Control stability issues while applying rules of precision engineering on an ultra-precise five-axis grinding machine

This paper presents work on the prototype of an innovative ductile 5-axis precision grinding machine tool with electrolytic in-process dressing (ELID) The Nanogrind machine, main objective is to verify the feasibility of making a facility for producing cheap, smooth and curved optical surfaces. To obtain maximal accuracy, the machine uses direct end-point measurement as far as possible. A conflicting design requirement was however encountered with respect to control stability. Although this design rule, known as collocated design, is well known within control technique, this issue is rarely mentioned within the design guidelines of precision machines. This paper describes how the design principles of precision engineering have been implemented in the presented machine concept. Next the mentioned conflict with the rules for stable control is discussed in more detail.status: publishe