydraulic actuator by gradually decreasing the duty ratio of an output signal to the lowering solenoid based on the lowering operation of the position lever. When the duty ratio reaches a prescribed level, the lowering speed is maintained at a constant level by a feed-back control based on the real speed calculation means.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a work machine control device for a mobile agricultural machine such as a tractor, and more specifically, the present invention relates to a work machine control device for a mobile agricultural machine such as a tractor, and more specifically, the present invention relates to a work machine control device for a mobile agricultural machine such as a tractor.
The present invention relates to a work machine control device for a mobile agricultural machine configured to output a signal to a lowering solenoid to operate a hydraulic actuator to raise and lower the work machine.

(b) Conventional technology In general, a mobile agricultural machine such as a tractor is equipped with a working machine such as a rotary at the rear of the traveling machine so that it can be freely raised and lowered based on the operation of a position lever. The rotary is configured to perform tillage work, etc. by operating the rotary to the position and driving the work equipment into the field, but if the rotary is lowered monotonously from the raised position, the lowering speed will be lower. As the weight of the rotary increases, the speed increases, and when the rotary suddenly comes into contact with the field, a dashing phenomenon occurs in which the traveling body is pushed forward by the rotation of the rotary.

Therefore, as shown in Japanese Patent Publication No. 58-48124, when a working machine such as a rotary is lowered from a position far above the field, a speed switching circuit installed in the machine body is used to adjust the speed at a predetermined speed. The descending speed is increased until it approaches the ground level, and when it approaches a lower set working height from the ground level, the descending speed is switched to slow down. An automatic working height control mechanism has been devised in which the working machine descends quickly and, when the working machine touches the ground, the descending speed becomes slow so that the dashing phenomenon does not occur.

(C) Problems to be Solved by the Invention However, the above-mentioned conventional automatic working height control mechanism rapidly reduces the speed of a working machine such as a rotary at a predetermined position near the ground surface to prevent dashing. Moreover, an unpleasant shock occurs during the deceleration, which worsens the operating feeling. In addition, since the work equipment deceleration position to prevent dashing is fixed at a predetermined position, the dashing prevention position must be changed each time depending on the field situation by adjusting the height adjustment volume, etc.
The operation by the operator is extremely troublesome.

(d) Means for Solving the Problems The present invention aims to solve the above-mentioned problems. For example, as shown in FIG. and lowering solenoid (
22) and (23) to actuate a hydraulic actuator (34) (see FIG. 6) to raise and lower the work implement (12). ), and the duty ratio of the output signal to the lowering solenoid (23) is gradually reduced based on the lowering operation of the position lever (9). a descending deceleration means (48) that decelerates the hydraulic actuator (34); and a descending deceleration means (48) that decelerates the hydraulic actuator (34), and from the time when the duty ratio reaches a preset value, the working machine (12) The present invention is characterized in that it is provided with feedback control means (28) for descending at a constant speed.

Further, a changing means (27) (see FIG. 4) for changing the rate of decrease in the duty ratio may be provided.

(E) Function Based on the above-mentioned configuration, when working with the mobile agricultural machine (1), the working machine (
When the position lever (9) is operated downward in order to ground the solenoid (12), the duty ratio of the output signal to the descending solenoid (23) is gradually reduced by the descending deceleration means (48) based on this (the third (see figure) is output, which causes the hydraulic actuator (34) to operate to gradually decelerate, thus working! as shown in figure 2. (
12) is lowered quickly and at a gradually slower rate. Then, from the time when the duty ratio reaches the set value, the feedback control means (28)
Accordingly, the duty ratio is increased or decreased as appropriate based on the calculation by the actual speed calculation means (24), and thereby the working machine (
12) descends at a constant low speed and touches the ground.

Furthermore, the constant speed descent start position is set by a changing means (27).
The settings can be changed as appropriate by changing the reduction rate of the duty ratio by operating .

Note that the symbols in parentheses do not limit the configuration in any way.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 9, the tractor 1 has front wheels 2 and rear wheels 3.
The vehicle has a traveling body 5 supported by a driver's seat 6, and a driver's seat 6 is disposed approximately in the center of the traveling body 5.
A steering wheel 7, a position lever 9, and a seat 10 are installed in the driver's seat 6, respectively.

Further, behind the traveling body 5, a rotary working machine 12 is provided.
is attached to the lift arm 8, the link 14, etc. so that it can be raised and lowered freely, and a hydraulic cylinder 34 (see FIG. 6) for raising and lowering the working machine is installed in the lift arm 8 portion. Further, as shown in FIG. 4, the driver's seat 6 is provided with a mode switching volume 26, the work equipment switching volume 20, a position adjustment volume 27, and the like.

Moreover, as shown in FIGS. 5(a) and 5(b), the body position.

The lever 9 is installed so as to freely rotate in the direction of the arrow B about the rotation base A, and the rotation angle of the lever 9 is detected by the position detection sensor 18.

