Week 1: Intros

Overview

We will get to know each other, understand what the class is (and what it is not).  And we’ll get into the basics of wheel design.

 

Intros

Who are we?  What are we expecting in this class?  What level of design, fabrication, mechanical know-how, and physical computing are we all at?

 

What the Class Is

This is a design class with design restrictions.  Good restrictions can lead to creative solutions.  Our major restriction: utilizing round, spinning, rolling devices.  Wheels.

This is a skill utilizing class.  It will be project and prototype heavy.  Projects will have both long and very short lead times.

 

Topics We’ll Cover

  • Mechanisms
  • Toy Design
  • Mechatronics
  • Robotics
  • Kinetic Sculpture

 

What the Class Is Not

This is not necessarily a skill building class.  You won’t be pushed to learn new machines, fabrication techniques, or CAD software.

 

What I’m Looking For and Care About

  • Safety
  • Working Hard
  • Experimentation and Documentation
  • Craftsmanship

 

Secrets to Success

  • Buy/gather materials and tools early and get more than you need
  • Fail fast, experiment, try things, then try something else
  • Start early

 

Graded On

 

“To reinvent the wheel is to duplicate a basic method that has already previously been created or optimized by others.”  – Wikipedia

 

The Wheel

One of the Simple Machines.  Typically, considered one of humanity’s greatest inventions.  On a daily basis, we come into contact with wheels numerous times.  The wheel is an easy concept to grasp and makes for a nice entry point into more complex topics.

 

Anatomy of the Wheel

 

Hub

The center of a wheel that makes contact with the axel or drive mechanism.

 

Spoke

A spoke is one of some number of rods radiating from the center of a wheel (the hub where the axle connects), connecting the hub with the round traction surface.

 

Tire

Tires cover the wheel’s rim to protect it and enable better vehicle performance. Most tires provide traction between the vehicle and the road while providing a flexible cushion that absorbs shock.

 

Bearings

A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts.

 

 

Bushing

A bushing is inserted into a housing to provide a bearing surface for rotary applications.

 

 

Axels

An axle is a central shaft for a rotating wheel. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle.

Axels come in a variety of profiles.

Round

Keyed

D-Profile

 

We will all be receiving standard hardware to use in the class.

 

The Enemy

Friction

Unbalanced, wobble, slop

Loss of traction

 

Shape

“You know, for the kids.”

 

Round 

For most of us, when we think of wheels, we think of circles.  Simple, round, flat objects.

DC Motor Compatible Wheels

 

Sphere

Also know as Ball Transfer Units

 

Spherical Drive System

 

Cylindrical

Mine Kafon

 

Square?

Shark Wheels

 

Square Wheel Tricycle at Museum of Math

 

 

Wheelset

When the wheels are fixed to the axel (they don’t freely spin) it is called a wheelset.

Free Spinning Wheel and Axel

When a wheel can spin freely on an axel, independent of other wheels on the same axel.

 

Caster

An undriven, single, double, or compound wheel that is designed to be mounted to the bottom of a larger object so as to enable that object to be easily moved.

 

Omni Wheels

Also know as Poly Wheels

Vex 2.75 Omni Directional Wheel

Mecanum Wheels

 

 

Tracks and Treads

VEX Tank Tread Kit

 

 

How to make round objects (wheels)

Router

Drill Press, Hole Saw, and Forstner bit

Laser Cutter

CNC Mill

Lathe – Wood and Metal

3D Printer

Vinyl Cutter

Power Sander

 

Non-Traditional Wheel Designs

Loop Wheel

Omni-Ball

 

NASA Rover Wheels

 

Hubless Wheels

 

Where to Buy

McMaster-Carr
Tinkersphere
Servo City – wheels,  Servo City – roller balls
RC4WD
AMain Performance Hobbies
Tetrix
Robot Shop
Robot Mesh
Makeblock – Mecanum Wheels

 

Hubs

Pololu
Servo City

 

Bearings

Servo City

 

Bushings

Servo City

 

Tip

Construction Toys and cheap wheeled toys are great resources too.

 

Assignment

You will be making wheels.  Use any technique and material you like.  Think about shape, how they will attach to something, friction, weight, balance.

Roll Your Own

 


Related Reading/Viewing

 

Types of Bearings and What to Use Them Fore

Omni-Crawler Drives in All Directions

Loop Wheel

Mecanum Wheel Drive (with code)

Mecanum Wheeled Robots

Making Wooden Wheels with a Drill Press