Research On Path Planning And Autonomous Obstacle Avoidance Control System Of Quadrotor

Due to its simple structure and flexibility,the rotary wing drone is widely used in geological exploration,logistics and transportation,and disaster relief.However,the UAV inevitably encounters obstacles when performing tasks,and is constrained by its own performance.Various collisions and crashes occur.Studying the path planning and obstacle avoidance control system of the rotorcraft can effectively improve the stability of the flight and the success rate of the operation.It has strong practical value,but its system involves many problems such as flight attitude calculation,trajectory tracking accuracy,and environmental perception.This paper will focus on the above issues.The six-degree-of-freedom mathematical model of the rotorcraft UAV is established.By studying the kinematics and dynamic mathematics equations,the system is characterized by nonlinearity,under-actuation and strong coupling.Aiming at the error characteristics of attitude sensor,the quaternion-based complementary filtering attitude solving method is improved.The accelerometer measurement value is used to modify the gyroscope measurement error by dynamic weight,and the accuracy of attitude calculation is improved.Aiming at the problem of controller integral saturation for the rotorcraft heading channel,the PD trajectory tracking controller is designed by PD linear feedback method.This method can alleviate the overshoot caused by integral saturation while ensuring the accuracy of yaw control.For the problem of obstacles in the flight path,the artificial potential field algorithm is used for path planning and obstacle avoidance.The path planning algorithm for the three-dimensional environment of the UAV is completed.By introducing the parameters such as the position,speed and acceleration of the UAV,the obstacle avoidance equation of the repulsive field function is reconstructed,which avoids the shortcomings of the traditional method which is easy to fall into the local minimum.The algorithm considers the kinematic constraints at the same time,so that the drone moves along the direction of the resultant force gradient,which realizes the path search and obstacle avoidance.In order to improve the obstacle sensing ability of the rotorless drone,a laser radar obstacle avoidance control system is designed.For the problem that the low-cost laser radar is susceptible to interference under strong light,the wild value point elimination processing can effectively provide the obstacle direction,distance and other information.Experiments were carried out on the constructed UAV path planning and obstacle avoidance platform.The experimental results show that the improved attitude algorithm can solve the output smoothing and can quickly follow the actual angle.The designed path trajectory tracking controller can quickly track the desired command with a small amount of overshoot.The actual flight path of the rotorcraft is basically the same as the planned route,and the obstacle avoidance control system can effectively avoid obstacles when it detects obstacles.