A Moving Cell Control Scheme for Automated Transportation Systems

Abstract

The longitudinal vehicle control problem associated with any automated transportation scheme is discussed. The two fundamental aspects of the problem are the logical aspect and the control aspect. The logical aspect of the problem concerns the decision of where vehicles should be at a future time, based on present system conditions, so that the level of service delivered by the system is good. The control aspect is concerned with how to control vehicles to attain and maintain their desired positions while giving a comfortable ride, not taking too long, not exceeding car capabilities, and maintaining safety. Previous work dealing with both the logical and control aspects of the longitudinal vehicle control problem is briefly reviewed. One approach to handling the logical aspects of the merging problem in automated systems assumes that vehicles occupy positions on a guideway within hypothetical “cells” that move at a constant velocity. This approach simplifies the logical aspect of the longitudinal control problem. The problem of controlling vehicles to attain and maintain an assigned cell on a guideway is modeled in the paper as a linear state regulator optimal control problem. The resulting vehicle control scheme requires less information feedback than alternative schemes, and exhibits good vehicle response characteristics. Alternative control strategies that lead to optimal control problems other than the linear state regulator are discussed, and the relative advantages of the scheme presented in the paper are pointed out.