On the other hand, the microcomputer 17 mounted on the tractor 1
(hereinafter referred to as a microcomputer), as shown in FIG.
and a work equipment switching volume 20 are connected, and on the output side, via an output interface 21, there are a lift arm raising solenoid 22 and a lift arm lowering solenoid 23 that operate the lift arm switching valve.
are connected. Furthermore, the microcomputer 17 includes an actual speed calculation means 24 that calculates the actual lifting speed by calculating the amount of change in value per unit time of the output signal from the lift arm angle sensor 19, and a rotary work machine 12 that calculates the lift arm angle. a descending deceleration means 44 that decelerates the actuator 19 by decreasing the duty ratio of the signal output to the lift arm raising solenoid 22 by a fixed ratio from the time when the height reaches a predetermined height based on the sensor 19; and the duty ratio. Feedback control means 28 is provided for lowering the rotary working machine 12 at a constant speed based on the actual speed calculation means 24 from the time when the value reaches a preset value. Further, based on the lowering operation of the position lever 9, the microcomputer 17 outputs an inching signal so that the duty ratio decreases by a fixed ratio, and controls the working part lifting hydraulic cylinder 34 to adjust the lowering speed of the rotary working machine 12. A descending deceleration means 48 operates to gradually slow down the speed, and from a predetermined duty ratio position, the feedback control means 28 operates the rotary work machine 1 based on the actual speed calculation means 24.
2 at a constant low speed.

Further, as shown in FIG. 6, the hydraulic pump 31 communicates with a tank 33 via a filter 32, and also communicates with a lift rod cylinder 36 via a priority valve 35.
The hydraulic cylinder 34 is connected to a hydraulic cylinder 34 for lifting and lowering the working machine via a control valve 37.

Next, the operation of this embodiment will be explained using the time chart shown in FIG.

In the figure, the horizontal axis shows the passage of time, the vertical axis (a) shows the position setting by the position lever 9, (b) shows the elevation angle of the rotary work machine 12 by the lift arm angle sensor 19, and (c) (d) shows a control signal to the lift arm raising solenoid 22, and (d) shows a control signal to the lift arm lowering solenoid 23. and,
When working with the rotary work machine 12, when the position lever 9 is operated to the highest position (a), the operating angle of the lever 9 is detected by the position detection sensor 18 and input to the microcomputer 17. Based on this, working department 11
In other words, the lift arm 8 is at an angle. (b) Continuously turn on the lift arm raising solenoid 22 until (
C) Immediately raise the rotary working machine 12. and,
Angle of lift arm 8. At the point in time (d), as shown in FIG. 3(a), the duty ratio of the control pulse signal is decreased by a fixed ratio every cycle by the ascending deceleration means 44, so that the rotary work machine 12 moves smoothly. The speed is reduced to Then, from the point when the duty ratio reaches a predetermined ratio, that is, from section C in the figure, the rotary work machine 12
The feedback control means 28 calculates and detects its actual rising speed based on the actual speed calculating means 24, increases or decreases the duty ratio of the pulse signal as appropriate, and raises it to the highest position at a constant speed (feedback control).
e) The rotary working machine 12 is held at the highest position (f) Therefore, since the rotary working machine 12 is raised quickly and slowly and smoothly from near the highest position, no unpleasant shock occurs.

Furthermore, when the tractor 1 traveling in this state reaches the working position, if the position control lever 9 is lowered (g)
The operating position of the lever 9 is detected by the position detection sensor 18, and the descending deceleration means 48 based on this detects the operation position.
An inching signal (h) in which the duty ratio is decreased by a constant ratio starting from a position close to 100% (shown enlarged in FIG. 3(b)) is outputted to the lift arm lowering solenoid 23. As a result, the rotary work machine 12 descends from the highest position quickly and with its speed gradually reduced (i). Then, from the point in time when the pulse signal to the lift arm lifting solenoid 22 reaches the preset duty ratio (j), the rotary work machine 12 controls the actual speed calculation means 24 by the feedback control means 28.
While calculating and detecting the actual descending speed based on the above, the duty ratio of the pulse signal (k) (shown enlarged in Fig. 3(c)) is increased/decreased as appropriate, and it is descended at a constant speed to the lowest position. (Feedback control) (β), Therefore, when the rotary work machine 12 descends, there is no inflection point where the speed suddenly changes, that is, there is no inflection point where the speed suddenly changes, that is, when the rotary work machine 12 is at a position significantly above the ground level, it has a high descending speed and a high ground level. There is no switching point to switch to a slow descending speed at the approaching position, and the work implement 12 decelerates smoothly, and when it touches down, it smoothly contacts the field at a constant low speed, and no dashing phenomenon occurs.

