Implementation trade-offs for a short-headway vehicle-follower automated transit system

An important aspect in the design of automated guideway transit (AGT) systems is the communication requirements for the longitudinal control of vehicles, that is, the requirements to measure vehicle states, transmit this information between vehicles, and subsequently control the individual vehicles. This paper examines the trade-offs in the data rates, word lengths, and allowable transmission time lags needed to maintain an acceptable level of vehicle performance, and how these requirements relate to the allocation of control computation between vehicle- and wayside-based computers. A nonlinear control law designed for short-headway vehicle-follower systems provides a baseline to examine these trade-offs. The specification of the parmeters entering the problem is approached through analytically derived results, using simplified linear models with verification and expansion of these results through a detailed simulation.