Active damping of structural modes in high-speed machine tools

This paper presents the conception, design, and development of an active damper to improve the stability of structural modes of a high-speed machine tool. The design of the active damper and the development of the control strategy are described. The damper is constructed as an electromagnetic actuator consisting of an aluminum housing, an I core, an E core, and a cast iron additional mass. Feedback from the structure is provided by an accelerometer. Experimental results illustrate the performance of the active damper on a structural mode that falls within the bandwidth and force limitations of the actuator. In this case, the active damper reduced the size of the negative real part of the frequency response function for the target mode by a factor of between 2.6 and 5.3, depending on the gain.