Real-time altitude robust controller for a Quad-rotor aircraft using Sliding-mode control technique

A real-time robust altitude control scheme is proposed for the efficient performance of a Quadrotor aircraft system. The sensing of altitude measurement sensing is performed by a pressure sensor in order to obtain a robust altitude control of the vehicle in hovering mode both indoor and outdoor. The altitude measurement has the advantage of introducing this state information directly in the closed loop control which should be very useful for achieving robust stabilization of the altitude of the vehicle. To this end, a Sliding Mode Control strategy is implemented for the Quad-rotor aircraft. We have assumed that the actuators are able to respond quickly and accurately and we have not enforced limits on the control signals. Finally, to verify the satisfactory performance of proposed nonlinear control law, simulations and experimental results of the Sliding Mode Control technique for the Quadrotor aircraft in the presence of bounded disturbances are presented.