JPH0365924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a working device with an ultrasonic sensor for detecting the height above the ground, and a control means for raising and lowering the working device to a standard height above the ground based on the detected height above the ground. Regarding agricultural machinery.

In conventional agricultural machinery, such as a combine harvester, in order to prevent the reaping part from entering the ground, the reaping part is raised and lowered at the same speed based on the height detected above the ground by the ultrasonic sensor, and the reaping part is brought to the reference height above the ground. I was keeping it.

Conventional agricultural machines raise and lower at the same speed, that is, the control gain on the ascending side and the control gain on the descending side are set to be the same, so the detected height above the ground is less than the reference height above the ground. There was a problem in which the response of the work equipment was delayed when the work equipment was low, causing it to crash into the ground. On the other hand, when the overall control gain is increased and the control response is set quickly, a so-called hunting phenomenon occurs, causing a problem in which the control does not converge.

The present invention solves the above-mentioned problems of the prior art, and aims to provide an agricultural machine that can avoid both the delay in control response and the hunting phenomenon as described above.

In order to achieve the above object, the present invention divides the height above the ground into a plurality of areas corresponding to the deviation from the standard height above the ground, and sets the control gain in the area on the ascending side to the area on the descending side. The control gain is set to be larger than the control gain in the area, and the control gain is set to be smaller in the area closer to the reference height above the ground.

Therefore, according to the agricultural machine of the present invention, the following effects can be obtained.

(b) When controlling the working device to ascend or descend, the response to the ascending operation is faster than the descending operation, and it is possible to avoid collisions between the operating device and the ground due to the delay in response as in the past. Moreover, when the working device is operated to descend, the control response is slower than when the operating device is operated to ascend, so that the hunting phenomenon can also be avoided.

(b) The height above the ground is divided into a plurality of areas corresponding to the deviation from the reference height above the ground, and the control gain is set to be smaller in the area closer to the reference height above the ground, which improves control responsiveness. is very good, and the occurrence of the hunting phenomenon described above can be easily avoided.

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

In FIG. 1, a harvester 3 is provided on the front part of a machine body 1 equipped with a crawler traveling device 2 so as to be swingable around a horizontal axis P by a hydraulic cylinder 4, thereby configuring a combine harvester as an agricultural working machine. ing.

The reaping section 3 includes a pulling device 5, a reaping device 6,
It is equipped with a conveyance device 7, and has a weed splitting device 8 fixed to a support frame 9 at the front end. An ultrasonic sensor 12 consisting of a transmitter 10 and a receiver 11 for detecting the height H of the cutting section 3 above the ground is provided behind the weeding tool 8 and above the support frame 9. Based on the height above the ground detected by the ultrasonic sensor 12, the hydraulic cylinder 4 is operated so that the reaping section 3 reaches the reference height _H0 above the ground, and the reaping section 3 is automatically raised and lowered.

Next, the mowing height control system for raising and lowering will be explained.

As shown in FIG. 2, a detection signal of height H above the ground from the ultrasonic sensor 12 is input to a control device 13 whose main part is a microcomputer. The control device 13 compares a preset reference height above the ground H ₀ with the detected height above the ground H, and adjusts the operating speed of the hydraulic cylinder 4 based on the comparison result.
That is, a control gain is calculated and a control signal for driving the electromagnetic valve 14 for operating the hydraulic cylinder 4 is output. The operating speed of the hydraulic cylinder 4, that is, the vertical speed of the reaping section 3, is determined by the duty ratio _D0 of the pulse current as a control signal for driving the electromagnetic valve 14, and this duty ratio _D0 is the control gain. corresponds to

As shown in FIG. 3, the duty ratio D ₀ is individually set for each of a plurality of areas H ₀ to _{H 7} that are divided and set in accordance with the deviation from the reference height above the ground H ₀ . The duty ratio DL for the raising operation of the reaping section 3 in the areas H ₁ to _{H 3} below the reference ground height H ₀ is the duty ratio DL for the raising operation of the reaping section 3 in the areas H ₄ to _{H 7} above the reference ground height H 0. The duty ratio is set larger than DH, so that the response of the raising operation of the reaping section 3 is faster than that of the lowering operation.

In addition, the duty ratio corresponding to each of the areas H ₀ to _{H 7} is tabulated as predetermined values D ₀ to D ₄ , and the closer the area is to the reference height above the ground H ₀ , the smaller the duty ratio is to prevent hunting. and the detected height above the ground H relative to the reference height above the ground H ₀
If there is a large difference, the reaping section 3 is raised and lowered at high speed to quickly reach the reference ground height _H0 , which is the target value. Incidentally, FIG. 4 is a flowchart showing the operation of the control device 13 explained above.

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]

Figure 1 is a side view of the front part of the combine, Figure 2 is a block diagram of the control system, Figure 3 is an explanatory diagram showing the relationship between ground height deviation and control gain, and Figure 4 shows the operation of the control device. It is a flowchart. 3... Working device, 12... Ultrasonic sensor, H
...Detection height above ground, H ₀ ...Reference height above ground, H ₀ ~
_H7 ...Height above ground area, DL, DH...Control gain.

Claims (1)

[Claims] 1. An agricultural machine equipped with an ultrasonic sensor 12 for detecting height above the ground on the working device 3, and a control means for raising and lowering the working device 3 to a reference height _H0 based on the detected height H above the ground, The height above the ground is divided into a plurality of areas H ₀ to _{H 7} corresponding to the deviation from the reference height above the ground H ₀ , and the control gain DL in the area on the ascending side is set as the control gain DH in the area on the descending side. , and the control gain is set to be smaller in the area closer to the reference ground height H ₀ .