JPH07246003A - Method for controlling tilling depth in tractor - Google Patents

Abstract

PURPOSE:To increase the number of rotation of an engine promptly, when the rotary load is increased to lower the engine rotation. CONSTITUTION:The difference in tilling depth from a target one is calculated from the value detected by a depth sensor, and simultaneously the change rate of engine rotation is also calculated. The depth sensor is actuated to effect depth control based on the difference and, when the rotation number of the engine is changed by the load on the rotary, the loading control is effected on the basis of the change rate of engine rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a working depth of a tractor, and more particularly to a method for controlling a working depth of a rotary in consideration of load fluctuation of an engine.

[0002]

2. Description of the Related Art When a rotary is connected to the rear part of the body of a tractor and the rotary is rotated to cultivate a field or the like,
A depth sensor is provided on the rear cover of the rotary, and the depth sensor reads the ground contact angle of the rear cover to detect the depth of cultivation of the rotary. Then, the height of the rotary is controlled so as to eliminate the deviation between the target value of the working depth set by the working depth adjustment dial and the detection value of the depth sensor.

[0003]

When a depth sensor provided on the rear cover is used for depth control, the rear cover hardly moves in a wet field because the soil does not rise up much.
However, in wetlands and the like, running resistance due to water is large, and even a slight change in plowing depth causes a large load on the rotary, and the engine speed decreases. Then, in the worst case, the rotation of the engine may stop before the rotary reaches the target value of the working depth.

Therefore, when the load on the rotary becomes large and the engine speed decreases, there arises a technical problem to be solved in order to increase the engine speed promptly. It aims to solve problems.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to achieve the above-mentioned object, and has a plowing depth adjusting dial for setting the plowing depth of the rotary, a depth sensor for detecting the plowing depth of the rotary, and an engine. A rotation sensor for detecting the number of rotations of the depth sensor is provided, and the depth control based on the working depth deviation between the detection value of the depth sensor and the working depth target value set by the working depth adjustment dial, and the rotation of the engine from the detected value of the rotation sensor. A method of controlling a working depth of a tractor, in which a rate of change in number is calculated, and load control is performed so as to maintain an engine speed that varies depending on a load at a target speed.

[0006]

The depth sensor detects the amount of tillage in the rotary, and the tillage depth deviation from the tiller depth target value set by the tiller depth adjustment dial is calculated. Further, the rotation speed of the engine is detected by the rotation sensor and the rate of change of the rotation speed of the engine is calculated from the detected value. Then, the depth control that eliminates the cultivation depth deviation between the detection value of the depth sensor and the cultivation depth target value, and the load control that maintains the engine rotation speed that varies depending on the load at the target rotation speed are mixed, When mainly raising the rotary, the plowing depth is controlled by the load control.

[0007]

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram of a plowing depth control system. A rotary lever is moved up and down by a position lever, and a plowing depth adjustment dial sets a rotary plowing depth amount. Then, the height of the rotary is detected by the lift arm sensor, and the depth of the rotary tillage is detected by the depth sensor, so as to eliminate the deviation from the target depth of the tillage set by the tillage depth adjusting dial. Depth control is performed by outputting an up signal or a down signal to the solenoid proportional valve for raising and lowering the rotary. Further, the rotation speed of the engine is detected by the rotation sensor, and the rate of change in the rotation speed of the engine is calculated by the control unit. Then, load control is performed so as to maintain the engine speed, which varies depending on the load, at the target speed.

FIGS. 2 and 3 are flowcharts of plowing depth control. First, set values of the position lever, plowing depth adjusting dial and the like, and detection values of the depth sensor and the rotation sensor are read (step 101). If the depth control auto switch is ON, the routine proceeds from step 102 to step 103, and the engine speed change rate is calculated based on the detection value of the rotation sensor.

As shown in FIG. 4, when the tilling depth of the rotary is shallow, the load on the rotary is small and the engine is driven at a rotation speed close to the rated rotation speed (2800 rpm). Then, as the plowing depth becomes deeper, the load on the rotary gradually increases and the engine speed decreases. That is, the rotary tillage depth and the engine speed change in a fixed relationship, and if the tillage depth is known, the target engine speed at that time can be obtained.

Therefore, as shown in the flow chart of FIG. 2, the plowing depth target value is first set based on the set position of the plowing depth adjustment dial (step 104), and the engine target at the plowing depth target value is set. The number of rotations is set (step 105). Then, it is determined from the detection value of the depth sensor whether or not the depth control is performed by the rear cover (step 106). If the depth control is being performed, the process proceeds from step 106 to step 107, and the rear cover is lifted in the state of ridge work. If you want to work, step 1
From 06, the process proceeds to step 113 to perform load control.

Even if the depth control is being performed, if the rear cover is lifted during the work, the depth control cannot be performed. In that case, the process proceeds from step 107 to 113 to perform the load control. Further, when the load on the rotary increases the rate of change of the engine speed, and when the engine speed falls below the work range and there is a request to raise the rotary, the process proceeds from step 108 to step 114 to perform load control.

