Efficient safety-critical trajectory planning for any N-trailer system with a general model

Trajectory planning for tractor–trailer vehicles (TTVs) in a cluttered environment is a highly challenging task owing to complicated kinematic and large-scale collision-avoidance constraints. It has stringent requirements for trajectory feasibility and computational efficiency. Moreover, the varying configurations of TTVs pose challenges to the scalability of the planning method. This article proposes a novel safety-critical trajectory planning method with a general model to address these challenges. Firstly, an algebraic general model is first presented to represent these N-Trailer systems with different hitching types and trailer types uniformly. Secondly, the planning problem is formulated as a nonlinear model predictive control scheme with two key efforts to accelerate calculation speed. One operation is that a novel search-guided optimization-based collision avoidance (SG-OBCA) method is developed to provide a high-quality initial guess. The other operation is that intractable non-convex collision-avoidance constraints are translated into a dual form based on exponential discrete-time control barrier function (DCBF). Finally, both comparative simulations and real-world experiments are conducted to demonstrate the efficiency and applicability of the proposed method in different complicated scenarios and configurations of TTVs.