| The gear whine problem that widely occurs in power transmission systems is typically characterized by one or more high amplitude tonal acoustic signals. The whine response originates from the vibration of the gear pair system caused by transmission error excitation that arises from tooth profile errors, misalignment and tooth deflections. In very severe cases, the gear vibrations can also reduce life and performance of the power transmission systems. The fundamental gear whine problem has been of interest to many researchers for a very long time. However, most of the work have focused on shaping the gear tooth profiles, adding vibration isolation to the gearbox, and other passive control methods. Effort involving active gearbox vibration control is still quite limited. In fact, other than those papers on the active control of the vibration transmitted through support struts of gearboxes, only a few isolated studies that directly deal with control of gearbox internal components have been seen. Therefore, addressing this research gap is the primary aim of this dissertation study.; In this research, a dynamic finite element model is first developed for a power recirculating gear train system for use to examine the feasibility of applying an active shaft transverse vibration control system near the gear pair in the effort to tackle the gear excitation problem more directly. For this particular actuator setup and gearbox system, a complete set of controller which is based on the FXLMS algorithm combined with improved frequency estimation technique is designed. A series of computational studies are performed to refine the algorithm design and to determine the most suitable parameters. Finally, a series of experimental studies are performed on an actual power re-circulating gearbox system that is equipped with the designed active control system. In some cases, up to 14 dB of reduction in the vibration response can be achieved. Also, the controller is capable of handling up to 6 harmonics simultaneously. Furthermore, the vibrations at other locations on gear housing and gear whine are also monitored and analyzed. The inadequacies of system are also quantified, and refinements are proposed for future research. |
