Vibration suppression of drilling tool system during deep-hole drilling process using independence mode space control

Abstract

Deep-hole drilling technology is commonly used in the aerospace and automobile industries, for new-energy equipment manufacturing, and in the high-tech industries. While this technology produces high-quality holes, higher quality is pursued. A method to improve the processing quality is to suppress the vibration modes associated with long shafts. This problem was addressed with an aim of real-time application. In addition, a higher goal was set by way of providing a solution (in full) to the associated problem, to shed light on processes that bear similar features in manufacturing and for other industries. An operable control scheme was constructed by transforming the system dynamics to modal space for modal decoupling and truncation. The modal displacement and velocity information estimated by the modal filtering were introduced into the feedback gain matrix. All obstacles in traditional physical space were shunned. A damper/sensor position optimisation algorithm was suggested to minimise the modal spillover and acquire modal orthogonality, which led to a new method that has an edge on all preceding methods because of its stronger ability. A system capable of real-time suppression of modal vibration in a deep-hole drilling tool was built and implemented. Using hole roundness error as the criterium, it was found that further improvement of hole quality was achieved. The idea presented in this work may pave the way for elevating the quality of other manufacturing processes with similar weak stiffness features, such as those seen in long-shaft tools or thin-wall workpieces. The method may also provide a reference for other industries with relevant or comparable problems.