Improving 3D Vision-Robot Registration for Assembly Tasks
Marek Franaszek, Geraldine S. Cheok, Karl Van Wyk, Jeremy A. Marvel
Quality registration between the coordinate frames of a perception system and a robot is important for the efficient operation of autonomous systems in vision-guided assembly lines. Rigid-body registration, which is based on the measurement of corresponding points (fiducials)in both frames, is a commonly used method. Noise and possible bias in the measured points degrade the quality of registration as gauged by the Target Registration Error (TRE). This paper presents a procedure which leads to decreased TRE when the bias is larger than the noise. Experiments performed with a motion tracking system and robot arm show that the Root Mean Squared target errors (RMST) can be reduced by as much as 84 % by placing fiducials in carefully selected locations in the working volume and through the use of the Restoration of Rigid Body Condition (RRBC) method.