JPH099717A - Position regulating device in working machine - Google Patents

Abstract

PURPOSE: To provide a position regulating device in a working machine having less hunching and capable of performing the position regulation good in regulating response without generating a 'hiccup phenomenon'. CONSTITUTION: This position regulating devise in a working machine is equipped with a regulating valve 9 of a hydraulic cylinder 7 for lifting a lift arm 4 up and down, a first potentiometer 10 detecting the up and down angles of the lift arm 4, a position lever 8 for setting multiple and successive plow heights, a second potentiometer detecting its operating position and a position regulating means A operating the regulating valve 9 so as to make the detected value by the first potentiometer 10 agree to the set value of the position lever 8. The device is also equipped with insensitive region range regulating means B for detecting whether or not the position lever 8 is moving and whether or not the detected value is in the insensitive region of the set values, extending the insensitive region in the case that the lever does not move and the detected value is in the insensitive region and narrowing the insensitive region in the other case, and a link-regulating means C detecting the position of the detected value relative to the set value and regulating so as not to narrow the insensitive region when the lever 8 is operated in the approaching direction of the setting value to the detected value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position control device for a working machine such as a tractor or a carrier. More specifically, it is remarkable when a heavy load such as a seeder is connected to a three-point link mechanism for connecting the working machine. It is related to prevention of hunting.

[0002]

2. Description of the Related Art A position control device for a working machine refers to a control valve for a hydraulic cylinder for lifting and lowering a work machine by operating a control valve of a lifting / lowering hydraulic cylinder so that a detected value of an angle sensor of a lift arm matches a set value by a position setter. The height is maintained at a set height, and for example, the one disclosed in Japanese Patent Laid-Open No. 7-87805 is known.

[0003]

In this case, in order to avoid unnecessary hunting, the dead zone setting device is adjusted before starting the position control to set an appropriate dead zone width. There were some inconveniences. That is, in order to prevent the hunting, it is sufficient to set the dead zone width to a relatively wide eye, but then there is a tendency that the lift arm does not move easily even if the position setter is operated, which lacks responsiveness.
Conversely, if the dead band width is set to a relatively narrow width in order to improve the responsiveness, then hunting tends to occur easily, and both good control responsiveness and elimination of useless hunting are achieved. Was difficult.

Further, when a relatively heavy working device such as a multiple plow or a seeder is connected, hunting tends to occur due to the bending of the lift arm and the like, and the dead band width is wide to deal with it. Since it is set, it is difficult to perform relatively fine position control, and there was room for improvement. An object of the present invention is to improve the above-mentioned inconvenience, and to provide a position control with less hunting and good control response.

[0005]

The first invention for achieving the above object comprises: A lift arm for raising and lowering the working device, a control valve of a hydraulic cylinder for operating the lifting arm, an angle detecting means for detecting a vertical angle of the lift arm, and a position setter for setting the height of the working device are provided. Position control means for operating the control valve so that the detection value of the detection means matches the set value of the position setter; The position setting device is provided with first detecting means for detecting whether or not the position setting device is operated, and second detection means for detecting whether or not the detected value is within a dead zone of the setting value. If there is not, and the detected value is within the dead zone, the dead zone width is widened, and in other cases, the dead zone width is narrowed, and the dead zone width control means operates based on the detection information of the first and second detection means, C. The position detector is provided with a third detector that detects a position of the detected value in the dead zone with respect to the set value, and a fourth detector that detects an operation direction of the position setter, and the position setter is operated in a direction in which the set value approaches the detected value. In this case, the linkage control means for linking the third and fourth detection means and the dead zone width control means is provided so that the control operation for narrowing the dead zone is not performed.

