Construction and Design of a Competitive Vex Robot
Erik Dyer, John Odo , Shelby Ray, Tommy Walker
July 19, 2013
Morehouse College Upward Bound Math/Science Southeastern Regional Institute

Table of Contents
Title Page …………………………………………………………………………………….1
Abstract ……………………………………………………………………………………..3
Background/ Introduction ……………………………………………………………………4
Literature Review………………………………………………………………………….....6
Methodology ……………………………………………………………………………...…7
Specifications page…………………………………………………………………………...10
Discussion …………………………………………………………………………………....11
Conclusion ……………………………………………………………………………………12
References ………………………………………………………………………………….…12

Abstract
A robot is a reprogrammable multifunctional manipulator. Over the course of five weeks, two robots were constructed in order to participate in the VEX Toss Up competition that was designed to test the abilities of the robots. Each robot had to meet certain criteria, such as size of 18 inches or less and they had many constraints that the robot’s builders set in place. This gave the builders the freedom to create what they pleased, but within a set barrier put in place by the VEX company. The designers only used a manual to build the base, and then developed specific parts as modifications to the robot. Both robots were built to play defensively and offensively but responsible for different tasks. One robot was intended to move balls in low goals and the other for high goals. As a result, the team constructed two robots that were able to compete against teams from other schools. This research shows that robots could assist people with transporting objects in the dangerous environments.

Introduction
Robotics is the science or study of the technology associated with the design, fabrication, theory, and application of robots (What is robotics, 2013). Robots are machines that can be used to do jobs. Robots must have a person telling them what to do. There are multiple types of robots, from remotely operated vehicles (ROVs), cyborgs, androids, to autonomous robots. The difference between these robots is that the ROV robots are remotely controlled while the autonomous robots do not require constant control from a person. Cyborgs are bodies with built in mechanical features and an android is a robot with a human appearance.
A robot is a reprogrammable multifunctional manipulator. The term robot was first used in Karel Capek’s play, R.U.R (Rossum Universal Robot) in 1921. The word robot comes from the Czech word, ‘robota’, which means forced laborer or serf. Throughout history, robots have been used as serfs, slaves, and comrades. From all of the non-fictional movies, robots’ role does not change. From Star Wars to Hal: the brain of the spaceship discovery robots have always been classified under one of those slots.
Since then, a lot of competition robots have been built in order to participate in a competition sponsored by Vex Robotics. Vex Robotic Designs has a competition every year, where different programs build robots that consist of only vex robotic parts. VEX Robotics Competition will provide students with a hands-on co-curricular competition for learning about science, technology, engineering, and mathematics (STEM) and will complement the existing technology-related competitions offered by TSA (TSA and IFI, 2009).The game changes every year, so each year there are different requirements. This year there will be a game called “Toss Up”. This game will be played on a 12ft x12ft foam mat, surrounded by sheet metal and Lexan perimeter. Your robot must be 18”x18”x18” inches or smaller, if the desires are not met the robot will be disqualified. The objective of the game is to transport the game objects in the designated areas. The robot can play defensively and offensively to score point for the red or blue team. The first 15 seconds of the game is for the autonomous programmed robots that can result in to scoring bonus points.
The field is divided into three parts: the ball zone, middle zone, and the goal zone. Each object is worth a different amount of points. There are a total of twenty Bucky Balls and eight Large Balls available. When placing the Bucky ball in the goal zone is worth two point and five points if you score with the large ball. Two Bucky balls are preloaded at the start of the game; therefore robots can score very early in the game. Additional points can be gained by hanging from the Hanging Bar. If the robot is low hanging that is an additional five points and high hanging is ten points.
Researchers built their design to play defensively and maneuver around the field to score points. The team used two motors, one for each side of the robot. Four motors were not used because the clutches restricted the movement of the wheels. Gears were also added to make sure that all the wheels of the motor would move at the same time. This design was based off of the Vex Proto bot, with modifications added to meet the team’s needs.

