Application of global sensitivity analysis to a tire model with correlated inputs

• Sensitivity analysis of the well-known Pacejka tire model is carried out.
• This model is nonlinear and depends on correlated parameters.
• The approach consists in decorrelating the parameters using the Nataf transformation.
• Then, the output is expanded onto polynomial chaos.
• To improve the accuracy of the output, the most influent parameters are highlighted.

When a vehicle equipped with tire is manoeuvred on the ground, the tires are submitted to a number of forces – longitudinal force when driving or braking torque is applied to the wheel and/or lateral force when the wheel is steered to turn at a corner. Pacejka model describes these forces that represent the reaction of the road onto the tire. This nonlinear model depends on correlated parameters such as the friction coefficient, the vertical load, and the cornering stiffness, which have to be identified from some measurements. The sensitivity of Pacejka model to these correlated parameters are studied using an approach based on polynomial chaos. It consists in decorrelating the parameters using the Nataf transformation and then, in expanding the model output onto polynomial chaos. The sensitivity indices are then obtained straightforwardly from the algebraic expression of the coefficients of the polynomial expansion.