Building Systems and Mechanical Design

Robin Tan

Robotics Kits and Mechanical Systems

Hardware Design

Robot Management

Topic Outline

Robotics Kits – TETRIX System

Advantages

“Default” and by far the most popular

Tried and true

Wide Variety

Tough and robust

Screws stay in tightly

Diverse pattern of holes

Robotics Kits – TETRIX System

Disadvantages

Motors not as reliable

Parts are expensive per piece

Usually requires additional

cutting/drilling

Robotics Kits – MATRIX System

AdvantagesNumerous pre-drilled holes

(good for mounting)

Lighter

Relatively newer robotics kit

Robotics Kits – MATRIX System

Disadvantages

Metal components are flimsier

Plastic gears slip easily

Screw strip easily

Poor quality axles

Unreliable electronic systems

Less popular

Robotics Kits – Actobotics System

AdvantagesAbundance of holes allows for

precise construction

Compatible with different kits

Impressive gearing, servo, and bearing optionsCountless mounting

possibilities

Robotics Kits – Actobotics System

Disadvantages

Takes a long time to build

Reported problem with tight axles

Robotics Kits – 80/20 System

Advantages

Incredibly rigid

Easy to assemble

Good option for slides

Easy to make changes with

Robotics Kits – 80/20 System

Disadvantages

Heavier than TETRIX

Mechanical Design: Drivetrain

4-Wheel Drive 6-Wheel Drive Swerve Drive

Relative ManeuverabilityLess weight + partsLess wheels = less pushing

power

Impressive ManeuverabilityRequires more motorsHeavyExpensiveComplex

Greater turning abilityMore pushing powerHeavierHarder to travel over

bumps

Mechanical Design: Drivetrain

Omni Wheels Mecanum Wheels

Exceptional maneuverabilityFaster than Mecanum wheelsLess pushing powerComplex to drive

Exceptional maneuverabilityMore pushing power than Omni WheelsSlower than Omni WheelsComplex to program

Mechanical Design: Slide System

Wire-Pulley SystemSingle-Stage

Linear Slide System

Can be multi-stageWire/belt = less reliable

Extremely reliableSimple linear motionLess reach

Multi-StageLinear Slide System

Greater reachReliableHeavier

Mechanical Design: Types of Linear SlidesDrawer Slides

Thinner than 80/20Material is weaker

80/20 Slides

Heavy DutyMore ReliableMuch thicker – takes more roomMuch heavier

Robot Repair and Wire Management

Robot structure is designed to make electronics easy to fix

Wires run down the slides in Chain-Link WireCarriers to reduce possibilities of frayed wires

+ easy replacement

ALL WIRES are zip-tied – NO STRAY WIRESUSB Relief – Ensure reliable connection

Mechanical Reliability

Assigned an “inspection crew” after each component is constructed to inspect if it is durable enough for competitions

Test program/Checklist that is run before each match - ensure that the robot is functioning

Drilled holes - reduce weight

Attached shields and plows - passively push debris away

Duct tape applied all over robot - reduce static discharge

Mechanical Reliability

Anti-static polycarbonate sheets – reduce static buildup

Don’t connect your motors directly to your axles

Loctite shaft collars – make sure no axles fall out

Passive systems – reduce risk of electronic failure

Stress tests are calculated using PTC Mathcad