JPS633707A - Plowing depth automatic control apparatus of tractor - 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 (A) Field of Industrial Application The present invention relates to an automatic tillage depth control device for controlling the tillage depth of a working machine such as a rotary tiller mounted on a tractor to a constant value.

(B) Prior Art Techniques for controlling the plowing depth of a rotary tiller mounted on a tractor to a constant value by pulse driving a solenoid valve have been known. For example, special public service in 1973
-138303 and Japanese Patent Publication No. 55-141103.

(c) Problems to be Solved by the Invention The present invention improves the above-mentioned conventional technology, and not only changes the pulse period during rising and falling, but also changes the position of the deviation angle at which the duty ratio starts to decrease, and finally The width of the decrease in the duty ratio until the condition is met is also varied, and the rate of decrease in the duty ratio is also varied as to whether it is "gradually" or "rapidly".

A data group is set for changing the duty ratio to an optimum state in which no impact occurs during rising and falling, and the pulse of the solenoid valve is changed accordingly.

Furthermore, due to differences in the characteristics of solenoid valves, characteristics of hydraulic pumps, characteristics of work equipment, etc., it is necessary to slightly change the data group of the duty ratio, and the tractors and work equipment equipped with electronic control devices are different. Then, it is necessary to separately store data groups with different duty ratios in a storage device. The present invention is designed for such cases by inputting data groups of several types of duty ratios into the storage device and selecting one of them to determine the highest duty ratio that matches the condition. It is configured so that it can be obtained.

(d) Means for Solving the Problems The objects of the present invention are as described above. Next, the configuration for achieving the objects will be explained.

In an automatic control device configured to approach the set plowing depth by switching a hydraulic switching valve operated by a solenoid valve to move the lift arm up and down in response to a set plowing depth, the solenoid is driven by pulses, In order to make the pulse period different between rising and falling times and change the duty ratio in the pulse period with respect to the deviation between the set value and the current value, a duty ratio data group corresponding to the deviation is stored in the storage device. This is what I did.

Further, a plurality of duty ratio data groups are stored, and the duty ratio data groups can be selectively used by switching a switch.

(E) Structure of the Embodiment The object and structure of the present invention are as described above. Next, the structure of the embodiment shown in the attached drawings will be explained.

FIG. 1 is a side view showing an automatic tillage depth control device for a tractor according to the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a plan view of an operation box 11 section.

The configuration will be explained with reference to FIGS. 1, 2, and 3.

A hydraulic case N is placed on top of the tractor's transmission case. Left and right lower links 14 protrude from the rear end side of the mission case M so as to be movable up and down. Further, a top link hinge 21 protrudes from the rear surface of the hydraulic case N, and a top link 15 is pivotally supported at the rear end. Power is transmitted from the PTO shaft 23 of the bevel gear box 22 of the rotary tiller gWR to the hemi- sion case M via a universal joint shaft.

The rotary tilling device R is configured to till the soil by rotating the tilling claws 7 and to level the tilled soil using the rear cover 1.

In the present invention, the rear cover 1 is also used as a sensor for detecting the plowing depth, and the vertical rotation state of the rear cover 1 is detected through a sensor wire 12 arranged on the side of the hydraulic case N. It is input to the rear cover sensor 5. The rear cover sensor 5 is composed of a potentiometer or the like.

Also, the lift straight arm 8 is moved up and down from the hydraulic case N.
・8 is protruding backwards. One section of lift links 13, 13 are connected to the rear ends of the lift arms 8, 8, and the lower ends of the lift links 13, 13 are pivotally connected to the middle portions of the lower links 14, 14.

A lift angle sensor 4 for detecting the rotation angle of the lift arm 8 is arranged at the rotation base of the lift arm 8 .

Further, a seat 24 is arranged above the hydraulic case N, and a position lever 2 is provided on the side of the seat 240 for the operator to manually set the height of the rotary tiller.
is located.

A position setting device 6 for detecting a value set by the position lever 2 is disposed at the rotation base of the position lever 2.

