When discussing projects we wanted to do for this class, something we kept coming back to is a robotic arm. Since the focus of this project is creating linkage mechanisms, we aimed to create a robotic arm that has a complex motion from a singular input motor. This complex motion consists of rotation, like a human arm about the shoulder joint, and extension, like the movement of the hand relative to the shoulder using the elbow joint.
A common setting for robotic arms are assembly lines and warehouses. See the video linked below, as well as many of the other videos available on the webpage. Each arm has actuators at various joints, each greatly increasing the cost to produce and purchase these arms. A robotic arm with a singular input would be cheaper to manufacture and purchase, while still maintaining efficiency along the assembly line. Thus, we decided on an assembly line arm and grabber for our project.
Our robotic arm will take up as little space as possible, where it is able to pick up objects on the assembly line, travel horizontally along the same axis, and deposit the object at a new location along that axis. We aim to have the motors in the base, an arm composed mainly of four-bar linkages, and a claw gripper. The claw will have an escapement mechanism to cycle between open and closed positions, and gears that rotate two four-bar linkages. The claw is able to pick up various size objects with different weights. Additionally, we plan on automating the process of picking and placing to mimic the function of the arm working on an actual assembly line.
Analysis that will need to be performed prior to the fabrication includes the following. We need to understand the motion profiles of the linkages as well as the rotary motion from the base to the claw. Furthermore, we will analyze the force profile of the grabber, the arm’s geometry/dimensions, and overall design via SolidWorks simulation. We would like to use the minimum amount of materials so the arm can take up as little space as possible, and we need to analyze the rotation of the base with respect to the other components such as wires.
The most exciting part of this project is learning how to design a functioning robotic arm. Specifically, going from an idea, to drawings, to CAD models, to fabrication. We are really excited about using the knowledge gained in lecture about four-bar linkages and applying it to the real world application of building a robotic arm that streamlines the manufacturing process. The main challenge will be to design a linkage system to account for the complex motion of the arm, an escapement mechanism to alternate between open and closed positions of the gripper, and powering these seemingly independent mechanisms in concert with a single rotary input. Furthermore, it will be a challenge to automate this process in addition to using our mechanical engineering knowledge for the build itself. The greatest constraint of all in this project is the limited timeframe in which we have to complete it in addition to balancing the other assignments in this course.
Juliana is interested in extending this arm in the future for streamlining the manufacturing process that builds plant grow chambers for her mechanical engineering internship. Specifically, the base of the design is complex and needs to be lifted up to address any issues within the assembly process. So an extension of this robotic arm would be making it strong enough to lift heavy objects and keeping it steady prior to moving to another position along the assembly. Tyler is interested in designing robots to lower costs associated with manufacturing. Many industry robots utilize expensive actuators to complete simple movements that could otherwise be accomplished with linkage systems. He hopes to iterate on this project and use it as inspiration in industry. Leo is interested in how easily this mechanism can be duplicated so that warehouses can have these lined up back to back. Since the mechanism will be designed to use up as little square footage as possible, there can be multiple next to each other.