Then, in step 109, the working depth deviation between the working depth target value set based on the working depth adjustment dial and the detection value of the depth sensor is calculated, and the depth is calculated based on the working depth deviation. Take control. That is, when there is a request to raise the rotary, the rise signal is output to the solenoid proportional valve at the on-time corresponding to the deviation of the working depth (step 109 → 11).
0), if there is a lowering request to the rotary, a lowering signal is output to the solenoid proportional valve in the on-time corresponding to the deviation of the working depth (step 109 → 111). When the deviation of the working depth is in the dead zone, the request for raising and lowering to the rotary becomes neutral, and the signal output to the solenoid proportional valve is turned off (step 109 → 112).

Next, the load control after step 113 will be described. FIG. 5 shows the relationship between the engine speed change rate and the rotary up-and-down speed (on-time to the solenoid proportional valve). For example, when the rotational speed of the engine decreases due to the load applied to the rotary and there is a request to increase the rotational speed, as shown by the line segment A, as the rotational speed change rate of the engine increases toward the down side, The load is controlled so that the rising speed of the rotary increases in a quadratic curve. The line segment A is represented by y = ax ² + b (Equation 1), but when the load on the rotary increases as the plowing depth increases, Set the value of a to large. In that case, as indicated by the broken line in FIG.
Becomes steep, the rotary can be quickly raised with respect to the change in the engine speed change rate, and the engine rotation stop can be prevented. Further, when the plowing depth is set to be shallow, the rate of rise of the rotary with respect to the engine speed change rate is reduced.

On the other hand, when there is a lowering request to the rotary, as shown by the line segment B, as the engine speed change rate increases to the up side, the lowering speed of the rotary becomes linearly linear. Control the load so that it becomes higher. The line segment B is represented by y = cx + d (Equation 2). However, when the load on the rotary increases as the plowing depth increases, c in Equation 2 Set the value of to small. In that case, the inclination of the line segment B decreases as indicated by the broken line in the figure, and the difference in the descending speed of the rotary decreases with respect to the change in the engine speed change rate. The decrease can be prevented.

Thus, in the load control, as shown in the flowchart of FIG. 3, it is judged whether or not the rate of change of the engine speed is neutral (step 113), and the engine speed is changed by the load applied to the rotary. When it is lowered and there is a request to raise the rotary, as described above, the rise signal is output to the solenoid proportional valve at the on-time corresponding to the rate of change of the engine speed (step 113 → 114).
On the other hand, when there is a lowering request to the rotary, as described above, the lowering signal is output to the solenoid proportional valve at the on-time corresponding to the rate of change of the engine speed (step 113 →
115). If the request for raising and lowering the rotary is neutral, the signal output to the solenoid proportional valve is turned off (steps 113 → 116).

As described above, even during the depth control, the load on the rotary lowers the engine speed, and when a request to increase the rotary is made, the control shifts from the depth control to the load control. An up signal is output to the solenoid proportional valve at an on-time corresponding to the rate of change of the engine speed (steps 108 → 114) to prevent the engine from stopping.

Therefore, the present invention can be variously modified without departing from the spirit of the present invention, and it is obvious that the present invention extends to the modified one.

[0018]

As described in detail in the above one embodiment, the present invention performs depth control by mixing depth control based on the deviation of plowing depth and load control based on the rate of change of the engine speed. . Therefore, if the rear cover is suspended, the depth sensor operates and normal depth control is performed.

When the rotational speed of the engine sharply drops due to the load on the rotary, the load can be quickly raised to reduce the load. Further, when the work is performed with the rear cover being lifted, since the plowing depth control is performed by the load control, there is no fear that the rotation of the engine will stop due to the load applied to the rotary.

Thus, it is possible to avoid troubles such as engine rotation stop, improve workability at the time of plowing, and perform smooth plowing depth control.

[Brief description of drawings]

FIG. 1 is a block diagram of a plowing depth control system showing an embodiment of the present invention.

FIG. 2 is a flowchart of tilling depth control, part 1.

FIG. 3 is a flowchart of tilling depth control, part 2.

FIG. 4 is a graph showing the relationship between the rotary depth and the engine speed.

FIG. 5 is a graph showing the relationship between the engine speed change rate and the lift signal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyuki Ishida 1 Hachikura, Tobe Town, Iyo-gun, Ehime Prefecture

Claims (1)

[Claims] 1. A tillage depth adjusting dial for setting a tilling depth of a rotary, a depth sensor for detecting a tilling depth of a rotary, and a rotation sensor for detecting an engine speed are provided, and a detection value of the depth sensor and a tilling depth adjusting dial. Depth control based on the deviation of the plow depth from the set plow depth and the rate of change of the engine speed is calculated from the value detected by the rotation sensor, and the engine speed that changes depending on the load is maintained at the target speed. A method for controlling the working depth of a tractor, which is characterized by mixing with load control.