| The straightening machine of steel bar plays an important roll in the modernization of industry. Though there has been a rapid development with regard to the theoretic research of the straightening machine of steel bar, little work has been done in the research of dynamic characteristic of the straightening machine. It's utterly important to provide a valid method of controlling vibration from the point of dynamics and frameworks through the research of the straightening machine, especially the dynamic characteristic of the straightening machine of steel bar. This dissertation applies rotor dynamics technique in the field of dynamic characteristics of the straightening machine of steel bar for the first time.The relevant theories include data acquisition and processing, signal and system, digital signal processing, automatic control, instruments and electronics, hydraulic transmission and control, machining.Through theoretical and experimental research work on straightening system, vibration rules of straightening system and vibration reducing methods are presented. The dynamic model constructed in this paper put a solid basis for future research work. The analysis of some main parameters of the straightening system gives a foundation for the establishment of valid dynamic model. The contacting stiffness and oil-film stiffness of the rotoring bearing can also be get from the research of dynamic characteristic. The key part of the paper is to establish the dynamic model by using the method of lump mass and to solve the system's unbalance response and critical speed by using the method of transfer matrix. In the end, the straightening system's natural frequency is get from the dynamic experiment. What's more, the experiment proves the calculated result is right.And the paper provides some methods to optimize the performance of the straightening machine through the studying and learning of the straightening machine and the straightening system.
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