Application of Adaptive Thresholds in Robust Fault Detection of an Electro-Mechanical Single-Wheel Steering Actuator

A fault detection scheme has been developed for an electromechanical steering actuator under closed-loop control. The closed-loop system is modeled as a 2nd order system with bounded parameter uncertainties given by the performance specifications. The residual is generated using an observer-based method. A dynamic adaptive threshold is generated based on the inputs and the measured system outputs to account for the residual deviating from zero under fault-free conditions due to parameter uncertainties. In addition to this, the error of the controlled system output due to a disturbance is handled by the residual evaluation function. This method is tested on a simple simulation as well as experimental data.