An interface between continuous and discrete-event controllers for vehicle automation

The work presented is part of a bigger effort to design an automated highway system (AHS) to improve the capacity and safety of current highways. Automation of highways and, in particular, platooning of vehicles raise a number of control issues. In the design proposed by Varaiya,(see IEEE Trans. Automat., Contr., vol.38, no.2, p.195-207, 1993), these issues are addressed by a hierarchical structure consisting of both discrete-event and continuous controllers. Our work is an attempt to construct a consistent interface between these two types of controllers. The proposed design is in the form of a set of finite-state machines (FSMs) that interact with the discrete controllers through discrete commands and with the continuous controllers by issuing commands that get translated to inputs for the vehicle actuators. The operation of the proposed design is verified using COSPAN and tested in simulation. The interface design provides insight into interesting problems related to the hybrid nature of the AHS as it touches on both the discrete and continuous worlds.