An accurate and flexible image clamping center locating algorithm for micro-gripper

In the process of microassembly, aligning the end effectors with the micro-parts using image information is the basis of automated assembly. In order to realize the flexible and accurate clamping center locating of the micro-gripper with various shapes of jaws, this paper proposes an iterative-based processing algorithm. First, the locating problem is transformed into a multi-parameter optimization problem through the geometric analysis of the clamping process. Second, an iterative optimal algorithm based on the block coordinate descent is developed, in which a scaling golden section (SGS) scheme is proposed to calculate the iteration scaling parameters. Third, the lookup table and variable threshold iteration techniques are utilized to further improve the performance of the SGS scheme. Simulation results show that the proposed algorithm can efficiently locate the clamping center for various types of jaws with sub-pixel accuracy. Finally, a microassembly experiment is carried out to demonstrate the effectiveness of the algorithm.