JPH08108854A - Steering control method of wheel type machine and device thereof - Google Patents

Abstract

PURPOSE: To stably control steering by eliminating overshoot in the steering control of a wheel type machine. CONSTITUTION: While detecting a reference object 2 such as a wood block for construction execution provided on the road surface by means of a reference object detecting sensor 3 provided on the body 1 of a wheel type machine, the steering angle of steering wheels 5a is controlled so that the body 1 follows up the reference object 2. The steering angle of the steering wheels 5a is detected by means of a steering sensor 31. When the reference object detecting sensor 3 is returned to the reference position shown by the reference object 2, a signal controlling the steering angle of the steering wheels 5a into the rectilinear direction is outputted from a controller 32. An electromagnetic type directional control valve 34 is controlled to be changed based on the output signal from the controller 32, an actuator 27 for steering control is controlled to expand/contract by means of the control valve 34, the spindles 24 of the steering wheels 5a are controlled to rotate ' with king pins 23 as fulcrum and the steering angle is returned into the rectilinear direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel that advances along a reference object such as a curb on the side of the road surface or a formwork for construction when paving and repairing roads such as asphalt finishers, repavers, remixers and motor graders. TECHNICAL FIELD The present invention relates to a steering control method for a rotary machine and an apparatus thereof.

[0002]

2. Description of the Related Art When the steering of an asphalt finisher for road pavement (hereinafter, simply referred to as a finisher) shown in FIG. 7 is to be controlled, the vehicle body 1 is a structure such as a curb on the side of the road surface or a formwork for construction. , A reference object detection sensor 3 for tracking the reference object 2 in order to travel along a reference (hereinafter referred to as a reference object) 2 for steering such as a laser beam. The vehicle body 1 is steering-controlled so that the sensor 3 is always located on the reference object 3.

When the finisher is a crawler type machine as shown in FIG. 7, the left and right crawlers (tracks) 4a,
Since the 4b is driven independently, it is only necessary to reduce the speed of the crawler 4b on the inside of the turn when turning, and to control the left and right crawlers 4a and 4b at the same speed when going straight.

Therefore, in the steering control of this crawler type machine, for example, when the reference object detection sensor 3 is likely to come off the turning outer side from the reference object 2 as shown by the chain double-dashed line in FIG. Slow down,
It is turned in the direction of approaching the reference object 2.

Then, when the reference object detection sensor 3 is again positioned on the reference object 2, the turning signal is stopped and the vehicle goes straight. That is, the vehicle goes straight in the direction of the machine when the turning signal is stopped.

As a result, the crawler type machine is controlled to move along the reference object 2 while repeating the turning T and the straight traveling S.

On the other hand, as shown in FIG. 8, in the case of a wheel type finisher having steering wheels (front wheels) 5a and driving wheels (rear wheels) 5b, the steering wheels (front wheels) 5a are steered. The steering control of the vehicle body 1 is performed by changing the hydraulic cylinder (not shown) for a vehicle through a link mechanism.

That is, when the reference object detection sensor 3 of the wheel type machine is about to come off the reference object 2, the steering hydraulic cylinder is controlled based on the signal detected by the reference object detection sensor 3. The steering control is performed so that the reference object detection sensor 3 tilts the front wheel 5a in the direction of approaching the reference object 2.

[0009]

In the case of such a wheel type machine, when the reference object detection sensor 3 returns to the reference object 2 again, it is output to the directional control valve for controlling the steering hydraulic cylinder. The control valve returns to the neutral position, the steering actuator remains stopped, and the front wheel 5a remains tilted.

Therefore, the reference object detection sensor 3 is used as the reference object 2.
The vehicle continues to turn at the fixed front wheel angle until the reference object detection sensor 3 outputs a turning signal in the opposite direction by overshooting above and coming off to the opposite side. Further, even if there is a reverse turning command, the reverse turning operation cannot be obtained until the front wheels 5a return to the straight traveling direction.

As a result of this, as shown in FIG. 8, hunting that makes steering control unstable due to a large overshoot may occur, and in the worst case, control may be impossible beyond the measurement range of the reference object detection sensor. There is also.

Further, if the reference object detection sensor 3 is provided so as to project directly from the front wheel spindle, this overshoot can be eliminated, but since the sensor suddenly and drastically swings due to steering operation of the front wheels, it is not suitable for control. . Further, particularly in the finisher, the presence of the protrusion in front of the vehicle body hinders smooth construction due to the feature of the construction method.

The present invention has been made in view of the above circumstances, and provides a steering control method for a wheel type machine and an apparatus therefor, which eliminates overshoot in steering control of the wheel type machine and enables stable steering control. The purpose is to do.

