Research Of Quadrotor Attitude Control Method

Compared with other aerocrafts, Quadrotor has simple mechanical structure, less space of landing and flexible flight attitude. In addition, it has vertical take-off and landing and hovering capability with camera, instrument of surveying and mapping and airborne communications node. Under the artificial or automatic control, it can accomplish the task such as aeroleveling, fire rescue and agriculture in specified flight routes and attitude.The aerocraft attitude control system with six degree of freedom and four controlled input, and its dynamic system is a complex system with multivariablity, nonlinearity, underactuation, strong coupling and interference susceptibility leading to very complicated design of aerocraft attitude control system. Therefore, attitude control algorithm of Quadrotor makes a significant sense to theory and practical engineering application of Quadrotor.This dissertation realizes the design and simulation of pole assignment and feedback linearization pole assignment controller through aircraft hardware platform and Matlab or Simulink simulation software on the application background of attitude control algorithm of Quadrotor. The main contents of the paper are as following:1) Nonlinear Dynamical Model of Quadrotor: Regarding system of Quadrotor as rigid body, from load-carrying capability and force moment, we can derive nonlinear dynamic equations of Quadrotor according to Euler equations and Newton's laws of motion, regardless of the friction and damping torque.2) Design of Pole Assignment Controller for Quadrotor: Under the situation of satisfaction of overshoot and adjusting time performance, in order to achieve the stable attitude control, we can linearize nonlinear dynamic equations of Quadrotor in equilibrium and configure closed loop pole for desired location by using state feedback pole assignment which has a lot of advantages such as simple calculation and fast dynamic response. The controller can make aircraft respond quickly and stabilize on the attitude angle after the inspection.3) Attitude Controller for Quadrotor Based on Theory of Feedback Linearization for Nonlinear System:This method transforms dynamic performance of nonlinear system of Quadrotor into that of linear system(entirely or partly) by using algebraic graph transformation. In the design process of feedback linearised controller, because decoupling matrix is irreversible, we study a virtual input approach, more simple and more efficient, to solving decoupling control principle. The simulation results show that this controller is more stable and more dynamic compared with linear approximation. With 20% of disturbance, it can still keep stable to verify the robustness of the control system.