Central Magnet Robotics

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CENTRAL ROBOTICS

Engineering Notebook TOTAL RECALL - 2010

Team #129

Central Magnet School

701 E. Main St. Murfreesboro, TN 37130

Sponsor: Marc Guthrie

[email protected]

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Table of Contents Page

I. Introduction Letter 3

II. Research Paper 4

III. About Central Robotics 7

IV. Implementation of the Engineering Design Process 8

1. Defining the Problem 8

2. The Engineering and Design Process 9

V. Brainstorming Approaches 13

1. Gathering Requirements 13

2. Brainstorming Sessions 13

3. Robot Design Features 14

VI. Analytical Evaluation of Design Alternatives 15

1. Wheel Analysis 15

2. Arm Analysis 17

3. Claw and Gripper Analysis 19

4. Trailer vs. Attached Box Analysis 21

VII. Programming the Robot 22

1. Motion Programming 23

2. Servo programming for the gripper 24

3. Lift Arm Programming 24

VIII. Offensive and Defensive Evaluation 24

1. Developing a Game Strategy 24

IX. Testing and Evaluation of the Competition 26

X. Safety 29

XI. Summary 29

XII. Appendices 30

Appendix A- Engineering Process documentation

Appendix B- CAD Drawings

Appendix C- Robot Programming

Appendix D- Additional Support Material

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Dear Judges,

On behalf of the entire Central Magnet B.E.S.T. Robotics Team, we

would like to thank you for taking time from your personal life to judge our

team’s Engineering Notebook. Because this is our school’s inaugural year,

there has never before been a Central Magnet Robotics Team. Instead, we

have students who have participated in B.E.S.T. before at other schools, and

those that are just starting out. The Notebook Committee itself is a balance

between the two, since it consists of two experienced members and two new

members.

For the first two to three weeks, the Notebook Committee diligently

documented the engineers’ brainstorming and design ideas. In the weeks

following that, however, the Committee focused more on compiling material

given by the programmers, CAD team, photographers, and some additional

changes made by the engineers. We also discussed via email about

improving the research paper and which organizational method would work

best for the notebook and feel that we have assembled the best notebook

possible to document our team’s engineering process.

We hope that everything contained within this Engineering Notebook

is to your utmost satisfaction and wish you luck in the search for the best

team.

Sincerely,

Central Robotics Notebook Committee

Andrew Heim Katie Lou McCusker Lin Ni Melody Jih

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II. RESEARCH PAPER

Production has come a long way from its simple origins. In fact, the modern

assembly line helps to create almost everything we use today. Mass production has

completely changed the industrialized world and made it a faster, more efficient place.

As production increased, so did the levels of automation. Automation allowed

manufacturers to produce goods more quickly and with fewer mistakes. While this in

theory is the perfect solution for a manufacturing business, even automation can create

flaws. Manufacturing businesses have tried to fix these problems within the

production process. One of the most popular methods is the Six Sigma strategy.

Six Sigma is a business management strategy that was introduced in the US by

Motorola in 1981 and is now deployed across a wide range of sectors. This strategy

strives to advance manufacturing processes and eradicate defects. General Electric and

Honeywell used varying forms of Six Sigma in the late 1990s and have most recently

used it in conjunction with Lean – a production practice that focuses on eliminating all

waste from the production chain. BEST Robotics practiced the Lean process two years

ago in the game Just Plane Crazy.

The ideas of Six Sigma can be easily related to the processes used in the

engineering design method as well as the scientific method. (De Mast, and Bisgaard

p.25) The Six Sigma concept is focused on reducing defects to a goal of 3.4 parts per

million. As manufacturing processes have improved in recent history, the ability to

produce quality goods with fewer defects is possible. For those companies that use the

strategies of Six Sigma, their manufacturing goal is based on the idea that if a company

has six standard deviations between the process mean and the nearest specification

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limit, then practically no items will fail to meet specifications – as demonstrated in this

statistical graph below. The mean is the highest point in the middle and as the

deviations move toward the right, the production quality is increased and Sigma values

rise.

(Graphical information used from www.pharmaceutical-technology.com)

The Six Sigma concept is used in all types of factories to determine how many

parts per million are defective. Factories use this type of calculation to control factory

waste and production issues that would result in a recall of the processed good. These

companies randomly test products for quality, and if a product is flawed, they must figure

out what is not performing correctly. This is similar to what engineers may try and do

when developing a new product or in the case of the BEST game, what the students do to

make their robot more competitive. This would include testing and evaluating current

designs and developing more efficient methods that make the end result more productive.

Mario Perez –Wilson discusses that manufacturers have often focused on final

product inspection when their emphasis should be on production processes that caused

the flaw to occur. Checking a final product for quality may keep a defective product out

of a customer’s hands, but the waste and cost to the manufacturer is still there.

Manufacturing companies can use the process of Six Sigma to help them determine how

http://www.pharmaceutical-technology.com/

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to run production in the most efficient way. This encourages optimal efficiency with as

little waste as possible. This year’s game has that same goal. The robot engineer and

process engineer are working together to eliminate unnecessary production and keep

factory waste to a minimum. Through the use of all available materials including the read

switches and the data port reader, the production process can occur at a more rapid and

efficient pace.

