Research On Key Technologies Of Unmanned Aerial Vehicle (UAV) For X-ray And γ-ray Detection

With the progress of society and the improvement of people’s quality of life,quadrotor drones have not only become a hot development field,but also gradually integrated into people’s lives.There may be X and γ rays that threaten human health in the human living environment,and the quadcopter can just replace humans to detect whether the X and γ doses have reached the standard values that threaten health.However,the micro-electromechanical inertial sensor device of the four-rotor UAV has the problems of low accuracy and easy interference by the outside world.In addition,the entire system has the disadvantages of strong coupling,under-driving,weak stability and the configuration of the detector will cause the overall stress of the unmanned aerial vehicle does not appear to be partial,and it is necessary to plan a reasonable path according to the target point.Therefore,accurate attitude data,a control algorithm with strong anti-interference ability and a reasonable path planning algorithm are needed to complete the detection task smoothly and efficiently.This article mainly expands research from attitude estimation,control algorithms and flight path planning.Firstly,a quaternion-based extended Kalman filter is proposed to improve the attitude measurement accuracy of quadrotor aircraft.Before data fusion,the inexact sensors of the quadrotor aircraft are calibrated and then applied to the attitude measurement system.Then a self-correcting measurement noise covariance matrix is designed in the filter.With the increase of the external disturbance value,the filter’s trust in the sensor observation quantity is reduced accordingly.The simulation results show that the proposed algorithm can estimate the attitude Angle accurately under the circumstance of external interference.Second,four rotor aircraft with detectors of physical structure more easily affected by the wind in the air,can lead to poor stability,so in order to improve the anti-interference ability of the four rotor aircraft flight process,put forward based on PID controller and ADRC(Active Disturbance Rejection Control,ADRC)of the double closed loop Control method,namely,the position of the outer ring circuits adopt PID controller,the attitude of the inner ring circuits adopt ADRC Control,the dependence of the mathematical model of ADRC is very low,Moreover,the internal state observer can not only consider the coupling of attitude Angle as a disturbance,but also capture the external disturbance,and finally the system compensates the disturbance.Simulation results show the effectiveness of the proposed control algorithm.Finally,the RRT algorithm is improved,A tree is maintained in both directions,and the path planned by the bidirectional RRT algorithm is optimized in combination with the A~* algorithm.There are too many twists and turns in the path planned by RRT algorithm,and it is random points on the whole environmental map,which leads to slow efficiency.Although building a tree in both directions improves planning efficiency,it still suffers from too many twists and turns.Therefore,A~* algorithm is introduced to optimize the tree path,and the effectiveness of the algorithm is verified by simulation.