PCCT: Trajectory Planning and Layered Control for Oversized Cargo Transport Via e-SPMTs in Confined Surroundings

The rapid expansion of global industrial infrastructure and modular construction has led to an unprecedented demand for the logistics of oversized cargo. Electrically driven self-propelled modular transporters (e-SPMTs) indicate significant advantages in oversized cargo delivery for both national defense security and social infrastructure due to inherent flexibility and high mobility efficiency, especially for long-distance transportation under complex road conditions. However, coordinating multiple e-SPMTs introduces nontrivial challenges: Trajectory planning on confined roads must account for collision avoidance and coupled dynamics, while the redundancy and nonlinearity of steer-by-wire systems further complicate the design of effective control strategies. To this end, this paper proposes a comprehensive framework comprising a two-stage trajectory plan strategy and a hierarchical control scheme. Specifically, the kinematic and dynamic models of the coordinated system are established to capture the rigid physical coupling effects. Subsequently, the planner generates a curvature-continuous and kinematically feasible reference trajectory via integrating safety corridor concepts into the two-stage optimization strategy. To track these reference signals, a hierarchical control architecture is designed, featuring an upper-layer tracking controller and a lower-layer tire force distributor, to manage actuator redundancy and further ensure lateral stability. Finally, co-simulation and hardware-in-the-loop tests under complex transportation scenarios demonstrate the feasibility and effectiveness of the proposed framework and approaches.