| 摘要 |
PURPOSE:To increase the photodetecting range with use of a small number of photodetecting elements by calculating the position of a working vehicle in its width direction based on the pohotodetecting position set right before a change at the non-photodetection of two sets of light sensors when said position of the vehicle is detected by receiving the guide beams by said light sensors containing plural photodetecting elements provided on the vehicle in a desired array form. CONSTITUTION:The two sets of light sensors S1 and S2 provided on a working vehicle V with a prescribed distance secured between them in the front-back direction are consists of plural photodetecting elements arranged laterally in a column state to the vehicle V, individually. Then the lateral position error of the vehicle V is calculated and detected against a guide beam A based on the position of the photodetecting element that received the beam A. In such a case, said position error is calculated by the outputs of both sensors S1 and S2 obtained right before these sensors are turned into the non-photodetecting states in the case of a non-photodetection mode. As a result, a photodetecting range is substantially increased even with decrease of the number of photodetecting elements. |
