Adaptive control of active balancing systems for speed-varying rotating machinery.

摘要

The harmful effects of imbalance-induced vibration cause significant productivity and precision reductions in a variety of industries. Implementation of next generation technology such as high-speed machining has been delayed and restricted because of unbalance issues. Standard off-line balancing techniques cannot address many of these unbalance problems because of the transient nature of both residual unbalance and machinery dynamics in operation. Active balancing technology promises to resolve many of these problems and to lead to significant economic benefits through increased reliability of machinery and the enabling of other advanced technologies.; However, previous state-of-the-art active balancing control methods were not able to deal with speed-varying situations which are often encountered in applications. In addition, adaptive control is preferable to deal with inconsistent rotor dynamics. The research presented here represents a significant contribution to enabling active balancing technology to be viable in both unknown dynamics and speed-varying situations. The specific contributions can be summarized as follows: (1) The transient dynamics were re-investigated and the qualitative condition for quasi steady-state approximation was found. A gain-scheduling control method for speed-varying quasi steady-state active balancing systems was developed and experimentally validated. (2) A quasi steady-state direct adaptive control method was developed for the system whose influence coefficient is not known a priori. The developed method utilizes the energy conservation concept to derive special properties of the influence coefficient. A simple direct adaptive control law was proposed based on the properties of the influence coefficient. This method was experimentally validated and found to be very effective for unknown dynamics rotor systems. (3) A direct adaptive control method for speed-varying Jeffcott rotors with high acceleration was developed considering full transient effect. From the positive realness, a direct adaptive control that minimizes a Lyapunov function was developed. The designed control law was tested by numerical simulation and found to be stable. (4) An extension of the direct adaptive control method to multiple- collocated-plane balancing of flexible rotors was developed. The direct adaptive control was designed based on a Lyapunov stability using positive realness. Similar to the Jeffcott rotor case, the developed control law was proven to be stable. The developed control method was tested by simulation studies and found to be very effective for reducing transient vibrations.