Positioning Cylindrical Target Based on Three-Microscope Vision System

New visual positioning and adjustment techniques for cylinder target are presented based on three-microscope vision system, which is used for visually guiding the manipulation of microparts with an eye-to-hand configuration. An image-based visual control (IBVC) with image Jacobian matrix and a position-based visual control (PBVC) algorithm for the three-microscope vision system are investigated. In IBVC, the image Jacobian matrix of three-microscope vision system is constructed and estimated based on the exploratory motions. Meanwhile, the singularity of the image Jacobian matrix is analyzed by the corresponding condition number. Then, the incremental PI controller is applied to make image features converge to the desired ones. In PBVC, the coordinate system of three-microscope vision is established by three clear imaging planes. The position and orientation adjustment algorithms are employed to drive the target to the desired pose. By the comparative experiments, the IBVC scheme demonstrates the better performance on sensitivity and precision, while the PBVC scheme exhibits the better performance on stability and robustness. The pose deviations can converge to within 15 μm along X-, Y-, Z-axis directions and within 0.02
^°
around X- and Z-axis directions.