W. P. Davidson High School Robotics
The Robot
Overview
RobotEx employs a modular design process when it brainstorms the parts of the robot. We determine the goals and constraints of each part of the robot, taking into account our strategy, the kit and consumables list, and the set constraints. We come up with the design of each individual part of the robot based on its intended function on the field, then once each part is designed, we create it in SolidWorks CAD software.
Manufacturing
RobotEx relies heavily on our homemade CNC machine to create precise gears and parts and maintain workplace safety for team members. A CNC machine, Computer Numerical Control machine, is a device that can be commanded to cut materials through computer software. First, the user designs a program using CAD software. Next, the program is exported as a 2D vector image. Using a computer aided manufacturing program, the user sets tool paths for desired cuts. These vectors are converted into G code, a series of directions, which are sent to the CNC machine's interface driving stepper motors to cut the material.
Programming
Once the robot is complete, a program coded in RobotC is developed to code the remote control inputs and drive the robot. The program is downloaded onto the Vex Cortex and controlled by remote. Designers and drivers work with the programmers to ensure ease of use and efficiency. To the left is the remote used to drive the robot.
Testing
Upon manufacturing the robot, RobotEx began the testing stage of the Engineering Design Process. Over the course of the season, RobotEx members built a practice course on which the robot could be tested. The team used exact specs from the BEST Robotics Field Guide to create a field that corresponds as closely as possible to the actual field used on Game Day. This allowed RobotEx to identify issues with the robot and improve upon the original designs. It also provided valuable driver training time in preparation for the competition.
The Wheels
Each wheel is simply mounted to the top of the baseplate.
The Base
The base is strategically cut to fit around the copper bucket. Two thin, triangular pieces of Polypropylene are attached along the interior edges of the base indention. These Polypropylene pieces allow the bucket to slide off the ground onto the robot and vice versa.
The Arm
The arm is has a small motor on one end allowing it rotate 180 degrees. The addition of the potentiometer adds an element of involuntary control by automatically stopping the rotation of the arm before it turns too far, freeing the operator of this additional responsibility and preventing damage to the electrical system.
The Claw
The design of the claw provides extensive motion capabilities. The claw can be divided in to two subassemblies, the Vertical Motion Assembly and the Clasping Motion Assembly.
The Vertical Motion Assembly
This subpart gives the claw its element of verticality. Two servos are attached to small gears and are programmed to turn two larger gears simultaneously. The larger gears are attached to the Clasping Motion Assembly, allowing it to move up and down.
The Clasping Motion Assembly
This assembly gives the claw the ability to open and close to grab various field pieces. A servo rotates a small gear that interlocks with a larger gear that is attached to one of the halves of the gripper.
Full Claw
These parts combined create an efficient and functional claw.
The Tower
The tower is the supporter and provider of vertical motion for the arm. It also doubles as the electronic hub and cortex housing for the robot. It consists of two wooden supports, a large gear, to raise and lower the arm, a gear locking mechanism, and a tensioner wheel to give stable and fluid motion.
The Arm's Range of Motion
Due to impeccable engineering and versatile design, the robot has a wide range of vertical motion. The arm can move over 180 degrees, allowing it to reach high and low field pieces with ease.
