Improved PID control for tilting trains

This paper delivers findings on advanced PID studies for tilt control. Single-input-single-output Nulling-type tilt control in tilting railway vehicles offers simplicity however suffers from dynamic performance limitations due to the non-minimum phase zeros (NMPZ). From a practical aspect this is due to the suspension dynamic interactions (given the strong coupling between roll and lateral vehicle dynamic modes) and the sensor measurement used for feedback control. We explore the extent of efficiency of simple PID-based nulling-type tilt control via optimization and loop shaping (the latter benefiting from fractional order filtering) to improve deterministic/stochastic tilt system performance trade off. Controllers are designed to illustrate different levels of tilt performance regarding the deterministic (curving acceleration response) and stochastic (ride quality) criteria. Results illustrated via simulation runs.