ROBOTIC ARM SENIOR DESIGN PROJECT
PROJECT DESCRIPTION
For my senior design project, I worked on a team of four over two semesters to design a robotic arm. The arm was intended to assist disabled veterans reach objects on high shelving units. The arm was made mostly out of aluminum, and had a reach of 7-feet high and 3-feet out. The end-effector was made mechanically self-leveling with a unique linkage design. The project consisted of creating a project plan and budget, designing and 3D modeling all parts in Creo, analyzing the design on paper and with ANSYS FEA, and fabricating and testing the final prototype. Below is a video presentation outlining the project outcomes.
3D MODELING
The first stage of the project consisted of coming up with design concepts, choosing a preliminary design, and creating a 3D model of the preliminary design. Creo 3.0 was used to create the final assembly shown to the right.
COMPONENT SELECTION
The applied loads were calculated at each point on the arm. The results of this analysis were used to select sufficiently robust components, such as the motors, gears, and clutches.
LINKAGE DESIGN
One of the main objectives of this project was to make the end-effector mechanically self-leveling. This was accomplished by designing the unique linkage system shown on the left.
MOTION ANALYSIS
All of the assemblies for this project were set up as mechanisms in Creo so that the motion of the arm could be analyzed. By defining the motor speeds and gear relationships, we were able to accurately analyze the speed, range, and overall motion of the arm. The video on the left is one of several animations I created in Creo to show the arm movement.
FINITE ELEMENT ANALYSIS
The arm design was first thoroughly analyzed on paper using machine design stress analysis methodologies. Once we were confident in the design, I performed FEA on the model using ANSYS. The picture on the right is an example of the analysis I ran on the complete assembly, but I also performed further analysis on specific components.
PROTOTYPE FABRICATION
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In the second semester of the project, a prototype was fabricated, assembled, and tested. The electrical parts and gears were purchased, the gripper assembly was 3D printed, and the rest of the metal parts were laser cut by a local shop. And the end of the semester, the assembled prototype was exhibited at NDSU's senior design expo.
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