Research On Conrtol And Autonomous Homing Ttajectory Planning Of Parafoil System

The parafoil has good performance of maneuverability and gliding, which provide the possibility of autonomous homing for the parafoil system and opens a wider space for the application of parafoil system, with the automatic control system. The autonomous homing of parafoil system is a complicated task, which involves in many fields and subjects such as textile, mechanics, computer, control and so on. The precise of autonomous homing is influenced by model, navigation, control, especially the disturbance of wind. In this paper, the issues of movement characteristics of parafoil system, wind identification, wind prediction, route (trajectory) planning and trajectory tracking control are studied systematically. Some new viewpoints and methods are represented and some research results are obtained.The main innovations of this paper are as follows:(1) A method of online wind identification for autonomous homing of parafoil system is represented. The flight of parafoil is classified into two cases:linearly gliding and turning. The change of flight trajectory under the effect of wind is studied and the wind identification model is built. Based on the relative theories of atmospheric dynamics, the equation of the wind profile (wind field) in generalized upper frictional layer is built. Combining with the wind identification model, the model of online wind prediction of parafoil system is represented. The predictive wind is compared with the information of actual wind through simulation, which verifies the correctness of the predictive model. This provides concrete method for parafoil system to identify its surrounding wind.(2) Because the gauss pseudospectral method has the advantages of high precision, fast convergence and so on, it is applied to the route planning of parafoil homing. The simulation results verify the feasibility of that method. The motion characteristics of parafoil system are studied and analyzed in the condition of symmetric and asymmetric brake and the conclusion provides theory support for the design of parafoil autonomous homing system in the condition of single motor working or two motors working abnormally. Aiming at the abnormal working condition during the process of homing, the method of fault-tolerant of homing trajectory is represented. The point masses model of3DOF (degree of freedom) of parafoil system in the abnormal working condition is built and the objective function and various restrain conditions are established. Then the optimal trajectory is planned combining with the gauss pseudospectral method.(3) Combining with the characteristic of optimization of the two algorithms of differential evolution and quantum evolution and considering the requirement of online optimization of parafoil system, the quantum differential evolution algorithm based on auxiliary population is represented and the performance evaluation index is established. Comparing the optimization perfo-rmance of aided population quantum differential evolution algorithm with differential evolution algorithm through many test functions, the results show that the represented algorithm is better than other algorithms and has strong global and local searching ability. Applying the aided population quantum differential evolution algorithm to the multiphase homing trajectory planning of parafoil system, the algorithm converges rapidly and shows a strong robustness when solving the optimal solution of the parameters of multiphase homing.(4) The trajectory tracking control of parafoil system is studied. Aiming at the shortage of navigation system, combining with cross track error and sight tracking method, a linear ADRC (active disturbance rejection control) controller based on data expansion is designed for the trajectory tracking control of parafoil system. The simulation results show that the designed controller tracks the desired trajectory well and has good anti-interference ability.