Team Two/Final Paper

From Maslab 2011

Contents 1 Team Members 2 Overview 3 Mechanical Design 3.1 Drive System 3.2 Electronics Mounting 3.3 Scoring Mechanism 4 Electrical Design and Sensors 4.1 Motor Controllers 4.2 Batteries 4.3 Sensor Choice 5 Software Design 5.1 Architecture 5.2 Multi-threading 5.3 States 5.4 Vision 5.5 Wall following 5.6 Stuck detection 6 Testing 6.1 Testing suite 6.2 Mechanical Issues 6.3 Electric Issues 6.4 Software Issues 7 Performance 8 Suggestions 9 Photos

Team Members

• Leighton Barnes - Course 18, 2013
• Cathy Wu - Course 6, 2012
• Stanislav Nikolov - Course 6, 2011
• Dan Fourie - Course 2, 2012

Overview

Mechanical Design

Our robot was designed for robustness and reliability. Our robot serves as a reliable platform for the software vision and control systems. As such it should be sturdy, constructed quickly, have extremely low mechanical failure rates, be able to withstand hours of testing, and be robust to positioning errors. The robot's structural members will be built primarily from acrylic sheet. It will utilize a rubber band roller powered by a DC motor to collect balls and 4-bar linkage hopper actuated by a servo to get balls over the wall. DC geared motors will drive no-slip wheels.

Drive System

3 boxes

no slip wheels

steel hubs

Electronics Mounting

Shock mounted laptop, monitor remove

ORC board plate

camera potting, adjustable

bump sensor suite

limit switches

battery slot

encoders

Scoring Mechanism

4 bar linkage

rubber band roller

Electrical Design and Sensors

Motor Controllers

power FET

H-bridge

protection diode

Batteries

NiCd and Lithium options reasons we used lead-acid

Sensor Choice

bump sensors

break-beam

encoders

IR range-finders

gyro (or lack thereof)

Software Design

Architecture

cathy

vision driven

color calibration

state machine with bump detection and timeouts

sensor abstractions

Multi-threading

cathy issues?

States

cathy

what states

timeouts

Vision

cathy

color calibration

data structures

botclient

documentary mode

Wall following

stan

Stuck detection

stan

Testing

Testing suite

cathy

Mechanical Issues

ball jamming

eeepc access

battery placement

bump sensor coverage

pins falling out

motor failing

Failure modes and Countermeasures

Electric Issues

leighton

single-conductor wire and broken connections

uORC sample rate

power for fourth motor

Software Issues

cathy & stan

multi-threading

ball jamming

wall following

stuck detection

Performance

Suggestions

• Form a team early and commit to doing MASLAB for all of IAP. We formed our team before the start of the school year.

• Have a well balanced team. It's important to cover all grounds with software, mechanical, and electrical. Our 2 software + 1 mechanical + 1 electrical combination balanced us very well.

• Work really really hard and stay motivated. We pulled endless all-nighters and never gave up. We continued to pester the staff mailing list with questions and even took a day to set up some legit practice fields in 26-100 before the seeding tournament.

• Start before IAP and aim to have most of everything done in the first 2 weeks of IAP. Because we did most of the design before IAP, We managed to have a functional robot (not the pegbot) by the first mock competition, which helped us out greatly. We also were able to spend the last week and a half making fixes for various edge cases and had time to just polish up things.

• Test often and relentlessly. You'll find something wrong with your robot every time.

Photos