Research On Flight Control Technology Of Tracking Ground Moving Target For Unmanned Helicopter

Unmanned helicopter(UMH)has unique flight capabilities such as vertical takeoff and landing,fixed-point hover,low/medium/high-speed flight,which is an ideal flight platform for target tracking tasks.Currently,most of the research on flight control technology for UMH focuses on basic flight functions and autonomous route,which is still difficult to meet the engineering application requirements of moving target tracking.Based on this,taking the AV500 UMH of China Helicopter Design Institute as the research object,this thesis has carried out the theoretical research and technical realization in the aspects of control law design,target state estimation and tracking guidance strategy design.Firstly,by analyzing the target tracking problem of UMH,the technical route and research plan of the research were proposed.Meanwhile,based on the analysis of UMH’s characteristics and the requirements of tracking flight,the flight mode and the inner/outer loop control laws of four channels for the target tracking were designed and optimized to improve the performance of the tracking flight.Secondly,for the motion state estimation of ground target,the defect of conventional single model method was analyzed.Based on this,an interactive multi-model target state estimation method based on current statistical model and CV model was proposed to improve the poor performance of single model state estimation,and provide the reliable and credible data source for tracking guidance.Thirdly,for the tracking guidance problem,the strategy of "Follow-up stage + Accompanying stage" was formulated.Meanwhile,a Dubins trajectory planning method based on time constraint was proposed to solve the path planning problem of the follow-up stage.The tracking modes such as the fixed-distance trailing were designed to solve the guidance problem of the accompanying stage.And tracking error was reduced by trajectory tracking control.Besides,the height maneuver strategy was proposed to reduce the risk of target loss.Then,the four-dimensional moving target tracking guidance scheme of "Maneuvering state estimation + Plane maneuver + Vertical maneuver" was formed.Finally,the tracking simulation and verification environment was constructed,and the tracking simulations for different moving targets were completed.The comprehensive simulation results show that the methods and strategies studied in this thesis are correct and feasible,which have completed the research content of the subject well and achieved the expected research goal.