State estimation of a semi-active suspension using acceleration sensors

This report presents a method to obtain the suspension deformation and velocity of a semi-active suspension system with a variable damping coe cient. The goal of this internship is to derive the suspension states by using only acceleration sensors, these sensors are relatively low cost and simple to install in an existing vehicle. The applications considered in this report are a quarter car vehicle model for computer simulations with a known road input and a BMW1200 motorcycle for experiments with an actual road input. The methods that are presented consist of two di erent observer designs. The rst observer makes use of two acceleration sensors, one on the sprung mass and one on the unsprung mass. Whereas the simulation results look promising, the practical experiments on the motorcycle show poor performance in determining the state estimates. Therefore, a second observer is designed, this is anH∞/LPV observer that makes use of only one acceleration sensor on the unsprung mass. Both the simulation and experimental results of this observer show accurate estimates for the suspension velocity. The suspension deformation shows to be more di cult to estimate accurately.