LPV Force Observer Design and Experimental Validation from a Dynamical Semi-Active ER Damper Model

Abstract

Abstract This paper presents an LPV damping force observer of Electro Rheological (ER) dampers for a real automotive suspension system, taking the dynamic characteristic of damper into account. First, an extended nonlinear quarter-car model is considered, where the time constant representing the damper dynamics is varying according to the control level. This is rewritten as an LPV model which is used to design an LPV observer. The objective of the LPV observer is to minimize the effects of bounded unknown input disturbances (unknown road profile and measurement noises) on the state estimation errors through an H∞ criterion, while the damper nonlinearity is bounded using a Lipschitz condition. Two low-cost accelerometers (the sprung mass and the unsprung mass accelerations) are used as inputs for the proposed methodology only. To experimentally assess the proposed approach, the observer is implemented on the 1/5-scaled real vehicle-INOVE testbench of GIPSA-lab. Experiments shows the ability of the observer to estimate the damper force in real-time, face to unknown inputs disturbance and sensor noises.