To learn more about Six Sigma, the team interviewed Mr. George Huttick, a

process engineer for Sanford L.P., a Newell Rubbermaid Company. Through this

interview, Mr. Huttick used the example of losing airline luggage. He explained that

when the airline loses a person’s luggage, the result is that the passenger may be mad, but

that losing luggage does not happen often enough to make passengers quit using that

airline altogether. The same example can be used for a product’s quality. When a

consumer purchases a product, there is a reasonable expectation that the product will

perform as expected. His company, Sanford, who makes Sharpie markers, strives to keep

their manufacturing mistakes to a minimum. A poor defect control system would mean

decreased productivity, decreased sales, and loss of customer confidence in the Sharpie

name. The Sharpie customer has a reasonable expectation that the marker will work for a

certain period of time. If it does not, the customer may not purchase a Sharpie marker

again and that hurts sales. He related that same idea to the purpose of the BEST game. In

our contest, the customer is expecting a good gizmo and gadget to be the proper one that

they purchased. If our team packages a defective product, that hurts not only our Sigma

production values, but also our customer confidence.

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In conclusion, our lives are touched each day by the amazing concept of mass

production. Whether it’s cars, markers, or just about anything else, it probably went

through some type of assembly line process before being delivered to the consumer. In an

economy where the customer has multiple choices for the same product, the need for

quality control is very important. The efforts of more efficient production processes,

systems like Six Sigma, and higher quality controls ultimately reward both the

manufacturer and the consumer.

Resources

De Mast, Joroen, and Soren Bisgaard. "The Science Of Six Sigma." Quality Progress

(2007): 25-29. Web. 13 Oct 2010. <http://www.scribd.com/doc/6812821/The-

Science-in-Six-Sigma-VG>.

Huttick, George. Personal Interview. 11 October 2010.

Owen, Tony. Assembly with Robots. London: Kogan Page, 1985. Print.

Peres-Wilson, Mario. "Six Sigma Strategies: Creating Excellence in the Workplace."

Quality Digest 1997: 1-5. Web. 14 Oct 2010.

<http://www.mpcps.com/SixSigmaStrategy.pdf>.

"The Six Sigma Remedy." www.pharmaceutical-technology.com. N.p., 25 Feb 2010.

Web. 14 Oct 2010.

<http://www.pharmaceuticaltechnology.com/features/feature77365>.

III. About Central Robotics

Central Robotics is a new corporation that looks forward to supplying all the

needs of it’s contractors in the field of robotics. The organization brings some highly

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successful experience into the industry. When Mustang Robotics dissolved its

corporation in May 2010, Central Robotics quickly attained many of its brightest

engineers and support personnel. Central Robotics was also able to attain quite a few of

the best engineers and support personnel from Discovery Robotics as well. It is believed

that the combination of both groups will allow Central Robotics to become a major

producer of top quality products in the following years.

This year, Central Robotics has received a new contract bid to design a robot that

effectively allows a corporation to achieve the highest production values in the industry.

Through a careful manufacturing process, it is believed that six sigma can be achieved by

a robot built by a team of qualified engineers. To complete this challenge, Central

Robotics used a carefully documented process and extensive evaluation period to

complete the task. The following pages outline that process in detail. The appendix offers

additional information and documentation about the process and how the final product

was achieved.

IV. Implementation of the Engineering Process

1. Defining the Problem

This year’s contest is based on the concept of attaining Six Sigma in the

manufacturing process. Each team has been given the responsibility to sort, process, and

package products called gizmos and gadgets. The gizmos are separated by their magnetic

properties while the gadgets are separated by their color. During each round, the team is

required to determine what color of gadget is defective and what type of gizmo is

defective (magnetic or non-magnetic). Teams must work to process and package as many

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non-defective gadgets and gizmos as they can in the three minute game period. Gizmos

resemble plastic Easter eggs while gadgets resemble golf balls. The package for the

gizmo resembles a plastic cone with a flying disk for the lid. The gadgets are packaged in

3” clear tubes. The team has three minutes to package as many gadgets and gizmos as

possible.

2. The Engineering and Design Process

Central Robotics knew that understanding the procedures of the game and using

the engineering process would be a vital part of successfully competing in the Total

Recall game this year. The team adopted the engineering process as recommended by the

BEST Robotics group. This was a multi-stage process that required a general knowledge

of the game as well as the overall restrictions on robot size and weight. Team members

also had to recognize the restrictions on materials that were allowed to be used during the

process. The four main phases of design are:

Phase Result (What You Get) Example

1. Conceptual Design Concept Four wheels, scoop, scissor arm

2. Preliminary Design Model or mockup Cardboard model of concept

3. Detailed Design Prototype Robot from kit parts

4. Production Design Product Refined robot from kit parts

As the team considered what needed to be accomplished, it was evident that the major

features of the robot had to perform well in order to score a maximum number of points

and be competitive. At the initial meeting the team developed a list of ten requirements

for the Total Recall Robot. These requirements were:

1. Pick up gadgets (golf balls), gizmos (eggs), packing materials (cones), and lids

(Frisbees) while reaching a maximum height of 30 inches

2. Determine magnetic gizmos vs. non magnetic gizmos

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3. Read the 4 data ports to determine gadget color and gizmo magnetic properties

4. Move and relocate the Mobile Recall Trailer

5. Robot must be less than 24”x24”x24” when closed and as the match begins

6. Robot must weigh 24 lbs or less

7. Robot should be able to clean up the floor – scoop, broom, push

8. Speed is important, but needs accuracy and precision for placing gadgets and

gizmos as well

9. Release gadgets into the sorting bin

10. Roll over the gadget pallet

With all of these requirements in mind, the team began creating a list of “needs versus

wants” to achieve each requirement. The team also determined what design targets would

be set for each requirement. These design targets were a starting point to begin the

brainstorming process that would eventually lead to the first cardboard models. The

design targets were based on the need vs. want list that had been assembled earlier. The

engineering team needed to consider what design targets would best work in the contest.

Design considerations were created based on the size of the game course and the game

objectives.

