JPH0154964B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention detects the height above the ground of a working part at predetermined intervals using an ultrasonic height above the ground sensor, and detects a predetermined value of the detected height above the ground sampled at the predetermined intervals. An agricultural machine configured to compare the average value for each sampling frequency with the target height above the ground adjusted by a setting device, and automatically drive the working part up and down based on the comparison and discrimination results to maintain the height above the ground within the set height range. This invention relates to a ground height control device.

Conventionally, in the cutting height control device of a combine harvester, which is an example of this type of agricultural machine, the control sensitivity has been set constant regardless of the cutting height (height above the ground) setting, and the control sensitivity has been set constant regardless of the cutting height (height above the ground) setting. The sensitivity was set to be high to ensure that the (working part) does not come into contact with the field or rush into the field. For this reason, there is no risk that the reaping unit will come into contact with the field, and even during high-level cutting, where high precision is not required, highly sensitive lifting and lowering controls are performed frequently, which only accelerates wear and tear on the equipment due to unnecessary lifting and lowering operations. Instead, the reaction force from the lifting/lowering operation was transmitted to the vehicle body, worsening the ride comfort.

The present invention aims to eliminate such problems, and in the above-mentioned height above ground control device, the higher the target height above the ground is set, the more automatically the predetermined average processing is performed. The feature is that it is configured to increase the number of samplings.

According to the above configuration, when the target height above the ground is set low, unevenness in the field is finely and sensitively detected and the elevation control is performed to ensure a predetermined low height above the ground without contacting the field. Can perform good work. Also, when the target height above ground is set high,
Elevation control is performed by roughly detecting irregularities in the field based on the results averaged over long travel distances, and although the fluctuations in height above the ground become somewhat larger, the frequency of elevating and lowering operations is reduced to reduce equipment wear and tear. This can prevent the deterioration of comfort.

In order to change the control sensitivity according to the height above the ground setting, the present invention employs a means of changing the number of sampling times for averaging the detected data. For example, when comparing the average value and the target height above the ground, This method can maintain high stability of the height above the ground when the target height above the ground is set higher than the method of changing the control sensitivity by changing the dead band width more as the target height above the ground is set higher. be.

That is, according to the dead band width changing means, when a high height above the ground is set with a large dead band width, the elevation control will not be performed unless the absolute value of the detected height changes so much that the average value exceeds the dead band. Fluctuations increase. In contrast, in the present invention,
The number of samplings is increased when a high height above the ground is set, in other words, control is performed based on the average value over a long distance of movement, so even if the absolute value of the detected height does not vary greatly, the same uplift tendency will be observed. Or, if the indentation tendency continues for a long time, the average value will fluctuate relatively significantly and the elevation control will be performed, making it easier to maintain good followability to the field situation compared to the case of using dead band width changing means. There is.

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

As shown in FIG. 1, a reaping section 1 (working section) consisting of a hoisting device 2, a cutting blade 3, and a reaped grain culm conveying device 4 is mounted on the front part of a traveling vehicle body equipped with a crawler traveling device 5 using hydraulic pressure. A combine harvester, which is an example of an agricultural working machine, is configured so that it can swing up and down by expanding and contracting the cylinder 6.

A weeding tool 7 is provided in front of the pulling device 2, and each of the weeding tools 7 is fixed to the support frame 8 of the reaping section 1 at the back thereof. An ultrasonic sensor 9 is attached to the support frame 8 to measure the height above the ground.

The ultrasonic sensor 9 consists of an oscillator 10 that emits ultrasonic waves towards the ground and a receiver 11 that receives the reflected waves. ,
It is configured to detect the height of the reaping section 1 above the ground.

Next, the basic configuration and operation of the ground height detection mechanism and cutting height control device using the ultrasonic sensor 9 will be explained with reference to FIGS. 2 and 3.

Control calculation device 1 consisting of a microcomputer
The oscillator 10 of the ultrasonic sensor 9 intermittently emits ultrasonic waves toward the ground in response to a timing signal P1 output from the CPU 16 through the I/O port ₁₇ at predetermined periodic intervals set by a timer 15 provided in the ultrasonic sensor 9. Emit sound waves and at the same time counter 18
is started.

When the reflected wave is received by the receiver 11, the received signal _P2 from the receiver 11 is input to the CPU 16 via the I/O port 17, and the counter 18 is stopped.

Next, the CPU 16 calculates the height above the ground li according to the program stored in the memory 19 based on the count value of the counter 18 that is started when the ultrasonic wave is transmitted and stopped when the ultrasonic wave is received. It is stored in a predetermined address, and if the number of samplings is less than the predetermined number N, the ultrasonic wave is transmitted and received again to measure the height above the ground, and the measured values are sequentially stored in the memory 19.

Thereafter, when the predetermined number of measurements N is reached, the measured values l ₁ to l _N-1 obtained by these N measurements are
l _N is calculated by the CPU 16 to obtain the average value l'.
Then _, the I /O port 17 to buffer circuit 2
0 to the electromagnetic valve 21 of the hydraulic cylinder 6
to drive.

After that, if the automatic elevation control of the reaping section 1 is to be continued, each of the measured values stored the predetermined number of times N is moved to the previous address one by one. Control is repeated based on the average value of measurement data.

In addition to the basic operations described above, the present invention is programmed to add the following operations.

That is, after the above-mentioned height above the ground l _i is calculated, the output V of the cutting height setter 22 (the value becomes larger as the set height becomes higher) is read, and the cutting height correction value is determined according to the output V. Δl is calculated. This calculation is based on the following equation.

△V=aV-b However, V≧0, a, b are positive constants Then, this correction value △l is added to the detection height l _i , and this corrected value is stored as the detection data at this time. Ru.

Next, the output V of the cutting height setting device 22 is set to a first reference value V ₁ and a second reference value V ₂ [V ₁
<V ₂ ], and it is determined which of the three ranges the set cutting height is in. Then, depending on whether the output V is in a low mowing region [V<V ₁ ], an intermediate mowing height region [V ₁ ≦V<V ₂ ], or a high mowing region [V ₂ ≦V], The size of the dead zone ε and the number of samplings N are ε ₁ , ε ₂ , ε ₃ [ε ₁ <ε ₂ <ε ₃
],
and N ₁ , N ₂ , N ₃ [N ₁ <N ₂ <N ₃ ]. In other words, the lower the mowing setting, the smaller the dead band ε and the smaller the number of samplings N to perform sensitive control, and conversely, the higher the mowing setting, the larger the dead band ε and the larger the sampling number N to perform less sensitive control. Do it.

In the above operation, it is also possible to omit either or both of the correction of the detected height l _i and the change of the dead zone ε.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the height control device for agricultural machinery according to the present invention, in which FIG. 1 is a side view of the front part of a combine harvester, FIG. 2 is a block diagram of the control device, and FIG. 3 shows the control operation. It is a flowchart. 1... Working part, 9... Ground height detection sensor,
22... Cutting height setting device, N... Sampling number,
l _p ...Target height above ground, l′...Average value.

Claims (1)

[Claims] 1 The height above the ground of the working part 1 is detected at predetermined time intervals by the ultrasonic height above the ground detection sensor 9, and the average value l of the detection results of the height above the ground sampled at the predetermined time intervals is determined for each predetermined number of sampling times N. ′ is compared with the target ground height l ₀ set and adjusted by a setting device 22, and based on the comparison and determination result, the working part 1 is automatically driven up and down to maintain it within the set ground height range. The above-ground height control device for an agricultural working machine is configured to automatically increase the predetermined number of sampling times N as the target above-ground height l ₀ is set higher.