Further, as shown in FIG. 7(a), when the position adjustment volume 27 is rotated counterclockwise (lower) from the standard position, the duty ratio of the pulse signal during deceleration as shown in FIG. 3(b) The ON time T is a predetermined length at which the rate of change is made small and the ON time is decreased little by little and feedback control is started, as shown in FIG. 8(a). Since it takes time to reach the point, the rotary work machine 12 is operated as shown in Fig. 7 (
As shown in (a) of b), the start of the feedback control, which is so-called dashing prevention control, is delayed, so that the rotary working machine 12 is switched to constant speed reduction after it is relatively close to the field. Furthermore, when the position adjustment volume 27 is operated to the central standard position shown in FIG. 7(a),
As shown in FIG. 8(b), since the duty ratio change rate of the pulse signal during deceleration is larger than that in FIG. 8(a), the ON time T. reached relatively quickly,
This allows the rotary work machine 12 to start its feedback control relatively quickly, as shown at the beginning of FIG. 7(b). Then, adjust the 1-position adjustment volume 27 as shown in FIG. 7(a).
When rotated clockwise (higher), the duty ratio change rate of the pulse signal during deceleration is further increased, as shown in Fig. 8 (C
), the rate of change per cycle of the ON time is further increased, and the ON time To is reached even faster.
As shown in FIG. 7(b), the downward movement of the rotary work machine 12 starts faster, and the feedback control starts faster.
As a result, the rotary work machine 12 is switched to a constant speed downward movement at a position relatively far from the field. Therefore, when adjusting the position adjustment volume 27, the duty ratio of the subsequent pulse is changed without changing the pulse width at the beginning of the change. can change in proportion to the amount of operation.

In this embodiment, the range of change in the duty ratio with respect to the manipulated variable is the same on the lower side when the position adjustment volume 27 is rotated counterclockwise from its standard position and on the higher side when the position adjustment volume 27 is rotated clockwise. However, when attempting to finely adjust the starting position of feedback control on the high side due to wheel subsidence, it is necessary to increase the range of change on the low side in the counterclockwise direction and reduce the range of change on the high side in the clockwise direction. It may be configured to be small, and according to this, when the position adjustment volume 27 is turned fully counterclockwise, the width of change in the duty ratio of the pulse signal becomes very large, so feedback control is not necessary. In reality, it will appear after the rotary working machine 12 comes into contact with the field, so the rotary working machine 12
In other words, the feedback control can be canceled and the operator can select a control pattern according to his preference.

For example, if a fertilizer seeding machine is installed together with the rotary working machine 12 to perform seed sowing and fertilizing work as well as tilling work, the range of change on the low side in the counterclockwise direction of the position adjustment volume 27 can be made small. In addition, by configuring the change range to be large on the high side in the clockwise direction, and by making it possible to finely adjust the feedback control start position at a part close to the field, even if the weight of the rotary work machine 12 increases, The rotary working machine 12 and the fertilizing seeding machine may be finely adjusted by feedback control so that they are in proper contact with the field.

(G) As described in detail, according to the present invention, when the position lever (9) is lowered, the lowering deceleration means (44) gradually decreases the duty ratio of the output signal to reduce the duty ratio of the output signal. ) is decelerated, and from the time when the duty ratio reaches a preset value, the actual speed calculation means (
Since the feedback control means (28) for lowering the work equipment (12) at a constant speed based on 24) is provided, the work f.
It is possible to quickly lower the f1 (12) from the raised position and naturally slow down the lowering speed when approaching the field. Therefore, it is possible to prevent dashing when a rotary work machine is attached, and to reduce the speed at low speeds. It is possible to reliably prevent the occurrence of unpleasant shocks when switching, and it is possible to improve the operational feeling as well as work efficiency.

Furthermore, a changing means (2
7), the position at which the duty ratio reaches the set value can be freely changed simply by operating the changing means (27), and thereby the feedback control starting position can be freely changed. Can be adjusted.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an electric circuit according to the present invention, Fig. 2 is a time chart showing changes in pulse signals when the rotary working machine is raised and lowered, and Fig. 3 is a diagram showing its duty cycle.
A time chart showing each change in the ratio, Fig. 4 is a diagram showing the work equipment switching volume, etc., Fig. 5 (a) is a side sectional view showing the installation structure of the position lever, and Fig. 5 (b) is a front sectional view thereof. Figure 6 is a diagram showing the hydraulic circuit, Figure 7 (a)
Figure 7(b) is a diagram showing the position adjustment volume, Figure 7(b) is a diagram showing changes in the feedback control start position etc. when the rotary working bridge is lowered, and Figures 8(a), (b), and (c) are position adjustment. 5 is a time chart showing changes in duty ratio during each volume adjustment. FIG. 9 is an overall side view showing a tractor to which the present invention can be applied. ...Descent deceleration means

Claims (2)

[Claims] 1. In a mobile agricultural machine configured to operate a hydraulic actuator by outputting a signal to a lifting and lowering solenoid based on the operation of a position lever to raise and lower the working equipment, an actual descending speed of the working equipment is calculated. a speed calculation means; a lowering deceleration means for gradually decreasing the duty ratio of an output signal to the lowering solenoid to decelerate the hydraulic actuator based on the lowering operation of the position lever; A work machine control device for a mobile agricultural machine, comprising: feedback control means for lowering the work machine at a constant speed based on the actual speed calculation means from the time when the actual speed calculation means is reached. 2. 2. The work machine control device for a mobile agricultural machine according to claim 1, further comprising a changing means for changing the rate of decrease of said duty ratio.