Research And Design Of Plant Protection Quadrotor

As a micro-aircraft,the quadrotor Unmanned Aerial Vehicle(UAV)has the characteristics of small size,light weight and flexibility.It has been widely used in many fields such as agriculture,military and commerce.In agriculture,the traditional plant protection methods are inefficient,and the pesticide spraying style is out-of-date that cannot meet the requirement of modern development.At present,the UAV technology for plant protection in China is in its infancy.In order to design a reliable,stable and flexible quadrotor for plant protection,the following work has been carried out.First,the attitude control algorithm is studied to improve the stability of the quadrotor for flying control.The quadrotor is a multi-variable,under-actuated,complex system that is sensitive to environmental changes,making it difficult to accurately control the attitude.For this purpose,a double closed-loop cascade PID attitude control algorithm is designed to improve the dynamic characteristics and stability of the system.Second,the issue of divergence drift of low-frequency MEMS is studied.In the process of attitude calculation,the angle data is obtained by integrating the angular velocities measured by the gyroscope of the quadrotor.However,the integral produces accumulated error.At the same time,due to the high sensitivity,the measured value is easy to be interfered by high-frequency noise such as vibration,which makes the solved attitude error larger.To address this problem,the attitude solution based on Balance filtering and the height resolution based on Kalman filter with delay correction are proposed,which can improve the accuracy of the attitude calculation and enhance the reliability of the quadrotor.Finally,as the quadrotor must keep flying at a specified height when spraying pesticides,the continuous decreasing weight of the pesticides is a disturbance.Hence,how to accurately achieve a fixed altitude during flight under such a circumstance is a problem.To solve this problem,a height-loop control structure based on linear auto-disturbance is proposed,which can achieve better disturbance suppression ability,faster response speed,and higher stability.Simulations are made for above researches,and the F330 quadrotor experimental platform is used to for testing.The results show that the proposed algorithms can effectively improve the dynamic performance of the plant protection quadrotor,which make the control precision higher and the anti-disturbance ability better.