Requirement Description

for the Total Recall Robot

Need or

Want

Design Target for the Total Recall Robot

Meets the 24x24x24 size limit Need Less than 23x23x23

Meets the 24 lbs requirement Need Less than 23 lbs

Speed

Want

The speed should be slightly faster than

walking speed to achieve the goal

Clean the floor up Need Bulldozer to push pieces if needed

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Pick up game pieces

Need

Target goal - 100 gadgets, 10 gizmos, 3

packages, 2 lids

Read data ports

Want

This requirement should be completed

within the first 20 seconds of the match

Move the cart

Need

This requirement should be completed

within the first 15 seconds of match

Dump gadgets into sorting bin

Need

This task should be completed within the

first 2 minutes of the match

Move gadgets from tube to

sorting bin

Need

This task should be completed within the

first 2 minutes of the match to allow the

process engineer to sort pieces into tubes

Determine magnetic/nonmagnetic

Need

Put this feature on the claw so that the claw

will open or close when reading the

required magnetic/non magnetic gizmo

Roll Over the egg holder

Need

Use large front wheels to drive over the

holder

Once design requirements and targets were completed, the team focused on the level of

importance for each requirement. This allowed the engineers to realize which options had

to be completed and which may have to be left out of the final production model.

Classifying the necessities from mere ambitions made everything much more organized.

The list compiled is based on a scale of 1-5 with 1 being least important and 5 being most

important.

Requirement Description for the Robot Level of

Importance

Meets the 24x24x24 requirement 5

Meets the 24 lbs requirement 5

Speed while maintaining precision 4

Clean up the floor if needed 5

Pick up game pieces 5

Read data ports 3-4

Move the mobile recall trailer and gadget trailer 5

Dump gadgets into sorting bin 4-5

Determine magnetic/non magnetic gizmos 5

Roll over the gizmo pallet 4

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The next step was to determine what the robot should be able to do to complete the

designed task and engineering requirements. Ideas for this part of the process included

moving the robot to the scoring area, obtaining game pieces by lifting or other means,

transporting game pieces, and successfully delivery of the game pieces. The team

designed a chart to outline each function.

FUNCTION CONCEPT or IDEA

A MOVING THE ROBOT

Chassis with wheels, casters, sliders

B OBTAIN GAME PIECE Claw, scoop, dowels, fingers or sticks

C LIFT GAME PIECES Lever arm, scissor lift, 180 degree arm, parallel arm

D READ DATA PORTS

Flag, dial, use springs to touch and read

E

SWEEP THE GAME

FLOOR

Bulldozer, dustpan

F

MOVE THE TRAILERS Hooks, grips, box cutout to turn the trailers, use the

chassis to move the box

The feasibility of each concept had to be considered before construction could begin.

Each concept was given a letter and a number to determine if the team should proceed

with that idea.

A – Mobility

B – Manipulate game pieces

C – Arm to raise lower the device that grabs game pieces

D – A device for reading the data port

E – Moving the game pieces across the game floor

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F – Moving the mobile recall trailer

DESIGN CONCEPT

Is this idea

feasible?

Yes or No

Can it meet the size,

weight, and task

requirements

A1 – Chassis with wheels to move the robot Yes Yes

A2 - casters to allow the robot to move Yes Yes

A3 - sliders to allow the robot to move Yes Yes

B1- Claw/gripper to pick up game pieces Yes Yes

B2- Scoop to pick up game pieces Yes Yes

B3- Dowels/sticks to pick up game pieces Yes No

C1- Lever Arm, either single or dual parallel

type to maintain a constant angle for the

gripper/claw

Yes

Yes

C2- Scissor Lift Yes No

C3- 180 degree Arm Yes Yes

D1-Flag to indicate gadget color and

magnetic/non magnetic gizmos

Yes, but may be

difficult to

create

No, flag material and

paint not allowed

D2-Dial to indicate gadget color and

magnetic/non magnetic gizmos

Yes Yes

D3-Springs – use the spring to push against

the reader

Yes Yes

E1-Bulldozer to push pieces Yes Yes

E2-Dustpan to scoop and collect game pieces Yes Yes

F1-Hooks to pull mobile recall trailer Yes Yes

F2-Grips to pull/push mobile recall trailer Yes Yes

F3-Use chassis to move the box Yes Yes

As the prototype drawings and models were created, the team looked at each one and

judged its effectiveness at accomplishing the task. The engineering team compared the

results with the expected measurements, agility, as well as other overall requirements.

Each one had to meet the necessary criteria to be considered for production.

V. Brainstorming Approaches

1. Gathering Requirements

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As the team began the brainstorming process, the task of gathering a list of robot

requirements was collected. The team used the engineering process results to guide them

during the brainstorming process. The major requirements on the list included:

1. Moving the robot

2. Collecting game pieces

3. Transporting game pieces

4. Moving the mobile recall trailer

5. Reading the data ports to determine gadget color and magnetic gizmos

6. Lifting game pieces – eggs, plastic cone, golf balls, and frisbees

7. Holding game pieces for placement

8. Determining if an object was magnetic or non-magnetic

2. Brainstorming Sessions

As the team began the brainstorming process, it was important that each team

member who would participate in the process understood the game concept and the rules.

The team was fortunate that most of the members of the team had attended the Game

kick-off day and were familiar with the task. That left the members with the

responsibility of knowing what building materials could be used to complete the task. On

the first day of brainstorming, ideas were just talked about and mentioned. Each member

who had an idea was able to stand in front of the group and share the idea. This allowed

each person an opportunity to communicate and for the other members to hear what was

being said. It was understood by the group that no idea would be criticized or thrown out

until all ideas had been considered, completely and thoroughly analyzed. As the

brainstorming session came to an end and the list of ideas was finalized, team members

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voted on the ideas that they wanted to pursue. The top rated designs were group approved

for development while all other designs were saved for future consideration.

