Robust Machining Force Control With Process Compensation

Force control is an effective means of improving the quality and productivity of machining operations. Force process models are difficult to accurately generate and, thus, there are large variations in the model parameters. This has lead to investigations into robust control techniques; however, these approaches have not directly accounted for process effects. A robust force controller is developed in this paper based on Quantitative Feedback Theory. This controller is novel in that it accounts for the inherent force-feed nonlinearity in metal cutting processes and it explicitly compensates for process effects. The controller is verified via simulations and experiments, and the results demonstrate that process compensation allows for tighter performance bounds to be achieved and greatly reduced performance variation as process parameters vary.