Novel gripper module and method for automated assembly of miniature parts

Abstract

During assembly process, the miniature part needs to be fixed in its assembly position. In some occasions where adhesive is used, the joining force is not established due to the adhesive curing process, in that case the locking of parts is required. Manual locking is difficult to meet the increasing demand for mass production. To solve this problem and realize fully automatic assembly, a novel gripper module was designed and corresponding locking method was proposed. Thanks to the functional integration, the gripper module is capable of manipulating and locking the part. This module is integrated into the assembly system and plays a crucial role in automatic assembly. The locking method for automatic assembly is based on the integration of the part picking up and the locking unit releasing. After being placed accurately at its desired position, the miniature part can be automatically locked by releasing the locking unit. The innovative structure and mechanism of the gripper module convert the spring force into the locking force of the miniature part, ensuring non-rigid locking and suitable small locking force. Locking principle, flexibility and limitations of the proposed method were clarified in detail. Moreover, an effective compensation strategy was used to achieve accurate and stable pickup of the part, which increased the reliability of the assembly process. During automatic locking, the disturbances to the part due to the eccentric load were analyzed. The effectiveness of the gripper module and proposed method was verified by experiment. Experimental results indicated that the modular system integrated with the gripper module could meet the requirements of fully automatic assembly. Manual locking is replaced by automatic locking, and workers are liberated from tedious manual operations. The improvement of automation level enables assembly equipment to be applied to mass production scenarios.