JPH0657782A - Automatic blade controlling device for bulldozer - Google Patents

Abstract

PURPOSE:To simply carry out land grading without operating a lever for operation of working equipment during traveling and save troubles for setting a reference level surface. CONSTITUTION:Tilt angle of a car body in stoppage is detected by a detector 2 for detecting acceleration in the forward and rearward directions of the car body, and the car is started with the position of a blade 7 in this state made a reference level surface. After the starting, changes in car body tilt angles are detected every moment with a car body pitching angle speedometer 3. Therefore, car body tilt angles after the starting can be detected without being affected by acceleration. A controller 4 corrects the output value of the detector 2 for detecting acceleration in the forward and rearward directions of the car body by using the car body tilt angle, and obtains car speed by using the integrated value of the correction. Then, the amount of vertical displacement of the car body 1 is computed by using the car speed and the car body tilt angle, and control target value for the blade 7 is calculated and the results of this calculation are sent to a solenoid controlled valve 5. Then, a lift cylinder 9 is operated, making the blade 7 follow the reference level surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic blade control system for a bulldozer.

[0002]

2. Description of the Related Art When performing ground leveling work with a bulldozer,
Regardless of the inclination of the vehicle body, if the blade is always positioned on a preset reference horizontal plane, a level ground can be obtained. However, when this is automated, conventionally, (1) a laser projector installed outside the vehicle body is used. Compare the reference horizontal plane obtained by rotating the blade with the height of the projector attached to the blade, and adjust the height of the blade based on the deviation, or (2)
The frame is always held at a constant angle based on the detection result of the inclinometer attached to the frame supporting the blade or the inclinometer attached to the vehicle body, or (3) the frame is inclined according to the inclination of the vehicle body. Or, I try to get a level ground.

[0003]

In the case of the above (1),
It takes time and effort to set the reference horizontal plane, and the laser may be shut off by many vehicles, which may cause a malfunction. Also, since the laser projector itself is expensive, it is difficult to use it for small-scale sites and small bulldozers. In the case of (2), the inclinometer attached to the frame supporting the blade or the inclinometer attached to the vehicle body starts and accelerates the vehicle body,
The inclination angle of the frame or the vehicle body cannot be accurately detected due to the influence of acceleration due to deceleration, stop, and the like.

In the case of the above (3), there is a problem that the blade cannot follow the reference horizontal plane when the vehicle body rises or falls below a preset reference horizontal plane at a constant angle. The present invention has been proposed in view of the above problems, and the object thereof is that it is not necessary to operate the work implement lever during traveling, and anyone can easily perform ground leveling work. In addition, the labor of setting the reference horizontal plane can be omitted. In addition, the laser is not blocked by another vehicle or the like, and no malfunction occurs. Further, it is an object of the invention to provide an automatic blade control device for a bulldozer, which does not require an expensive laser projector, can reduce the manufacturing cost, and can be applied to a small site or a small bulldozer.

[0005]

In order to achieve the above object, a blade automatic control device for a bulldozer according to the present invention comprises:
The vehicle body longitudinal acceleration detector that detects the longitudinal acceleration of the vehicle body, the vehicle body pitching angular velocity meter that detects the vehicle body pitching angular velocity, and the vehicle body pitching angle and vertical displacement amount from the detection signals obtained by these detectors. It has a controller for computing, a lift cylinder for moving the blade up and down, and an electromagnetic control valve for operating the lift cylinder based on a control signal from the controller to cause the blade to follow a preset reference plane. .

[0006]

The blade automatic control device for a bulldozer according to the present invention is configured as described above, and detects the vehicle body inclination angle when the vehicle body is stopped by the vehicle body longitudinal acceleration detector and determines the position of the blade in this state as the reference horizontal plane. Start as. After starting the vehicle, the vehicle body pitching angular velocity meter constantly detects changes in the vehicle body inclination angle. Therefore, the vehicle body inclination angle after starting can be detected without being affected by the acceleration. Further, the controller corrects the output value of the vehicle body longitudinal acceleration detector during traveling using the vehicle body inclination angle, obtains the vehicle speed using the integrated value, and then uses this vehicle speed and the vehicle body inclination angle to determine the vertical direction of the vehicle body. The displacement amount is calculated, the control target value of the blade is calculated, the result is sent to the electromagnetic control valve, the lift cylinder is operated, and the blade is made to follow the reference horizontal plane.