3. Robot Design Features

Using the results of the brainstorming sessions, the engineering design process,

and the preliminary game strategy the team decided to focus our effort on two main areas.

These were the claw and the collection trailer. The claw needed to manipulate a plastic

cone, a plastic Easter egg, and a plastic flying disk. This proved to be the most

challenging element of the design process. The claw would also need to turn 180 degrees

in order to place the cone. The engineering team considered a variety of claw designs.

Two of the more popular ones were quickly prototyped for evaluation and are pictured

below.

Figure 1 – Scoop made of PVC Figure 2 – stick model design

After a second vote within the engineering team, it was decided that the cup type claw

and the golf ball collection tube be prototyped and tested.

The next main component of the robot was the gadget collection trailer. The

design constraints of the trailer required that the base be at least four inches tall and open

at the right time to release the gadgets (golf balls). The trailer would also need to be

lightweight to roll smoothly and should probably include caster wheels to move easily in

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any direction. The caster wheels would allow the robot and trailer to turn easily in the

same direction.

Figure 3 – CAD design Figure 4 – actual production box

VI. Analytical Evaluation of Design Alternatives

The team looked at of the elements of the design process to determine which

features best met the requirements of the contest. Some of these functions were analyzed

mathematically while others were evaluated through actual testing.

1. Wheel Analysis

It was stated in the engineering process that the robot needed to be quick enough

to accomplish the required tasks in the three minute time period. This would require

making sure that the wheels were large enough to move quickly, but not be too large and

not allow the robot to maneuver as needed. The engineering team asked the programmers

to help design a chart that would calculate the maximum speed each size wheel could

attain. Using the formula below, the programmers were able to determine the speed.

Game Box Dimensions:

Maximum Length: 20 feet

Maximum Width: 10 feet

Drive Motors:

Specifications:

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Speed: 42 rpm

Control:

Forward: 0 to 127 (max. 42 rpm) in increments of 1

Reverse: 0 to -127 (max. 42 rpm) in increments of 1

Maximum revolutions per second: 42 rpm / 60 sec yields ~ 2/3 of one

revolution

Digital Resolution: 127 / 42 rpm yields ~ 3 increments / rpm

~ 1 /3 rpm / digital increment

Wheel Speed and Maneuverability Table: (diameter x pi (3.14) = circumference of

wheel)

Size

Rounded

Circumference

Maximum

ft/sec

Minimum

inches/sec

Travel

Time(1)

Round

Trip

Time(2)

Maximum

Trips

6 ” 19 ” 1.0 0.11 20 s 40 s 4.5

7 ” 22 “ 1.2 0.12 17 s 34 s 5.3

8 ” 25 “ 1.4 0.14 14 s 28 s 6.0

9 ” 28 “ 1.6 0.15 13 s 26 s 6.5

10 ” 31 “ 1.7 0.17 12 s 24 s 7.5

11 ” 35 “ 1.9 0.19 11 s 22 s 8.2

12 ” 38 “ 2.1 0.21 10 s 20 s 9.0

13 ” 41 “ 2.3 0.23 9 s 18 s 10.0

14 ” 44 “ 2.4 0.24 8 s 16 s 11.2

15 ” 47 “ 2.6 0.26 7.5 s 15 s 12.0

16 ” 50 “ 2.8 0.28 7 s 14 s 12.8

Figure 5 – The full calculation sheet can be found in Appendix A

The robot wheels were designed to maximize speed. The programming team calculated

the speed of different sized wheels and the engineering team used that data to design the

final wheel for the robot. A 13” wheel was determined to be the best size to meet the

team needs for both speed and precision.

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Figure 6 – CAD designed wheel Figure 7 – production wheels

When the engineering team consulted with the programming team regarding the

speed of the robot, it was realized that the Cortex could be programmed to slow down the

robot for precise placement of the game pieces. Because of this, the engineering team

chose the largest possible wheel size to attain maximum speed when moving across the

field. The larger wheel size would also allow the robot to roll over the gizmo pallet if

needed. The team also decided to add a rubber to the wheels to maximize traction while

moving the robot and the trailers.

2. Arm Analysis

The arm of the robot would be a vital part of the gripping process. The arm would

have to support the weight of the claw while moving vertically. The arm would also need

to maintain a perpendicular direction to the floor to accurately place the plastic cone and

the eggs. The team considered a single arm, but it would have to bend in a way to

maintain the upright motion of the claw. A second arm idea was a lift that moved

vertically up and down would complete the task and keep the claw in the right place. The

problem with the vertical lift is that it could not reach high enough to place the cone in

the holding hole. The third arm design is called a parallel arm. This arm design actually

has 2 arms to move together up and down. It acts like a single arm in the way it moves up

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and down, but because it connects to the claw in two separate places, it allows the claw to

stay perpendicular to the floor and capture and place the objects effectively. Because of

this ability, this is the arm that was chosen.

Figure 8 – parallel arm design using SolidWorks

Figure 9 – parallel arm prototype

3. Claw and Gripper Analysis

The claw for the robot was the most challenging part of the process. Because of

the additional 360 points benefit of a dual production bonus, the engineering team

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believed that collecting gizmos and gadgets was an essential part of being successful in

this competition. The claw could be built several different ways. The design

considerations required the claw to pick up eggs, grab a cone and rotate it, and pick up

and place a flying disk. To do all three of these tasks would require a claw that was very

specialized. Many different claws were designed and each was tested on the practice

field. The problem that kept coming up was that the claw could perform one function

well, but could not perform all functions effectively enough to satisfy the engineers. The

first design that was built was a cup design out of cardboard. This would allow the driver

to scoop eggs from both sides.

