Attitude Control of Hansa-3 Aircraft with Perturbation Using Sliding-Mode Controller

This paper presents a robust control design law for stabilizing the fixed-wing aircraft attitude. For stable flying within the flight envelope, attitude control is the crux for conventional aviation flight control systems. For practical implications, control laws are designed in such a way to reject disturbances and uncertainties. One of the robust control methods is sliding mode control (SMC) which has established itself over the last few decades due to its simplicity and wide applicability in numerous engineering systems. SMC with the first-order error dynamics has been exploited in this paper to track the reference signal for Hansa-3 research aircraft. Power rate reaching law (PRRL) has been used in combination with SMC to rapidly drive the aircraft states from the reaching phase to the sliding phase. The manifold sliding surfaces of pitch, roll and yaw attitudes are designed systematically in combination with the PRRL. Five attitude profiles including the perturbation in aircraft's inertial properties were considered to substantiate the working of the proposed control law. These profiles test the robustness of the control law and are pertinent to the real-world scenarios. In this paper, it is demonstrated through exhaustive simulations of the considered profiles that SMC design explicitly follows the desired input signals with asymptotic stability without the well-known problem of chattering. Simulations show that there is finite-time convergence of the desired aircraft states achieved within the constrained design limits of respective control surfaces. These simulation results exemplify the efficacy of the proposed control law.