Introduction Since last season Team 302 has been busy continuing to learn to design with Autodesk Inventor. Several students worked all through last summer and into the preseason this year learning to design and build small parts and assemblies. Six students are now proficient in Inventor 11 and quite a few more have lesser degrees of capability. The design sub team for the 2007 Rack ‘N’ Roll robot consists of three full time students Senior Peter Chan, Sophomores Josh Young and Ian Norman. Assistance was provided from other students as required. The robot design was accomplished using Inventor 11 and where possible downloaded kit part designs were used. The students learned how to use both the Design Accelerator and the Ansys Stress Analysis modules contained within Inventor 11. This presentation of this years robot will take you through Team 302’s brainstorming process and the details of our subassemblies with some highlights of the key features of our 2007 Rack ‘N’ Roll robot.
Brainstorming This year’s competition prompted a desire to have a highly maneuverable robot. Using Autodesk Inventor 11 Senior team member Neil Cooper developed a new concept for steering a robot. Along with teammate Matt Tucker a prototype of the steering mechanism was created and showed promise. A serious attempt was made to develop this concept further using the 2007 frame kit. This was a great help in displaying the strengths and weaknesses of incorporating this idea. In the end the team decided that due to risks of timing and final feasibility issues a more conventional steering method was chosen.
The team decided on a final chassis construction using two side pods. Even though this construction has been a Team 302 tradition it was decided to investigate alternative methods for constructing the pods. The team decided to look at a aluminum plate, aluminum angular frame and steel angle frame constructions. Weight and strength are key factors in design. This was an excellent opportunity to investigate the Ansys Stress Analysis module contained within Inventor 11. Looking at the deflection characteristics of a pod construction the team was able to decide that a plate construction with holes would offer the best solution for weight and stiffness. Brainstorming
Everyone joins in on concepts, prototypes and brainstorming! The Gripper mechanism idea started from a concept of a simple hook. This concept took the path of creating physical prototypes of the Gripper working them through game scenarios before any CAD was generated. This brainstorming method quickly led the team to Sophomore team member Ian Norman’s final design which the whole team is very proud of. Brainstorming
<ul><li>Robot Specs </li></ul><ul><li>Speed: 10ft/sec </li></ul><ul><li>Starting height: 47.50 in. </li></ul><ul><li>Weight 119.5 lbs. </li></ul><ul><li>Steering Pneumatic </li></ul><ul><li>Pick up tubes: Yes </li></ul><ul><li>Reach top goal Yes </li></ul><ul><li>Autonomous Yes </li></ul>Robot Assembly
Robot Assembly Starting Position Pick-up Position Raised Position Scoring Position
Robot Assembly Digital photographs of the robot showing the different positions (Note: bumpers not shown)
0.125” Solid Pod Mass 7.06 lbs Deflection 1.037 0.15” Slotted Pod Mass 7.36 Deflection 1.192 The stress analysis module was called on again when trying to make some decisions on the final plates used in the side pods. Traditionally the team has used 0.15” plates for this type of construction. When the need to lose weight comes prior to robot shipment holes and more holes are usually machined into the plates. Neil Cooper decided to see if there is an opportunity to use an overall lighter material to achieve a lighter assembly. Neil decided to use the Stress Analysis module in Inventor 11 to compare the strength and stiffness of the pod assembly using 0.15” plates (material that we needed to special order) with holes and a construction using 0.125” (material we had readily available in the shop). To everyone’s surprise the lighter plate material (with some additional spacers) was both lighter and stiffer than the heavier plate material using a couple of different arrangements of lightening holes. Chassis