Also, the controller 16 is connected between the seat 24 and the hydraulic case N.
A microcomputer, an A/D converter, etc. as a control device are arranged within the controller 16.

Also, the solenoid valve 3 is installed inside or on the side of the hydraulic case N.
Hydraulic switching valve 17 using 0.31 as a pilot valve
is located. The output signal after being controlled and determined by the controller 16 is sent to the solenoid valves 30 and 31 of the hydraulic switching valve 17, and is fed-banked.

Further, a travel gear shift lever 3 for operating a forward/reverse transmission disposed inside the mission case M is rotatably arranged for speed change operation, and at the base of the travel gear shift lever 3,
A back switch 19 is arranged to detect the state in which the traveling speed change lever 3 is shifted to the reverse position.

Furthermore, an operation box 11 for automatic reverse control is fixedly installed on the lower surface of the rear part of the dash board 25. A plowing depth setting dial 9 and a lift switch 10 are arranged on the top surface of the operation box 11.

The plowing depth setting dial 9, lift angle sensor 4, rear cover sensor 5, and position setting device 6 are all constituted by potentiometers whose voltage values change when rotated.

In addition, the lift switch 10 is turned ON only when the operator operates it to the upward or downward direction, and turns ON when the operator releases it.
It is composed of switches serving as FF.

Further, an auto-off switch 28 is arranged, which is turned on when the plowing depth setting dial 9 is fully rotated in the "depth" direction. When the plowing depth setting dial 9 is rotated and is in a position other than "off", the auto-off switch 28 is OFF and in an automatic control state.

FIG. 13 is a schematic diagram of the controller 16. Inside the controller 16 is a microcomputer/A/D.
Converter, input terminals, etc. are arranged, engine start key 26, plowing depth setting dial 9, depth sensor 5
- Signals from the lift angle sensor 4, position setting device 6, lift switch 10, etc. are input.

Furthermore, in the present invention, a changeover switch W is also provided for selecting the optimum data group from the duty ratio data group.

The output signal is a signal that activates the solenoids 30 and 31.

(F) Function of the Embodiment Next, the function of the automatic tillage depth control device of this embodiment will be explained with reference to the drawings of FIGS. 4 to 12.

Fig. 4 is a drawing showing an overview of the control flowchart, Fig. 5 is a drawing of the flowchart with parts of "position mode", "auto mode", and "lift-up mode when reversing", Fig. 6, Fig. 7, Figure 8 is a diagram showing the entire flowchart of the present invention divided into the first stage, interruption stage, and second stage, Figure 9 is a diagram showing the operation routine of "auto mode", and Figure 1O is a diagram showing the operation routine of "position mode". FIG. 11 is a drawing showing the operation routine of the "lift-up mode", and FIG. 12 is a drawing showing an example of a data group of duty ratios with respect to deviations between set values and lift angles.

First, in FIG. 4, an overall outline of the control flowchart of the present invention is shown.

That is, first, when the tractor's engine start key is turned ON, the control is started and the auto-off switch 28, lift switch 10, and reverse switch 19 are turned on and off.
The F state is detected and stored every 8 ns.

Next, the tilling depth setting dial 9 in the operation box 11 is rotated to specify the tilling depth. 0 in conjunction with the tilling depth setting dial 9.
The auto cut switch 28 that is turned off is turned off and the plowing depth value is set. Furthermore, lift angle sensor 4,
Signals from the rear cover sensor 5 and position setting device 6 are also stored.

The control mode is selected with the various signals stored.

There are the following types of control modes:

There are six modes: ``auto mode,'' ``position mode,'' ``lift-up mode when reversing,'' ``safety mode,'' ``lift amplifier mode,'' and ``abnormal mode.''

The operation for each mode is performed according to the flowchart.

Then select 1 mode out of 8 modes and select 1 mode, ■
When the control flow of the flowchart is completed, it is configured to return to the starting position again via the self-diagnosis flowchart (SD) and the monitor communication (870-CHAR) CM-C).

