Semi-active control of a new quasi-zero stiffness air suspension for commercial vehicles based on H 2 H ∞ state feedback

To further improve the comprehensive vibration isolation performance of commercial vehicles equipped with traditional passive air suspensions under complex driving conditions, this paper proposes a damping control method based on a new configuration of quasi-zero stiffness air suspension . First, the nonlinear model of quasi-zero stiffness air suspension is established by combining gas thermodynamics and suspension dynamics theories. The semi-active control model of a quarter vehicle quasi-zero stiffness air suspension system is generalized to a linear system considering the uncertainty of stiffness parameter based on the Taylor series expansion. Then, the H₂ norm of the sprung mass acceleration is adopted as the control output performance index, while the suspension dynamic deflection constraint and the tire dynamic load constraint are taken as the H _∞ performance constraint output index. Based on Lyapunov stability theory, the H₂H _∞ state feedback control law is designed, and the control law design problem is transformed into a convex optimization problem with linear matrix inequalities. Finally, co-simulation and hardware-in-the-loop test results demonstrate that the proposed new semi-active quasi-zero stiffness air suspension structure and H₂H _∞ robust control method are effective in substantially improving the multi-objective comprehensive performance of commercial vehicles under different driving conditions.