A Measurement Method For Robot Peg-In-Hole Prealignment Based On Combined Two-Level Visual Sensors

Vision measurement plays a significant role in robot automatic assembly. In this study, a new measurement method for robot peg-in-hole prealignment via a combined two-level vision system is proposed. The assembly system and a global coordinate system calibration procedure based on a dynamic coordinate system are developed to construct an accurate transformation between the coordinate systems. The subsequent hole pose is obtained with the proposed image processing method and the hole edge matching method, followed by the 3-D hole reconstruction and spatial circle fitting algorithm. A low-cost pose determination is proposed based on hole edge point selection. The experiment and analysis indicate that the hybrid measurement system has high precision in the local hole pose and global robot pose measurement accuracy. The peg-in-hole assembly results verify the measurement and calibration accuracy sideways. Our hybrid measurement system enhances the vision measurement range, local accuracy, and robot automation.