Backing-Up Maneuvers of Autonomous Tractor-Trailer Vehicles using the Qualitative Theory of Nonlinear Dynamical Systems

Abstract

This paper presents an approach, based on the qualitative theory of nonlinear dynamical systems, for the analysis and design of control systems for autonomous articulated vehicles. In particular, backing-up maneuvers are considered. These maneuvers are dangerous because the vehicles tend to `jackknife' when the angle between the tractor and the trailer is greater than a certain value. This danger is increased when the actuators are saturated because they can cause a lack of controllability in the state space and control becomes complicated. The paper proposes a two-level control system with an orientation controller in the lower level and a look-ahead controller in the higher. In the paper, a general orientation feedback controller is presented. This control strategy represents a wide family of different nonlinear controllers and can be applied with different particular control laws. The paper applies the qualitative theory of nonlinear dynamical systems to study the stability of the control system. Thus, the stability of the system under some constraints is demonstrated. The paper includes both simulation and experimental results of the implementation on the Romeo 4R autonomous vehicle, which is a full-size autonomous electrical golf cart with a trailer.