Fault Tolerant Control for a 4-Wheel Skid Steering Mobile Robot

This paper studies a fault tolerant control strategy for a four wheel skid steering mobile robot (SSMR). Through this work the fault diagnosis procedure is accomplished using structural analysis technique while fault accommodation is based on a Recursive Least Squares (RLS) approximation. The goal is to detect faults as early as possible and recalculate command inputs in order to achieve fault tolerance, which means that despites the faults occurrences the system is able to recover its original task with the same or degraded performance. Fault tolerance can be considered that it is constituted by two basic tasks, fault diagnosis and control redesign. In our research using the diagnosis approach presented in our previous work we addressed mainly to the second task proposing a framework for fault tolerant control, which allows retaining acceptable performance under systems faults. In order to prove the efficacy of the proposed method, an experimental procedure was carried out using a Pioneer 3-AT mobile robot.