Model-based disturbance attenuation for CNC machining centers in cutting process

A disturbance attenuation method in a control system, called the model-based disturbance attenuator (MBDA), is proposed, and its properties are studied in this paper. The MBDA makes the plant perform similarly to the nominal plant, as much as possible, using a compensator. Then, a controller is designed based on the nominal plant. It is very simple and easy to implement. It is shown that the MBDA is extremely robust with respect to large variations of load inertia, The MBDA is implemented in a position control system of a computer numerical control (CNC) machining center, where the velocity control system is composed of a servo-pack (proportional plus integral speed controller), a servo motor, and a load, The MBDA attenuates external disturbances significantly in the cutting process containing high-frequency components, as well as the frictional forces containing large de component. To show the effectiveness of the MBDA, several other controllers are also implemented in a position control system of a CNC machining center in a similar way as the MBDA, and the experimental results are compared with one another.