Research On Path Planning And Tracking Control Of Quad Rotor For Terraces Environment

As an agricultural country, China has 1.8 billion mu of farmland that needs to be treated with pesticides. Manned spraying pesticides which is low efficiency and big intensity of labor easily leads to pesticide poisoning and pollution. With the development of agricultural modernization, the unmanned plant protecting aerial vehicle is used in the fields of diseases and pests control more and more popular. It has more advantages than manned spraying pesticides, such as high spraying efficiency, more less pesticide pollution and not needing man to spray in the field. Due to the irregular shape and complex terrain of the farmland, the special constraint condition in the mission should be considered. Furthermore, it requires much higher and more complex technologies for the path planning and path tracking. The research purpose focuses on the complete coverage of terrace area by the quad rotor. The algorithm of the coverage path planning with combination of laser sensor and ultrasonic sensors, and path tracking control are the main research contexts. A laser sensor and ultrasonic sensors are using to detect the horizontal direction and vertical direction respectively, to complete the coverage of the terrace area with combining wall-following motion. Through building the dynamics model of the quad rotor and analyzing the motion model, design cascade proportion integration differentiation(PID) controller realizes tracking the path of the complete coverage of the terrace area. The paper mainly introduces the following three aspects:1) Summarize the control rule of the quad rotor and force analysis of quad rotor's two-dimensional linear and circular motion. According the flying environment and horizontal detecting, the laser sensor is selected to advance the strategy to detect the horizontal direction. Design the obstacle avoidance method and the strategy of the wall-following motion. Utilize Fuzzy logic control to avoid obstacle and realize the simulation of avoiding obstacle logic.2) Design the structure of the quad rotor to detect the vertical direction environment. Aiming at vertical environment detection, the structure uses ultrasonic sensors to measure the distance from the canopies of crops. Then the quad rotor judges whether crops exist. Do the ultrasonic ranging experiment indoor and put forward the solution for the noises of multi-channel ultrasonic sensors.3) The quad rotor's dynamics model is established and the movement characteristic is analyzed. Cascade PID control method is adopted to realize the path tracking. The coverage area model of the terrace is established. For the model, design a complete coverage path planning method combined with laser sensor and ultrasonic sensors. Simulation realizes coverage of the terrace.