Active vibration control using an electromagnetic absorber with two degrees of freedom

A novel design for an actively controlled, two degree-of-freedom electromagnetic absorber is considered for reducing chatter in a boring bar. The absorber is suspended inside the free end of the boring bar and consists of a mass with eight poles, each pole having a coil attached to it. The proper motion of the absorber is achieved by controlling the electromagnetic force via the applied current to the coils so as to suppress the chatter of the boring bar. A theoretical study to prove the proposed concept is conducted by first obtaining the dynamics of the system. The control system is then designed to control the lowest vibration mode of the boring bar, which is the mode dominating the chatter, using feedback control theory.