Accuracy synthesis of a multi-level hybrid positioning mechanism for the feed support system in FAST

Abstract This study examines the terminal accuracy synthesis of a multi-level hybrid positioning mechanism for the feed support system in a Five-hundred-meter Aperture Spherical Radio Telescope (FAST) project, specifically considering three types of error influence factors such as time-varying barycenter, geometric error, and structural deformation. An error model caused by a time-varying barycenter and that for the entire mechanism are first established, and the physical meaning of the latter is further explained. The three factors that influence terminal accuracy are then analyzed. An efficient approach for acquiring the terminal error boundary over the entire workspace is proposed on the basis of the vector set theory and a linear algebra method. After employing an error compensation method for the first-level mechanism through control strategy, terminal accuracy synthesis is conducted by using a nonlinear optimization algorithm. Both constraints for accuracy and weight are satisfied after introducing measurement systems. Moreover, the proposed method of accuracy analysis and synthesis can be applied to other multi-level hybrid mechanisms.

[1]  Damien Chablat,et al.  Technology-Oriented Optimization of the Secondary Design Parameters of Robots for High-Speed Machining Applications , 2010 .

[2]  L. Romdhane,et al.  A combined genetic algorithm-fuzzy logic method (GA-FL) in mechanisms synthesis , 2004 .

[3]  R. Nan.  Five hundred meter aperture spherical radio telescope (FAST) , 2006 .

[4]  Shao Zhufeng.  Terminal Accuracy Analysis of a Multi-level Hybrid Support System Based on Time-varying Barycenter , 2011 .

[5]  Xiaoqiang Tang,et al.  Error modeling and accuracy analysis of a multi-level hybrid support robot , 2012, 2012 IEEE International Conference on Robotics and Automation.

[6]  Han S. Kim,et al.  The kinematic error bound analysis of the Stewart platform , 2000 .

[7]  Rui Yao,et al.  Dimensional Design on the Six-Cable Driven Parallel Manipulator of FAST , 2011 .

[8]  Di Li,et al.  The Five-hundred-meter Aperture Spherical radio Telescope (FAST) project , 2011, 2015 International Topical Meeting on Microwave Photonics (MWP).

[9]  Liu Xinjun.  Accuracy analysis of parallel mechanisms based on set theory , 2007 .

[10]  Kornel Ehmann,et al.  Volumetric Error Analysis of a Stewart Platform-Based Machine Tool , 1997 .

[11]  Haitao Liu,et al.  A General Approach for Geometric Error Modeling of Lower Mobility Parallel Manipulators , 2011 .

[12]  Xiaoqiang Tang,et al.  Similarity model of feed support system for FAST , 2011 .

[13]  J. Merlet.  Jacobian, Manipulability, Condition Number and Accuracy of Parallel Robots , 2005, ISRR.

[14]  Xiaoqiang Tang,et al.  Dynamic modeling and wind vibration control of the feed support system in FAST , 2012 .

[15]  H. P. Jawale,et al.  Investigation of Positional Error in Two Degree of Freedom Mechanism With Joint Clearance , 2012 .

[16]  Lu Qiang,et al.  Accuracy Synthesis of a Hexapod Machine Tool Based on Monte-Carlo Method , 2002 .

[17]  Shih Ming Wang,et al.  Error model and accuracy analysis of a six-DOF Stewart Platform , 1995 .

[18]  Jean-Pierre Merlet,et al.  Dimensional Synthesis of Parallel Robots with a Guaranteed Given Accuracy over a Specific Workspace , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.