Research On Path Planning And Flight Control Of Quadrotor UAVs

In recent years,the rapid progress of materials,electronics,energy science and other related disciplines have promoted the development of multi-rotor UAVs.More and more people can directly use or experience the functions and benefits of multi-rotor UAVs.The multi-rotor UAV has a simple structure,featuring vertical take-off and landing,low-altitude flight,and stable hovering,thus can be applied to various complicated flight spaces.As one of the most widely used multi-rotor UAVs,the quadrotor UAV has the advantages of easy operation,high reliability and convenient maintenance.This paper mainly studies the path planning,flight control technology and parameter optimization algorithm for the quadrotor UAVs.Flight control is the basis for a quadrotor UAV to finish all missions.As a nonlinear control method,the active disturbance rejection control(ADRC)does not rely on a precise controlled object model,and has high control precision,strong anti-interference ability,fast output response,and decoupling capability for strong coupled systems.The linear ADRC,obtained by linearizing both the extended state observer and the nonlinear feedback law,provides a simplified version of the traditional ADRC without too much loss of performance.Based on the analysis of coordinate transformation,attitude representation,principle of kinematics and dynamics,this paper establishes a complete control mathematical model of a quadrotor UAV.Considering that the control model of the quadrotor UAV is a multi-channel,strongly coupled and under-actuated nonlinear system,efficient controllers need to be designed to overcome these deficiencies.Therefore,based on the general linear ADRC,this paper retains the tracking differentiator to polish the command signals,and designs six-channel attitude controller and position controller respectively,so as to accurately and stably control the flight process.Path planning is the key for a quadrotor UAV to achieve autonomous flight and complete related tasks.The flight environment of the quadrotor UAV is so complex that the path planning is difficult.Therefore,it is very important to plan the optimal flight path under proper performance indexes.In this paper,the geometrical models of buildings,threats and other obstacles in the flight environment are represented by geometric models.The appropriate path cost indexes are designed to evaluate the performance of different flight paths.The disturbed fluid dynamical system algorithm is used to calculate a smooth trajectory yielding relevant performance requirements.The parameter optimization problem of the ADRC,as well as the disturbed fluid dynamical system algorithm is a complex computational optimization problem with nonlinear,derivative forbidden and multi-peak characteristics.The meta-heuristic optimization algorithm can be used to solve such an optimization problem.The whale optimization algorithm adopted in this paper has many advantages,e.g.,simple and easy implementation,less parameter setting,strong optimization ability and local optima avoidance.The parameters in flight controller and path planning can be optimized quickly by taking the relevant fitness function as an optimization index.