Synthesis of a robust linear structural feedback linearization scheme for an experimental quadrotor

In this paper, we show in detail a synthesis procedure of the control scheme recently proposed in [3]. This control scheme has the advantage of combining the classical linear control techniques with the sophisticated robust control techniques. This control scheme is specially ad hoc for unmanned aircraft vehicles, where it is important not only to reject the actual nonlinearities and the unexpected changes of the structure, but also to look for the simplicity and effectiveness of the control scheme. I. INTRODUCTION Recently, there has been a great interest in finding simple and effective control schemes for unmanned aircraft vehicles, able to reject the actual nonlinearities and the unexpected changes of structure. In [6], the authors present two types of nonlinear controllers for an autonomous quadrotor helicopter. However, to program this control scheme in the embedded autopilot of the quadrotor is rather difficult due to the needed derivative estimations. In [13], the authors present attitude and trajectory tracking control designs based on an inner/outer-loop control structure for normal flight conditions. Once again, to program this control scheme in the embedded autopilot of the quadrotor is rather difficult due to the needed derivative estimations. In [7], the authors propose a robust controller based on the timescale separation approach to achieve the automatic takeoff , hovering, trajectory tracking, and landing missions for a quadrotor helicopter. The authors only show experimental results in indoor environments. In this paper, we present a synthesis procedure of the recently robust linear control scheme proposed in [3], which is based on failure detection techniques. Such a linear control approach is intended to reject linearly structured uncertainties, which are treated as failure signals affecting the systems dynamics. The implementability and efficiency of the proposed robust control methodology is illustrated with a quadrotor laboratory prototype in hover flying. We present simulation results and experimental results in open field (outdoor environments).