JPH0233334B2 - NOSAGYOKI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a sensor for detecting the height above the ground of a working device in order to control the height above the ground, and a target value setting means for setting a control target value for the height above the ground. The present invention relates to an agricultural machine equipped with an elevation control means for automatically controlling the elevation of the working device in order to maintain the height above the ground detected by the height above the ground sensor within a predetermined tolerance with respect to a control target value.

Conventionally, in this type of reaping and harvesting machine, the cutting height is adjusted to a predetermined height by raising and lowering the reaping section based on the height above the ground detected by a height above the ground sensor such as an ultrasonic sensor. The cutting height is controlled to achieve this. And the set cutting height,
That is, in order to prevent hunting in the control response to the control target, a predetermined tolerance (dead zone) is provided, but since this tolerance is a constant value, there are the following disadvantages.

In other words, even if the control target value is readjusted during the reaping operation in response to the field conditions, grain culm conditions, etc., the adjustment is small, for example, if the new target value is within the tolerance. In this case, cutting height control based on this new target value may not be performed substantially, or the actual cutting height may not match the new target value even if it is outside the tolerance. There was an inconvenience.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to automatically control the cutting height when the target cutting height is adjusted or changed, even during automatic cutting height control. To provide a reaping and harvesting machine equipped with a means capable of accurately controlling the cutting height with respect to a target cutting height.

In order to achieve the above object, the characteristic configuration of the reaping and harvesting machine according to the present invention includes a detection means for detecting the presence or absence of a change in the control target value by the target value setting means,
Tolerance changing means is provided for automatically narrowing the tolerance for a predetermined period of time when there is a change in the control target value than the tolerance would be if there was no change. , its actions and effects are as follows.

That is, even during automatic control of the cutting height, if there is a change in the control target value, the control tolerance with respect to the control target value is automatically adjusted until the control target value is not changed for a predetermined period of time. Since the tolerance is narrower than the tolerance when the cutting height is lowered, there is better agreement between the actual cutting height and the new control target value, making it possible to adjust the cutting height control target value with high precision during work. It is.

Furthermore, since the control tolerance is narrowed only for a predetermined period of time, after that, the cutting height is controlled using the normal tolerance, which causes unnecessary hunting in the control response. There is no possibility that the control will not converge.

In order to achieve the above object, the agricultural machine according to the present invention is provided with a means for detecting the presence or absence of a change in the setting position of the operating tool with respect to the target value setting means, and when there is a change in the setting position of the operating tool. The present invention is characterized in that means is provided for automatically narrowing the tolerance of the control with respect to this new target value over a predetermined period of time.

Because of the above characteristics, the following excellent effects have been achieved.

In other words, even during automatic height control, if there is a change in the set target value, the control tolerance for the target value is automatically made narrower than normal for a predetermined period of time. The correspondence between the height above the ground and the new target value has improved, and therefore the target value of the height above the ground can be adjusted with high precision during work.

Furthermore, since the control tolerance is narrowed only for a predetermined period of time, after that, the elevation control is performed with the normal tolerance, which causes unnecessary control response hunting and control failure. There is no such thing as non-convergence.

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

FIG. 1 is a side view of a reaping section 1 as a working device provided at the front part of a combine as an agricultural working machine, and the reaping section 1 has a pulling device 2, a reaping device 3, a conveying device 4, A weeding tool 5 is provided in front of the pulling device 2, and a lower end tip of the weeding tool 5 is fixed to a support frame 6 of the reaping device 1. An ultrasonic sensor 9 as a ground height detection sensor consisting of a transmitter 7 and a receiver 8 is mounted behind the weeding tool 5 and above the support frame 6 to prevent malfunctions caused by grain culms. With it placed,
The height above the ground of the reaping section 1 is adjusted by operating the hydraulic cylinder 10 based on the height detected by the ultrasonic sensor 9 and swinging the reaping section 1 around the horizontal axis P. In other words, it is configured to adjust the cutting height.

A control system for controlling the cutting height based on the height above the ground detected by the ultrasonic sensor 9 will be described below.

