Active control of a magnetically levitated spindle

Active magnetic bearing (AMB) technologically has received significant attention especially in applications where contaminants are an issue. AMBs offer some important advantages over conventional ball, roller or journal bearings such as no physical contact in the bearing and consequently no need for lubricants. Additionally, given the active actuator capabilities, the AMB is well suited to controlling shaft position and therefore offers the potential for actively balancing spindles and micro-shaping capabilities for machine tools. This work focuses on utilizing AMB actuator capabilities to dynamically center spindles. In this study, an intentionally unbalanced spindle was actively centered using an AMB. To perform this task, a modeling, simulation and test program was implemented to design the adaptive LMS controller. The LMS controller was implemented on the MBC500 where significantly improved the concentricity of the unbalanced shaft. This paper presents the dynamic system analysis, model validation, control simulation and implementation of the multi-axis spindle centering AMB project.