Adaptive Controller for a Metal Cutting Process

As presently practiced, metal cutting is a relatively inefficient process. The equations relating input parameters and the finished product are mainly empirical, and they are applicable only over limited ranges and conditions. A particularly significant problem is the machining of recently developed high-strength materials for the aerospace industry. Present numerical control systems cannot achieve optimum machining because the feedback loops are closed only around the dimensional position of the tool and workpiece. This paper describes the design of an adaptive controller which, in conjuction with a numerical control system, extends the process measurement to the actual tool-work interface and adjusts the process input parameters so as to optimize cutting performance. The system can be programmed to optimize a selected performance criterion such as cost while applying constraints on other factors such as surface finish and machine horsepower.