Curvature-Based Ground Vehicle Control of Trailer Path Following Considering Sideslip and Limited Steering Actuation

In this paper, a curvature-based control method capable of both forward and backward path following is developed for off-axle hitching trailers. Compared with earlier methods, this controller handles varying path curvature better while also being easy to implement and tune. The controller also addresses two major issues that deteriorate tracking accuracy: limited steering actuation and sideslip. An active speed limiter brakes the vehicle when the steering angle error is too high and therefore allows the same set of control gains to work across a relatively large range of reference speeds without significantly increasing lateral error or losing stability, which further simplifies controller tuning. An extended Kalman filter (EKF) sideslip estimator is designed to allow sideslip compensation, which considers the varying noise magnitude in GPS measurements caused by varying vehicle speeds so that the braking maneuver will not significantly deteriorate the estimations. To our knowledge, this paper presents the first publication of these two algorithms with trailer control. This method is compared with results from two earlier hitch-angle-based control methods in simulation and experiment. The active speed limiter and the EKF are also implemented on these control methods for fair comparison, during which it is found that the two algorithms can directly work with other control methods and benefit their performance. The results show the curvature-based controller provides better maneuverability and reduced tracking error.