Active suspension H_∞/generalized H₂ static output feedback control

Abstract

This paper proposes an approach of H ∞ /generalized H 2 ( GH 2 ) static output feedback control for vehicle active suspension. To address the conflicting performance requirements in active suspension, the H ∞ norm is minimized to optimize the ride comfort performance, while the GH 2 norm is designed to meet time-domain hard constraints, including suspension stroke, road-holding performance, and actuator saturation. As not all states of active suspension are measurable in practice, the static output feedback control is designed using suspension stroke and sprung mass velocity as feedback signals. An invertible matrix condition is introduced in the static output feedback control design, which transforms the control problem into a convex optimization problem that can be solved using linear matrix inequalities (LMIs). Simulation and hardware-in-the-loop (HiL) experiments are conducted on both bump and random road responses for active and passive suspension of a 2-degree-of-freedom quarter vehicle. The proposed active suspension H ∞ / GH 2 static output feedback controller is compared with H ∞ state feedback controller and the existing controller solved by LMIs and genetic algorithms (GAs), demonstrating that the proposed strategy achieves better ride comfort performance under various road conditions while satisfying all time-domain hard constraints.