Comparison between failure detection test signals for continuous systems and sampled-data systems

In active failure detection it is essential to have auxiliary signal inputs that are capable of identifying the status of observed systems while the operations of the systems are minimally disturbed by the extra input. Recently, two signal-design-algorithms for active failure detection were introduced: one that computes optimal continuous detection signals for continuous systems (CS) and the other that designs optimal piecewise-constant signal inputs for sampled-data systems (SDS). In some applications simple piecewise constant inputs are sought. In this paper, we combine the key ideas of the two previous algorithms and present an algorithm that finds optimal piecewise-constant signals for continuous systems. This modified algorithm provides a suboptimal detection signal inputs for continuous systems and would appear to be greatly faster than the original CS algorithm. We also compare the three algorithms and the corresponding optimal signals through a computational experiment