Figure 10 – cardboard cup design

The next design used the same idea as the cup design, but one side was flattened while

the other side slid into it. This design would grab the cone, scoop the eggs, but not grasp

the flying disk. At one time, the team was going to fully develop this idea and disregard

the flying disk task. The bottom was also brittle and broke off during testing.

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Figure 11 – plastic cup design

Another method used a long tube and had the design features of a golf ball pick-up tube.

This same design is also used for tennis balls. The design worked in testing, but required

a large amount of force to capture the eggs and the claw did not grasp the cone

effectively. The cone would slip through the grippers. More drawings about this design

and how it works can be found in Appendix D.

Figure 12 – pickup tube design with claw on top

The final production model came from a mixture of the previous designs. This

claw would use the cup method of scooping the eggs while allowing the sides of the cups

to grip the cone. The sides of the cone are made of green PVC due to its strength while

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the bottom of the claw is created from thin pieces of white PVC that bends and flexes.

These thin pieces keep the cone in place and allow eggs to slip through and sit on top of

the pvc pieces without falling back through. The gripper can then be turned over to let the

gizmos roll out the side of the gripper. This is the design that was agreed upon to be the

most effective. The team recognized that grabbing a few eggs reliably would be more

beneficial that trying to grab all of them and miss.

Figure 13 – cup design Figure 14 – cup design side view

Figure 15 – final production cup design

4. Trailer vs. Attached Box Analysis

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The process of designing a trailer to carry the gadgets was a primary part of the

game strategy. Without this feature, the robot would have to sit under the drop tube and

wait to be filled. Although this would be easier to gather and release the gadgets, it would

not allow for other tasks to be done while the spotter was loading the gadgets. Although

both ideas were initially considered, it was decided by the majority of engineers to build a

separate trailer that would collect and then deliver the gadgets. This strategy and design

feature proved to be effective at the Game Day with our local hub.

Figure 16 – gadget collection box Figure 17- box in chassis

VII. Programming the Robot

1. Motion Programming

The robot has been programmed and tested by our team of programmers. The

programming team met with the engineers during the brainstorming process to determine

the necessary functions and work from those notes to program the VEX Cortex controller

to perform as needed. The first task was to get the robot rolling. The programmers had

assisted the engineers with wheel size and after the wheels had been cut out and mounted

to the chassis, the programmers worked on motion of the robot. It was determined by

both groups that to allow for speed and precision, the robot should have varying speeds.

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The regular speed would be 100% while the slower speed would be activated by a pushed

button that would then change all of the drive motors to 50% speed. This allows the robot

to turn slowly and maneuver into tight places with fewer mistakes.

2. Servo programming for the gripper

The next part of the programming task was to program the servos to work

together to close the claw. The claw slides on a rail so that all movement is horizontal and

parallel to the floor. One servo moves clockwise while the other servo has been

programmed to move counterclockwise. Another servo has been programmed to release

the magnetic detection arm located on the front of the robot.

3. Lift Arm programming

The last part of the programming was to determine the speed of the lift motor and

the rotational motor. The engineers again met with the programming team and

determined that the rotational motor for the claw should be slower than full speed. The

rotational motor is set at 50% speed to allow the claw to rotate the cone without losing it

in its grasp and to allow the claw to pour out the gizmos (eggs).

VIII. Offensive and Defensive Evaluation

1. Developing a Game Strategy

Another part of the brainstorming process involved developing a game strategy.

On the team this year, it was decided that the team would have a separate Strategy Team.

This team would develop a game strategy that allowed for the most points to be scored

and use the allotted amount of time effectively. The team considered defensive and

offensive strategies. With the design of the game this year, many had not considered

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defensive strategies, but it was determined that a strong offensive strategy would provide

for a good defensive strategy. It’s far better to be safe than sorry.

Offensive Strategy

Design the robot to complete multiple tasks at the same time. You must

efficiently collect gadgets while also collecting gizmos. This could be

completed using a separate gadget collector that is left to only collect gadgets.

Determine what color gadgets need to be collected to eliminate excess factory

waste and eliminate extra time required to sort the waste gadgets. This will

also serve as a defensive strategy. In practice rounds, spotters were able to

average 120 gadgets in the estimated 90 seconds that was available for gadget

collection. The team goal is 120 gadgets with at least half of those gadgets

begin packaged.

Work toward a dual production bonus of 360 points. This would be equal to

120 properly packaged gadgets.

On each and every round, focus on attaining the highest Sigma value for each

round. It is believed that scoring less gadgets and gizmos in a particular round

is less important than keeping a good Sigma value.

The scoring for each round would be as follows:

* Gadget – 2 points per gadget, 3 points per packaged gadget

* Gizmo – 10 points per packaged gizmo, 20 points per packaged/sealed gizmo

* Gizmo package – 50 points

* Dual Production Bonus – 360 points

* Perfect Sigma score – multiply by 6

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Expected total points per round:

60 gadgets (unpackaged) + 60 gadgets (packaged) + 3 Gizmo Packages + 2

Gizmos + Dual production bonus x 6 (for gadgets and gizmos) = 2430

Defensive Strategy

A strong offensive strategy was a key part of our defensive strategy.

Determining which gadgets we needed before the other teams had a chance to

determine their needed gadgets, allows us to work on collecting our particular

colors. We also have a time period where we do not have to compete for pieces

with other teams. When we collect 120 pieces, we can feel confident that all one

hundred will score instead of having to take the chance that a third of them will be

factory waste. Also, keeping our sigma values at the highest level keeps our team

from having to change our offensive strategy during the game.

IX. Testing and Evaluation of the Competition

As the team prepared for it’s first public exhibition, there were several problems

that the robot was experiencing. The robot was three pounds heavier than the ideal goal

of twenty four pounds. This meant that the robot had to be lightened to be legal for the

competition. The robot also had some trouble accurately grasping the gizmo package.

