Position control for direct landing of elevator using time-based position pattern generation

In this paper, the position control system for direct landing of an elevator is addressed. Conventional systems have employed independent microprocessors for speed, car, and group control respectively and the car controller usually generates a velocity command by combining the time-based and distance-based velocity pattern. In the scheme, it is inevitable that an elevator creeps or stops abruptly in the vicinity of target position. The proposed position control system uses only one high performance microprocessor, which can execute the car and group control algorithm as well as the speed control algorithm. It simply generates the desired position trajectory (s-curve) based on time and on-line corrects a velocity pattern to make the position error be zero. Experimental results show the feasibility of the proposed control scheme.