Next, the conditions for selecting the "position mode" will be explained mainly with reference to the flowcharts of FIGS. 5 and 7.

Move the lift arm 8 to any position using the position lever 2.
■If the auto-off switch 28 is turned on when the "safety mode", "abnormal mode", or "lift-up mode" is not selected.

(2) When the set position of the position lever 2 is above or equal to the position of the lift arm 8.

When entering the "position mode" with ■ or Enters "auto mode".In other words, it enters "position mode" only when the lift arm is operating.

The operation of the "position mode" is as follows.

That is, the position of the lift arm 8 and the set position of the position lever 2 correspond one-to-one, and if the position lever 2 is moved, the lift arm 8 will also move accordingly.

While moving, it is in ``position mode,'' but when it enters a dead zone and stops, it switches to ``auto mode.''

In the "auto mode" position, the lowering is restricted by the position of the position lever 2, so even if the "auto mode" is entered, the lift arm 8 remains stationary. However, if the value of the rear cummer sensor 5 moves upward, it will rise in "auto mode".

This state becomes what is called mix control.

Next, we will show the conditions under which "Auto mode" is selected.

If the auto cut switch/notch 28 is OFF in a mode other than "safety mode", "lift-up mode", or "abnormal mode", if any of the following conditions are satisfied, "auto mode" is selected.
becomes.

(a) When the position lever 2 is near the lowest position.

(b) When the set value of position lever 2 is below the lift arm 8 position.

(C) Even if the vehicle is in the "position mode", the operation of the lift arm 8 completes position control and the vehicle enters the Fuwazai zone again.

It is.

The operation in the "auto mode" is performed as follows according to the routine diagram shown in FIG.

The lift arm 8 is moved upward based on the deviation between the set value of the plowing depth setting dial 9 and the detected value of the rear cover sensor 5. On the descending side, the deviation (X-Y) between the set value of the plowing depth setting dial 9 and the detected value of the rear cover sensor 5, and the deviation (X-Y) between the set value of the position lever 2 and the position of the lift arm 8 (
It operates with the smaller deviation of A-B).

Therefore, if the setting value of the tilling depth setting dial 9 is above the setting value of the position lever 2, the tilling depth setting dial 9 may stop at the setting value of the tilling depth setting dial 9, but it may exceed the setting value of the position lever 2 and move downward. There is no going down. Therefore, even in the "auto mode", the downward movement is regulated by the position of the position lever 2.

Further, the determination operation in the "position mode" is performed according to the routine shown in FIG. 10, and the determination operation in the "lift-up mode" is performed according to the routine shown in FIG. 11.

As shown in FIGS. 9, 10, and 11, in each mode, the deviation between the set value and the lift angle sensor 4 is calculated, and the optimum value is calculated based on the deviation from the duty ratio data group shown in FIG. The duty ratio is taken out, and the solenoid valves 30 and 31 are energized using the duty ratio to keep the lift angle sensor 4 constant at the set value.

In the duty ratio data group shown in the example of FIG. 12, the pulse period is set to 48 seconds on the rising side, and conversely, the pulse period on the falling side is set to 241 seconds. By providing this difference, it is possible to frequently operate the solenoid valve 30 during descent and control the return amount of hydraulic oil, thereby achieving a convergence state without overshoot.

Also, it is basic to match the set value and the value of the lift angle sensor 4, but in reality, if a slight dead zone is not set between the set value and the lift angle sensor 4, a hunting state will occur in the control near the set value. This results in an unstable control state.

In this embodiment, the unfavorable zone is set to 1.5 degrees when approaching the set value from the ascending position, and 1.5 degrees when approaching the set value from the descending position, for a total of 3 degrees.

The maximum lift angle deviation is set to 75 degrees.

The essential part of the present invention is that a plurality of data groups of duty ratios shown in FIG. 12 are stored in a storage device of a microcomputer.

Let me explain about the duty ratio data group.

