Robust Constraint-Following Control for Bio-Inspired Structure Oriented Active Suspension System of High-Speed Trains

A robust constraint-following control (CFC) scheme is proposed for active suspension system to improve ride comfort of high-speed trains (HSTs) by employing nonlinear stiffness of bio-inspired structure (BIS). The control problem of driving active suspension system to emulate nonlinear dynamics of BIS is formulated as servo constraint-following. The disturbance observer is theoretically integrated into CFC framework to address critical practical issues, including parameter uncertainty, suspension nonlinearity and aerodynamic disturbance. The complex uncertainty decomposition and uncertainty bound function design can be avoided in the control design compared with past adaptive CFC. Lyapunov stability theory is applied to prove the uniform ultimate boundedness of proposed robust CFC, enabling the constraint-following error to converge to a very small range. The simulation results demonstrate that the active suspension system could exactly follow the servo constraints of reference BIS with high constraint-following accuracy regardless of parameter uncertainty and external disturbance. And the active suspension system can effectively suppress the vibration and improve the ride comfort steadily with random structure parameters and strong aerodynamic loads. This study also provides a new insight and an alternative approach for designing robust CFC in the active suspension of HSTs.