Software implementation and verification of sliding-mode control and fault detection methods

Software veriffcation of model reference sliding-mode control and sliding-mode fault detection methods are considered in this paper. Sliding-mode methods are developed for robust control and online fault detection and estimation, and have been implemented in aerospace applications. However, several design parameters should be adjusted for those detectors to operate well. Diffcult tuning during design procedure, together with computational complexity of the variable structure methods, leads to complicated software implementation compared to the linear control and fault detection approaches. For the purpose of software verification, we insert annotations in the software in order to include mathematical proofs in software level. As such, computer experts and maintenance engineers can understand and verify the idea behind control and fault detection algorithms. Two invariant sets based on two Lyapunov functions are introduced in software level for either methods to guarantee that sliding motion takes place and sliding motion is stable after system states reach the sliding surface.