Literature Review
Innovation First International, creators of the largest and fastest growing middle and high school robotics program, and the Technology Student Association (TSA), a national organization dedicated to increasing technological literacy in middle school and high school students announced that VEX Robotics Competition will provide students with a hands-on co-curricular competition for learning about science, technology, engineering and mathematics (STEM) and will complement the existing technology-related competitions offered by TSA (TSA and IFI, 2009). Tournaments are held with the combination of private and public schools. May of 2013, Walker’s Robotic Club hosted the final Vex Robotics World Championship Qualifier where thirty teams competed in eight total qualifying matches. Some matches were played in alliances from different schools, but Walker’s team ended up playing one another (King, 2013). Researchers are going to participate in the Toss Up competition which is similar to the Walker’s Robotics Club event. The VEX Robotics Design System helps takes the inspiration from the competition to the next level by supplying the ideas to make the proto bot , which should have the ability to do the following : push and pull, be defensive and offensive, score with a six inch Bucky ball and large ball, and climb up a two inch platform.
The robotics construction kit is the very core of a successful built Proto bot and Tumbler (Robotics, 2013). Building a robot involves simply following procedures and pictures. The kit provides all materials such as gears, screws, metals, wheels, and etc. Builders made their design to compete in the competition concerning to the idea to pick up the ball. The Vex manual has illustrations that state where the material should connect. Each chapter of the manual includes a description of the components used, the concepts involved in designing and building the subsystem, and how the subsystem interacts with other subsystems. According to Travis Lehman, VEX Robotics System is the best way to deliver a fun and challenging robotics and engineering curriculum (2009). Robotics is the science or study of technology associated with the fabrication, design, theory, and application of robots. These tools were created to help accomplish tasks, work in factories, and explore places that humans cannot reach (What is robotics, 2013). Most robots have three main parts: a controller (a brain); mechanical parts to help it move (robots can be powered by air, water, or electricity), and sensors that can tell the robot about its surroundings. These parts work together to control how a robot functions.
Methods
Materials

• 2- 5inch knobby tires
• 1 vex approved battery
• 2 crystals
• 2 y connector wires
• 1 extended jumper cable
• 1 pair of treads
• 4 84 teeth gears
• 4 36 teeth gears
• 4 long bars
• 5 chassis rails
• 2 chassis bumper
• 2 long angle bars
• 4 plates
• 5 c channels
• 7 fully threaded beams ½ inch
• 2 fully threaded beams 2inches
• 6 fully threaded beams 1 inch
• 56 keps nut ¼ inch
• 10 lock nuts
• 8 square bars 3 inches
• 1 square bar 4 inch
• 1 square bar 2 inch
• 89 screws (8-32, ¼ inch, 3/8 inch, ½ inch, ¾ inch)
• 20 collars
• 1 pivot gusset
• 20 threaded screws for collars
• 9 plastic spacers .182 inches
• 8 plastic spacers .318 inches
• 2 controllers
• 20 motor screws
• 2 60-tooth gears
• 1 servomotor
• 6 three-wire motors
• 3 two wire motors
• 1 transmitter
• 1 receiver antenna
• 1 RF receiver module
• 1 receiver antenna sleeve holder
• 1 battery strap
• 3/32-inch hex L Driver
• Wrench
• 5/64 inch
• 2 single body wheel assembly
• 1 cinch strap
• 2 45-degree gussets
• 2 c channel coupler gusse
• 2 motors

