Object position and condition detection system

摘要

A lift truck (16) carries a leftwardly directed ultrasonic receiver (32L) and a rightwardly directed ultrasonic receiver (32R) and an RF transmitter (34). Upon depositing its load in an assigned bin in a warehouse (FIG. 1), a load sensor (22) is actuated to cause transmission of a coded signal as to lift height and vehicle identification to a central station (60). This initiates a vehicle search by energizing ultrasonic transmitters (42-52). The ultrasonic receivers (32L and 32R) on a vehicle in a path under surveillance detect the sonic signal and relay this to the central station by way of the RF transmitter (34). The time duration which elapsed from energization of the ultrasonic transmitter to detection of the sonic signal is used to measure vehicle path depth and a comparison of the magnitudes of the sonic signals received by the receivers (32L and 32R) indicates the heading direction of the vehicle.