JP2534400B2 - Steering control device for mobile work vehicle - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device for a mobile work vehicle in which both front wheels and rear wheels are steered.

2. Description of the Related Art Conventionally, in a mobile work vehicle with a four-wheel vehicle body in which both the front wheels and the rear wheels are steered, the in-phase mode in which the front wheels and the rear wheels are steered in the same direction and the front and rear wheels are It is generally provided with an antiphase mode that steers in the opposite direction. When turning the mobile work vehicle, the front wheel and the rear wheel are steered in opposite directions by the anti-phase mode, and when the mobile work vehicle is diagonally translated, the front wheel and the rear wheel are operated by the same phase mode. Are operating in the same direction.

Furthermore, the steering mechanism for the front wheels and the rear wheels is generally configured to satisfy the Ackermann theory when the mobile work vehicle is turned by the steering operation in the antiphase mode. That is, as shown in FIG. 6, the steering angle of the right front wheel is greater than the steering angle of the left front wheel in the case of right steering, and the steering angle of the left front wheel is in the case of left steering as shown in FIG. Is larger than the steering angle. On the other hand, as shown in FIG. 7, for the rear wheels, the steering angle of the left rear wheel is larger than the steering angle of the right rear wheel in the case of right steering, and the steering angle of the right rear wheel in the case of left steering. The angle is larger than the steering angle of the left rear wheel.

Therefore, when the mobile work vehicle is diagonally translated by the steering operation in the in-phase mode, the steering angle between the right front wheel and the right rear wheel, and the left front wheel and the left rear wheel. The steering angles with and cannot be matched.

Further, on a sloping ground, the center of gravity of the mobile work vehicle moves to the valley side and the driving force of the wheels on the valley side increases, so that the traveling direction of the mobile work vehicle is between the front wheels on the valley side and the rear wheels on the valley side. Although it will be determined according to the heading angle, it is difficult to move the front wheel on the valley side and the rear wheel on the valley side in parallel because the steering angles are different.

Means for Solving the Problems A front wheel steering drive unit connected to front wheels, a rear wheel steering drive unit connected to rear wheels, and the front wheel steering drive unit based on a steering operation signal from a steering operation unit. In a mobile work vehicle provided with a control device that outputs a drive signal that drives the rear wheel steering drive device in a state that satisfies the Atkaman theory, an inclination angle sensor that detects a lateral inclination of the mobile work vehicle is provided, Correcting means for correcting the drive signal based on the detection result from the tilt angle sensor so that the front wheel and the rear wheel located on the valley side have the same steering angle during the steering operation in the same phase mode. Is provided.

Action When the mobile work vehicle is diagonally translated by the steering operation in the in-phase mode, the drive signal output from the control device to the front wheel steering drive device and the rear wheel steering drive device becomes the detection result from the tilt angle sensor. Based on the corrected drive signal, the front wheel steering drive device and the rear wheel steering drive device are driven.

Embodiment An embodiment of the present invention will be described with reference to the drawings. On the abdomen of the mobile work vehicle 5 in which the left and right front wheels 1 and 2 and the left and right rear wheels 3 and 4 are steered, a mobile work vehicle 5 is located between the front wheels 1 and 2 and the rear wheels 3 and 4. The mower 6 is attached so as to be able to move up and down. The front wheels 1 and 2 are connected to each other by a link mechanism 7 configured to satisfy the Ackermann theory, and the rear wheels 3 and
The four members are connected by a link mechanism 8 configured to satisfy the Ackermann theory.

Next, on the rear wheels 1 and 2 side, there is provided a movable member 10 which extends in the front-rear direction and is rotatable around a support shaft 9 in a horizontal plane. The distal end portion of the movable member 10 is the link mechanism. 7
The steering drive device 11 for steering and driving the front wheels 1 and 2 is connected to the rear end of the moving member 10. Similarly, on the rear wheels 3 and 4 side, there is provided a movable member 13 extending in the front-rear direction and rotatable around the support shaft 12 in a horizontal plane, and the rear end portion of the movable member 13 is the link. A rear wheel steering drive unit 14 for steering and driving the rear wheels 3, 4 is connected to a front end portion of the moving member 13 which is connected to the mechanism 8. A front wheel steering angle detector 15 for detecting a front wheel steering angle is provided on an outer peripheral portion of the support shaft 9, and a rear wheel steering angle detector 16 for detecting a rear wheel steering angle is provided on an outer peripheral portion of the support shaft 12. Is provided.

