Active incipient fault detection with two simultaneous faults

The problem of detecting small parameter variations in linear uncertain systems due to incipient faults, by injecting an input signal to enhance detection is considered. Unlike previous work where it is usually assumed that there is only one fault, in this paper we allow for two faults which is a natural assumption in the incipient case. A constructive method for the construction of an optimal input signal for achieving guaranteed detection with specified precision is presented in the discrete model case. The method is an extension of the multi-model approach used for the construction of auxiliary signals for failure detection, however, new technical issues must be addressed.