ABSTRACT
The capacity of a vehicle to avoid collisions is predominantly defined by the friction potential of the tyres. A robustness analysis of a Collision Avoidance System is executed by simulation and experiments for extreme changes in tyre friction. The collision avoidance controller which utilizes steering angle is based on the State Dependent Riccati Equation technique. This technique can consider nonlinearities and is fault tolerant by design. The controller has been extended with an estimation concept to obtain information of the road friction prior to execution of the steering action. The friction estimation concept is experimentally evaluated and the results show a reproducible reduction of the friction after entering a low friction road section. With a simulation study the control performance for varying conditions is elaborated, whereas experimental results are provided for extreme conditions of combined slip. The results demonstrate that the controller is capable to achieve collision avoidance for the variety of driving conditions with sufficient stability.
