A286 - Lego RCX Replacement

Works like prototype - February 8th, 2011

A prototype demonstrating the functionality of the motors, sensors, screen, and microcontroller. This works-like prototype exists to check compatibility and functionality of the motors and sensors with the Arduino microcontroller. At this time, finished plugs will not be used, the wires and pins on the controller will be exposed to allow for easy access to making modifications on the fly.

Construction components - March 1st, 2011

This deliverable is a presentation of the main construction parts in the final product. The construction components include the structural beams, gears, shafts, wheels, and fasteners. In addition to the construction components, the CAD drawings of all components will be available as well as contacts of suppliers for mass production.

Enclosures for motors and sensors - March 29th, 2011

The enclosure will provide a casing for the microcontroller and auxiliary electronics required by the motors and sensors. The casing will provide a plug system to interface the motor and sensor wires with microcontroller wiring. The casing will also allow for construction components to be attached directly to the case.

Final Product - April 19th, 2011

The final product will be the summation of Team A286 capstone project and will include a prototype of the completed robotics kit with all enclosures and construction components. In addition, full documentation on the fabrication methods for every component will be provided, as well as the result of all testing for both material strength and usability of the kit.

• SolidWorks - Designs, modeling, and to output STL data for rapid prototyping.
• Cosmos Express - Stress and strain analysis of construction components.
• Catalyst - Reads STL files from SolidWorks and prints to the rapid prototype machine.
• WPLM2000 - Writing gCode for ProLight CNC machine.
• Spreadsheet Software - For calculation of stresses and failure modes of parts.

Bending Testing

Bending testing was conducted and determined that the aluminum construction components could withstand 10 ft-lb. of force before undergoing plastic deformation. This force meets the design expectations of Team A286.

Student Testing

Student testing has revealed some weaknesses in the provided construction components of our kit, namely that students were limited by the linearity of our construction components. Team A286 responded by introducing flat plate pieces, construction components that provide a surface to which students could attach pieces to in multiple dimensions.

Metric vs. US Standard

Original plans called for using metric dimensions and tolerancing, but unfortunately during development it was discovered that obtaining metric-sized parts for nuts and bolts in the United States was rather difficult. Team A286 converted all drawings and plans to US Standard and resized the parts to better reflect standard bolts, shafts, and tools available.

CNC Machine Issues

Securing the work material into the CNC machine was difficult due to the size of the work material relative to the CNC machine. This lead to some shifting of the work material during the machining process, causing some minor defects in the prototype products. Currently Team A286 is looking into other methods of manufacturing the construction components.

Changes in Manufacturing

Original plans called for the channel and angle bars to recieve shallow cuts along the bending line to facilitate the bending process. It was discovered that the cut put too much stress on the material during bending and resulted in defects and that the materials could be bent without making the cut.

Manufacturing Processses

Current manufacturing processes for the prototype kit take too long and are too inaccurate for full scale use. New processes will need to be implemented, such as using injection molding for the enclosures and punching and blanking for the construction components.