FLL Robot Design Workshop Tool Design and Mechanism

Prepared by Dr C H (Tony) Lin Principal Engineer Tire and Vehicle Mechanics Goodyear Tire amp Rubber Company tony_lingoodyearcom

Description

Mechanism (Attachment) is extending a simple robot into a powerful robot that can control and change its environment Learning about how properly design attachments for your robot to meet a particular challenge can make for a winning robot

A Systematic Design Methodology

1 Identify the functional requirements based on mission requirements of a class of mechanisms of interest

2 Determine the nature of motion (ie planar spherical or spatial mechanism) degrees of freedom (DOF) type and complexity of the mechanisms

3 Identify the structural characteristics associated with some of the functional requirements

4 Enumerate all possible kinematic structures that satisfy the structural characteristics using graph theory and combinatorial analysis

5 Sketch the corresponding mechanisms and evaluate each of them qualitatively in terms of its capability in satisfying the remaining functional requirements This results in a set of feasible mechanisms

6 Select a most promising mechanism for dimensional synthesis design optimization computer simulation prototype demonstration and documentation

7 Enter the Building phase

Robot Design and Construction

Planning ndash what does the team want to achieve and how will they achieve it Let the kids do it

Design iteration

Brainstorm (what to build)

Design (how to build it)

Build it

Test it

Repeat until itrsquos perfect (or good enough)

Trade-offs Good Quick Cheap ndash pick two (at most) Quality ndash Schedule ndash Budget

How to make things stiff

Use your hypotenuse Use right triangles 3-4-5 6-8-10 12-16-20 (51213) etc

Interlock bricks amp beams

Two thin bricks in between Lock with vertical beam

Triple beams (double shear)

Three-pins instead of two pins

Technic Design School httptechniclegocomtechnicdesignschooldefaultasp

Courtesy of Team RED Robot Construction and Design

Description

Mechanism (Attachment) is extending a simple robot into a powerful robot that can control and change its environment Learning about how properly design attachments for your robot to meet a particular challenge can make for a winning robot

A Systematic Design Methodology

1 Identify the functional requirements based on mission requirements of a class of mechanisms of interest

2 Determine the nature of motion (ie planar spherical or spatial mechanism) degrees of freedom (DOF) type and complexity of the mechanisms

3 Identify the structural characteristics associated with some of the functional requirements

4 Enumerate all possible kinematic structures that satisfy the structural characteristics using graph theory and combinatorial analysis

5 Sketch the corresponding mechanisms and evaluate each of them qualitatively in terms of its capability in satisfying the remaining functional requirements This results in a set of feasible mechanisms

6 Select a most promising mechanism for dimensional synthesis design optimization computer simulation prototype demonstration and documentation

7 Enter the Building phase

Robot Design and Construction

Planning ndash what does the team want to achieve and how will they achieve it Let the kids do it

Design iteration

Brainstorm (what to build)

Design (how to build it)

Build it

Test it

Repeat until itrsquos perfect (or good enough)

Trade-offs Good Quick Cheap ndash pick two (at most) Quality ndash Schedule ndash Budget

How to make things stiff

Use your hypotenuse Use right triangles 3-4-5 6-8-10 12-16-20 (51213) etc

Interlock bricks amp beams

Two thin bricks in between Lock with vertical beam

Triple beams (double shear)

Three-pins instead of two pins

Technic Design School httptechniclegocomtechnicdesignschooldefaultasp

Courtesy of Team RED Robot Construction and Design

A Systematic Design Methodology

1 Identify the functional requirements based on mission requirements of a class of mechanisms of interest

2 Determine the nature of motion (ie planar spherical or spatial mechanism) degrees of freedom (DOF) type and complexity of the mechanisms

3 Identify the structural characteristics associated with some of the functional requirements

4 Enumerate all possible kinematic structures that satisfy the structural characteristics using graph theory and combinatorial analysis

5 Sketch the corresponding mechanisms and evaluate each of them qualitatively in terms of its capability in satisfying the remaining functional requirements This results in a set of feasible mechanisms

6 Select a most promising mechanism for dimensional synthesis design optimization computer simulation prototype demonstration and documentation

7 Enter the Building phase

Robot Design and Construction

Planning ndash what does the team want to achieve and how will they achieve it Let the kids do it