[0014]

According to a first aspect of the present invention, the vehicle body follows the reference object while detecting the reference object installed on the road surface by the reference object detection sensor provided on the vehicle body. In the steering control method of a wheel-type machine that controls the steering angle of the steering wheel, the reference object detection sensor detects the reference object while incorporating information about the steering wheel steering angle, and the reference object detection sensor indicates the reference object. This is a steering control method for a wheel-type machine configured to control the steering angle of the steered wheels to go straight when it is determined that the steering wheel is in the reference position.

According to a second aspect of the present invention, the steering wheel steering is performed so that the vehicle body follows the reference object while detecting the reference object installed on the road surface by the reference object detection sensor provided on the vehicle body. In a steering control device for a wheel-type machine that controls an angle, a steering sensor that detects a steering angle of the steered wheels and a steering sensor when the reference object detection sensor determines that the reference position is indicated by a reference object. A wheel type machine configured to include a controller that outputs a signal that controls the steering angle of the steered wheels that are being monitored in a straight direction, and a steering control mechanism that controls the steering angle based on the output signal from this controller. Is a steering control device.

The invention described in claim 3 is the steering control device for a wheel type machine according to claim 2,
As a steering sensor, a steering direction display potentiometer that informs the operator of the direction of the steered wheels is used.

[0017]

According to the invention described in claim 1, when the reference object is bent, the direction of the steering wheel is controlled so as to approach the reference object, and the reference object detection sensor is set to the reference position indicated by the reference object. When it reaches, the steering angle of the steered wheels is returned to the straight direction.

According to a second aspect of the present invention, when the vehicle body is turned along the reference object, the reference object detection sensor is operated at the reference position indicated by the reference object. The controller outputs a signal for controlling the steering angle of the heading wheel in a straight direction. Based on the output signal from the controller, the steering control mechanism returns the steering angle to the straight direction. At that time, the steering angle of the steered wheels is monitored by a steering sensor, and the steering control mechanism is stopped at the time when the straight traveling direction is confirmed.

According to the third aspect of the invention, the potentiometer for displaying the steering direction, which informs the operator of the direction of the steering wheel, is used as a steering sensor for steering control.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS.

FIG. 3 shows an asphalt finisher (hereinafter, simply referred to as a finisher) as a wheel type machine. In this finisher, a hopper 11 is provided at the front of the vehicle body 1, an endless bar conveyor (not shown) is provided at the lower portion of the vehicle body from the front portion to the rear portion of the vehicle body 1, and a screw conveyor 12 is provided at the rear portion of the vehicle body. , And the main screed towed by the vehicle body 1 via the left and right side arms 13.
A pair of left and right expandable screeds 15 are provided to the main screed 14 so as to be movable in the width direction.

The mixture fed into the hopper 11 is sent to the rear part of the finisher by a bar conveyor, unwound in the width direction by a screw conveyor 12, and fed by a main screed 14 and a telescopic screed 15 having a vibrating mechanism. It is spread and leveled.

An arm 16 is projectingly provided on the front side of the vehicle body 1, and at the tip of the arm 16 along a formwork (board wood) laid laterally on the construction road surface as the reference object 2. A reference object detection sensor 3 for performing construction such as road paving while moving the vehicle body 1 is provided. It is easy to adjust the arm 16 by a hydraulic cylinder or the like that can be expanded and contracted so that the reference object detection sensor 3 is located above the reference object 2 at the start of construction.

FIG. 1 shows a steering control device of a wheel type machine for controlling a steering angle of a steering wheel (front wheel) 5a so that a vehicle body 1 is along an externally mounted reference object 2.
A rocking beam 22 is provided for vertically moving both wheels with a pin 21 between the two wheels as a fulcrum, and king pins 23 are integrally fitted to both left and right ends of the rocking beam 22.

Spindles 24 of both wheels are rotatably fitted to the king pin 23, respectively.
The arms 25 projecting more integrally are axially connected by an interlocking link 26, and the rod tip of a steering actuator (hydraulic cylinder) 27 is axially connected to the interlocking link 26.

A steering sensor 31 for detecting the steering angle of the steered wheels 5a is provided on one of the kingpins 23 by a mounting method described later with respect to the reference object detection sensor 3 for detecting the position of the reference object 2.

The reference object detection sensor 3 and the steering sensor 31 are connected to the controller via respective signal lines.
Connected to 32. The controller 32 performs a calculation for returning the steering angle of the steered wheels 5a to a straight traveling direction while monitoring the steering angle of the steered wheels 5a in a state where the reference position is detected by the reference object detection sensor 3 and controls the steering angle. A control signal is output to the control mechanism 33.

