Research On Multi-rotor Automatic Control System Of UAV Based On Pixhawk

Plant protection unmanned aerial vehicles as one of the emerging plant protection machinery,because of its high efficiency,good control and other characteristics,so in recent years has been rapid development.The flight control system is to ensure that plant protection unmanned aerial vehicle can be successfully completed the key to plant protection operations.In this paper,how to achieve full automation of plant protection UAV for the research objectives,plant protection UAV flight control system to do the following research:1.Based on the cascade PID,the attitude controller?height controller and position controller in the flight control system are designed.In the attitude controller,the information of three attitude angles(pitch angle ??roll angle ??yaw angle ?)calculated by each sensor is fused by EKF algorithm,and the attitude information of high precision is obtained.In the height control,the height data is removed by the limiting method,and the height data is processed by weighted average filtering.The weighted mean smoothing algorithm can not only smooth the height data,but also improve the response speed of the flight control system to the height change.2.The key function of the flight control system is designed and realized by software coding to realize the automatic operation of the plant protection unmanned aerial vehicle(UAV).Including automatic landing function,automatic cruise function,autonomous obstacle avoidance function,the resumption of flying function and variable spray control.The autonomous obstacle avoidance is based on the laser displacement sensor.The flight control system firstly divides the obstacle into two types of obstacle according to the obstacle information from the obstacle avoidance detection unit.Then the flight control system According to the different obstacle types,different obstacle avoidance strategies are adopted,and the bar obstacle takes the arc around fly strategy.The face type obstacle adopts the polyline obstacle avoidance strategy.After successfully avoiding the obstacle,the plant protection unmanned aerial vehicle can return The original planning routes to continue the implementation of plant protection operations tasks.While the breakpoint continued flight function refers to the flight control system can be based on the remaining dose,power information to calculate the planned route in the best return position and landing position,when the plant protection UAV needs to return,the flight control system can record plant protection UAV current operating status and current location as a breakpoint,and the replacement of liquid and battery,plant protection UAV can return directly to the breakpoint location and continue to perform outstanding plant protection operations tasks.Finally,the main task of the spray management system is to control the spraying radius and the spraying amount of the medicinal liquid in real time according to the different speed and position of the plant protection UAV.3.The experimental platform of four-axis and eight-rotor plant protection unmanned aerial vehicle was completed.4.The flight test system is designed to test the flight control system's automatic landing function,automatic cruise function,breakpoint continuation function and automatic obstacle avoidance function.The final experimental results show that the flight control system designed in this paper can realize the plant protection unmanned aerial vehicle Of the fully automated operation.