Design iteration

Brainstorm (what to build)

Design (how to build it)

Build it

Test it

Repeat until itrsquos perfect (or good enough)

Trade-offs Good Quick Cheap ndash pick two (at most) Quality ndash Schedule ndash Budget

How to make things stiff

Use your hypotenuse Use right triangles 3-4-5 6-8-10 12-16-20 (51213) etc

Interlock bricks amp beams

Two thin bricks in between Lock with vertical beam

Triple beams (double shear)

Three-pins instead of two pins

Technic Design School httptechniclegocomtechnicdesignschooldefaultasp

Courtesy of Team RED Robot Construction and Design

Robot Design and Construction

Planning ndash what does the team want to achieve and how will they achieve it Let the kids do it

Design iteration

Brainstorm (what to build)

Design (how to build it)

Build it

Test it

Repeat until itrsquos perfect (or good enough)

Trade-offs Good Quick Cheap ndash pick two (at most) Quality ndash Schedule ndash Budget

How to make things stiff

Use your hypotenuse Use right triangles 3-4-5 6-8-10 12-16-20 (51213) etc

Interlock bricks amp beams

Two thin bricks in between Lock with vertical beam

Triple beams (double shear)

Three-pins instead of two pins

Technic Design School httptechniclegocomtechnicdesignschooldefaultasp

Courtesy of Team RED Robot Construction and Design

How to make things stiff

Use your hypotenuse Use right triangles 3-4-5 6-8-10 12-16-20 (51213) etc

Interlock bricks amp beams

Two thin bricks in between Lock with vertical beam

Triple beams (double shear)

Three-pins instead of two pins

Technic Design School httptechniclegocomtechnicdesignschooldefaultasp

Courtesy of Team RED Robot Construction and Design

Demonstration

Three-pins vs two-pins when used with more than three beams

Two pin structures bend

Three-pins much more rigid

Stacked beams with

black two-pins

Stacked beams with

grey two-pins

Stacked beams with

blackblue three-pins

Courtesy of Team RED Robot Construction and Design

How to make things strong

Use large parts Donrsquot use several small parts when one large part will

suffice

Stiffness decreases with the number of parts used to do a task

Use L-beams to form right angles Do not use two beams and a pin use an lsquoLrsquo

Make structures out of beams not axles when possible Axles are more flexible than beams ne consistency and

precision

Courtesy of Team RED Robot Construction and Design

Stiffness v Length Demo

If we need something longer than 15hellip

Two beams overlapped

More overlap = stronger beam

2 x 11 2 x 15

Courtesy of Team RED Robot Construction and Design

Classification of Mechanisms

No DOF Mechanisms

Planar Mechanisms (1-2 DOF)

Planar Linkages

Geared Mechanisms

Chain amp Pulley

Spatial Mechanisms (1-3 DOF)

Spherical Mechanisms (gt= 3 DOF)

Remember your robot can move

Examples

Examples

FLL Robot Attachments (Standard Kits)

Passive Attachments

Pushing attachment

Hooking attachment

Dumping attachment

Collecting attachment

Spring-loaded attachment

Power Attachments

Grabbing attachment

Lifting attachment

Pushing attachment

Turning attachment

Hooking attachment

Dumping attachment

Collecting attachment

Passive Attachments

Pushing attachment

Flat surface or Angled surfaces

Move game elements independently or in a container (Flat surface )

Move game elements out of robotrsquos path (Angled surfaces)

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

How to make things strong

Use large parts Donrsquot use several small parts when one large part will

suffice

Stiffness decreases with the number of parts used to do a task

Use L-beams to form right angles Do not use two beams and a pin use an lsquoLrsquo

Make structures out of beams not axles when possible Axles are more flexible than beams ne consistency and

precision

Courtesy of Team RED Robot Construction and Design

Stiffness v Length Demo

If we need something longer than 15hellip

Two beams overlapped

More overlap = stronger beam

2 x 11 2 x 15

Courtesy of Team RED Robot Construction and Design

Classification of Mechanisms

No DOF Mechanisms

Planar Mechanisms (1-2 DOF)

Planar Linkages

Geared Mechanisms

Chain amp Pulley

Spatial Mechanisms (1-3 DOF)

Spherical Mechanisms (gt= 3 DOF)

