A computational approach for time-optimal planning of high-rise elevators

An important issue in “elevatoring” is to transport passengers in minimum time while satisfying elevator´s intrinsic dynamics, hoist motor torque/power constraints, and comfort constraints. In this paper, an approach for minimum time trajectory generation of high-rise elevators is presented. It is shown that for systems characterized by linear differential equations, subject to linear or nonlinear inequalities, the time-optimal trajectory possesses a special property that at least one constraint is always active. This property is exploited to get an efficient algorithm for minimum-time solutions. Through simple dynamic models of the elevator using first principles of mechanics, it is shown that for both linear and nonlinear constraints, demands for near real-time trajectory planning can be met