High-Performance Elevator Control Systems

Smooth, fast, precise operation of high-speed elevators has been achieved using closed- loop control together with microprocessors, refined motion transducers, and either SCR or Ward-Leonard drives. The design principles for these systems are discussed starting with a description of hoistway dynamics. Then two fundamental velocity-control strategies are presented. Next, landing of the elevators is considered using a digitally-implemented position control of the phase-plane type. Finally, the performance characteristics of these controls are presented on the basis of field experience and test data and shown to be close to the theoretical limits.