An exchangeable gripper module integrated in the assembly system for multi miniature parts

The assembly of multi miniature parts needs a variety of grippers, a single gripper has difficulties in completing the task of picking up and operating many different miniature parts. In a formerly developed system, a combination type gripper module was integrated. It was comparatively complicated and difficult to be adapted to a new set of parts to be assembled. As a more preferable solution for the situation, an exchangeable gripper module is being developed and will be integrated in an assembly system under development. The module consists of assembly tool magazine and mechanical arm. According to the size and shape of the miniature parts to be assembled, the tool heads were designed for the purpose of the pickup and place operation of different miniature parts. The gripper assembles miniature parts in the way that mechanical arm picks up the tool head from the assembly tool magazine, then after the specific part is assembled, puts the tool head back and ready for picking up another tool head, thus the exchange of tool heads can be accomplished. As the process of repetitive exchange may cause position error, the position of the reference central point of the tool head need to be measured by the machine vision module integrated in assembly system to guarantee the accuracy of assembly. The measurement and precision position control method of tool head in the process of miniature parts assembly is illustrated in the paper.