1. Intro & Motivation

Being a one-man team with a busy schedule of research and business development, I limited the scope of my project to something attainable. A robotic gripper is something I had always wanted to build, especially since most of my research up to this point had been related to ground-based driving robots (and little to no experience with manipulators). Also the lab I work in, the Nuclear and Applied Robotics group, uses robots to do work in hazardous areas, such as picking up radioactive materials. While we have plenty of grippers which can do these jobs effectively, I thought it would be good for me to find out what all goes into the design and build of a robotic gripper. I found a simulation of a robotic gripper online that met the requirements of this project, which was a design that utilized a four-bar mechanism (Figure 1 and 2).

Figure 1: Robotic Gripper Design

Figure 2: Robotic Gripper Simulation

This design expanded on that requirement with use of two mechanisms (one a five-bar with a linear input and one a four-bar with a rotational input). After sketching out the mechanism based on a rough model of the gripper found online, I re-created the simulation with Matlab in order to gain an understanding about the velocities and accelerations involved. This design was then modeled in Solidworks, where I could also verify the closing of the gripper from the linear motion of the middle link. The build brought on its own set of challenges and compromises, but a working prototype was realized as shown below (Figure 3). 

Figure 2: Prototype