Vehicle-Follower Control for Dynamic Entrainment of Automated Guideway Transit Vehicles

Abstract

This paper describes a method of vehicle-follower longitudinal control which has been developed to enable automated guideway transit (AGT) vehicles to join (entrain) and leave (extrain) trains or close-formation platoons (at 30 cm spacings) while traveling at cruise speed. Because a linear controller cannot be designed to have the accuracy and response speed needed for operations at very close inter-vehicular spacings without producing excessive control action at large spacings, the suggested controller is a nonlinear vehicle follower in which the gains are continuous functions of the spacing between the vehicles. The nonlinear control law is defined and its simulated behavior in a typical dynamic entrainment is shown. Sample simulated responses of nine-vehicle platoons demonstrate the asymptotic stability which the control system must have to be applicable for long platoons. The use of a disturbance estimator to resist external force loadings and the implementation of the control system using sampled, smoothed data are explained and demonstrated via simulation.