The second invention is a. A lift arm for raising and lowering the working device, a control valve of a hydraulic cylinder for operating the lifting arm, an angle detecting means for detecting a vertical angle of the lift arm, and a position setter for setting the height of the working device are provided. Position control means for operating the control valve is provided so that the detection value of the detection means matches the set value of the position setter, and d. If the work device is above a certain height, widen the dead band,
It is characterized in that dead zone width changing means that operates based on the detection information of the angle detecting means is provided so as to narrow the dead zone width when the height is less than the predetermined height.

[0007]

In the configuration of claim 1, the configuration b. Thus, when the position setter is not operated and the detected value is within the dead zone, the dead zone width is widened, and in other cases, the dead zone width is narrowed. That is, when the position lever 8 is operated, as shown in FIG.
Since the narrow dead zone L related to the set value s is set, the detected value k, that is, the lift arm 4 is set even with a fine lever operation.
Follows and moves up and down, enabling fine position setting.

When the operation of the position lever 8 is stopped and the lever is stopped, the wide dead zone 3L is immediately set when the detection value k of the first potentiometer 10 reaches the narrow dead zone L at that time. Even if the detected value k may pass through the narrow dead zone L due to the inertia of, it does not pass so much, and most of it stops within the narrow dead zone L, and it is possible to maintain good position control accuracy when the lever is stopped. Next, the lift arm 4 can be finely adjusted up and down when the position lever 8 is operated.

However, even if the above-mentioned technique is fully utilized,
In addition, an unfavorable situation may occur. That is,
As shown in FIG. 5, when the position lever 1 is in the stopped state, the dead zone width is 3L with the same width on both the rising side (high side) and the falling side (low side), and the dead zone in the moving state is 3L or more. It is assumed that L is also small (one-third in the figure). The problem is when the detected value k stops after passing the narrow dead zone due to the inertia of the lift arm 4 after the last stop of the operation of the position lever 8.

Example 1 As shown in FIG. 3, the position of the position lever 8 operated toward the rising side is stopped, and the wide dead zone 3L is set at the moment when the detection value k reaches the lower limit of the narrow dead zone L at that time. However, it is assumed that the detection value k is stopped at a position slightly higher than the upper limit of the dead zone L due to inertia. Since the wide dead zone 3L is set in the lever stopped state, the detected value k may exceed the upper limit of the narrow dead zone L. The position of the detected value k in FIG. 3 shows the state at the moment when the position lever 8 is stopped.

Next, when the position lever 8 is again operated toward the rising side as indicated by the arrow B, the narrow dead zone L is reset at that moment, so the detected value k is the rising side of the narrow dead zone L. And the lift arm 4
Shows a behavior of descending, and then the narrow dead zone L is entirely moved to the ascending side, and the lift arm 4 turns to the ascending movement through the lever operation only when the detection value k is included in the range. is there. That is, the position lever 8
When is operated to the up side, the lift arm 4 once descends and then moves upward in an extremely short period of time, which causes a so-called "shaking phenomenon" to generate a shock and significantly impair the operation feeling.

Example 2 As shown in FIG. 4, the position lever 8 which has been operated toward the descending side (or the ascending side may be stopped) is stopped, and the stop position of the detected value k at that time is just below the lower limit of the dead zone L. It was supposed to be. In that state, the lift arm 4 may be slightly lowered due to leakage over time, and the detection value k may exceed the lower limit of the narrow dead zone L. At this time, since the detected value k exists in the wide dead zone 3L in the lever stopped state, the position control does not operate.

Next, in order to set the set height of the lift arm 4 to the descending side, the position lever 8 is operated toward the descending side as indicated by the arrow a, and at the same time the operation is started, the dead zone width is changed from 3L to L. Since the detection value k becomes narrower than the narrow dead band L, the detection value k moves upward in order to return to the dead band by the position control, but the entire dead band of the width L descends by the lever operation. As it moves to the side, the detected value k immediately starts to move downward. As a result, the position lever 8
Despite the lowering operation, the lift arm 4 once rises within a very short time and then descends, a so-called "shaking phenomenon" occurs in the same manner as in the case described above, and the control response is temporarily deteriorated. However, there is still room for improvement as it causes shocks. In particular, when a heavy working device such as a multiple plow or a seeding device is connected, the cricket phenomenon is remarkable.

