Adaptive Cutting Force Control on a Milling Machine with Hybrid Axis Configuration

In the re-contouring process of aircraft engine components, the unknown geometry and inhomogeneous material properties of the workpiece are major challenges. For this reason a new repair process chain is supposed which consists of noncontact geometry identification, process simulation and NC-path planning, followed by a force controlled milling process. A new milling machine prototype is employed to ensure an effective force control loop. By use of a magnetic guided spindle slide, higher dynamics and precise tracking are enabled. Since variation of the process forces result in variable control plant characteristics, an indirect adaptive controller has been designed. Consequently, models of actuator and process are presented and the estimation of the present parameters by a recursive least square algorithm is outlined. Once the parameters are known, the control polynomials are calculated on the basis of a pole placement control approach. First experimental results of a force controlled milling process are put forward.