A nonlinear parameter varying observer for real-time damper force estimation of an automotive electro-rheological suspension system

This paper proposes a nonlinear parameter varying (NLPV) observer to estimate, in real-time, the damper force of an electrorheological (ER) damper in a road vehicle suspension system. The objectives are to minimize the effects of bounded unknown road profile disturbances and measurement noises on the estimation errors in the Script capital H infinity framework. Furthermore, the nonlinearity coming from the damper model (and considered in the observer formulation) is handled through a Lipschitz condition. The observer inputs are data given by two low-cost sensors (two accelerometers data from the sprung mass and the unsprung mass). For performance assessment, the observer is implemented on a 1/5-scaled real vehicle testbench of GIPSA-lab, namely INOVE (see www.gipsa-lab.fr/projet/inove). Both simulation and experimental results demonstrate the effectiveness of the proposed observer in terms of the ability to estimate the damper force in real-time and to minimize the effects of measurement noises and road disturbances.