EncoderBot - VEX Robotics Chassis

thingiverse

Chassis for a two-motored, four-wheeled, programmable robot using VEX EDR components extends and attaches to the microcontroller's mounting points. This project completes my attempts at completely replacing VEX metal structural components with 3D printed plastic, while teaching myself SketchUp Make. I aimed to make it as compact as possible within the given parameters by placing the largest motors possible back to back, then working out from there. Print Settings I used a MakerBot Replicator (5th Generation) printer. Rafts and supports were included in the print settings for better stability. A high resolution was selected to ensure accuracy. Infill defaults were chosen for the most effective use of material. To prepare for printing, the flat top of the chassis should be placed upside down against the build plate. Post-Printing After printing, I used a letter opener and razor blade to scrape off excess support structure plastic. The excess was then cleaned up. Needed Parts The following components were required: * 1 VEX Cortex Microcontroller with accompanying mounting screws and nuts * 2 VEX 2-wire motors (393) with Integrated Encoder Modules, accompanied by their respective mounting screws * 1 7.2V robot battery attached to the chassis using twist ties * 6 square shafts (4 at 3" and 2 at 2") * 6 36-tooth gears * 12 nylon washers * 10 lock collars * 4 black plastic spacers All VEX EDR components are available through VEX: http://www.vexrobotics.com/vexedr/products/accessories. Assembly and Programming The wheel gear assemblies were first assembled, then the battery was hung off the chassis using twist ties. The robot's control loop was programmed using the Purdue Robotics Operating System IDE. Motor ports 1 and 10 were used for left and right motor control. The Cortex brain was programmed to read driver controller joystick axes. Extending the Chassis I extended the chassis by attaching a line tracking sensor bundle using stand-offs on the underside of the microcontroller's mounting points. This allows me to add more features as needed. Design Process This project was created using SketchUp Make 2016 from scratch. I have been exploring the software for creating objects compatible with VEX robotics components.