An Interval Algebraic Approach for vehicle lateral tire forces estimation

This paper presents a new methodology for guaranteed and robust estimation of vehicle lateral tire forces with respect to cornering stiffness variations resulting from changes in tire-road friction and/or driving conditions. A Switched interval observer is designed and provides the set of admissible vehicle state values. Sufficient conditions for the existence of such an observer are provided using Multiple Quadratic ISS-Lyapunov function and Linear Matrix Inequalities (LMIs) formulation. Using an interval relaxation tire model, the upper and lower bounds of lateral tire forces are estimated algebraically. Performance of the proposed algorithm is evaluated through field data acquired using a prototype vehicle. Simulation results show that the proposed estimation scheme succeeds to accurately estimate the upper and lower bounds of vehicle lateral tire forces.