The effect of tire contact force measurement on sideslip angle estimation

Sideslip angle could provide important information concerning vehicle’s stability. Unfortunately, direct measurement of sideslip angle requires a complex and expensive experimental set-up, which is not suitable for implementation on ordinary passenger cars. The usual way to know this quantity is to estimating it by the measurements of vehicle lateral/longitudinal acceleration, speed, yaw rate and steer angle but the estimation value that achieve with these measurement are very sensitive to the disturbances, especially in low friction coefficient surfaces that the amount of error is very high. In recently years by huge improvement and advances in sensor technology especially by birth of smart tire that are able of providing a real-time estimation of contact forces between tire and roads and can measure friction coefficient causes a new generation of stability control systems. An enhancement of the performances of present control systems are expected by including this additional information into the control strategies. In particular, the present paper investigates the improvements that Smart tire would bring into Estimation of Sideslip angle. The work that was done in this thesis is to design new observers with help of smart tire to estimate Sideslip angle in high level of accuracy also in low friction coefficient surfaces. In order to assess the benefits associated with the introduction of smart tire into the estimation of sideslip angle, a series of observer with help of smart tire hve been designed in matlab Simulink, a four degree of freedom vehicle and sensors model. For knowing better the performance of this observer that use measurements of the tire force, a couple of observer (linear and nonlinear) base on measuring vehicle acceleration and yaw rate are designed and the comparison between them in different situation (different friction coefficient and Road bank angle) are presented.