Vehicle-Follower Control With Variable-Gains for Short Headway Automated Guideway Transit Systems

Abstract

The use of the vehicle-follower approach for the longitudinal control of vehicles in an automated transit system is discussed for the short headway (0.4 to 3.0 s) range of operation. It is shown, if one adopts a constant gain approach, that the required bandwidth of such controllers increases rapidly with a decrease in nominal headway if safe operation is to be assured. Initial conditions typically encountered during merge and overtake maneuvers can cause unacceptably large jerk and acceleration levels if applied to such constant gain controllers. A candidate for overcoming these problems is a control technique which first employs gains appropriate to the initial conditions and then varys the gains to achieve the desired values as controller errors are reduced. Under nominal operating conditions, this time-varying gain approach is also demonstrated to satisfy performance requirements based upon the kinematics of ride quality constraints.