2016 年 82 巻 844 号 p. 16-00202
In this study, the optimal mechanical design method for fixed-pitch coaxial-rotor helicopter is proposed. The fixed-pitch coaxial-rotor helicopter has several advantages compared with other type helicopters. For example, it has great simplicity of the mechanisms, well maintainability, and well energy conversion efficiency, and so on. However, fixed-pitch coaxial-rotor helicopter has a drawback in forward flight named pitch-up phenomenon, and it causes a little cruise speed of the helicopter. To overcome such a problem, optimal mechanical design of the helicopter is required. The optimal design is based on the precise mathematical model and numerical optimization method. The mathematical model is derived by using Multi Body Dynamics (MBD) theory. The characteristics of the fixed-pitch coaxial-rotors are considered to the model by aerodynamics of the rotors. The mechanical parameters are examined to maximize the cruise speed of the helicopter. Particle Swarm Optimization (PSO), which is one of the population based stochastic optimization methods, is adopted as optimization method. The fundamental optimization of mechanical parameter is performed to show the validity of proposed optimal design method and to obtain the optimal mechanical parameters of fixed-pitch coaxial-rotor helicopter.
