Ball Retrieving Robot
May 2019 - Aug. 2019
Project Description
Our Design and Manufacturing Laboratory class was assigned to design and prototype a mobile device that could enter into a 10’ x 20’ arena bounded by two 2x4s, collect eight of the twenty-seven racquetballs stationed throughout the arena (some atop PVC pipes while others on the ground), and deposit them into a 4” diameter PVC goal within a five-minute time limit.
All students were put into groups of four to complete the assignment, and two groups would be competing in the same arena at the same time to stimulate real-world engineering competitiveness. For the mobile device, there were size, motor count, and budget restrictions, along with other competition rules such as avoiding collision into other mobile devices.
Personal Contribution to Project at Each Phase
To facilitate the design and prototyping process, every group had to complete three design reports, each highlighting different facets of the design process, before beginning the manufacturing and assembly stage. A final design report was also assigned to assess competition results, discussing strengths and weaknesses in the final design.
First Design Report
For the first design report, which was done individually prior to group assignment, I conducted extensive research on robotic mechanisms such as steering, ball manipulation, storing, and dispensing. Afterwards, I hand sketched three orthographic views of my design, one isometric view, nine separate detailed sketches of each mechanism, and wrote a one-page written report justifying my concept and material selections for the design.
Second Design Report
The second design report entailed concept selection, which required establishing objectives and weighting factors to decide which mechanisms from each group member’s design would contribute to the final, hybrid robot. My contributions included assisting in writing detailed objective definitions and weighting factor justifications for each subsystem, creating cardboard prototypes and documenting the results, and organizing and formatting various Excel sheets pertaining to cost estimates, manufacturing time estimations, and decision matrices for each concept's subsystems. Additionally, my concept for the ball manipulator (the metal wires seen below in the bottom right image) was selected for the final design.
Third Design Report
For the third design report, I wrote a detailed description of how the final design accomplishes the project goals. I explained the function of each subsystem and reason we selected those subsystems, using research, analysis, and testing to substantiate our decisions. I also created a project schedule for the manufacturing phase and organized all off-the-shelf SOLIDWORKS files, adjusting their drawings when necessary.
Manufacturing Phase
For the manufacturing phase, I created motor mounts for the mobile device by using a band saw to cut aluminum from rectangular stock and a mill to drill holes into the aluminum. I also assisted in putting together the robot once everything was manufactured.
Fourth Design Report
For the final design report, I contributed to a few paragraphs, which dealt with how well the mobile device solved the problem and what could have been done differently if the project could be done again.
Shortcomings & Lessons Learned
The cardboard prototyping phase made me realize how essential it is to test out ideas before manufacturing. My idea, especially for the ball hopper, seemed very plausible until I created a cardboard prototype of it, which made me realize how excessive and inconvenient it would have been if actually manufactured.
Meeting frequently and distributing the workload evenly among teammates is also very important. For our very first submission as a group, we pulled an all-nighter to have the assignment done in time, working a total of 15 hours straight with very little breaks. We realized very quickly that we had to meet more frequently and distribute tasks in a more efficient manner in order to avoid finishing so close to the deadline, which we were able to accomplish with our following submissions.
Also, I learned just how much a design can change even after establishing a final concept. We collectively submitted many Engineering Change Notice Forms to tweak our final design and make appropriate changes.
Results
Our mobile device performed very well, meeting every requirement and accomplishing its task. We managed to place fifth out of thirty-one groups. We were also able to finish manufacturing and assembling our robot in only two and a half lab sessions, which gave us sufficient time for testing and adjusting before competition day. A trial run on one of our testing days can be seen at the bottom of this page.
Overall Experience & Skills Attained
Participating in this group project taught me how to break down a complicated task into smaller portions through the design process. I learned about each step of the process, from recognizing the need, defining the problem, and gathering information, to creating and selecting concepts and communicating those concepts through detailed designs and justifiable analysis. I also gained exposure to prototyping ideas and using machines such as the band saw, mill, and lathe. I further improved upon my team working skills and ability to communicate thoughts and ideas through written reports. This invaluable experience reinforced the importance organization, task distribution, and time management when taking on a project, especially one of this magnitude.