[0007]

1 is a side view showing an outline of the blade automatic control device of the present invention. FIG. 2 (a) is a side view showing the outline of the blade automatic control device. )-(C) are explanatory views showing the behavior of the bulldozer,
FIG. 3 is a block diagram of the blade automatic control device, and FIG.
FIG. 3 is a block diagram showing a control flow of the blade automatic control device.

1 is a vehicle body of a bulldozer, and FIG. 1 and FIG.
2 is a vehicle body longitudinal acceleration detector (G sensor) that detects longitudinal acceleration of the vehicle body 1, and 3 is a vehicle body pitching angular velocity meter (gyro) that detects the pitching angular velocity of the vehicle body 1.
Is. Reference numeral 4 in FIGS. 1 and 3 is a controller, and the controller 4 includes a low-pass filter 4a as shown in FIG.
It has an A / D converter 4b, an interface 4c, an arithmetic circuit 4d, a memory circuit 4e, a D / A converter 4f, and an automatic / manual changeover switch 4g.

1 and 3 are electromagnetic control valves provided in the hydraulic circuit of the lift cylinder 9 described later, 6 is a frame in which the rear end of the vehicle body 1 is pivotally supported, and 6a is upward from the middle part of the frame 6. A protruding bracket, 7 is a blade attached to the tip of the frame 6, and 9 is a bracket 6a of the frame 6.
With the lift cylinder interposed between the vehicle body 1 and the vehicle body 1, the lift cylinder 9 is operated in the expansion / contraction direction, the frame 6 is swung in the vertical direction about the rear end portion, and the blade 6 is moved in the vertical direction. It is like this. 8 is a lift cylinder angle sensor.

Next, the operation of the automatic blade control device for the bulldozer will be described in detail. FIG. 2A shows a state in which the vehicle body 1 of the bulldozer is stopped. In this state, the automatic / manual changeover switch 4g of FIG. 3 is automatically switched, and the pitching angle θ ₀ of the vehicle body 1 in the stopped state is detected by the vehicle body pitching angular velocity meter 3. The position of the reference horizontal plane that the blade 7 follows is the position of the blade 7 when the automatic / manual switch 4g is automatically switched.

FIG. 2B shows that the vehicle body 1 is started and Δt
The state of the bulldozer after 2 seconds is shown. The pitching angle θ ₁ of the vehicle body 1 in this state is obtained by adding θ ₀ to the vehicle body pitching angle increment Δθ ₁ for Δt seconds, and Δθ ₁ is obtained by integrating the output ω of the vehicle body pitching angular velocity meter 3. . Therefore, the pitching angle θ ₁ of the vehicle body 1 after Δt seconds after the vehicle body 1 starts to move is

[0012]

[Equation 1] become. Further, the acceleration α ₁ accompanying the traveling of the vehicle body ₁ is calculated from the output value α ₁ ′ of the vehicle body longitudinal acceleration detector 2 by the gravity component gs.
Calculated by subtracting in θ ₁

[0013]

[Equation 2] become. Therefore, the vehicle speed is

[0014]

[Equation 3] become. By the above calculation, the hitching angle and the vehicle speed of the vehicle body 1 are obtained momentarily, and the vertical displacement amount of the vehicle body 1 for Δt seconds is obtained from these data.

