| Over the years, autonomous quadrotor has drawn researchers’ interest increasingly due to its simple structure and high mobility. Yet the dynamic model of quadrotor is an underactuated nonlinear system with strong coupling and the unknown drag as well as resisting moment can’t be modelded precisely, which indicates that designing a stable and robuts flight control protocol is a huge challenge. Besides, under certain complicated circumstances, we need to use several quadrotors to accomplish a task cooperately for the limited payload, sensor, cruising ability of a single quadrotor, and the consensus of multiple quadrotor is a key problem of multiple quadrotors. In this thesis, we mainly studied the control algorithm for quadrotor and the distributed consensus protocal for multiple quadrotor, where our main contents and contributions are summarized as follows:1. Based on the analysis of dynamics for quadrotors and flight principle, we first establish the dynamic model of quadrotors using Newton-Euler equation. Different from traditional control protocol(double loop strategy), we devide the whole system into full-actuated and unde-actuated subsystems according to the characteristics of input channels. We design control algorithm for each subsystem accordingly and draw the overall flight strategy according to two separate algorithms.2. For the independent full-actuated subsystem with fast response, we choose a nonsingulara terminal sliding mode controller to stabilize its states and couplings and the stabilization analysis and simulation can demonstrate the validity of controller. Baded on the assumption that the full-actuated subsystem has been stabilized already, we design the control protocol according to dynamic surface method for the four-order under-actuated subsystems, with disturb observer to improve robustness. We also prove our algorithm by therotical analysis and Matlab simulations.3. After integrating the two subsystems into a whole flight system, we verify the effectiveness of our whole flight solution and its robust ability to restrain uncertain disturbs.The flight simulations of spot hover, rotary trajectory tracking show that flight stability can be ensured by the proposed controller.4. For the consensus problem of multiple quadrotors under time-invariant communications, we integrate the dynamic surface method and one-order basic consensus frame to draw the consensus strategy for quadrotor models without simplification. We also introduce several obersers to track the time-variant unknown disturb and compensate theeffect of disturb in control loop. The contrastive simulation results verify the robustness and high performance of the proposed distributed consensus protocol. |
