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VISUAL

SOFTWARE TO

UNDERSTAND

ROBOT

FUNCTIONS

National Instruments, a leader in computer-based data

acquisition, was one of the sponsors and mentors of

FIRST

Robotics Team 418, from the Liberal Arts and Science

Academy of Austin (Texas) at

LBJ High School. With that

kind of expertise, it’s not surprising that Team 418 was one

of the best in the area of control innovations. Not only did

the team design a high-performing robot, but also it created

a measurement and display system to monitor robot

performance, and programmed a variety of autonomous

operations to provide versatility at the start of each match.

The control and display systems combined effectively to

help the team better understand the robot and its operating

characteristics.

“SEEING”

SOFTWARE

AS A CONTROL

ADVANTAGE

TEAM 418

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Innovation in Control Award

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Camera Aiming for

Controlled Shooting

The robot skeleton began as a thin, alu-

minum angle frame that was riveted and

welded to form a strong machine foun-

dation. This material was selected for its

easy construction and flexibility in sup-

porting robot subcomponents. In addi-

tion, the lightweight structure helped

keep the robot’s center of gravity low.

Team

418’s scoring system relied on

a dual set of rollers to trap balls and lift

them into a storage hopper. A conveyor

belt lifted the stored balls nearly 4 feet

(1.2 m), where they were ejected from

the robot by a powerful, dual-wheeled

shooting device.

The shooter was solidly housed in

an aluminum box frame with precision

bearings supporting each side of the

wheel’s drive shaft. A cowling, first pro-

totyped with wood and later fabricated

aluminum, served as a back-plate

against which the shooter wheels com-

pressed the balls. The complete shoot-

ing system was compact, rugged, and

protected to prevent damage from

opposing teams.

The frame, lightened to conserve weight,

supports all the motors, rollers, and sensors that

transport the balls from the playing surface to

the shooting system.

The robot frame is constructed with an alu-

minum angle, welded and riveted together. This

simple frame is the central structure of an inte-

grated ball-gathering and scoring system.

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Balls enter the bottom of the robot and

ride through the central frame to the shooting

wheel. Sensors detect the location of the balls,

and monitor robot functions to ensure the accu-

racy of each shot.

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Aiming was accomplished by rotating

the robot with the drive system. A pow-

erful, dual-speed, four-wheel drive sys-

tem was designed to quickly cover the

field and easily align the robot with the

goal. The drive and shooting systems

were used in tandem to position the

mechanisms and propel the balls into

the upper goal.

The camera provided in the

FIRST Kit

of Parts was an important sensor on

Team 418’s robot. The camera con-

stantly searched for the illuminated tar-

get on top of the goal. Once the light

was detected, the camera’s servo

motors kept the target centered in the

camera’s view. Data on the orientation

of the servo motors, when locked on

the target, was used to develop a tar-

geting solution for the robot. The cam-

era pan determined the alignment of the

robot, and the camera tilt established

the distance to the goal.

The distance the shooter could propel

a ball was a function of shooter speed—

a parameter that could be adjusted to

accommodate the robot’s distance from

the goal. The speed and resulting trajec-

tory were determined from testing. These

results were stored in the robot con-

troller’s computer memory, and could be

accessed to determine the required

speed based on the camera’s tilt angle.

These automated processes—to align

the robot and determine the shooting

speed—were just two of Team

418’s

many control innovations.

Computer models closely match the final

robot configuration. It is much easier to move

parts around in a computer model to examine

options and ensure fit, thereby eliminating prob-

lems during the construction phase.

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A stable shooing platform is needed to

reduce vibrations and deliver accurate shots into

the goal. Aluminum box tube is carefully fitted to

form the frame and support the shooting wheel.

Wood is a useful material to prototype

robot systems. The shooter system prototype

is constructed with wood to evaluate the

optimal spacing between the cowling and

the shooting wheel.

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FIRST Robots: Aim High by Vince Wilczynski, Stephanie Slezycki, Dean Kamen, Woodie Flowers

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