Collision Avoidance for Parametric Railway Lines by Supervisor Control

In the present paper, two collision avoidance supervisor schemes are developed for a single line and one-way railway system, with a parametric number of stations and a parametric number of trains. The consecutive sections of the railway line are linked by Traffic Management Points, being equipped with either motion detectors and/or generalized traffic light indicators, in parametric positions. The parametric model of the railway system is developed. The goal of collision avoidance is translated to three alternative desired behaviors, for three different control schemes. The desired behaviors are formulated in sets of regular languages, being analytic and parametric with respect to the trains and the Traffic Management Points of the railway line. The supervisors realizing each language are designed in simple and transparent forms that can be implemented in different control architectures. The advantages of the supervisors of the second control scheme, regarding the arrival time of the trains, are demonstrated through the application of the supervisors to a developed testbed. The first supervisor scheme covers published results regarding one-way railway lines with two operating trains as a special case. For all control schemes, a reconfigurable supervisor control scheme, towards resilience to new faults and attacks, is designed.