The design of the gizmo package makes it slippery and difficult to hold. Some form of

friction would need to be added to the gripper to make it easier to pick up and hold the

gizmo package.

When comparing the robot with other robots, the engineering team realized that

the robot was not as effective at picking up parts on the playing field as the competition.

The gripper moved too slowly and did not have enough contact area with the game

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pieces. When the engineering team returned back to the workshop later that afternoon,

several designs were reconsidered. One team member mentioned using a design that

looked like a split cup. The team member used a foam drinking cup as the model. When

cut in half and placed at an angle, the cup fit the gizmo package or orange cone on each

side fairly well. The top of the angled cups could also be used to pick up the gizmos and

gadgets. This new system would be lighter than the existing system as well. The team

decided to move forward with this new gripper design and used four inch green PVC pipe

to create the new gripper. The gripper was formed so that the curve would fit both the

cone and hold eggs and golf balls. The new gripper was lined with foam rubber to

increase friction and keep the game pieces in the gripper.

Figure 18 – cup design concept Figure 19 – production design

After testing the new gripper, the team realized that the drivers could also place

the packaging lid or flying disk with the gripper. A magnetic read switch was added to

the end of the gripper to help determine correct gadgets during the game. The switch was

programmed using the data port and does not allow the operator to pick up defective

pieces. The new gripper allows the team to use this function effectively where the

existing gripper did not plan to use this function.

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Another problem with the robot was precision. While it moved all game pieces,

the ability to be precise was not possible. The problem was with the mobile recall trailer.

The building team had built the practice trailer too wide. When the team tested the real

trailer at Mall Day, it was realized that the trailer at our testing facility was too wide by

1.5 inches. This made our pickup area too wide and moving the mobile recall trailer

accurately was more difficult. The engineering team decided to add a simple trailer

grabber to help fix this problem and make placement of the trailer more accurate.

Other fixes to the robot included a new box that acted as a gadget collector. The

existing collector weighed six pounds and was too big. The new collector weighs three

pounds, is smaller, and still holds 150 gadgets if needed. With those three fixes, Central

Robotics believed that it would be able to be competitive on Game Day. When Game

Day arrived the team had major issues with the gadget box release. The gadgets released

onto the field twice during competition. The engineers determined that the clothespin that

was used to hold the box shut was being opened when the box was placed under the

gadget sorting tube. To fix this, the team added a small piece of wood to the top of the

clothespin. If the clothespin hit something, the top of the pin would hit first and actually

close the pin instead of allowing it to open.

The team was able to make it to the semifinal rounds and with this modification

the team had no more issues and won the Game Day competition. At this point in time,

the team plans to make minor adjustments to the robot. One change is to make the gadget

box smaller to allow more space in the starting area for maneuverability. Another change

is to add an additional support piece to the parallel arm as a backup in case the holding

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pin should fail during competition. These changes have yet to be made and are in the

planning stages, CAD design, and evaluation process before final production begins.

X. Safety

All production must focus on safety as the main component of any work area.

This is true at Central Robotics as well. The engineers and building team members (those

who built the booth) as well as the electricians were required to have basic safety

instruction for proper tool use. Some of the members had previous experience and helped

new engineers and builders with proper safety practices when using powered equipment.

On other specialized equipment such as the metal lathe and milling machine, students

were instructed by a mentor with the program. During the building of the robot and other

pieces of construction, Central Robotics had a perfect safety record with no lost time due

to an on the job injury. The team adopted four basic safety rules for the team.

Safety Rules:

1. No one can use a piece of equipment unless they have been trained to use that

piece of equipment.

2. Safety glasses must be worn at all times.

3. Clean up wood, metal and plastic shavings and put all tools away at the end of

each work session.

4. All excess wood and plastic should be returned to its proper container.

XII. Summary

Central Magnet used a three-step process to design and build their Total Recall

robot. During the first step, the engineers and the strategists reviewed the requirements

and began to brainstorm different ways to make the robot meet and exceed those

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requirements. The team began to build the robot with the help of small prototypes during

step two. For the third and final step, Central’s BEST team tested out the newly-

completed robot, trying to make it more efficient, and fixing any design flaws that may

have appeared. Central’s robot has a lever arm attached to bungee cords that allow for

forward and backward movement. At the end of the lever arm is a gripper. A small motor

is used to control the arm. Four springs near the bottom of the robot allows the robot to

read the data ports, and an indicator made out of colored duct tape enable understanding

of the state the game pieces are in. Through teamwork, planning, and a carefully designed

building process, the Central Magnet BEST team was able to build a robot that mets the

requirements of the client and compete in this year’s Total Recall game.

Figure 19 – side view Figure 20 – rear view

Figure 21 – top view Figure 22 – angle view

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APPENDICES

Appendix A: Engineering Process

Appendix B: CAD Design

Appendix C: Robot Programming

Appendix D: Additional Support material

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Appendix A

Engineering Process

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EEnnggiinneeeerriinngg PPllaann ffoorr CCeennttrraall RRoobboottiiccss

The four main phases of design are:

Phase What You Get Example

1. Conceptual Design Concept Four wheels, scoop, scissor arm

2. Preliminary Design Model or mockup Cardboard model of concept

3. Detailed Design Prototype Robot from kit parts

4. Production Design Product Refined robot from kit parts

CONCEPTUAL DESIGN

There are eight (8) steps to coming up with a concept. STEP 1: LIST ALL REQUIREMENTS FOR THE ROBOT

This list is generated after reviewing the rules and developing a general strategy. You

may need to draw a picture of the playing field and also layout/sketch scoring strategies. Requirements for the Total Recall Robot

