Robust Control of Pantograph–Catenary Contact Force Under High Disturbance: A Comparative Study

Abstract

This paper presents a comparative study of three control strategies for regulating the contact force in pantograph–catenary systems operating under high disturbances and nonlinear dynamics. A high-fidelity multi-layer physical model is developed to capture key system behaviors, including severe catenary oscillations and variations in pantograph mass. The evaluated control methods include: (1) Sliding Mode Control (SMC) augmented with a state observer, (2) observer-free SMC incorporating input signal filtering, and (3) classical PID control with low-pass filtering. Simulation results show that the observer-free SMC achieves the best overall performance, exhibiting strong robustness, minimal force deviation, and high stability under both dynamic scenarios. In contrast, the observer-based SMC suffers from estimation-induced lag, while the PID controller becomes unstable under severe conditions. The findings suggest that observer-free SMC with filtering is highly suitable for real-time implementation in high-speed rail systems, where resilience, simplicity, and computational efficiency are critical.