Remember your robot can move

Examples

Examples

FLL Robot Attachments (Standard Kits)

Passive Attachments

Pushing attachment

Hooking attachment

Dumping attachment

Collecting attachment

Spring-loaded attachment

Power Attachments

Grabbing attachment

Lifting attachment

Pushing attachment

Turning attachment

Hooking attachment

Dumping attachment

Collecting attachment

Passive Attachments

Pushing attachment

Flat surface or Angled surfaces

Move game elements independently or in a container (Flat surface )

Move game elements out of robotrsquos path (Angled surfaces)

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Stiffness v Length Demo

If we need something longer than 15hellip

Two beams overlapped

More overlap = stronger beam

2 x 11 2 x 15

Courtesy of Team RED Robot Construction and Design

Classification of Mechanisms

No DOF Mechanisms

Planar Mechanisms (1-2 DOF)

Planar Linkages

Geared Mechanisms

Chain amp Pulley

Spatial Mechanisms (1-3 DOF)

Spherical Mechanisms (gt= 3 DOF)

Remember your robot can move

Examples

Examples

FLL Robot Attachments (Standard Kits)

Passive Attachments

Pushing attachment

Hooking attachment

Dumping attachment

Collecting attachment

Spring-loaded attachment

Power Attachments

Grabbing attachment

Lifting attachment

Pushing attachment

Turning attachment

Hooking attachment

Dumping attachment

Collecting attachment

Passive Attachments

Pushing attachment

Flat surface or Angled surfaces

Move game elements independently or in a container (Flat surface )

Move game elements out of robotrsquos path (Angled surfaces)

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Classification of Mechanisms

No DOF Mechanisms

Planar Mechanisms (1-2 DOF)

Planar Linkages

Geared Mechanisms

Chain amp Pulley

Spatial Mechanisms (1-3 DOF)

Spherical Mechanisms (gt= 3 DOF)

Remember your robot can move

Examples

Examples

FLL Robot Attachments (Standard Kits)

Passive Attachments

Pushing attachment

Hooking attachment

Dumping attachment

Collecting attachment

Spring-loaded attachment

Power Attachments

Grabbing attachment

Lifting attachment

Pushing attachment

Turning attachment

Hooking attachment

Dumping attachment

Collecting attachment

Passive Attachments

Pushing attachment

Flat surface or Angled surfaces

Move game elements independently or in a container (Flat surface )

Move game elements out of robotrsquos path (Angled surfaces)

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Examples

Examples

FLL Robot Attachments (Standard Kits)

Passive Attachments

Pushing attachment

Hooking attachment

Dumping attachment

Collecting attachment

Spring-loaded attachment

Power Attachments

Grabbing attachment

Lifting attachment

Pushing attachment

Turning attachment

Hooking attachment

Dumping attachment

Collecting attachment

Passive Attachments

Pushing attachment

Flat surface or Angled surfaces

Move game elements independently or in a container (Flat surface )

Move game elements out of robotrsquos path (Angled surfaces)

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Examples

FLL Robot Attachments (Standard Kits)

Passive Attachments

Pushing attachment

Hooking attachment

Dumping attachment

Collecting attachment

Spring-loaded attachment

Power Attachments

Grabbing attachment

Lifting attachment

Pushing attachment

Turning attachment

Hooking attachment

Dumping attachment

Collecting attachment

Passive Attachments

Pushing attachment

Flat surface or Angled surfaces

Move game elements independently or in a container (Flat surface )

Move game elements out of robotrsquos path (Angled surfaces)

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

FLL Robot Attachments (Standard Kits)

Passive Attachments

Pushing attachment

Hooking attachment

Dumping attachment

Collecting attachment

Spring-loaded attachment

Power Attachments

Grabbing attachment

Lifting attachment

Pushing attachment

Turning attachment

Hooking attachment

Dumping attachment

Collecting attachment

Passive Attachments

Pushing attachment

Flat surface or Angled surfaces

Move game elements independently or in a container (Flat surface )

Move game elements out of robotrsquos path (Angled surfaces)

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Passive Attachments

Pushing attachment

Flat surface or Angled surfaces

Move game elements independently or in a container (Flat surface )

Move game elements out of robotrsquos path (Angled surfaces)

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Example 2010 MampMrsquos design

