JPS6433802A - Automatic spotlight chaser - Google Patents

Abstract

PURPOSE: To automatically track a moving object with high precision with a relatively simple system structure by calculating the distances between the moving object and ultrasonic detectors via the detection of the time differences between a clock oscillator and the ultrasonic detectors to determine the position of the moving object. CONSTITUTION: Ultrasonic waves are generated accurately at constant intervals by the clock oscillator 11 of an ultrasonic oscillator 4 held by a moving object 3. When the ultrasonic waves are detected by multiple ultrasonic detectors 6, 7, the time differences between ultrasonic signals and the clock oscillator of a control device 8 are detected by time difference detectors 14, 15. The time difference signals are fed to an arithmetic unit including a computer. The distance between multiple ultrasonic detectors 6, 7 is constant when it is measured at the time of installation, the positional relations between the moving object and multiple ultrasonic detectors 6, 7 are calculated by the arithmetic unit, and the position of the moving object is determined. The position signal is fed to the motor control device of a spotlight, a motor is rotated to the right or left to make the error from the present light projection direction '0', and thus the moving object can be automatically tracked.