Procedures Designers used a Vex robotic kit to build a proto bot base. First, inventory was done of all parts and separated into different compartments in a professional deep organizer. An essential part of the procedure was to overview the objectives of the game to meet the requirements. Designers also had to read the rules of the Toss Up game to decide the model of their robot. After all materials were provided, researchers began building the frame or chassis of the robot. After locking everything in place with kep nuts and collar screws the frame became stronger. The motors were connected on the inside of the chassis base with bearing flats and pop rivets. Motor screws were also used and tightened with an allen wrench. They used two fifteen hole c-channels to connect four wheels and two motors. Then eight gears were added to distribute the power provided by the motors.
Once the base was completed, the team began working on the manipulator, which would move around in game objects. The team decided that it would be best to create a scoop for the robot, because it would be easy to maintain and would work well with the competition. The scoop was made using a chassis rail and metal plates to hold objects; then put in the front of the robot and connected using a 5x15 metal plate. The procedures for constructing the the scoop were flexible because modifications had to be made after test trials. The researchers had to change the length of the metal strips so that they would meet the length requirements of 18 inches.
The next step for the team was to add software to the robot. The Vex microcontroller or the central computer for the robot had to be attached using screws and kep nuts. The researchers then updated the software on both the cortex microcontroller (controller) and joystick. Then, the adapter keys were added to both so that the robot and its joystick were synchronized. Next we connected the robot to a laptop via usb and created a program that allowed the joystick to move the motors on the robot. This program synchronized the motors so that they would rotate the wheels in unison to propel the robot forward. Then a program was added to the controller to allow the researchers to operate the robot.
Specification Page
Gear Ratios
Figure 1

Figure 2 Gear 2
Gear 2
Gear 1
Gear 1

Gears are used for multiple reasons such as the following: to increase or decrease the speed of rotation, reverse the direction of rotation, move rotational motion to a different axis, and keep the rotation of two axes synchronized. Figure 1 has a gear ratio of one to one, which means the gears rotate at the same speed. In figure 2 shown above; the gear ratio on the motor is three to one (3:1) meaning that gear 1 would turn three times to every one turn of gear 2. If the motor is attached to gear 1 the robot would accelerate faster than a robot that has a gear ratio of one to one (1:1). Discussion
Two robots were entered into the competition; one from team A and the other from team B. Team A utilized a shovel design to manipulate game objects. The shovel was made from a metal bar and strips put perpendicular to the bar. The shovel was lightweight and thus allowed the robot to have a lot of mobility and power while still allowing it to transport small game objects. On the other hand team B built a scoop that could lift game objects and carry them to their destinations. This scoop also used metal strips to create the manipulator that would be lightweight while still being able to manipulate larger game objects.
During the competition robot A had a strong start. It was able to push in game objects, called Bucky balls, into the goal area so that the team would score. Because of the robot’s small design the balls could be pushed quickly and efficiently, allowing the robot to move on to other tasks. However, because the robot was so lightweight it was also more fragile; the team had to tighten screws and secure parts after every competition match. Also, there were several malfunctions with the adapter key, thus impairing our robot by disrupting communication between the joystick and the controller. Despite these minor setbacks Team A’s robot still performed well. It was able to effectively push and otherwise influence the game objects to the goal area.
Conclusion
Through six weeks of hard work and dedication to the project the team was able to design a fully functioning vex competition robot. To do this the team built a simple chassis and added modifications to suit their needs. This process has been proven successful by the triumphs of the robot. The team was not only able to compete, but was also capable enough to create a robot that made it to the semifinals of a vex educational tournament.
References
(2013). Vex robotics competition – toss-up. (p. 2). New York: Vex Robotics Inc. Retrieved from http://content.vexrobotics.com/docs/vex-toss-up/VEX-Toss-Up-GameManual_Rev041913.pdf
Interview by VEX []. Tsa and ifi announce partnership to introduce signature robotics competition using vex., Retrieved from http://www.vexrobotics.com/news/2009/11/tsa-and-ifi-announce-partnership-to-introduce-signature-robotics-competition-using-vex/
King, T. (2013, May 14). Retrieved from http://twswolverine.net/2013/03/14/walkerrobotics/
Lehman, T. (2009, September 15). Interview by VEX []. A teachers's experience with vex.., Retrieved from http://www.vexrobotics.com/news/2009/09/a-teachers-experience-with-vex/
What is robotics?. (2013). Retrieved from http://engineering.nd.edu/NDNRW/what-is-robotics