Suppressing vibrations of machining processes in both feed and radial directions using an optimal control strategy: The case of interrupted cutting

An optimal control strategy for isolating the vibrations of a machine tool structure in two directions (radial and feed) from the cutting tool in machining operations is applied in this study. Maintaining a constant relative position between the cutting tool and the workpiece, as a result of isolating the vibrations, is assumed to assist in improving both surface quality and geometrical accuracy of the machined surface. Performance of the control strategy is tested under the cutting process force characteristics generated from interrupted cutting conditions. The dynamic model for the machining process utilizes two identical Tefenol-D magnetostrictive transduced actuators, placed in orthogonal directions (radial and feed), to apply forces on the cutting tool. The actuators transform input currents from a digital estimator into forces needed to manipulate the cutting tool position. The accelerations of the cutting tool in both the radial and the feed directions before and after applying the control strategy indicate that the proposed control process succeeded in reducing the cutting tool vibration.