Efficient Path Following Control Design for Tractor With Multiple Trailers Systems Utilizing Movement Rules and Passive Multi-Steering Angles

This paper proposes a straightforward and robust control strategy for a tractor with multiple trailers system (TMTS, for short) to effectively follow identical paths. Hereto, the control design is structured into four steps for path-tracking precision. Firstly, a suitable passive steering angle is assigned to each trailer, granting it some steering capability to follow the moving path of its direct leader. Secondly, movement rules of the TMTS with passive multi-steering angles are explored in-depth for the first time, facilitating the convenient deduction of kinematic and dynamic models. Thirdly, a desired movement task of the TMTS is reduced to a tracking control by the tractor through the implementation of suitable passive steering angles. Additionally, by virtue of a curvature tracking method, cumulative location errors could be greatly reduced by tracking the relative curvature. Fourthly, a combination of feedback linearization, optimal control, and integral sliding mode control methods is employed to design two driven torques for the tractor to precisely follow the geometric path. Consequently, both the tractor and all trailers are capable of simultaneously following an identical path. In the end, numerical simulations are presented to demonstrate the effectiveness, feasibility, and robustness of the resulting control strategy for practical applications.