Potentials of Change Detection Algorithms for Diagnosis in Electronic Steering Systems

Active front steering is starting to establish as steering technology for passenger cars that realizes a mechatronic superposition of an angle to the hand steering wheel angle that is prescribed by the driver. This contribution describes algorithms, used to ensure - along with others - the overall functional safety of the system (i.e. preventing hazardous behavior). A kinematic constraint, modelled as a dynamic system, is used to estimate the steering wheel angle. This estimated signal is compared with the measured signal. Using change detection algorithms typical failure patterns of the steering wheel sensor are detected quite easily. Sample results and measurements from a prototype vehicle are presented.