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Complete Examples

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Exercise 1

Build Push Plate (15 minutes)

Pins Guide Attachment

BOM

Instruction

Passive Attachments

Hooking attachment

Fork and Hook attachments

Collecting special objects

Can be combined with power assist to lift sweep and drop

Example 2010 MampMrsquos design

Complete Examples

Exercise 2

Hooks(15 minutes)

BOM

Instruction

Example 2010 MampMrsquos design

Complete Examples

Exercise 2

Hooks(15 minutes)

BOM

Instruction

Complete Examples

Exercise 2

Hooks(15 minutes)

BOM

Instruction

Exercise 2

Hooks(15 minutes)

BOM

Instruction

Passive Attachments

Dumping attachment

Container to move game elements to specific location

Based on basic four-bar linkage or simple hinge mechanism

Example 2011 Brazing Brainsrsquo design

Exercise 3

Four-Bar Carrier(30 minutes)

BOM

Instruction

Example 2011 Brazing Brainsrsquo design

Exercise 3

Four-Bar Carrier(30 minutes)

BOM

Instruction

Exercise 3

Four-Bar Carrier(30 minutes)

BOM

Instruction

Passive Attachments

Collecting attachment

Object trap - Box opens only inward

Sweeper ndash moving object in certain direction

Capture objects to return to base

Example 2011 Brazing Brainsrsquo design

Exercise 4

Trap Box (30 minutes)

BOM

Instruction

Example 2011 Brazing Brainsrsquo design

Exercise 4

Trap Box (30 minutes)

BOM

Instruction

Exercise 4

Trap Box (30 minutes)

BOM

Instruction

Passive Attachments

Spring-loaded attachment

Snap or pre-loaded

Collecting hitting or turn

Combining with other mechanisms or trigger

Example 2011 Brazing Brainsrsquo design

Exercise 5

Spring Loaded Hook (20 minutes)

BOM

Instruction

Example 2011 Brazing Brainsrsquo design

Exercise 5

Spring Loaded Hook (20 minutes)

BOM

Instruction

Exercise 5

Spring Loaded Hook (20 minutes)

BOM

Instruction

Exercise 6

Spring Loaded Trigger (20 minutes)

BOM

Instruction

Courtesy of Team RED Robot Construction and Design

FLL Robot Attachments

Passive Attachments Pushing attachment Hooking attachment Dumping attachment Collecting attachment Spring-loaded attachment

Power Attachments Grabbing attachment Lifting attachment Pushing attachment Turning attachment Hooking attachment Dumping attachment Collecting attachment

Power Attachments

Using third motor as power source to generate controllable motion

Attachments would be designed to connect to the fixed motor

Considerations Motor location

Moving space

Moving speed amp torque

Power Attachments

Grabbing and Collecting attachment

Claw Vise Grip Trap

Power Attachments

Lifting Hooking and Dumping attachment

Lever Forklift Trap

Example 2010 MampMrsquos design

Exercise 7

Forklift(40 minutes)

BOM

Instruction

Power Attachments

Using third motor as power source to generate controllable motion

Attachments would be designed to connect to the fixed motor

Considerations Motor location

Moving space

Moving speed amp torque

Power Attachments

Grabbing and Collecting attachment

Claw Vise Grip Trap

Power Attachments

Lifting Hooking and Dumping attachment

Lever Forklift Trap

Example 2010 MampMrsquos design

Exercise 7

Forklift(40 minutes)

BOM

Instruction

Power Attachments

Grabbing and Collecting attachment

Claw Vise Grip Trap

Power Attachments

Lifting Hooking and Dumping attachment

Lever Forklift Trap

Example 2010 MampMrsquos design

Exercise 7

Forklift(40 minutes)

BOM

Instruction

Power Attachments

Lifting Hooking and Dumping attachment

Lever Forklift Trap

Example 2010 MampMrsquos design

Exercise 7

Forklift(40 minutes)

BOM

Instruction

Example 2010 MampMrsquos design

Exercise 7

Forklift(40 minutes)

BOM

Instruction

Exercise 7

Forklift(40 minutes)

BOM

Instruction

Power Attachments

Pushing attachment

LEGO Actuator or Custom Actuator

Power Attachments

Turning attachment

Controllable turning action

Define turning angle direction and arm length

Gear type ratio and direction

Gears and Usage

Regular spur gears Gearing up or down changing speed or torque Converting rotary to linear motion (rack and pinion)

