JPH0755082B2 - Lifting control device for work equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a lifting control device for a working machine.

(B) Conventional technology Conventionally, the lifting control device for a working machine for maintaining a constant working depth mainly detects the vertical position of the rear cover of the working machine to detect the working depth, and works based on this detection signal. It is configured to feedback control the lifting operation of the machine.

(C) Problems to be Solved by the Invention However, the automatic plowing depth control having such a configuration has the following drawbacks.

a. In the tillage depth detection by the rear cover, only the volume of tilled soil after plowing is detected, and the actual tillage depth cannot be detected, and unevenness occurs on the tiller below the tillage soil.

b. If the tractor inclines in the front-back direction due to the unevenness of the field, the detection value by the rear cover will be inaccurate, and accurate plowing depth control cannot be performed, resulting in a large error. Also,
When the rear wheel of the tractor invades the recess, the plowing depth becomes too deep instantaneously, and the plunging depth load suddenly increases, which may cause an engine stall.

c. Since the feedback control uses the rear cover as a sensor, there is a time lag and there is a drawback that it is not possible to completely follow the unevenness of the field.

(D) Means for Solving the Problems In the present invention, in a lifting control device for a working machine, which is provided with a lifting mechanism between a tractor and a working machine connected to the rear of the tractor, the working machine can be lifted and lowered. On the airframe side of the tractor, a plowing depth setting device, a pitching center for detecting the longitudinal inclination of the airframe, a lift sensor for detecting the rotation angle of the lift arm of the lifting mechanism, and a ground clearance sensor provided on the front side of the airframe. It also has a vehicle speed sensor that detects the traveling speed of the aircraft, a storage device that stores the signals from each sensor and the plowing depth setting device, and a controller that outputs a control to the lifting mechanism based on each signal. The elevator control output value of the working machine is compared and calculated from the detection value of the sensor and the detection value of the elevator sensor to feedback control the lifting operation of the working machine. It is intended to provide a lifting control device for a working machine, characterized in that the lifting control output value is corrected from the detection value of the high speed sensor and the detection value of the vehicle speed sensor to minimize the time lag of the feedback control. Is.

(E) Action / Effect In the present invention, the pitching sensor for detecting the longitudinal inclination of the machine body, the lifting sensor for detecting the rotation angle of the lift arm of the lifting mechanism, and the controller are provided. Therefore, the vertical movement of the working machine can be feedback-controlled to maintain a constant working depth.

Furthermore, by providing a ground clearance sensor provided on the front side of the machine body and a vehicle speed sensor for detecting the traveling speed of the machine body, while detecting irregularities in the field scene in the forward direction,
It is possible to detect in advance the time required for the wheels of the tractor and the working machine to pass through the unevenness.

Therefore, by correcting the elevation control output value by the feedback control by the detection values of the ground clearance sensor and the vehicle speed sensor, the time lag that cannot be avoided by the feedback control can be reduced as much as possible, and the accurate plowing depth control becomes possible. It is possible to perform flat tillage depth control with a flat platter while following the unevenness of the field almost completely.

In addition, it is possible to prevent problems such as fluctuations in plowing depth and stall due to the front and rear inclination of the tractor.

(F) Embodiment An embodiment of the present invention will be described in detail with reference to the drawings.
Indicates an agricultural tractor, which is equipped with a prime mover (4) containing an engine (2) and a hydraulic pump (3) directly connected to the engine (2) on the upper surface of the frame (1). The transmission case (6) is connected to the rear part of the clutch housing (5) connected rearward to drive the left and right rear wheels (7) arranged on the left and right sides of the case (6), and the frame (1 The left and right front wheels (8) arranged on the lower left and right sides of () are steered by the steering wheel (10) standing on the driving section (9) to drive the tractor (A).

Further, on the rear surface of the mission case (6), a hitch (11) that can be tilted left and right is continuously provided, and a working machine (B) is connected through the hitch (11). B) is
The tiller shaft (13) mounted below the machine frame (12) is rotated through the interlocking mechanism (14), and the field scenes are cultivated by the plurality of tiller claws (15) planted on the same axis (13). It is configured to do.

A rear cover (16) that is rotatable around an upper end that is continuous with the rear end of the upper cover is provided behind the tiller claw (15), and further behind the machine frame (12). The tail wheel (18) is hung from the depth adjusting frame (17).

A hydraulically operated lift mechanism (19) is provided on the upper surface of the mission case (6), and lift arms (20) (20) extending rearward from the mechanism (19) are connected to the lift case (19). The arm (20) is rotated up and down around the mechanism (19).
The tip ends of (20) are respectively connected to the machine frame (12) of the working machine (B) through the lift rods (21), and the working machine (B) is moved up and down by the operation of the mechanism (19). It is a thing. The work machine (B) is raised by the hydraulic pressure from the hydraulic pump (3), while the work machine (B) is lowered by the weight of the work machine (B).

The operation of these hydraulic actuators is controlled by the control device (C) configured as described below.

