| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a straight travel controller by laser light at a low price so that a four-wheel steering working vehicle travels along a straight course. SOLUTION: A light projector 14 is installed at the border of a field 11 and emits laser light on the straight travel course of a tractor 10. Further, 1st and 2nd photodetectors 17F and 17S are provided on the axes of the front wheels 15 and rear wheels 18 of the four-wheel steering tractor 10 and receive the laser light. At this time, the travel attitude of the vehicle is decided according to the photodetection positions of the photodetectors 17F and 17S and steering quantities of the front and rear wheels for returning the vehicle to the straight travel course are calculated to output a steering signal. Therefore, even when the tractor 10 deviates from the straight travel course, the front wheels 15 and rear wheels 18 are steered with optimum steering quantities to put the tractor 10 back to the specific straight travel course speedily.</p> |