Therefore, a third detecting means c for detecting the position of the detected value k in the dead zone with respect to the set value s and a fourth detecting means d for detecting the operating direction of the position lever 8 are provided, and the set value s is the detected value. When the position lever 8 is operated in the direction approaching k, the third and fourth detection means c and d and the dead zone width control means B are set so that the control operation for narrowing the dead zone from 3L to L is not performed. Since the configuration C provided with the linkage control means C linked with each other is provided, the dead zone is not narrowed from 3L to L but left at 3L in the situations such as the first and second embodiments.

Then, by operating the position lever 8, the dead zone is narrowed from 3L to L when the set value s moves away from the detected value k, that is, when the detected value k matches the set value s. Then, the detected value k, that is, the lift arm 4 starts to move in the direction (ascending or descending) according to the lever operation. That is,
The lift arm 4 is temporarily prevented from moving in the direction opposite to the direction in which the position lever 8 is operated, and the above-described "shaking phenomenon" does not occur.

According to the configuration of claim 2, the configuration b. Thus, when the position setter is not operated and the detected value is within the dead zone, the dead zone width is widened, and in other cases, the dead zone width is narrowed. That is, when the position lever 8 is operated, as shown in FIG. 5, a narrow dead zone L regarding the set value s is set,
Even with a fine lever operation, the detected value k, that is, the lift arm 4 follows up and down, and fine position setting can be performed.

By the way, when the working device 3 such as a multiple plow is in a ground work posture in which it is digging into the soil, the lift arm 4 rarely swings up and down due to its frictional resistance, and hunting is difficult to occur. When the work device 3 is levitated above ground due to traveling or the like and is in a non-working posture, the weight of the work device causes the link mechanism 2 to easily bend and hunting to occur (see FIG. 7).

Therefore, the configuration d. Thus, when the work device 3 is at or above a predetermined height, the dead band width is widened to 2L, and when it is below the predetermined height, the dead band width is narrowed to L. The dead band width is operated based on the detection information of the first potentiometer 10. Since the changing means D is provided, the dead zone is widened to make it difficult to cause hunting when the lift arm 4 or the like is easily bent and hunting is likely to occur. You will be able to set fine position.

[0019]

As described above, in the position control device according to any one of claims 1 and 2, the dead zone is widened in a situation where hunting is likely to occur and narrowed in a situation where hunting is difficult to occur. Since it is automatically adjusted, it is possible to provide a position control with less hunting and good control response.

In the position control device according to the first aspect, there is an advantage that the "shaking phenomenon" in which the working device moves up and down temporarily in the direction opposite to the operation direction is eliminated, and a smoother control operation can be performed. In the position control device according to the second aspect, there is an advantage that a desired effect can be obtained with a relatively simple control device that changes the width of the dead zone with a predetermined height as a boundary.

[0021]

Embodiments of the present invention will be described below with reference to the drawings in the case of a tractor which is an example of a working machine.
The rear part of the tractor is shown in FIG. 6, where 1 is the tractor fuselage and 2
Is a three-point link mechanism, 3 is a multiple plow which is a working device, 4 is a lift arm, 5 is a lower link, 6 is a top link, 7 is a hydraulic cylinder for lifting the lift arm 4 and 8
Is a position lever. This tractor includes position control means A for maintaining the height of the multiple plows 3 with respect to the machine body 1 at a set position.

As shown in FIG. 1, an electromagnetic control valve 9 for the hydraulic cylinder 7, a first potentiometer (an example of angle detecting means) 10 for detecting the vertical angle of the lift arm 4,
A position lever (an example of a position setter) 8 for setting the height of the multiple plows 3 is provided. The position control means A detects the detection value k of the first potentiometer 10.
Is to operate the control valve 9 so as to match the set value s of the second potentiometer 12 of the position lever 8, and is provided in the control device 11. Also, the control device 11
Is provided with a dead zone width control means B, a linkage control means C, and a dead zone width changing means D.

