Research Of Control System For Plant Protection Unmanned Aerial Vehicle Based On Pixhawk

Compared to the traditional way of plant protection,the UAV(Unmanned Aerial Vehicle)of plant protection has the advantages of strong adaptability,high efficiency and high security.So it has great application values and broad prospects in the field of agricultural plant protection.Based on the Pixhawk open source flight control system,the study of control system of plant protection UAV are developed.According to the functional requirements of plant protection UAV,this paper proposes the overall resolution of control system of plant protection UAV,and respectively provides the design scheme from hardware system and software system.The whole control system is divided into the flight control system and the intelligent spraying system for achieving spraying function of plant protection UAV,depending on serial communication among subsystems.The Pixhawk flight control system was developed further as the flight control system of plant protection UAV.It mainly includes Pixhawk,GPS module,data transmission module,power supplying module,integrated module,driving module and remote control module in the hardware;Its software system includes the PX4 firmware that is supported in Pixhawk as well as some function module such as serial communication,drug displaying and auto spraying.Intelligent spraying control system mainly consist of STM32F103 core board,power supplying module,remote control module,sensor module,spraying module in the hardware;Its software system introduces uC/OSII embedded operating system with the semaphore and semaphore completing the task synchronization.A detailed analysis about each task and its switch,achieving the function of serial communication,liquid monitoring,control decoding,ultrasonic ranging,variable spraying of intelligent spraying control system.On the other hand,the experimental platforms was established for verifying the feasibility of the control system of plant protection UAV,including UAV experimental platform and spraying experimental platform.Based on the experimental platform,the flight experiments of UAV,the subsystem communication experiments and spraying system experiment were carried out,verifying the stability of the Pixhawk and the reliability of serial communication among subsystems.The results show that the proposed scheme can meet the functional requirements of UAV of plant protection.In addition,the flight principle was analyzed in detail and the dynamic modeling was build about the four-rotor UAV.The cascade PID control method of UAV flight control in PX4 firmware is simulated on Matlab.At the same time,the fuzzy PID control method is used to optimize the flight control algorithm,aiming at the defects of cascade PID control method.The results on Matlab for simulation analysis show that the fuzzy PID control method is more suitable for flight control of plant protection UAV.