Path-Tracking Cascade Control of Hydraulic- Tracked Vehicles Based on Port-Controlled Hamiltonian Model

Path-tracking control represents a crucial technology for achieving autonomous driving in tracked vehicles. This paper presents a novel cascade control approach based on a port-controlled Hamiltonian model that incorporates position, velocity, and flow loops to improve the robustness and stability of path-tracking in tracked vehicles. Firstly, the nonlinear kinematic model undergoes an equivalent transformation to tackle the challenge of converting the hydraulic-tracked vehicle kinematic model into a port-controlled Hamiltonian model. The effectiveness of this substitution is evaluated through a phase portrait analysis. Subsequently, an interconnection and damping assignment passivity-based controller is formulated to achieve position control and generate a desired velocity reference. Leveraging the dynamics of the tracked vehicle, a velocity controller is developed to calculate the desired vehicle torque and hydraulic motor angular velocity, facilitating velocity tracking. Flow control is realized through a novel passivity-based L2-gain robust control method designed in conjunction with the port-controlled Hamiltonian model. This method empowers the electro-hydraulic servo system to track the desired angular velocity at the expected torque, mitigating the adverse impact of the electro-hydraulic servo system on the tracking performance of tracked vehicles. Finally, a comprehensive comparison is made with two existing control strategies. The results show that the overall performance of the controller is improved by 20.3% and 10.92%, and the tracking accuracy is improved by 15.01% and 5.97%, respectively.