Design and validation of observer-based control for railway vehicles with driven independently rotating wheels: an experimental validation on a 1:5 scale test rig with coupled front and rear axis

This paper presents a comprehensive study on the modelling, control, and observation of railway running gears with driven independently rotating wheels (DIRWs), focusing on both analytical derivations and experimental validation. A detailed system model is developed, capturing the coupling between front and rear axes, their different stability properties. A combined control and observer framework is proposed, with analytical formulations and closed-loop derivations provided. The control gains are tuned based on a decoupled axis assumption. Validation on the coupled system demonstrates that the dynamic behaviour remains consistent across configurations. This consistency is reflected in the eigenvalue comparisons, regardless of whether coupling or observation is included. Experimental tests conducted on a 1:5 scaled test rig confirm the effectiveness of the proposed approach. The system achieves satisfactory reference tracking within a few seconds, with steady-state deviations below 0.5 mm. Observations highlight small oscillations at wheel rotation frequencies, with the front axis exhibiting slightly higher deviations due to its inherent instability without control.