Robust Continuous Finite-Time Control of a Helicopter in Turbulence

This letter synthesizes a C
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smooth, continuous, output-tracking sliding mode controller for a full-scale helicopter operating in high-intensity turbulence. The closed-loop dynamics are required to satisfy ideal on-axis attitude and rate response characteristics. Additionally, robust command tracking and suppression of off-axis responses are required in the presence of matched and unmatched uncertainties. Lyapunov based theoretical proofs are utilized for the tracking problem via application of a continuous second-order sliding mode (SOSM) controller. A second order sliding mode observer is employed to estimate the higher derivatives of the sliding variable for the output feedback controller. Simulations in hover illustrate the continuity, smoothness, and robustness properties of the proposed controller as compared to a conventional sliding mode controller and a linear quadratic controller.