Research on vibration control of magnetically controlled variable damping boring bar

Abstract

During machining, boring bars with a large length-to-diameter ratio face significant challenges in vibration state perception and vibration control. To address this problem, this study proposes a vibration control method for a magnetically controlled variable-damping boring bar. The proposed method enables accurate perception of the vibration state of the boring bar. Based on the identified vibration state, the boring bar is adaptively regulated, thereby achieving effective vibration reduction. First, a magnetically controlled variable-damping boring bar is proposed based on dynamic vibration absorber theory. A two-degree-of-freedom dynamic model of the boring bar was then established. Based on this model, the influence of damping on the performance of the vibration absorber was analyzed. Subsequently, a vibration control platform for the variable-damping boring bar is designed. The process of vibration signal sensing and the principle of vibration control are described in detail. The platform can monitor the vibration frequency of the boring bar and extract multiple features from the acceleration signal, providing a more intuitive perception of the vibration state of the boring bar. The vibration control platform of magnetically controlled variable damping boring bar is built based on LabVIEW. Finally, the boring experiment verifies that the vibration of the boring bar can be suppressed obviously by this control method, and the maximum vibration reduction is about 37.2%, while the surface roughness Ra is improved by up to 44.1%, indicating a significant improvement in surface machining quality.