The first detecting means a for detecting whether or not the position lever 8 is operated (moving) is constituted by the second potentiometer 12 provided at the swing fulcrum, and as a result, the detected value k. The second detection means b for detecting whether or not is within the dead zone of the set value s is composed of a comparison circuit 13 for comparing the detection information of both the first and second potentiometers 10, 12. Therefore, the dead zone width control means B
Means that the dead band width is widened when the position lever 8 is not operated and the detected value k is within the dead band (the dead band in this case is L), and the dead band width is narrowed otherwise. The second detection means a and b, that is,
First and second potentiometers 10, 12 and comparison circuit 1
It operates based on the detection information of 3.

The third detecting means c for detecting the position of the detected value k in the dead zone with respect to the set value s is the above-mentioned comparison circuit 13, and the fourth detecting means d for detecting the operating direction of the position lever 8 is the second. Each of the potentiometers 12 is constituted, and the comparison circuit 13 constitutes a lever direction detecting means e for detecting whether or not the position lever 8 is operated in a direction in which the set value s approaches the detected value k. Therefore, the second potentiometer 12 and the comparison circuit 13
By linking the dead band width control means B with the dead band width control means B, when the position lever 8 is operated in a direction in which the set value s approaches the detected value k, control is performed so that the widened dead band is not narrowed. The link control means C is configured.

The dead zone width changing means D widens the dead zone width when the multiple plows 3 have a predetermined height or more and narrows the dead zone width when the multiple plows 3 have a height less than the predetermined height.
The circuit is configured to operate based on the detection information of 0, and to operate in priority to the dead zone width control means B. In other words, when the working height position is changed by operating the position lever 8, in a working state in which the multiple plows 3 are working in the soil, the lower link 5 is less likely to swing up and down due to the frictional resistance thereof. However, since it is difficult to cause hunting, the dead zone is made narrow to enable fine position adjustment.

On the other hand, when a work device such as mobile running or headland turning is raised to a position where it floats above ground, the work device does not have a damper function like soil in the working state.
Since hunting is likely to occur due to bending of the lower link 5, etc., a wide dead zone is set in advance to prevent unnecessary hunting. Therefore, in a normal field, the predetermined height position is stored in advance in the dead zone width changing means D so that the working zone such as the multiple plows 3 has a wide dead zone in the range in which it floats above the ground and a narrow dead zone in the range in which it acts on the ground. I am allowed. Incidentally, as shown in FIG. 1, it is convenient to provide a setting dial 14 capable of adjusting and setting a predetermined height at which the dead zone width is automatically changed depending on the type of the working device such as the seeding device and the tilling device.

Next, a series of operations in position control will be described with reference to the flowchart shown in FIG. Here, as shown in FIG. 5, the dead zone of the set value s by the position lever 8 is a so-called "center stop" having the same width on the high side and the low side, and the narrow width L and the wide width 3L.
And 3 types of 2L in the middle are prepared. The width relationship between the dead zones is set to 2L = L × 2, 3L = L × 3.

First, at the start of control, the dead zone width changing means D which operates based on the information of the first potentiometer 10 determines whether the height of the working device 3, that is, the height of the lift arm 4 is equal to or more than a predetermined height or less. Judge (step # 1),
If the height is less than the predetermined height (when the work device is in the ground working state), hunting is hard to occur, so the dead zone is set to 2L, which is relatively narrow (step # 2).

If the height is equal to or higher than a predetermined height (when the working device is in a floating state above ground), hunting is likely to occur, so the dead zone is basically widened. However, the dead zone is set depending on the operating condition of the position lever 8 at that time. Is different. That is, it is detected whether or not the position lever 8 is operated (moved) by the second potentiometer 12 (step # 3), and when it is operated, the process proceeds to step # 4 for determining the operation direction.

