Vibration Characteristics And Control Stability Of A Helicopter Transmission System

Under the background of vibration characteristics analysis of a helicopter main reducer, a torsional vibration analysis computer program on gear-meshed rotor system is developed. This program is based on the theory of transfer matrix method, and capable of visual modeling of different structural forms. The general framework and main operations of the program is given in this paper.During the development of the program, a new algorithm for natural frequencies and modes based on polynomial whole transfer matrix method is proposed. Higher precision on multiple frequencies calculation and mode calculation of this algorithm is proved by details and numerical examples.Natural vibration characteristics analysis of a helicopter transmission system is carried out by this program. And some new laws are obtained.Finally, an attempt on study of coupling instability between helicopter transmission system and power control system is made. A general method against such problem is given and then applied on a certain system. During the analysis, the main reducer model of different simplification is used. And result shows that a system with main reducer is more unstable than without main reducer. Meanwhile, the instability is caused by several parameters, not only the parameters of the main reducer. This paper suggests that a more detailed main reducer model should be considered in such coupling instability problems.