Research On Controllability/stability Analysis And Control Method For Helicopter-slung Load Coupling System

Flying with Slung-load is a special capability of helicopters.It is possible to transport any cargo,equipment that much larger than helicopter cabin size to anywhere by using slung-load flight function.Therefore,slung-load flight has already been widely used both in civil and military domain.Compared with normal flight without slung load,helicopter slung-load flight introduces the slung-load degrees of freedom.The movement of slung-load changes the forces and moments of helicopters at the center of gravity.Moreover,there exists kinematic and dynamic coupling between helicopters and slung load.Therefore,the controllability and stability of a helicopter are changed during slung-load flight.This dissertation does research on the controllability/stability analysis and control method for helicopter-slung load coupling system.Firstly,the aerodynamic modeling of a CONEX slung load is implemented based on CFD method and the aerodynamic characteristics of the slung load are obtained.Secondly,the flight dynamics model of a helicopter is constructed based on original code.The modeling method for slung load is developed and a dynamic model of the slung load is obtained.Then,modifications have been made to independent models of the helicopter and slung load based on the coupling relationship between them.Finally,the flight dynamics model of helicopter-slung load coupling system is obtained.The controllability and stability of the coupling system is analyzed according to the ADS-33E-PRF,and the flight control law that can improve the controllability and stability of the coupling system is designed and validated based on PID control method.The results show that the methods developed in this dissertation can solve the problem of controllability and stability controllability and stability for helicopter-slung load coupling system.The developed control law design method can count the influence of slung load motion to stability of a helicopter,so it is applicable to flight control system design in slung load flight.