11. Pick up golf balls, eggs, and cones, Frisbees – 30 inches 12. determine magnetic eggs vs. non magnetic eggs

13. read the 4 data port

14. move the cart 15. less than 24x24x24 when closed or match begins

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16. 24 lbs or less

17. clean up the floor – scoop, broom,

18. speed is important, but need accuracy

19. dump golf balls – see #1

20. roll over the egg holder

STEP 2: BREAK DOWN LIST INTO NEEDS AND WANTS

Requirement Need or Want

The robot cannot be any larger than 24x24x24 inches Need

The robot cannot weigh more than 24 lbs Need

Speed Want

Clean up the floor Need

Move the cart Need

Pick up game pieces Need

Determine magnetic gizmos/non magnetic gizmos Need

Read data ports Want

Dump gadgets Need

Roll over the egg holder Need

Move gadgets from tube to sorting bin Need

STEP 3: SET DESIGN TARGETS FOR EACH REQUIREMENT:

Requirement Description for the robot

Need or Want

Design Target for the Robot

Meets the 24x24x24 size limit

Need Less than 23x23x23

Meets the 24 lbs requirement

Need Less than 23 lbs

Speed Want Slightly faster than walking speed

Clean the floor up Need Bulldozer

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Pick up game pieces Need 100 golf balls, 10 eggs, 3 cones, 2 frisbees

Read data ports Want Read within 20 seconds of the match start

Move the cart Need Within the first 15 seconds of match

Dump golf balls Need Within 2 minutes

Determine magnetic/nonmagnetic

Need Put this feature on the claw

Roll Over the egg holder Need Use front wheels to drive over the holder

Move the gadgets to sorting bin

Need Create a separate cart to hold gadgets

STEP 4: Rank each requirement based on its level of importance on a scale

where “1” is least important and “5” is most important

Requirement Description for the Robot Level of Importance

Meets the 24x24x24 requirement 5

Meets the 24 lbs requirement 5

Speed 4

Clean up the floor 5

Pick up game pieces 5

Read data ports 3-4

Move the cart 5

Dump golf balls 4-5

Determine magnetic/non magnetic 5

Roll over the egg holder 4

Move gadgets from tube to sorting bin 5

STEP 5: LIST ALL ROBOT FUNCTIONS THAT NEED TO OCCUR

MOVE TO SCORING AREA OBTAIN GAME PIECE SECURE GAME PIECE LIFT GAME PIECE STEP 6: DEVELOP CONCEPTS FOR EACH FUNCTION

FUNCTION CONCEPT or IDEA (MAKE SKETCH ON A SEPARATE SHEET OF PAPER)

A MOVING THE ROBOT Chassis with wheels, casters, sliders

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B OBTAIN GAME PIECE Claw, scoop, dowels,

C LIFT GAME PIECES Lever arm, scissor lift, 180 degree arm

D READ DATA PORTS

Flag, dial, use springs to read

E

SWEEP THE GAME FLOOR Bulldozer, dustpan

F

MOVE THE MOBILE RECALL TRAILER AND GADGER CART

Hooks, grips, use the chassis to move the box

STEP 7: ASSIGN A LETTER AND NUMBER TO EACH CONCEPT

1. Feasibility – can this be done? 2. Go / No Go – does it meet all needs? 3. Decision Matrix – does it meet wants?

Feasibility

Concept Feasible? Yes or No

A1 – Chassis with wheels Yes

A2 - casters Yes

A3 - sliders Yes

B1- Claw Yes

B2- Scoop Yes

B3- Dowels Yes

C1- Lever Arm Yes

C2- Scissor Lift Yes, but not needed

C3- 180 degree Arm Yes

D1-Flag Yes

D2-Dial Yes

D3-Springs Yes

E1-Bulldozer Yes

E2-Dustpan Yes

F1-Hooks Yes

F2-Grips Yes

F3-Use chassis to move the box Not likely

Go – No Go (needs only) – This is the prototype planning stage Does each concept meet the requirements from the previous section

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Requirement A1 A2 A3

Meet weight requirements Yes

Yes Yes

Meet size requirements Yes Yes Yes

Pick up game pieces Yes Yes Yes

Requirement B1 B2 B3 not feasible

Meet weight requirements Yes

Yes

Meet size requirements Yes Yes

Pick up game pieces Yes Yes

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Appendix B

CAD DESIGN

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production Model with gadget collection box

parallel arm

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trailer pick-up arm

production model – rear view

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production gripper design for collecting gizmos (eggs) and holding

gizmo package

original production gripper side view

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gadget collection box

production model without gadget collection box

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production model – side view

production model – top view

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parallel arm support

production wheel at 13” diameter

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Appendix C

Programming

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Functionality Requirements

Mobility Drive Requirements: 1) Normal Drive Control - Right-hand joystick movement.

a) Forward movement – upward positioning of the joystick vertical axis.

b) Backward movement – downward positioning of the joystick vertical axis.

c) Left movement – left positioning of the joystick horizontal axis.

d) Right movement – right positioning of the joystick horizontal axis.

2) Tank Style Pivot Control – Right-hand joystick movement.

a) Left in-place pivot – left positioning of the joystick horizontal axis with zero

vertical axis movement.

b) Right in-place pivot – right positioning of the joystick horizontal axis with zero

vertical axis movement.

3) Proportional Speed Control –Right-hand joystick movement.

a) Forward/Backward speed – based upon the positional value returned from the

joystick vertical axis.

b) Left/Right speed – based upon the positional value returned from the joystick

horizontal axis.

4) Maximum/Slow Speed Control – Right-hand joystick position and Group 6 Up button.

a) Maximum speed – determined by calculation of angular velocity of diameter of

the drive wheels. Predefined variable to be used for governing the maximum

speed allowed.

b) Slow speed – determined by the setting of the predefined slow speed divisor

variable used for governing the speed allowed. Finer control of the robot

positioning with larger drive joystick inputs. Requires press and hold of the

Group 6 Up button for slow speed.