The steering control mechanism 33 includes an electromagnetic directional control valve 34 which is switched by a signal output from the controller 32, and the steering control which receives the supply of pressure oil whose direction is controlled by the directional control valve 34. The actuator 27 and link mechanisms 22 to 26 driven by the actuator 27.

FIG. 4 shows an example of the mounting structure of the steering sensor 31 for detecting the steering angle of the steered wheels (front wheels) 5a. A rotary potentiometer for detecting the rotation angle of the steering wheel spindle 24 with respect to the king pin 23 is provided concentrically with the king pin 23 of the steering wheel 5a.

The main body 31b of this rotary potentiometer is integrally attached to the upper surface of the steering wheel spindle 24 via a bracket 31c. On the other hand, the potentiometer shaft 31d is attached to the king pin 23 by the bracket 31
It can be attached integrally with a and set screws.

Since the swing beam 22 and the king pin 23 are integrated by inserting the rotation stop pin 35, when the steering actuator 27 is operated, the spindle 24 rotates with respect to the king pin 23. This rotation amount is equal to the relative rotation angle generated between the potentiometer body 31b and its shaft 31d, and an electric signal corresponding thereto is output.

The steering sensor 31 may be of any type and attachment method other than the potentiometer shown in this example, as long as it outputs a signal corresponding to the steering angle of the front wheels.

As shown in FIG. 5, the reference object detection sensor 3 is, for example, a distance between a pair of ultrasonic sensors 3a and 3b arranged in the vehicle width direction and the road surface 37 or the upper surface of the reference object 2. Is measured, and the relative position of the reference object detection sensor 3 with respect to the reference object 2 is detected from the difference in the measurement amounts of the ultrasonic sensors 3a and 3b.

FIG. 6 shows an example of steering control of the vehicle body with respect to the reference object 2 by the reference object detection sensor 3, and a reference distance L0 for determination for determining the presence or absence of the reference object 2 and one sensor.
The detection distance L1 of 3a and the detection distance L2 of the other sensor 3b are compared, and in the case of L1> L0 and L2 <L0 shown in FIG. 6B, it is determined that the reference object detection sensor 3 is at a suitable reference position. Judge,
In other cases, a command signal for the moving direction and the moving amount is output according to the relationship between L0, L1 and L2.

For example, when both the sensors 3a and 3b are on the road surface 37 as shown in FIG. 6A, the control signal is inching output until the reference position shown in FIG. When moving to the right and when both sensors 3a and 3b are on the reference object 2 as shown in FIG.
The control signal in the opposite direction is output by inching until the vehicle reaches the reference position of (B), and the vehicle body is moved to the left. Also, as shown in FIG. When the sensor 3b of 3 is on the road surface 37, the inching control is performed to the reference position of FIG. 6B after continuously outputting the control signal to the position shown in FIG. 6C.

The above description shows one example of the conventional reference object detection sensor 3 for convenience of showing the operation of the present invention. If the signal corresponding to the relative position with respect to the reference object can be output, the type of reference object detection sensor The usage method, mounting method, output signal form, etc. are arbitrary.

Next, the operation of the embodiment of the present invention will be described.

As shown in FIG. 1, the controller 32
The reference object detection sensor 3 while the steering sensor 31 takes in information about the steering angle of the steering wheel 5a.
When the reference object 2 is detected by the reference object 2 and the reference object detection sensor 3 determines that the reference object 2 is at the reference position indicated by the reference object 2, the steering wheel is
Control to return 5a to straight ahead is started.

That is, the electromagnetic directional control valve 34 is switched by a control signal calculated and amplified by the controller 32, and the steering actuator 27 is expanded / contracted by the control valve 34, and is operated via a link mechanism. The steering wheel 5a turns around the kingpin 23 to control the steering angle of the steering wheel 5a in a straight direction. That is, the steering wheel 5a is controlled to go straight when the turning signal disappears.

FIG. 2 is a flow chart showing a steering control method processed by the controller 32.
Circled numbers are step numbers indicating the processing procedure.

A pair of ultrasonic sensors of the reference object detection sensor 3
Measure the distance to the reference object 2 such as construction boards and the road surface by 3a and 3b (step 1), and determine the position of the reference object detection sensor 3 with respect to the reference object 2 (step 2). When the object detection sensor 3 is located on the right side,
The controller 32 outputs a left turn signal (step 3), and when the position of the reference object detection sensor 3 with respect to the reference object 2 is determined to be the reference position shown in FIG. 6B (step 4), the left turn signal is output. Is stopped (step 5).

