Dynamic H∞ observer for real-time damper force estimation of a semi-active automotive suspension system

This paper presents a dynamic H∞ observer for damper force estimation of a semi-active Electro- Rheological (ER) damper in an automotive suspension system. Firstly, an extended nonlinear quarter-car model is developed to capture the main behaviors (dynamic and nonlinear) of the ER dampers. The dynamic H∞ observer is designed to minimize the effects of unknown disturbances (measurement noises and road profile) on the estimation errors by using an H∞ approach, while the nonlinearity coming from the damper model is satisfied a Lipschitz condition. This new estimation method only uses two low-cost sensors (sprung mass and unsprung mass accelerometers) as the inputs of the proposed observer. Then, the observer is implemented on the INOVE test bench from GIPSA-lab (1/5-scaled real vehicle) to assess experimentally the performances of the approach in real-time. Both simulation and experimental results demonstrate the effectiveness of the proposed observer.