That is, the same tractor (A)
A pitching sensor (22) is arranged on the left side of the driving section (9) to detect the front-back inclination of the vehicle, and the lift mechanism (19) has one lift arm (20) at the base end thereof. An elevating sensor (23) for detecting the vertical position of the working machine (B) by detecting the vertical rotation angle of the (20) is provided, and further, at the front end of the machine body of the tractor (A), left and right An ultrasonic type ground clearance sensor (24) is provided in front of the front wheels (8) to detect the ground clearance between the front of the left and right front wheels (8) and the airframe, and the front left and right wheels. One wheel (8 ') of (8) has a pulse counter type vehicle speed sensor (2
5) is provided.

The operation of the lifting mechanism (19) is controlled by the detection results of the above-mentioned sensors (22) (23) (24) (25), and the control box (26) for initial setting of this control is used. It is arranged on the upper surface of the right side fender of the driving part (9).

The control box (26) has a controller (27) and a memory circuit (28) built therein, and a plowing depth setting device (29) is arranged on the surface of the box (26).

And each sensor (22) with the controller (27)
Electromagnetic hydraulic control valve (30) for processing the outputs from (23), (24) and (25) by referring to the installation position of the working depth setting device (29) and controlling the operation of the lifting mechanism (19). Solenoid for (31)
It is configured to control output to.

The embodiment of the present invention is configured as described above, and when starting the plowing work, first, by setting the plowing depth setter (29) to a required plowing depth, the set value of the plowing depth is set to the controller ( 27), and the value calculated from the detected value of the pitching sensor (22) at this point and the set value,
By comparing the detected value of the lift sensor (23) and outputting the control output in the direction in which there is no difference between the calculated value and the detected value of the lift sensor (23) to the solenoid (31) of the lift mechanism (19). , Raise or lower the work implement (B) to match the required working depth.

Next, the work machine (B) is towed by the tractor (A) and travels in the field, but when the left, right, front, rear wheels (8) and (7) reach the unevenness of the field, the body of the tractor (A) tilts. As the working machine (B) moves up and down, the plowing depth tends to be disturbed, but this tilting is caused by the pitching sensor (2
It is detected in 2) and the elevating mechanism (19) is controlled via the controller (27) to maintain a constant working depth.

It should be noted that the above control alone is feedback control in which the result of pitching of the tractor (A) is detected and control output is performed. Therefore, the time lag of the control system cannot be eliminated by any means. The ground level sensor (24) arranged in front of the left and right front wheels (8) of the tractor (A) causes unevenness in the field where the left, right, front and rear wheels (8), (7) pass through the wheels (8), (7). Since it was detected in advance before the passage of the vehicle, this is stored in the storage device (28), and from the traveling speed of the tractor (A) detected by the vehicle speed sensor (25), the left, right, front and rear wheels (8), (7) are detected. The time when the vehicle passes through the unevenness is calculated, and the control output value in the feedback control is read out from the storage device (28) at a time corresponding to the time lag, which is earlier than the ground height sensor (24). By correcting with the detected value of
Plowing depth control with less time lag can be performed.

That is, the time lag is reduced by predicting the unevenness of the field scene, which is the main factor of disturbance in the tillage depth control, and correcting the control output.

As described above, the tillage depth detection by the rear cover is abolished, and the tillage depth is calculated based on the detection values of the pitching and the elevation sensor arranged on the tractor, so that the tillage depth control based on the actual tillage depth can be performed. As a result, it is possible to perform plowing work with a flat platter, and because it is possible to detect irregularities in the field before the front and rear wheels pass, it is possible to control the plowing depth with a small time lag. There is an effect that engine stall due to unevenness can be prevented.

[Brief description of drawings]

FIG. 1 is an overall side view of a tractor and a working machine having a lifting control device according to the present invention. FIG. 2 is a block diagram showing the configuration of the control device. (A): Tractor (B): Working machine (19): Lifting mechanism (20): Lift arm (22): Pitching sensor (23): Lifting sensor (24): Ground height sensor (25): Vehicle speed sensor (27) ): Controller (28): Storage device (29): Working depth setting device

Claims (1)

[Claims] 1. A lifting control device for a working machine, wherein a lifting mechanism (19) is provided between a tractor (A) and a working machine (B) connected to the rear of the tractor (A) so that the working machine (B) can be raised and lowered. At the machine side of the tractor (A), the plowing depth setting device (29) and the pitching sensor (22) for detecting the front-back inclination of the machine
And a lift sensor (23) that detects the rotation angle of the lift arm (20) of the lift mechanism (19), a ground clearance sensor (24) provided on the front side of the aircraft, and a vehicle speed sensor that detects the traveling speed of the aircraft. (25) and each sensor (22) (23) (24) (2
5) and a storage device (28) for storing signals from the working depth setting device (29) and a controller (27) for controlling and outputting to the lifting mechanism (19) based on each signal. , The lift control output value of the working machine (B) is compared and calculated from the detected value of the pitching sensor (22) and the detected value of the lift sensor (23) to feedback control the lifting operation of the work machine (B). Detection value by ground clearance sensor (24) and vehicle speed sensor (25)
The lifting control device for a working machine, wherein the lifting control output value is corrected based on the detected value to reduce the time lag of the feedback control as much as possible.