Predictive Contour Control With Adaptive Feed Rate

Contour control is an important issue in motion system development. In this paper, a contour-control methodology combining predictive control and adaptive feed rate is proposed. To reduce the computational time required for online optimization, a simple unconstrained model predictive controller is first designed to perform biaxial contour-position control. The performance index introduced in this paper allows the designer to manipulate the importance between contour error, axial tracking error, and control usage. The controller is then implemented to track diamond and free-form contours. The results demonstrate that the controller is capable of not only tracking both contours with high precision (contour and axial) for steady motions, but also improving contour precision during transient periods. To further reduce the contour error during transient periods, an adaptive feed-rate scheme is proposed, which utilizes the predicted contour error to adjust the feed rate online. This adaptive feed-rate scheme is experimentally validated using diamond and limacon contours. The results demonstrate that in comparison with constant feed-rate schemes, the proposed adaptive feed-rate scheme is capable of significantly reducing the transient contour error at high feed rates, while maintaining comparable tracking performance at low feed rates.

[1]  Chieh-Li Chen,et al.  Observer-Based Contouring Controller Design of a Biaxial Stage System Subject to Friction , 2008, IEEE Transactions on Control Systems Technology.

[2]  Chih-Ching Lo,et al.  Tangential-Contouring Controller for Biaxial Motion Control , 1999 .

[3]  Uk-Youl Huh,et al.  Fuzzy logic control for the contouring accuracy of XY positioning system , 2001, ISIE 2001. 2001 IEEE International Symposium on Industrial Electronics Proceedings (Cat. No.01TH8570).

[4]  Dong Sun Position synchronization of multiple motion axes with adaptive coupling control , 2003, Autom..

[5]  Pau-Lo Hsu,et al.  An optimal and adaptive design of the feedforward motion controller , 1999 .

[6]  Pau-Lo Hsu,et al.  Estimation of the contouring error vector for the cross-coupled control design , 2002 .

[7]  Ming-Yang Cheng,et al.  Motion Controller Design for Contour-Following Tasks Based on Real-Time Contour Error Estimation , 2007, IEEE Transactions on Industrial Electronics.

[8]  K. Zhu,et al.  Cross-coupling design of generalized predictive control with reference models , 2001 .

[9]  Gon-Jen Wang,et al.  Neural-network cross-coupled control system with application on circular tracking of linear motor X-Y table , 1999, IJCNN'99. International Joint Conference on Neural Networks. Proceedings (Cat. No.99CH36339).

[10]  Jih-Hua Chin,et al.  Improving contour accuracy by Fuzzy-logic enhanced cross-coupled precompensation method , 2004 .

[11]  Robert G. Landers,et al.  Precision Motion Control Methodology for Complex Contours , 2007 .

[12]  James Kennedy,et al.  Particle swarm optimization , 2002, Proceedings of ICNN'95 - International Conference on Neural Networks.

[13]  K. Srinivasan,et al.  Optimal Contouring Control of Multi-Axial Feed Drive Servomechanisms , 1989 .

[14]  Shyh-Leh Chen,et al.  Contouring control of biaxial systems based on polar coordinates , 2002 .

[15]  Yoram Koren,et al.  Cross-Coupled Biaxial Computer Control for Manufacturing Systems , 1980 .

[16]  K. Srinivasan,et al.  Cross-Coupled Control of Biaxial Feed Drive Servomechanisms , 1990 .

[17]  Pau-Lo Hsu,et al.  Theory and Applications of the Robust Cross-Coupled Control Design , 1999 .

[18]  S. Joe Qin,et al.  A survey of industrial model predictive control technology , 2003 .

[19]  Shyh-Leh Chen,et al.  Contouring Control of Smooth Paths for Multiaxis Motion Systems Based on Equivalent Errors , 2007, IEEE Transactions on Control Systems Technology.

[20]  Masayoshi Tomizuka,et al.  Contouring control of machine tool feed drive systems: a task coordinate frame approach , 2001, IEEE Trans. Control. Syst. Technol..

[21]  Masayoshi Tomizuka,et al.  Zero Phase Error Tracking Algorithm for Digital Control , 1987 .

[22]  Yoram Koren,et al.  Variable-Gain Cross-Coupling Controller for Contouring , 1991 .