As shown in FIG. 2, the control system inputs the signal from the receiver 8 of the ultrasonic sensor 9 to the control device 11 as the lifting means, which mainly includes a microcomputer, and also inputs the signal from the receiver 8 of the ultrasonic sensor 9. The output signal of the potentiometer 12 as the target value setting means for presetting the target value Ho is input, and the height H above the ground detected by the receiver 8 is the reference target value Ho set by the potentiometer 12.
The electromagnetic valve 13 is driven so that the reaping section 1 is automatically raised and lowered by the hydraulic cylinder 10.

The detection means detects whether or not the target value adjustment knob 12a as an operating tool of the potentiometer 12 is operated, that is, whether or not the target value is changed, each time the cutting height control loop is passed. The stored current target value Ho and the newly sampled target value Ho' are compared to detect the presence or absence of a change. If there is a change, the control tolerance Δ is changed to the preset normal tolerance Δ ₁
Then, the cutting height is controlled by changing the tolerance Δ ₂ which is narrower than the tolerance Δ ₁ over a predetermined time τ.

The predetermined time τ may be a fixed time corresponding to the control response of the control system, or, as shown in this embodiment, a normal tolerance after the detected height H from the ground converges within the narrow tolerance _Δ2 . The configuration is configured to automatically return to the difference Δ ₁ , so that the detected value H is essentially the target value.
Any time interval may be used, such as the time required to fall within the tolerance Δ ₂ with respect to Ho.

Further, the detection means for detecting the presence or absence of operation of the potentiometer 12, that is, the presence or absence of a change in the target value Ho, samples the target value Ho itself and compares it with the previous sampling value, as shown in this embodiment. Instead of a means, a sensor may be provided separately to detect changes in the operation of the knob 12a.

By the way, in the cutting height control in this embodiment,
In order to optimize the control response, the drive gain of the solenoid valve 13 (intermittent drive pulse current
By automatically changing the ratio (ON, OFF ratio, etc.) into multiple stages, the larger the deviation ΔH, the faster the reaping unit 1 can be moved up and down. This drive gain G, together with the tolerances Δ ₁ and Δ ₂ , is stored in a table in advance in a memory (not shown) in the control device 11.

FIG. 3 is a flowchart showing the operation of the control device 11 described above, which not only controls the cutting height but also checks the status of other sensors (threshing switch, automatic/manual changeover switch, etc.). Control flags for other controls are also set using the control flag.

Moreover, FIG. 4 shows the drive gain G and tolerance Δ
This is the table.

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

[Brief explanation of drawings]

The drawings show an embodiment of the agricultural machine according to the present invention,
FIG. 1 is a front side view of the combine, FIG. 2 is a block diagram of the control system, FIG. 3 is a flow chart showing the operation of the control device, and FIG. 4 is a gain and tolerance table. 1... Working device, 9... Height above ground detection sensor, 12... Target value setting means, Ho... Control target value, H... Detected height above ground, Δ... Tolerance, τ...
Predetermined time.

Claims (1)

[Claims] 1. In order to control the height above the ground, it has a sensor 9 that detects the height above the ground of the working device 1, and a target value setting means 12 that sets a control target value Ho of the height above the ground. , Agricultural work equipped with a lifting control means for automatically controlling the lifting and lowering of the working device 1 in order to maintain the height H above the ground detected by the height above the ground detection sensor 9 within a predetermined tolerance Δ with respect to the control target value Ho. The machine is provided with a detection means for detecting the presence or absence of a change in the control target value by the target value setting means 12, and the tolerance Δ is set to a predetermined time τ when there is a change in the control target value Ho. The agricultural working machine is provided with a tolerance changing means that automatically makes the tolerance difference Δ narrower than the tolerance difference Δ would be if the change did not occur. 2. The detection means for detecting the presence or absence of a change in the control target value by the target value means 12 is
2. The agricultural machine according to claim 1, which samples the change in the target value Ho outputted by the agricultural machine according to claim 1. 3. Agricultural work according to claim 1 or 2, wherein the predetermined time τ is the time required for the detected height H above the ground to converge within a tolerance Δ with respect to the target value Ho. Machine. 4. The agricultural machine according to claim 1 or 2, wherein the predetermined time τ is a certain preset time.