Design methods for six-degree-of-freedom displacement measurement systems using cooperative targets

• Published in: Precision engineering 2002, Vol.26 (1), p.99-104
• Main Authors: Kim, Jong-Ahn, Bae, Eui Won, Kim, Soo Hyun, Kwak, Yoon Keun
• Format: Article
• Language: English
• Subjects: Applied sciences; Cooperative target; Degrees of freedom (mechanics); Electronics; Exact sciences and technology; Industrial metrology. Testing; Magnetic and optical mass memories; Measurement errors; Measurement theory; Measurements common to several branches of physics and astronomy; Mechanical engineering. Machine design; Metrology, measurements and laboratory procedures; Optimization; Performance index; Physics; Precision engineering, watch making; Six-degree-of-freedom; Spatial dimensions (e.g.: position, lengths, volume, angles, displacements, including nanometer-scale displacements); Spatial dimensions (eg, position, lengths, volume, angles, displacements, including nanometer-scale displacements); Storage and reproduction of information
• ISSN: 0141-6359; 1873-2372
• DOI: 10.1016/S0141-6359(01)00105-2

Six-degree-of-freedom displacement measurement systems generally employ various kinds of cooperative targets, and calculate displacement from the coordinate values of reflective rays. To improve the performance of measurement systems, a new design methodology is required, which considers the relationship between each axial output and the coordinate values, Jacobian matrix. Several performance indices are derived from Jacobian matrix and the design parameter values are determined through the optimization process. In a design example, the improvement of performance is verified by evaluating resolution, accuracy and crosstalk. The newly designed measurement system shows a maximum error of ± 0.5 μm for translation and ± 2 arcsec for rotation.