Research On Control Method Of Four - Rotorcraft Based On Backstepping Method

With the increasingly mature and prefect of embedded processor, micro-sensor technology and control theory, quadrotor unmanned aerial vehicle (UAV) is developing towards the direction of highly intelligent and miniaturized. and also has been playing an increasingly important role in the field of the military and civil. At the same time, a large number of research scholars have been attached by the UAV’s unique mechanical structure and complex aerodynamic characteristics. In this paper, Qball-x4 quadrotor UAV is regarded as the research object, we attach importance to the model of UAV and the control algorithm, the purpose is to improve the robustness and stability of system. The contents of the research mainly include the following aspects:Firstly, we introduce the structure characteristics and analyze UAV’s working principle in detail,and the conventional coordinate system and body coordinate system are selected. Based on this, the mathematical model of UAV is derived by using Newton’s second law and external torque law.And based on the experimental flight condition, the mathematical model of the aircraft is simplified.Secondly, aiming at the shortage of the tradition linear algorithm, the controller design is used by nonlinear control algorithm. The backstepping algorithm is used to design the controller for UAV’s mathematical model. The system is divided into six subsystem, such as internal loop (attitude loop) and external loop (position loop). Simulation results show that the algorithm is effective and is worth learning from.Then, Backstepping combined with sliding mode variable structure control algorithm. Considering uncertainty and random disturbance in the process of aircraft flight, We use the sliding mode variable structure to improve system robustness. In the second chapter, we have got the mathematical model of aircraft, to design the controller, periodic interference on the system, Through the data analysis of simulation, the sliding mode variable structure takes advantage in improving system robustness.Finally, backstepping combined with adaptive control algorithm. For the same problem of uncertainty and random disturbance, especially for the uncertain interference exist in aircraft axis and attitude inertia parameters during the flight. A dot hovering simulation and a path tracking simulation show that the adaptive is effective in terms of dealing with uncertain results.