A review of mathematical modelling techniques for advanced rotorcraft configurations

The paper will review the development and application of the mathematical modelling of the advanced rotorcraft configuration, including compound helicopter configurations and tilt-rotor vehicles. The mathematical model is the basis for the design of the flight control system and an essential tool to assess the flying and handling qualities for helicopters. As the helicopter is a multi-body system, the mathematical modelling of helicopter should consider the coupling effects among motion, inertia, structure, and aerodynamics, as well as the unsteady and nonlinear characteristics, to give the physical principles and mathematical expression of each part. Therefore, the mathematical modelling of a helicopter is a process of analysing and synthesizing different hypotheses and subsystem models. Moreover, the advanced helicopter configuration puts forward higher requirements for the helicopter mathematical modelling in terms of the aerodynamic interference, blade motion characteristics, and manoeuvre assessment. The critical issues of helicopter modelling, especially the modelling of the advanced rotorcraft configurations, will be illustrated in this paper. The emphasis is put on the modelling of rotor aerodynamics and aerodynamic interaction among the rotor, fuselage, and other parts. Integrated modelling methods and the manoeuvrability investigation are also the foci of the paper. Suggestions for future research on helicopter flight dynamics modelling are also provided