Control Method Designs and Comparisons for Tractor-Trailer Vehicle Backward Path Tracking

Tractor-trailer path tracking in backward motion is a challenging nonlinear control problem in automated vehicle development. The control challenges arise from the fact that a backward driving articulated vehicle is an underactuated system with unstable internal dynamics and coupled nonlinear terms. Additionally, there exists a relative body angle margin for saturated steering input beyond which a jackknife accident is unavoidable if backing further. In this work, three different controllers were designed for tractor-trailer reverse motion: a proportional integral controller, a sliding mode controller, and a neural network controller. A generic control safety governor was developed to supervise the tracking control algorithms, which overrides control when necessary to ensure jackknife-free operation. The controllers' path tracking performance was tested on an increasingly rigorous path with introduced discontinuities, and a comparative study of the three controllers was conducted. The performance differences and characteristics of each control algorithm are analyzed for the studied scenario.