[0015]

[Equation 4] Required by. Here, if the height from the fulcrum of the frame 6 to the tip of the blade 7 is L, the blade 7 is h
_The frame rotation angle to move up and down by ₁ is

[0016]

[Equation 5] become. From the above, in order to make the blade 7 follow the reference horizontal plane, the frame 6

[0017]

[Equation 6] It is necessary to swing only up and down. Figure 2 (c) shows
Δt × n seconds later (n = 1.2.3 ...),
The body pitching angle is

[0018]

[Equation 7] And the vehicle speed is

[0019]

[Equation 8] And the vertical displacement is

[0020]

[Equation 9] And the frame swing angle is

[0021]

[Equation 10] And the control swing angle is

[0022]

[Equation 11] become. The above calculation is performed every Δt (sampling time) to control the vertical position of the blade 7 so that the blade 7 follows the reference horizontal plane. The swing angle of the frame 6 is detected by the lift cylinder angle sensor 8 of the lift cylinder 9.

FIG. 3 shows a control flow of the blade automatic control device. The controller 4 signal-processes the input value from the vehicle body front-rear direction accelerometer 2, the input value from the vehicle body pitching angular velocity meter 3, and the input value from the lift cylinder angle sensor 8, and a control signal ( A control signal for causing the blade 7 to follow a preset reference horizontal plane) is output to the electromagnetic control valve 5, and the lift cylinder 9 is operated in the expansion / contraction direction to cause the blade 7 to follow the preset reference horizontal plane. FIG. 4 shows a control flow of the blade automatic control device at this time.

[0024]

As described above, the blade automatic control device for a bulldozer of the present invention detects the vehicle body inclination angle when the vehicle body is stopped by the vehicle body longitudinal acceleration detector, and starts the blade position in this state as the reference horizontal plane. . After starting the vehicle, the vehicle body pitching angular velocity meter constantly detects changes in the vehicle body inclination angle. Therefore, the vehicle body inclination angle after starting can be detected without being affected by the acceleration. Further, the controller corrects the output value of the vehicle body longitudinal acceleration detector during traveling using the vehicle body inclination angle, obtains the vehicle speed using the integrated value, and then uses this vehicle speed and the vehicle body inclination angle to determine the vertical direction of the vehicle body. Calculate the displacement amount, calculate the blade control target value, send the result to the electromagnetic control valve, operate the lift cylinder, and make the blade follow the reference horizontal plane, so operate the work equipment lever while traveling Anyone can easily perform the grading work without the need.

Further, as in the prior art, the reference horizontal plane obtained by rotating the laser projector mounted outside the vehicle body is compared with the height of the projector mounted on the blade, and the height of the blade is adjusted based on the deviation. In this case, it takes time to set the reference horizontal plane. The laser may be cut off by many vehicles and cause malfunctions. Since the laser projector itself is expensive, there is a problem that it is difficult to adopt it for small-scale sites and small bulldozers, but the blade automatic control device of the present invention does not rely on external input (laser projector) Since the blade is automatically controlled only by each of the provided devices, the labor of setting the reference horizontal plane can be omitted. The laser will not be blocked by other vehicles, and no malfunction will occur. No expensive laser projector is required, the manufacturing cost can be reduced, and it can be applied to a small field or a small bulldozer.

[Brief description of drawings]

FIG. 1 is a side view schematically showing an embodiment of an automatic blade control device for a bulldozer according to the present invention.

FIG. 2 is an explanatory diagram showing the behavior of the bulldozer.

FIG. 3 is a block diagram of the blade automatic control device.

FIG. 4 is a block diagram showing a control flow of the blade automatic control device.

[Explanation of symbols]

 1 Bulldozer body 2 Body longitudinal acceleration detector 3 Body pitching angular velocity meter 4 Controller 5 Electromagnetic control valve 6 Blade 7 frame 7 Blade 8 Lift cylinder angle sensor 9 Lift cylinder

Claims (1)

[Claims] 1. A vehicle body longitudinal acceleration detector for detecting longitudinal acceleration of a vehicle body, a vehicle body pitching angular velocity meter for detecting a vehicle body pitching angular velocity, and a vehicle body pitching angular velocity meter for detecting the vehicle body pitching angular velocity. A controller that calculates the pitching angle and vertical displacement of the vehicle body from the detection signal, a lift cylinder that moves the blade in the vertical direction, and a reference that presets the blade by operating the lift cylinder based on a control signal from the controller. An automatic blade control device for a bulldozer, which is equipped with an electromagnetic control valve that follows a surface.