Design of a Single DOF Gripper based on Four-bar and Slider-crank Mechanism for Educational Purposes

This paper presents the design and the realization of a novel robot gripper which can be used in various automation processes including “pick and place” operation. This project is mainly developed for educational and research purposes, especially for mechatronic and robotics students. The gripper consists of four fingers which move simultaneously allowing the gripper to open and close. It is a single degree of freedom (DOF) system. One finger is driven by an electrical motor via a four-bar mechanism. The motion is transmitted from the driver finger to the other three fingers by slider-crank mechanism. This gripper has two closed loop structure, a study is performed to determine its geometric and kinematic models. This leads to find a geometrical solution space, which is verified via a CAD model of the gripper. Considering some given dimensional constraints, the acceptable functional dimensions and the singular configurations are determined. The finger profile is designed to grasp diverse object shapes. In order to validate our design, a prototype is developed and tested. The student should analyze the system and propose other solutions in order to reply to pre-defined objectives. Thus, the gripper design will be modified or optimized, whether at the level of the mechanism embodiment design and/or at the level of the finger profile. The mechanical design and the electrical circuit of the gripper prototype are also described.