Conventionally, this state is maintained as it is, and therefore the steering angle becomes constant and the turning operation is continued. In the case of the present invention, the right turn signal opposite to the above is output (step 6). While measuring the steering wheel (front wheel) 5a orientation at that time, that is, the steering angle by the steering sensor 31 (step 7), the steering wheel 5a orientation is determined (step 8), and the steering wheel 5a is determined to be straight ahead. When it becomes, the output of the right turn signal is stopped (step 9) and the process returns to step 1.

Similarly, in step 2, in the position determination of the reference object detection sensor 3 with respect to the reference object 2, when the reference object detection sensor 3 is located on the left side of the reference object 2, a right turn signal is sent from the controller 32. Output (step 10), and when the position of the reference object detection sensor 3 with respect to the reference object 2 is determined to be the reference position shown in FIG. 6 (B) (step 11),
The output of the right turn signal is stopped (step 12).

At the same time, the counterclockwise turning signal opposite to the above is output (step 13). While measuring the steering wheel (front wheel) 5a direction at that time, that is, the steering angle by the steering sensor 31 (step 14), the steering wheel 5a direction is determined (step 15), and the steering wheel 5a is determined to be straight ahead. When this happens, the output of the left turn signal is stopped (step 16) and the process returns to step 1.

By controlling the steering angle of the steered wheels 5a in this manner, the vehicle body 1 repeats the turning T and the straight traveling S, similarly to the crawler type machine shown in FIG. The movement of the object 2 is controlled.

[0046]

According to the present invention, the reference object is detected by the reference object detection sensor while taking in the information about the steering angle of the steered wheels, and the reference object detection sensor indicates the reference position indicated by the reference object. The steering angle of the steered wheels is controlled to go straight when it is determined that there is no overshoot in the steering control of the wheel type machine, and the wheel type machine uses the same control system as the crawler type machine. Stable steering control is possible.

According to the second aspect of the present invention, the steering of the wheel type machine used for carrying out the method invention of the first aspect is achieved by the steering control device including the reference object detection sensor, the steering sensor, the controller and the steering control mechanism. A control device can be provided, and stable steering control that eliminates overshoot in steering control and does not cause hunting is possible.

According to the third aspect of the invention, the potentiometer for displaying the steering direction, which informs the operator of the direction of the steered wheels, can be effectively used in the automatic steering control system as a steering sensor for steering control.

[Brief description of drawings]

FIG. 1 is a schematic view of a control system showing an example of a steering control device for a wheel type machine according to the present invention.

FIG. 2 is a flowchart showing an example of a steering control method for a wheel type machine according to the present invention.

FIG. 3 is a plan view of the same wheel type machine.

FIG. 4 is a sectional view showing a mounting portion of a steering sensor in the same wheel type machine.

FIG. 5 is a simplified cross-sectional view showing a reference object detection sensor in the same wheel type machine.

FIG. 6 is an explanatory diagram showing an operation of the reference object detection sensor of the above.

FIG. 7 is a plan view showing steering control of a crawler type machine.

FIG. 8 is a plan view showing steering control of a conventional wheel type machine.

[Explanation of symbols]

 1 vehicle body 2 reference object 3 reference object detection sensor 5a steering wheel 31 steering sensor 32 controller 33 steering control mechanism

Claims (3)

[Claims] 1. A wheel-type machine for controlling a steering angle of steering wheels so that a vehicle body follows a reference object installed on a road surface by a reference object detection sensor provided on the vehicle body. In the steering control method, the reference object detection sensor detects the reference object while taking in information about the steering angle of the steering wheel, and when the reference object detection sensor determines that the reference object is at the reference position indicated by the reference object, the steering operation is performed. A steering control method for a wheel type machine, characterized in that a steering angle of a wheel is controlled in a straight direction. 2. A wheel type machine for controlling a steering angle of a steering wheel so that the vehicle body follows the reference object while detecting the reference object installed on the road surface by a reference object detection sensor provided on the vehicle body. In the steering control device, a steering sensor that detects the steering angle of the steering wheel, and a steering wheel that is monitored by the steering sensor when the reference object detection sensor determines that the reference position is indicated by the reference object. A steering control device for a wheel-type machine, comprising: a controller that outputs a signal for controlling the steering angle of the steering wheel in a straight direction; and a steering control mechanism that controls the steering angle based on an output signal from the controller. 3. A steering control device for a wheel type machine according to claim 2, wherein a steering direction display potentiometer that informs an operator of the direction of the steered wheels is used as the steering sensor.