In addition, the front wheel steering angle detector 15 and the rear wheel steering angle detector 16 are connected to the mobile work vehicle 5, and the front wheel steering drive device 11 and the rear wheel steering drive device 14 are connected. Control device
17 are provided. Further, the mobile work vehicle 5 is provided with a tilt angle sensor 18 for detecting the tilt of the mobile work vehicle 5 in the left-right direction, and the tilt angle sensor 18 is connected to the control device 14.

Next, a remote setting device 19 which is a steering operation unit for remotely controlling the mobile work vehicle 5 is provided, and a steering operation signal from the remote setting device 19 is wirelessly input to the control device 17. To be done. The remote setting device 19
Is the steering target operation angle (operation direction and operation amount)
There are provided a steering setting device 20 for setting the steering wheel, a steering mode switching device 21 for switching the steering mode between the in-phase mode and the anti-phase mode, and a vehicle speed setting device 22 for setting the vehicle speed of the mobile work vehicle 5. Then, a drive signal is output from the control device 17 to the front wheel steering drive device 11 and the rear wheel steering drive device 14 based on the steering operation signal from the remote setting device 19, so that the mobile work vehicle 5 operates. Steering operation is performed.

Here, in the control device 17, the front wheel 1 (or 2) on the valley side and the rear wheel 3 on the valley side are based on the detection result from the inclination angle sensor 18 during the maneuvering operation in the same phase mode.
Correction means (not shown) for correcting the drive signal is provided so that the steering angle with (or 4) matches.

In such a configuration, first, the overall steering control of the mobile work vehicle 5 will be described based on the flowchart of FIG. The steering target operation angle is input from the steering setting device 20, and the steering mode is input from the steering mode switching device 21. When the steering mode is the anti-phase mode, depending on the steering direction,
In the case of turning right, as shown in FIG. 5 (a), the right front wheel 2
The steering angle "θ ₂ " of the right rear wheel 4 becomes equal to the steering angle "θ ₄ " of the right rear wheel 4, and in the case of a left turn, the steering angle of the left front wheel 1 " theta ₁ "and steering angle of the left rear wheel _3" θ 3 "and is equal steering operation is performed. Therefore, the mobile work vehicle 5 smoothly turns with a small turning radius. On the other hand, when the steering mode is the in-phase mode, the tilt angle sensor
The drive signal is corrected by the correction means based on the detection result from 18, and the steering operation is performed based on the corrected drive signal.

Next, the correction of the drive signal (correction of the steering angle) during the steering operation in the same phase mode will be described with reference to FIG. On a sloping ground, the center of gravity of the mobile work vehicle 5 moves to the valley side as shown in FIG. 3, and along with this, the driving force between the front wheels on the valley side and the rear wheels on the valley side increases, and the moving work is performed. The traveling direction of the vehicle 5 is determined by the front wheels on the valley side and the rear wheels on the valley side. The detection value (inclination angle) "α" detected by the inclination angle sensor 18 is input to the determination means in the control device 17, and this inclination angle "α" and the determination value "-" for determining the left inclination.
.beta. "is compared with the judgment value" + .beta. "for judging right tilt.

In the case of “α <−β”, it is determined that the work area is tilted to the left, and as shown in FIG. 4 (a), the steering angle “θ ₁ ” of the left front wheel 1 and the left rear The drive signal is corrected so that the steering angle “θ ₃ ” of the wheel 3 becomes equal, and the steering angle is corrected in accordance with the correction of the drive signal.

