Development of bilateral control system for process machining subject to changing cutting conditions

Finishing processes such as deburring are performed on a wide variety of products in various quantities by machinists on a piece-by-piece basis in order to improve surface finish. Deburring is a major contributor to time and cost of the improvement of the surface finish. During deburring, the intended quality of the surface finish is very much dependent on the operator's skills. This work is concerned with understanding and interpreting how a bilateral robot can assist the deburring process. We propose a control method based on a machining model that is made up of several components, including the cutting tool, spindle speed, feedrate of the tool and other important constituent elements of the machining system. Machining operations are carried out for selected cutting conditions. A haptic robot is directly connected to the machine-tool and the operator. The motion of the haptic robot is controlled automatically under machining conditions in which it is possible to achieve highly accurate surface finish. The force feedback from the haptic robot influences the continuous adjustments made by the machining operator. Mathematical equations for the haptic interaction between the robot and process machining, involving time delays, are established. For specific range of cutting conditions, the regimes wherein the bilateral control system enhances the surface finish of the work piece in a sustained way are located. The regimes and effectiveness of the control system are quantified experimentally.