JPS57160005A - Method and device for detecting position of crane - Google Patents

Abstract

PURPOSE:To detect the position of a crane highly accurately by the simple processing of received light, by optically scanning a specified region including a mark at a lower position from the top of the crane, and detecting the light reflected from the mark by a light receiving device on the crane. CONSTITUTION:A light emitting device 1 and the light receiving device 2 are arranged on a trolley 93 on the crane 90. The region with a scanning angle thetam including the mark P on the ground is scanned by the light from the light emitting device 1. The output of the light receiving device 21, which has detected the reflected light, is coded into a binary signal within a specified threshold value by a binary coding circuit 32 and sent to a computing device 33 through a counter 31. Meanwhile, the output of a metalic approach switch 17 sends a count starting signal for counting a clock pulse signal of a high frequency oscillating circuit 30 to the counter 31. The position of the crane is computed by the computing device 33 from the counted value of the scanning angle at the time when the reflected wave from the mark P is detected. Since the optical detecting method is used, the position of the crane 90 can be detected highly accurately by the simple processing of the received signal.