Active Vibration Control of a Three Degree of Freedom Oscillator Using Two Eccentrically Rotating Masses

An active mass damper utilizing rotating masses to damp the vibrations of an oscillator with two translational degrees of freedom in a horizontal plane and one rotational degree of freedom about a vertical axis is presented along with a corresponding closed-loop control algorithm. The damper consists of two masses rotating about a single vertical axis, powered by two actuators. In a preferred mode of operation, these masses rotate with a nearly constant and equal angular velocity in opposite directions, thus producing a harmonic control force in a single horizontal direction. By varying the relative angular position of the rotating masses, this control force can be directed in an arbitrary direction and used to damp the translational motion. In previous research, a control algorithm was derived for this purpose. The rotational degree of freedom can additionally be controlled by producing a moment by imposing angular accelerations on the rotating masses. In this paper, the previous control algorithm is augmented such that the rotational degree of freedom is additionally controlled. The augmented control algorithm is verified with help of numerical simulations.