Integrated structure/control design of micropositioner for boring bar tool insert

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 redesign the system using an integrated structural/control methodology. The purpose of the micro-positioner is to improve precision by: (1) isolating the finish cutter from tool vibrations, (2) absorbing energy from the tool during rough cuts, and (3) compensating for small geometric or thermal 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 mechanism, 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, actuator saturation, and life expectancy as explicit functions of the design variables. The proposed integrated methodology both simplifies the design process of the prototype boring tool, and improves the performance over the original design, as shown by simulation results.

[1]  Keith E. Rouch,et al.  H/sub /spl infin//-vibration control for machining using active dynamic absorber technology , 1995, Proceedings of 1995 American Control Conference - ACC'95.

[2]  Fumio Obata,et al.  Active Chatter Suppression of Slender Boring Bar Using Piezoelectric Actuators , 1994 .

[3]  P. A. McKeown,et al.  A Fast Response Piezoelectric Actuator for Servo Correction of Systematic Errors in Precision Machining , 1984 .

[4]  Eric R. Marsh,et al.  A new damper design for machine tool structures: the replicated internal viscous damper , 1994 .

[5]  Yoram Koren,et al.  Design of a Precision, Agile Line Boring Station , 1999 .

[6]  Chen-Jung Li.  Tool-tip displacement measurement, process modeling, and chatter avoidance in agile precision line boring. , 1999 .

[7]  M. J. D. Powell,et al.  Variable Metric Methods for Constrained Optimization , 1982, ISMP.

[8]  G. L. Slater,et al.  A disturbance based control/structure design algorithm , 1989 .

[9]  Sanjiv G. Tewani,et al.  Active optimal vibration control using dynamic absorber , 1991, Proceedings. 1991 IEEE International Conference on Robotics and Automation.

[10]  J.-H. Park,et al.  A control-configured flexible arm: integrated structure control design , 1991, Proceedings. 1991 IEEE International Conference on Robotics and Automation.

[11]  Yuichi Okazaki.  A Micro Positioning Tool Post using a Piezoelectric Actuator for Diamond Turning Machines , 1988 .

[12]  Byung-Kwon Min,et al.  Precision piezoelectric micro-positioner for line boring bar tool insert , 1998 .

[13]  Akio Nagamatsu,et al.  Simultaneous optimum design of structure and control systems by sensitivity analysis , 1993 .

[14]  John G. Proakis,et al.  Probability, random variables and stochastic processes , 1985, IEEE Trans. Acoust. Speech Signal Process..

[15]  A. Galip Ulsoy,et al.  Modal analysis of a distributed parameter rotating shaft , 1988 .

[16]  Ramana V. Grandhi,et al.  Optimal structural design with control gain norm constraint , 1987 .

[17]  W. Thomson.  Theory of vibration with applications , 1965 .

[18]  Eugene Rivin,et al.  Enhancement of dynamic stability of cantilever tooling structures , 1992 .

[19]  Christopher S. Lynch,et al.  Mechanics of Materials and Mechanics of Materials , 1996 .

[20]  Tsu-Chin Tsao,et al.  Piezoelectric tool servo system for variable depth of cut machining , 1992 .

[21]  M. J. Carpenter,et al.  Optimal Redesign of Linear Systems , 1993, 1993 American Control Conference.

[22]  Joseph Edward Shigley,et al.  Mechanical engineering design , 1972 .

[23]  H. Harry Asada,et al.  Integrated Structure/Control Design of High Speed Flexible Robots Based on Time Optimal Control , 1995 .

[24]  Robert E. Skelton,et al.  The Optimal Mix of Structure Redesign and Active Dynamic Controllers , 1992, 1992 American Control Conference.

[25]  Zoran N. Martinovic,et al.  Enhanced vibration controllability by minor structural modifications , 1984 .

[26]  K. F. Eman,et al.  In-Process Control of Cylindricity in Boring Operations , 1987 .

[27]  Karolos M. Grigoriadis,et al.  Optimal mix of passive and active control in structures , 1992 .

[28]  Jahng-Hyon Park,et al.  Concurrent Design Optimization of Mechanical Structure and Control for High Speed Robots , 1993, 1993 American Control Conference.