When raising the working machine, it is raised only by hydraulic pressure, so it can be directly controlled by operating the solenoid valve 31, and the change in the duty ratio directly changes the raising speed. As a result, it is possible to obtain a state in which overshoot that exceeds the set value does not occur. That is, the duty ratio begins to decrease when the lift angle deviation is about 12 degrees, is gradually reduced at first, and the rate of decrease in the duty ratio is accelerated as it approaches the dead zone. Even so, the duty ratio before the final matching state is reduced only to about 70%, and the duty ratio is suddenly reduced to 0 when the dead zone is entered.

The data curve on the rising side is convex upward.

However, when descending, it is due to the weight of the work equipment, so
The acceleration of gravity is added and a lowering state different from the operation of the solenoid valve 30 occurs. That is, in order to stop the descending state with acceleration, it is necessary to quickly reduce the duty ratio from a position separated from the set value.

That is, when the lift angle deviation is around 24 degrees, the duty ratio starts to be reduced in order to shorten the time for closing the solenoid valve 30, and the reduction in the duty ratio is also started when the deviation angle is 18 degrees.
It rapidly decreases to a degree. As the dead zone approaches, the rate of decrease becomes slower, and before stopping, the duty ratio has already been reduced to about 40%, creating a state that is almost at a standstill, and finally reaching zero.

This example of the duty ratio data group is for the case where different types of tractors are attached to different types of work equipment.If the work equipment or tractor is changed, the duty ratio data is It is necessary to change the group.

In the present invention, a plurality of data groups of the duty ratios are stored in a storage device in the microcomputer shown in FIG. 13, and selection is made possible by a changeover switch W.

(G) Effects of the Invention Since the present invention is constructed as described above, it achieves the following effects.

Firstly, by storing data groups of multiple duty ratios in the storage device in the microcomputer in the electronic control unit of the present invention, it is possible to prevent・Also, when conditions change, such as in fields and rice paddies, it is possible to select the optimal duty ratio for control convergence.

Second, a plurality of data groups of the duty ratios are stored in the microcomputer (thereby, the data group of the optimum duty ratios is automatically selected depending on the vibration of the aircraft and the degree of control hunting). It was created so that it can be done.

[Brief explanation of drawings]

Fig. 1 is a side view showing the automatic tillage depth control device for a tractor of the present invention, Fig. 2 is the same (plan view), Fig. 3 is a plan view of the operation box 11, and Fig. 4 is an overview of the control flowchart. Figure 5 is a flowchart showing the "position mode", "auto mode", and "bank lift-up mode", and Figures 6, 7, and 8 are overall flowcharts of the present invention. Figure 9 is a diagram showing the operation routine of "auto mode", and Figure 10 is a diagram of "position mode".
Section 11 is a drawing showing the control operation routine of "lift amplifier mode", FIG. 12 is a drawing showing an example of a data group of duty ratio with respect to the deviation of the set value and lift angle, and Section 13 is a drawing showing the control operation routine of "lift amplifier mode". The figure shows controller 16
This is a schematic drawing. 1... Rear cover 2... Position lever 3... Travel shift lever 4... Lift angle sensor 5... Rear cover sensor 6... Position setting device 7... Tilling claw 8... Lift arm 9... Tillage depth setting dial 10... Lift switch 19... Bank switch W... Changeover switch

Claims (2)

[Claims] (1). In an automatic control device configured to approach the set plowing depth by switching a hydraulic switching valve operated by a solenoid valve to move the lift arm up and down in response to a set plowing depth, the solenoid is driven by pulses, In order to make the pulse period different between rising and falling times and change the duty ratio in the pulse period with respect to the deviation between the set value and the current value, a group of duty ratio data corresponding to the deviation is stored in the storage device. An automatic tillage depth control device for a tractor, which is characterized by: (2). An automatic tillage depth control device for a tractor, characterized in that a plurality of duty ratio data groups according to claim 1 are stored, and the duty ratio data groups can be selectively used by switching a switch.