Flight and Hover Control System Design for a Mini-quadrotor Based on Multi-sensors.

Mini-quadrotor is difficult to control in the air due to its small size and light weight. This paper presents the flight and hover control system for a mini-quadrotor, including design and simulation of calculations and controllers. Firstly, the attitude and position of the mini-quadrotor are obtained by distributed multi-sensors. Since attitude calculation of aircraft needs a number of combined rotations and vectors transformed by rotation, quaternions are applied to express the attitude model. About error compensation of gyroscope and accelerometer, IMU_Updata algorithm of Mahony filter are applied and improved to realize data fusion [1]. In order to realize accurate hovering at certain position, UWB (UltraWideband) are applied to gain positional information of mini-quadrotor and correct the antenna delay caused sensor error by base station positioning. The discrete Kalman filter of original data is used to achieve the optimized estimation of the airborne position. Px4flow optical flow sensor is able to gets velocity information and avoid the noise problem, which is caused by differential of position data. Then, the mathematical model of a mini-quadrotor's flight and hover control system can be established. Herein, integral items are solved by the integral separation and integral limiting to mitigate the serious overshoot and oscillation of the system caused by the cascade PID. Finally, the simulation of the attitude controller and position controller are applied with the MATLAB Simulink library. The simulation result shows that the designed attitude controller and position controller can enable the mini-quadrotor to fly smoothly, move in all directions and hover. [ABSTRACT FROM AUTHOR]