Auxiliary signal design for failure detection in high index differential-algebraic equations

Auxiliary test signals for active fault detection have been studied by several authors but traditionally for systems with discrete time or continuous time nonimpulsive causal models. Recently, a method for designing test signals for systems modeled by higher index differential algebraic equations has been developed. This paper examines more carefully when such a test signal exists and also how to get a useful test signal when the previous algorithm breaks down.