Bevel gears and crown gears Change shaft direction by 90 degrees hellip Note direction of rotation changes (4 tooth is also good for this task)

Torque Will only apply a given level of torque before slipping

Worm Changing direction speed and torque (itrsquos a 1 tooth gear) Eliminates back driving bull Gear Ratio =

No Teeth InputNo Teeth Output

Example 2011 Brazing Brainsrsquo design

Exercise 8

Gear amp Grip (40 minutes)

BOM

Instruction

Power Attachments

Turning attachment

Controllable turning action

Define turning angle direction and arm length

Gear type ratio and direction

Gears and Usage

Regular spur gears Gearing up or down changing speed or torque Converting rotary to linear motion (rack and pinion)

Bevel gears and crown gears Change shaft direction by 90 degrees hellip Note direction of rotation changes (4 tooth is also good for this task)

Torque Will only apply a given level of torque before slipping

Worm Changing direction speed and torque (itrsquos a 1 tooth gear) Eliminates back driving bull Gear Ratio =

No Teeth InputNo Teeth Output

Example 2011 Brazing Brainsrsquo design

Exercise 8

Gear amp Grip (40 minutes)

BOM

Instruction

Gears and Usage

Regular spur gears Gearing up or down changing speed or torque Converting rotary to linear motion (rack and pinion)

Bevel gears and crown gears Change shaft direction by 90 degrees hellip Note direction of rotation changes (4 tooth is also good for this task)

Torque Will only apply a given level of torque before slipping

Worm Changing direction speed and torque (itrsquos a 1 tooth gear) Eliminates back driving bull Gear Ratio =

No Teeth InputNo Teeth Output

Example 2011 Brazing Brainsrsquo design

Exercise 8

Gear amp Grip (40 minutes)

BOM

Instruction

Example 2011 Brazing Brainsrsquo design

Exercise 8

Gear amp Grip (40 minutes)

BOM

Instruction

Exercise 8

Gear amp Grip (40 minutes)

BOM

Instruction

Example Videos

httpwwwyoutubecomwatchv=h3PS7nIihOw

Passive and power attachments

httpwwwyoutubecomwatchv=o7RiDjcm5Dg

Power attachment ndash forklift amp actuator

httpwwwyoutubecomwatchv=VT5_ziLhENEampfeature=related

Passive and power attachments

Identify mechanisms that had been used within each video

FLL Robot Attachments (Non-Standard Kits)

Pneumatics operation

Pneumatics give the robot another power source of manipulation besides LEGO NXT servos (motor)

Powerful

Partial controllable motion - Onoff switch with pneumatic actuator

Examples

lifting attachment

References

Mechanism Design Enumeration of Kinematic Structures According to Function Lung-Wen Tsai

Winning Design LEGO Mindstorms NXT David J Trobaugh

Designing for FLL with Lego Mindstorms Hints and Tips Team Unlimited FTC0001 unlimitedsyraweborg

Robot Mechanisms and Mechanical Devices Illustrated Paul E Sandin

Building Robots with LEGO MINDSTORMS Mario Ferrari Giulio Ferrari and Ralph Hempel

Examples

lifting attachment

References

Mechanism Design Enumeration of Kinematic Structures According to Function Lung-Wen Tsai

Winning Design LEGO Mindstorms NXT David J Trobaugh

Designing for FLL with Lego Mindstorms Hints and Tips Team Unlimited FTC0001 unlimitedsyraweborg

Robot Mechanisms and Mechanical Devices Illustrated Paul E Sandin

Building Robots with LEGO MINDSTORMS Mario Ferrari Giulio Ferrari and Ralph Hempel

References

Mechanism Design Enumeration of Kinematic Structures According to Function Lung-Wen Tsai

Winning Design LEGO Mindstorms NXT David J Trobaugh

Designing for FLL with Lego Mindstorms Hints and Tips Team Unlimited FTC0001 unlimitedsyraweborg

Robot Mechanisms and Mechanical Devices Illustrated Paul E Sandin

Building Robots with LEGO MINDSTORMS Mario Ferrari Giulio Ferrari and Ralph Hempel