+ All about Electric Motors Building a Robot Arm Christopher Lester Yvonne Pelham Douglas Gorham...

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All about Electric Motors

Building a Robot Arm

Christopher Lester

Yvonne PelhamDouglas GorhamKapil Dandekar

TISP: Montreal15 – 16 May 2009

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Christopher LesterIEEE Educational Activities

Exercise 1:

ElectricMotors

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+All About Electric Motors

Learn basic theory of electric motors

Learn basic theory of electro-magnetic forces

Apply theory to everyday uses of electric motors

Build a working model of an electric motor

Objectives for Students

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Physical Science: Develop an understanding of motion and forces,

transfer of energy Develop an understanding of the interactions

between energy and matter

Problem Solving: Develop an understanding of the role of

troubleshooting, research and development, invention and innovation, and experimentation in problem solving

Principles & Standards for School Mathematics – 1

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Personal and Social Perspectives: Learn about science and technology in society and

through history Develop an understanding of the risks and

benefits of technology Understand the abilities of science and technology

Principles & Standards for School Mathematics – 2

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Nearly every mechanical motion you interact with everyday is run by either a DC or AC electric motor

Motors are everywhere!

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+All About Electric MotorsParts of the Electric Motor

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6 Main Parts

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2

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4

5

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North pole of magnetic field and armature repel each other

South pole of magnetic field and armature repel each other

Torque is generated in clockwise direction

All About Electric MotorsOperation of the Motor

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Motor shaft rotates clockwise

Torque continues to be generated in the clockwise direction


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Armature poles reach the point where they are the furthest away from the same magnetic field.

Rotational inertia keeps motor shaft moving until brushes swap sides of the armature


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The brushes have moved to the opposite sides of the commutator: The south pole of the

armature now becomes the north pole

The north pole of the armature now becomes the south pole

The cycle starts over


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Images courtesy of Wikimedia Commonshttp://commons.wikimedia.org

+All About Electric MotorsAn Actual Toy Motor

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Brushes inside the motor

Transfer power from battery to commutator as the rotor shaft spins

All About Electric MotorsAn Actual Toy Motor

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The rotor shaft holds the armature and the commutator

The armature is a set of electromagnets, in this case three

The two ends of each wire (one wire for each pole) are soldered onto a terminal, and then each of the three terminals is wired to one plate of the commutator


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Magnetic field provided by 2 curved permanent magnets


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Images courtesy of HowStuffWorkshttp://howstuffworks.com


Build your own electric motor Wind the armature Wind the field coil Assemble the motor

Materials provided in kit

Assembly Instructions

What Are We Going To Do?

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Think about the classroom setting:What measure of performance could

you introduce to quantifythe success of themotor build?

As you work…

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Winding both the field coil and armature Use tape to hold pieces together as you wind

Cut the tubing to size after youwind the armature coil to ensureproper alignment

Keep the field coilwindings as flat aspossible to ensure thearmature can spin freely

A Few Helpful Tips

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You are a consultant tasked with adapting your proprietary electric motor to be used in a hair dryer.

What design modifications would you need to make?

What materials would you change?

What safety considerations would need to be addressed?

Design Discussion

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How would you quantify performance of the electric motor that students build?What properties would you measure?What additional materials would you

need?

What additional elements would you add to this activity?

Application Discussion

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Christopher LesterIEEE Educational Activities

Exercise 2:

Robotic Arm

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+Robot Arm

We will build a robot arm from simple materials

What will we do today?

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+Robot ArmWhy is this experiment useful to teachers and students?

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It teaches technological design

It requires mathematical calculations for design

It relates to the studies of motion and force

It requires communication through writing (design) and orally (explaining the design principles)

+Robot Arm

Geometry: Use visualization, spatial reasoning, and geometric modeling

to solve problems Analyze characteristics and properties of two- and three-

dimensional geometric shapes and develop mathematical arguments about geometric relationships

Problem Solving: Recognize and apply geometric ideas in areas outside of the

mathematics classroom Apply and adapt a variety of appropriate strategies

Communication: Communicate mathematical thinking coherently and clearly to

peers, teachers, and others

Principles & Standards for School Mathematics

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Canadarm 1, also known as Shuttle Remote Manipulator System

Used on the space shuttle to maneuver loads of up to 29 tons

Developed by SPAR Aerospace Ltd., out of Edmonton

Robot ArmThe Canadarm

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Canada’s primary contribution to the International Space Station

Mobile Servicing Station Space Station Remote

Manipulator Mobile Remote

Servicer Base System Special Purpose

Dexterous Manipulator

17 meters fully extended

Robot ArmThe Canadarm 2

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Dextre

+Robot Arm

We will build a robot arm from simple materials

The arm must pick up a plastic cup from a distance of 45cm Lift the cup to a height of at least 15cm Bring the cup back to rest and release it

Pick up cup upside down

Building the Canadarm 3

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+Robot ArmYou cannot get too close…

You cannot get any closer than 45cm to the cup at any time

CupStudent

Robot Arm

45cm

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+Robot ArmAvailable Materials

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+Robot Arm

Divide into teams of two (2)

Review the requirements

Discuss a solution and create a sketch of your design

Build a model of your design with given materials

Test your model

Outline and Procedures

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+Robot Arm

Discuss and agree upon a redesign If needed after testing, or to enhance the previous design

Rebuild your robot arm

Retest your model

Answer reflection questions as a team

Redesign after testing

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+Robot Arm

1. The arm must pick up a plastic cup from a distance of 45cm

Lift the cup to a height of at least 15cm

Bring the cup back to rest and release it

2. Lift and release the cup when it is upside down

Design requirements

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NEW DESIGN REQUIREMENT

Lift and release the cup when it is full with weight, or water bottle

Use materials on yourtable to fill cup(candy, pencils…)

Robot ArmUPDATE FROM SPACE AGENCY

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+Robot Arm





3. Lift and release water bottle

Design requirements

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NEW DESIGN REQUIREMENT

Need a single device that can manipulate a cup as well as a pen.

Device can use twodifferent endmanipulators

Robot ArmUPDATE FROM SPACE AGENCY

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+Robot Arm





3. Lift and release water bottle

4. Use the same design (possibly with a modified end manipulator) to lift a pen

Design requirements

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+Robot Arm

What was one thing you liked about your design? What is its main weakness?

What is one thing you would change about your design based on your experience

Are there algebraic and physical principles that can be applied to this activity?

How would you modify the instructions to create a better experience for the participants?

Reflection Questions

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+ All about Electric Motors Building a Robot Arm Christopher Lester Yvonne Pelham Douglas Gorham...

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