Integrated structure/control design of micro-positioner for boring bar tool insert

摘要

Previous papers by these authors presented an effort to develop a prototype boring tool, utilizing a piezoelectric actuator and photosensitive detectors to actively control a cutting insert. This paper describes an effort to reduesing the system using an integrated structural/control methodology. The purpose of the micro-positioner is to improve precision by: i) isolating the finish cutter frm tool vibrations, ii) absorbing energy from the tool during rough cuts, and iii) compensating for small geometric or hermal errors. These characteristics enable tools with large length to diameter ratios (L/D) without loss in machining precision, and facilitate automated tool changes. The integrated structural/control design variables consist of the structural shape of the mecchanism, including the piezoelectric actuator, and the controller feedback gains. The design variables are determined simultaneously in a single optimization problem. The objective and constraints equations quantify system performance, stability, actuatory saturation, and life expectancy as explicit functions of the design variables. The proposed integrated methodology both simplifies the design process of the prototpe boring tool, and improves the perofrmance over the original design, as shown by simulation results.