“THE 13TH HOUR” TECHNICAL REPORT PREPARED BY SITE 3 ENGINEERING Jesuit High School Robotics Sacramento, California Mentors: Jerry Glasser Head of Robotics JohnJay Peli Isaacs Mentor John Pelochino Mentor Gerry Maginnity Mentor Team Members: NAME YEAR POSITION Patrick Dills (Junior) Team Co Captain/CAD Eric Guess (Sophomore) Team Co Captain/Computers Jason Isaacs (Sophomore) Chief Electrician Steven Kesich (Senior) Chief of Engineering Michael Freeman (Senior) Chief of Construction Brendan O’Connell (Junior) Chief of Design James McMonagle (Junior) Public Relations Steven Larsen (Freshman) Design Intern Uriah Mitchell (Freshman) Photography Intern E.J. Borg (Freshman) CAD Intern/Historian Thomas Jacobi (Sophomore) Staff Engineer Chris McMonagle (Sophomore) Staff Engineer Andrew Petel (Freshman) Staff Engineer John Taseff (Freshman) Staff Engineer Joseph Maginnity (Freshman) Staff Engineer Site 3 Engineering MATE Technical Report TABLE OF CONTENTS I. Abstract.............................................................................................................................. 2 II. Pictures of ROV.................................................................................................................. 3 III. Team Organization.............................................................................................................. 4 IV. Design Rationale................................................................................................................. 4 V. Challenges........................................................................................................................... 8 VI. Troubleshooting ................................................................................................................ 10 VII. Future Improvements........................................................................................................ 11 VIII. Polar Civilizations............................................................................................................. 12 IX. Lessons Learned................................................................................................................ 13 X. Reflections ........................................................................................................................ 14 XI. ROV Specifications.......................................................................................................... 14 XII. Electrical Schematic.......................................................................................................... 16 XIII. Software Flow Chart......................................................................................................... 17 XIV. Bill of Materials ................................................................................................................ 18 XV. Acknowledgements........................................................................................................... 19 June 1, 2007 Page 1 Site 3 Engineering MATE Technical Report I. Abstract A three-year veteran of FIRST’s (For-Inspiration-and-Recognition-of-Science-Technologies) robotics competitions, the Jesuit Robotics Team (Figure 1) had little trouble transferring from land to water. In our second year in the MATE competitions, we were given the opportunity to step up to the Explorer class, and we graciously accepted this new challenge. Drawing on our experience from previous years, we began looking into how we would build our ROV. We modeled our ROV in SolidWorks and were able to prevent design flaws in the process. We also looked into stronger, more flexible and advanced technologies. Instead of using PVC, we used high-density polyethylene (HDPE). HDPE was great for us because it was sturdy, neutrally buoyant, and readily available to us and easy to work with. Also we reached our goal of a more versatile control system, specifically the use of the Innovations FIRST controller. This new control system allowed for better control and more powerful motors. In addition to this we water proofed two linear actuators that were used in our claws. Among our training regimen was the Discover Scuba Program, construction of our own indoor test pool and countless hours of large pool testing in order to bring our ROV up to our own high standards. Through the Discover Scuba Program, our entire team learned the basics of scuba diving. We learned the importance of neutral buoyancy, and we were better able to understand the environment surrounding our ROV would be in. Figure 1: Our Team 2007 June 1, 2007 Page 2 Site 3 Engineering MATE Technical Report II. Pictures of ROV Figure 2: “The 13th Hour” Figure 3: CAD Model Figure 4: ROV Arm June 1, 2007 Page 3 Site 3 Engineering MATE Technical Report III. Team Organization Team organization and a diversity of skills on the team were crucial to our success. Our captins managed the entire operation and work was delegated to “specialists” to complete tasks requiring different talents. In order to complete a task, everyone would need to be involved and organized. For example, when we were in an advanced prototype stage we had to split up the tasks to maximize our efficiency. Some members would be working on the arms, some on mounting cameras, some on adjusting our buoyancy, and so forth, but they all talked together and organized into a team. Figure 5: Team Organization IV. Design Rationale A. Design Methodology Like all great creations our ROV originated on the drawing board. Our brainstorming phase was made up of many hand drawn sketches and cardboard prototypes. Once these prototypes were created, tested, and refined, we were able to use solid works to create our final ROV design (Figure 6). Once the final design was built a few more changes were made. In retrospect it would have been better to spend more time in the design process so we could have avoided these late changes. June 1, 2007 Page 4 Site 3 Engineering MATE Technical Report Figure 6: CAD Model B. Frame Construction We built our robot out of HDPE (High density polyethylene) with aluminum crossbars (Figure 7). We used HDPE because we did not want to make our ROV from PVC and wanted it to look professional. We researched what materials professional consultants were using to construct their ROVs One material that grabbed our attention was HDPE . We found HDPE to be relatively affordable, easily attainable, good impact resistance, light weight, very low moisture absorption, and high tensile strength, chemical resistant, not a good candidate for gluing but easily mechanically fastened. HDPE has a tensile strength of 4550 psi and a maximum temperature of 248°F/120°C Figure 7: A cut frame side from HDPE C. Thrust Motors In order to maximize our efficiency , we used commercially available trolling motors (Figure 8), ranging from 28lbs to 32lbs of thrust. The trolling motors were modified and mounted on the ROV. Our ROV utilizes a total of three motors. Two horizontal motors were used for tank drive and a more powerful vertical motor. This operating system gives our ROV mobility in tight situations, and if necessary a great amount of speed and power. June 1, 2007 Page 5 Site 3 Engineering MATE Technical Report Figure 8: A 28lb thrust Trolley Motor D. Arm Construction Our arm (Figure 9) design incorporates two arms. This design will be extremely useful when working in a current, and when working with tiny objects underwater. While creating these arms we had to keep in mind the environment that they would be surrounded by. This led us to encase our motors in a case that would protect them and keep them dry. Figure 9: Final design for our arm E. Scupper The scupper (Figure 10) is designed to go along the underside of the ice sheet and suck down the ping pong balls. This motor is controlled from the surface so that we don’t waste any unnecessary power. Figure 10: The scupper June 1, 2007 Page 6 Site 3 Engineering MATE Technical Report F. Cameras We went with a three camera (Figure 11) design so that we could have better vision in the water. These cameras are infrared which will help in the environments that have low lighting levels. These three cameras are set up with two at the top of the ROV and one center mounted with easily adjustable mounts. The two top cameras will give us a binocular like view of the water, and the center mounted camera will let us see the grabbers. Figure 11: Underwater camera G. Tether The tether (Figure 12) consists of three power cords, one communication line, and three camera leads. Having power on the surface was important because it allowed us to reduce space and weight on the ROV, avoid recharging and replacing batteries, and manage our power source on land. In addition, if something were to go wrong we would be able to fix the ROV’s power from the surface. Figure 12: Our tether H. Control System We have two joysticks (figure 13) that control the left and right motors. We are using a potentiometer in our control box to control the vertical thruster. We went with the potentiometer so that we could leave it at a certain power level without holding a spring- loaded joystick. The claws are controlled by the triggers and buttons on the main joysticks. The bilge pump motor and the lights on the system are operated by switches in the control box. June 1, 2007 Page 7 Site 3 Engineering MATE Technical Report Figure 13: Control system I. Sensors Two sensors are used on the ROV to sense the environment. These devices will allow us to monitor our moisture and heat. Both of these factors are very