Rotating machinery is widely used in industry. Vibration caused by mass imbalance is a common problem in rotating machinery. Refined balancing that can eliminate the system imbalance is essential to the proper functions of rotating machinery.; Therefore, this dissertation studies the problems of modeling, estimation, and active balancing of rotor systems. In particular, the speed-varying transient rotor dynamics and the active balancing scheme under speed-varying conditions are the focuses of this research. In many practical scenarios, balancing during the speed-varying period is required, and there are many technical challenges to such balancing. The results from this research contribute to the fundamental scientific base of knowledge in the fields of rotor transient dynamic modeling, system identification, and adaptive control synthesis.; The fundamental issues that are studied in this dissertation, and the respective contributions are summarized as follows. (1) Fundamental contributions in transient rotor dynamics modeling. An analytical imbalance response for the Jeffcott rotor with constant acceleration is developed. This analytical solution provides guidelines for rotor design and the synthesis of active vibration control and balancing of rotor systems. (2) New techniques for dynamic analysis and estimation of the imbalance for rotor . A new technique for on-line parameter estimation and determination of the significances of several nonlinear and time varying effects in rotor systems is developed. This method provides an effective scheme for fault diagnosis and condition monitoring of a rotor system. A time varying observer technique is also developed to estimate the imbalance of the rotor system. This observer technique provides a fast and reliable way for the imbalance identification in adaptive vibration control and active balancing schemes. (3) Active balancing schemes under different conditions. Several active balancing schemes are developed. They work under different conditions and satisfy the basic industrial needs for active balancing in rotating machineries. (4) Integrated design and optimization for active control schemes and actuator/sensor placement. Given an active balancing scheme, the optimal actuator/sensor placement procedure is developed. This research provides guidelines for the design and installation of the active balancing scheme.; In addition to these fundamental researches, an experimental and comprehensive testbed was designed and built. This testbed was based on a Fadal® vertical machining center and in Dspace real-time control development environment. This testbed served as an essential tool for testing and evaluating the active balancing schemes.
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