Novel design of ball-lens-based laser tracker using pulsed interferometer

Abstract

A new laser tracker using an optical frequency comb with ball lenses as a reference and targets is proposed. In this system, high-accuracy absolute length measurement based on pulsed interferometry of an optical comb is utilized. By using a ball lens with a refractive index of 2.0 as a reference, it can avoid the error caused by reference point displacement. As targets, ball lenses have a wider acceptance angle than a conventional retroreflector. In this work, two new designs of the laser tracker are proposed. The simulation and experimental investigation of the refractive index characteristics of a ball lens were examined to obtain the optimal parameters for each design. Using these designs, the one-axis absolute length measurement of as much as 10 m was performed, and its combined uncertainty was evaluated to be [(0.145 µm) 2 + (3.05 × 10 −7 l) 2 ] 1/2 , where l is measured length.

Automatic Guidance Method for Laser Tracker Based on Rotary-Laser Scanning Angle Measurement

“…As shown in Figure 1 , laser tracker is mainly composed of retroreflector and several function modules, including the distance measurement module, angle-measuring module, and tracking control module [ 25 , 26 , 27 ]. The distance measurement module includes IFMs and ADMs.…”