Research On The Dynamics And Homing Project Of Parafoil System

Parafoil system could be used widely in many areas, e.g. military or aerospace & aviation, to realize precise airdrop and precise-undamaged landing. Recently it has been a hotspot in airdrop and recovery. But its academic research could not keep up with its development in engineering. And the study of parafoil inland lagged behind greatly. In this thesis, the problems, related with research of automatic and precise homing of parafoil system, were analyzed thoroughly and systematically in method of theoretical analysis and numerical simulation, including dynamics, trajectory design and trajectory following. Some valuable conclusions were drawn and shown as following:Three models were brought forward, i.e. 6DOF rigid-connected model, 8DOF rigid-jointed model and 12DOF non-rigid connected model. The basic dynamic properties of the system, the relative motion between parafoil and payload, and some geometric parameters'effects on the system dynamics were analyzed and summarized. Based on comparison of different dynamic models of parafoil system, the character and applicability of each model was concluded. All those studies would be references and theoretical bases to design and working-process analyses of parafoil system.Homing project research of parafoil system on optimal control was developed. And the characters of it were analyzed and summarized. To solve the optimal control problem, some methods about pre-solver analysis and treatment were put forward, such as moving equations translated into frame of wind and normalized. Those methods not only simplified the computation, but also favored the selection of weighting coefficient, and unified the solving methods for the optimal control problem in reachable or unreachable target point.A multi-phase homing project was obtained, including three different homing trajectories according to the height of initial point being high, or proper, or short. And selection criterion for trajectories was also discussed. To optimize the multi-phase homing trajectory, an improved adaptive genetic algorithm (IAGA) was proposed, which could efficiently improve convergence speed and avoid the occurrence of premature. The improvements in the IAGA contained adding strengthen operator, improving evaluation index of premature, etc. Multi-phase homing project, making use of the flight properties of parafoil system in gliding and turning, was simple in control and facile in practice.Based on Frenet frame, the linear time-variable error equations of parafoil system were built. And the error variable was solved analytically making use of"Project Point". Then the traditional PD controller and gain-scheduling fuzzy PD controller were designed to realize path following of parafoil system. Simultaneously, several control strategies were brought forward in view of the basic flight properties of parafoil system. The important one was described as following: the...