Research On Modeling Of A Helicopter Engine/Rotor/Transmission System

Flight simulator can safely and realistically reproduce the behavior of aircraft flying through the air, which is the indispensable simulation equipment for the development of new aircraft and flight training in aviation industry. The engine /rotor /transmission system,as integral parts of the helicopter flight simulator, is of the important influence on helicopter performance. Helicopter engine,rotor and transmission system are closely linked. Parameters influence each other and the coupling effect is serious.Therefore, research on coupling modeling of rotor / engine / transmission system is very necessary.To meet the requirements of a certain helicopter flight simulator, the engine/rotor/transmission system model was established in this paper. Firstly, the engine model is established to analysis the engine output characteristics including exhaust temperature, cylinder head temperature, oil temperature and pressure, and manifold pressure. The output power of the engine in different speeds is calculated. According to the mechanism model and comparing with the actual situation, the result proves the feasibility of modeling method. Secondly, the rotor load model is established according to the theory of blade element theory. Then, the collective pitch, flight speed, and atmospheric environment on the rotor load dynamic effects have been researched through theoretical calculation.Thirdly, the model of the transmission system is established considering the engine output power friction loss and power allocation. The engine and rotor integration model with speed and power coupling was developed. Combined with the working state of engine speed under various control requirements through the introduction of the collective pitch and flight speed feed forward, the engine/rotor speed control was realized based on MATLAB / Simulink platform. Results show that the speed controls is of fast response, high stability to ensure the rotor speed stability under the different flight conditions.Finally, the Simulink model was transformed into VC + + code through the RTW. C++ code was embed in the existing helicopter flight training platform. The effectiveness and stability of the integration model of rotor/engine / transmission system are verified. Simulation results show that the entire flight engine speed control precision can meet requirements.