On the measurement of unsprung mass displacement of road vehicles through a model-based virtual sensor

In the automotive industry, sensors represent an enabling technology for autonomous vehicles. Physical sensors are often too expensive or impractical. Therefore, virtual sensors constitute a feasible and economical alternative in which quantities of interest can be estimated using other available measurements coupled with analytical models of road vehicles. A virtual sensor for measuring the vertical displacement of the unsprung masses of a road vehicle, functional for the control of vehicle suspension systems, is presented in this work. The virtual sensor consists of a 7-degree-of-freedom vehicle model, in which the measured vehicle longitudinal and lateral accelerations are employed as inputs. The developed sensor has been tested by comparing experimental data obtained by a Range Rover vehicle with the estimated data. The obtained results show the suitability of the developed sensor for measuring the vertical displacement of unsprung masses, as confirmed by values related to the adopted performance indexes composed of the average RMSE and the NRMSE.