Stergios I. Roumeliotis, Gaurav S. Sukhatme and George A. Bekey :

"Sensor Fault Detection and Identification in a Mobile Robot"



Multiple model adaptive estimation (MMAE) is used to detect and identify sensor failures in a mobile robot. Each estimator is a Kalman filter with a specific em­ bedded failure model. The filter bank also contains one filter which has the nominal model embedded within it. The filter residuals are postprocessed to produce a probabilistic interpretation of the operation of the sys­ tem. The output of the system at any given time is the confidence in the correctness of the various embedded models. As an additional feature the standard assump­ tion that the measurements are available at a constant, common frequency, is relaxed. Measurements are as­ sumed to be asynchronous and of varying frequency. The particularly difficult case of 'soft' sensor failure is also handled successfully. A system architecture is presented for the general problem of failure detection and identification in mobile robots. As an example, the MMAE algorithm is demonstrated on a Pioneer I robot in the case of three different sensor failures.