When the position lever 8 is stopped without being operated, the process proceeds to step # 7, and if the detection value k of the first potentiometer 10 is within the narrow dead zone L at the time of stopping the lever, the position control operation is performed. Completion, expanding the dead zone to the widest 3L (step # 9),
Prevent unnecessary hunting. If the lift arm 4 is still moving and the detected value k is outside the narrow dead zone L, the position control is in operation and the narrow dead zone L is continuously set (step # 8).

In step # 4, it is determined whether or not the operating direction of the position lever 8 is a direction in which the set value s approaches the detected value k, and if it is in the away direction, the dead zone is set to a narrow L (step # 4). 5) If the direction is approaching, the wide dead zone 3L is set (step # 6). That is, even if the height of the lift arm 4 is equal to or higher than a predetermined height, the dead zone width is narrowed or widened depending on the operation state of the position lever 8 at that time and the positional relationship between the set value s and the detected value k. As a result, fine position setting can be performed while preventing hunting as much as possible.

It should be noted that although reference numerals are given in the claims for convenience of comparison with the drawings, the present invention is not limited to the configuration of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional system of a position control device.

FIG. 2 is a diagram showing a flowchart of position control.

FIG. 3 is an operation diagram showing passing through a narrow dead zone due to inertia of detected values.

FIG. 4 is an action diagram showing passing through a narrow dead zone due to leakage of detected values.

FIG. 5 is a diagram defining the width of a dead zone.

FIG. 6 is a side view showing the rear part of the tractor.

FIG. 7 is a diagram showing a graph of a hunting state in which the work device is at a high position.

[Explanation of symbols]

 3 Working device 4 Lift arm 7 Hydraulic cylinder 8 Position setter 9 Control valve 10 Angle detection means A Position control means B Dead zone width control means C Linkage control means D Dead zone width change means a 1st detection means b 2nd detection means c No. 3 detecting means d 4th detecting means

Claims (2)

[Claims] 1. A lift arm (4) for raising and lowering a working device (3), a control valve (9) of a hydraulic cylinder (7) for raising and lowering it, and a vertical angle of the lift arm (4). An angle detecting means (10) and a position setting device (8) for setting the height of the working device (3) are provided, and a detection value of the angle detecting means (10) is set by the position setting device (8). Position control means (A) for operating the control valve (9) so as to match the value, first detection means (a) for detecting whether or not the position setting device (8) is operated, and A second detecting means (b) for detecting whether or not the detected value is within the dead zone of the set value, the position setting device (8) is not operated, and the detected value is within the dead zone. Widen the dead zone width when inside, otherwise Is a dead zone width control means (B) which operates based on the detection information of the first and second detection means (a) and (b) so as to narrow the dead zone width, and the setting of the detection value in the dead zone. A third detecting means (c) for detecting a position with respect to a value and a fourth detecting means (d) for detecting an operation direction of the position setting device (8) are provided, and the set value is closer to the detected value. When the position setter (8) is operated, the third and fourth portions are controlled so that the control operation for narrowing the dead zone is not performed.
Detection means (c), (d) and the dead zone width control means (B)
A position control device for a working machine, which is provided with a link control means (C) for linking the. 2. A lift arm (4) for raising and lowering a working device (3), a control valve (9) of a hydraulic cylinder (7) for raising and lowering the work arm (4), and a vertical angle of the lift arm (4) is detected. An angle detecting means (10) and a position setting device (8) for setting the height of the working device (3) are provided, and a detection value of the angle detecting means (10) is set by the position setting device (8). Position control means (A) for operating the control valve (9) to match the value is provided, and the dead zone width is widened when the working device (3) is at or above a predetermined height, and is below the predetermined height. And a dead zone width changing means (D) which operates based on the detection information of the angle detecting means (10) so as to narrow the dead zone width.