Control-oriented modelling and experimental validation of a controllable multichamber air spring suspension

This paper presents the characterization and validation of a multichamber air spring, a pneumatic suspension system comprising a primary chamber linked to multiple auxiliary air reservoirs through electronically controlled valves. Multichamber air springs represent complex electromechanical systems, where valve control and chamber states significantly influence the suspension's equivalent stiffness. The primary objective of this study is to introduce a novel control-oriented mathematical model for the air spring that more accurately captures the intricate dynamical behaviours than traditional models. By incorporating the dynamics of air mass flow through the valves, the proposed model captures the elastic force during both the opening and closing of the valves, while also accounting for damping phenomena induced by internal friction. Experimental validation is conducted using a suspension test bench, demonstrating that the simulated forces match the measured values across various tests, including realistic driving scenarios characterized by high-frequency stiffness modulation on off-road terrains. This study illustrates how approaching the dynamics from a control-oriented perspective paves the way for enhanced vehicle dynamics control.