In the case of “α> + β”, it is determined that the work area is tilted to the right, and as shown in FIG. 4 (c), the steering angle “θ ₂ ” of the left front wheel 2 and the right rear wheel. The drive signal is corrected so that the steering angle “θ ₄ ” of ₄ becomes equal, and the steering angle is corrected in accordance with the correction of the drive signal.

On the other hand, in the case of “−β <α <+ β”, it was determined that the work area was flat, and as shown in FIG. 4 (b), the average steering of the left and right front wheels 1 and 2 was determined. Horn And the average steering angle of the left and right rear wheels 3, 4 The drive signal is corrected so that and become the same, and the steering angle is corrected along with the correction of the drive signal.

Therefore, when the mobile work vehicle 5 is diagonally translated in the same phase mode while traveling on a sloping ground, the front wheel on the valley side and the rear wheel on the valley side that determine the traveling direction of the mobile work vehicle 5 are Since the steering angles are equal, the mobile work vehicle 5 can be accurately translated in parallel to the target position.

As described above, the present invention is based on the front wheel steering drive unit connected to the front wheels, the rear wheel steering drive unit connected to the rear wheels, and the front wheel based on the steering operation signal from the steering operation unit. In a mobile work vehicle provided with a steering drive device and a control device for outputting a drive signal for driving the rear wheel steering drive device in a state satisfying the Atkaman theory, a tilt angle for detecting a lateral tilt of the mobile work vehicle. A sensor is provided, and the drive signal is output during the steering operation in the same phase mode so that the steering angles of the front wheels and the rear wheels located on the valley side match based on the detection result from the tilt angle sensor. Since the correction means for correcting is provided, when the mobile work vehicle is diagonally translated in the sloping ground,
Since the front wheels and the rear wheels on the valley side have the same angle, it is possible to accurately move the wheels to a target position.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a block diagram showing a steering control system, FIG. 2 is a side view showing the entire mobile work vehicle, and FIG. 3 is a mobile work vehicle on a sloping ground. 4 is an explanatory view showing a change in the position of the center of gravity of the vehicle, FIG. 4 is an explanatory view showing the steering angles of the front wheels and the rear wheels after being corrected by the correcting means, and FIG. 5 is the antiphase mode of the steering mode. 7 is an explanatory view for explaining the steering angles of the front wheels and the rear wheels in the case, and FIG. 6 is an explanatory view showing the relationship between the steering angles of the front wheels and the steering angles of the front wheels in a state where the correction means does not perform correction. FIG. 8 is an explanatory diagram showing the relationship between the rear-wheel steering angle and the rear-wheel steering angle when no correction is made by the correction means.
FIG. 9 is a flowchart for explaining the entire steering control, and FIG. 9 is a flowchart for explaining correction by the correction means. 1,2 …… Front wheel, 3,4 …… Rear wheel, 5 …… Mobile work vehicle, 11 ……
Front wheel steering drive, 14 …… Rear wheel steering drive, 17 …… Control unit, 18 …… Inclination angle sensor, 19 ……
Steering operation part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Takahashi 1-1-1 Ishishiba, Matsumoto City, Nagano Ishikawa Shimashibaura Machinery Co., Ltd. Matsumoto Factory (56) Reference JP-A-61-253263 (JP, A) JP 62-110568 (JP, A)

Claims (1)

(57) [Claims] 1. A front wheel steering drive unit connected to front wheels, and a rear wheel steering drive unit connected to rear wheels,
In a mobile work vehicle provided with a control device that outputs a drive signal for driving the front wheel steering drive device and the rear wheel steering drive device in a state that satisfies the Atkaman theory based on a steering operation signal from a steering operation unit. Provided with a tilt angle sensor for detecting the tilt of the mobile work vehicle in the left-right direction, and the front wheel located on the valley side based on the detection result of the drive signal during the steering operation in the same phase mode from the tilt angle sensor. A steering control device for a mobile work vehicle, comprising: a correction unit that corrects a drive signal so that a steering angle with a rear wheel matches.