This presentation covers the two robots I designed for the VEXU robotics competition in 2016. I built and programed the robots with a team, and we competed in the regional VEXU robotics competition.

1. Kristopher Kerames
December 2016
VEXU Project Overview

2. Competition Objective and Parameters
• Objective
o Fire more balls into the net than the
opposing team
• Parameters
o Robots must operate autonomously
o Each team gets two robots
o Each team is assigned a color and must fire
balls into the net that matches their color
o Scoring:
- Green balls are worth 1 point each
- Orange balls are worth 5 points each
o Each match will last for one minute
o One robot must fit within 2 ft3 box, the
other must fit within 1 ft3 box

3. Competition Strategy
• One robot (firing robot) collects and fires balls
o Fires at an angle of 52˚ to maximize range
when firing at a taller target
• Another robot (collecting robot) collects and
feeds balls into the firing robot
o This robot will have a large container for
collecting balls
o Stores balls before other team can gain
access to them
• The system of two robots will rapid-fire balls as
one feeds balls into the other for the remainder
of the competition
Collecting
Firing
Firing Robot
Collecting Robot
Collecting
& Feeding

4. Designing Each Robot
• Without access to CAD software, to-scale
designs were done on paper before robots were
assembled
• Orthographic projections were drawn, and
designs were prototyped
o The robots were drawn in layers to help the
building team interpret drawings

5. Front View of Firing Robot
Chassis and Drivetrain Chassis and Firing Mechanism
Completed Robot

6. Top View of Firing Robot
Chassis and Drivetrain Chassis and Firing Mechanism
Completed Robot
(no photo of top view available)

7. All Views of Firing Robot

8. Components of Firing Robot
• Sensors
o Proximity sensors used to determine presence
of objects
o Lidar used to determine distance and
differentiate between objects on field
o Encoders used to gauge wheel speed and slip
• Drivetrain
o Two VEX 393 motors power the 4-wheel drive
system
o Robot steers via tank steering
o Perpendicular rollers attached to rear wheels
to reduce friction caused by tank steering
Oblique View
• Firing Mechanism
o Two motors used to rotate firing wheels
o Gear ratio optimized for speed
o Wheels are programmed to build momentum
before ball is fired

9. Overcoming Challenges
• Robots were being stored in a classroom due to
lack of space
• Two days before the VEXU competition, new
students in that classroom unknowingly
disassembled parts of collecting robot
• Without time to do a full rebuild, collecting robot
was altered to fire balls using one of the working
prototype firing mechanisms
• The firing robot was reprogrammed to search for,
pick up, and fire balls from anywhere on the
competition floor throughout the entire duration
of the match
Altered Collecting Robot

10. Final Build in Action
Robot Firing Ball at Camera

11. Thank You to Our Sponsors!