Optimized chattering‐attenuated sliding mode controller for a perturbed VTOL system

This study presents a novel design of an optimized chattering‐attenuated quasi‐sliding mode controller for the stabilization of a vertical take‐off and landing aircraft affected by external disturbances. We propose a methodology based on a particle swarm optimization algorithm to provide an optimal boundary layer thickness of the quasi‐sliding mode controller (QSMC) structure based on a sigmoid‐type function approximation to reduce the chattering noise in the control signal while an adequate stabilization quality is guaranteed. This represents an alternative to the common strategies based on a trial and error tuning of such boundary layer thickness of sigmoid‐type approximations. Also, the Lyapunov formalism is applied to restrict the search space of the QSMC gain to guarantee stability conditions. Some simulation tests were carried out to demonstrate the enhanced chattering attenuation capability of the proposed solution against a standard sliding mode controller and the superior stabilization performance versus other robust controllers.