5) Joystick Dead Zones – Programmable defined areas of no actions from drive joystick

inputs.

Notes:

See drive wheel calculations table for details on mobility speed control.

Micro-Controller Programming Team


BEST 2010 Competition

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Manipulation Devices Requirements:

Gripper Device Requirements: 1) Gripper Open/Close Movement Control – Group 7 joystick buttons.

a) Open movement – press and hold Group 7 Left button.

b) Close movement – press and hold Group 7 Right button.

2) Gripper Rotation Movement Control – Left-hand joystick horizontal axis.

a) Counter-clockwise rotation movement – press and hold Group 5 Down

button with left directional movement of the horizontal axis.

b) Clockwise rotation movement – press and hold Group 5 Down button

with right directional movement of the horizontal axis.

Lift Arm Device Requirements:

1) Up/Down Movement Control – Left-hand joystick vertical axis.

a) Up movement – upward positioning of the joystick vertical axis.

b) Down movement – downward positioning of the joystick vertical axis.

2) Proportional Speed Control – Left-hand joystick vertical axis movement.

a) Up/Down speed – based upon the positional value returned from the

joystick vertical axis.

3) Maximum/Slow Speed Control – Left-hand joystick vertical axis position and

Group 6 Up button.

a) Maximum speed – determined by rotation motor’s maximum rpm rating.

Predefined variable to be used for governing the maximum rotation speed

allowed.

b) Slow speed – determined by the setting of the predefined slow speed

divisor variable used for governing the speed allowed. Finer rotation

speed control with larger joystick vertical axis input. Requires press and

hold of the Group 6 Up button for slow speed.

4) Joystick Dead Zones – Programmable defined areas of no actions during lift arm

movement of joystick.

Swept Arm Device Requirements: 1) Up/Down Movement Control – Group 8 Up and Down buttons.

a) Down movement – press and hold the Group 8 Down button to lower and

position the swept arm.

b) Up movement – press and hold the Group Up button to raise and position

the swept arm.

2) Movement Limits Control – Programmable predefined variables to limit

maximum up and down positions of swept arm.




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Data Port and Sensors Requirements:

Data Port Requirements: 1) Data Port Sampling Control – Three digital inputs and Group 7 Up button.

a) Defective Gadget detection – digital input ports 1 and 2 used for sampling

of defective Gadget type.

b) Defective Gizmo detection – digital input port 3 used for sampling of

defective Gizmo type.

c) Sampling control – press and hold Group 7 Up button to record sample

from digital input ports.

2) Data Port Data Analysis – Determine if sample data is valid.

a) Gadget sample analysis – digital port 1 represents bit 0 data and digital

port 2 represents bit 1 data. Use provided truth table from BEST 2010

competition handbook to validate Gadget data sample from bit 0 and bit 1

data only.

b) Gizmo sample analysis – digital port 3 represents bit 2 data. Use provided

truth table from BEST 2010 competition handbook to validate Gizmo

magnetic or non-magnetic status using bit 2 data only.

3) Indicate Sampling Validation Results – Servo controlled zones chart.

a) Invalid sampling results – servo moves indicator to red zone.

b) Valid magnetic sampling results – servo moves indicator to magnetic

quadrant and defective Gadget zone.

c) Valid non-magnetic sampling results – servo move indicator to non-

magnetic quadrant and defective Gadget zone.

Truth Table From Page 24 – BEST Game Specific Rules (ACMR00006 Rev 1.2)

Factory Data

Port Defective Products

P2 P1 P0 Gadgets Gizmos

0 0 0 Black Magnetic

0 0 1 Yellow Magnetic

0 1 0 White Magnetic

1 0 0 Black Non-Magnetic

1 0 1 Yellow Non-Magnetic

1 1 0 White Non-Magnetic

0 1 1 No Connection

1 1 1 No Connection




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Joystick Assignments

Drive Control: Right-Hand Side Joystick:

Group 1 (Horizontal) – Controls Turning Left and Right.

Group 2 (Vertical) – Control Forward and Backward Movement.

User Options:

1) Better control for positioning robot via slow speed selection.

Press and hold Group 6:Up button to shift into slow speed drive mode. Release

button to return to normal drive speed.

2) Tank style pivot, in place, movement of robot.

Move joystick left or right with No Forward/Backward joystick input.

3) Emergency pause of robot movement.

Press and hold all four (4) buttons, Group 5:Up and Down, Group 6:Up and Down,

at the same time on the front of the joystick control unit. Release all buttons to

resume normal operation after one (1) second pause.

Gripper Arm Control: Left-Hand Side Joystick Group 3 (Vertical) – Controls Gripper Lift Arm movement.

Forward lowers the gripper lift arm assembly.

Backward raises the gripper lift arm assembly.

Group 7:Left/Right Buttons – Controls Gripper open and close movement.

Left button opens the Gripper assembly.

Right button closes the Gripper assembly.

Left-Hand Side Joystick Group 4 (Horizontal) – Controls Gripper rotation.

Press and hold Group 5:Down button while moving joystick to the left to rotate

gripper assembly counter-clockwise.

Press and hold Group 5:Down button while moving joystick to the right to rotate

gripper assembly clockwise.

Data Port Read Control:

Group 7:Up button – Controls Data Port Reading Request

Press Group 7:Up button to attempt reading of valid data from Data Port. If valid

data is read from Data Port, then bad Gadget and Gizmo type (Magnetic or

Nonmagnetic) is indicated on Gadget/Gizmo Indicator Scale.

Note: Drive and Rotation direction indicated based upon driver’s rear to front view of robot.




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Mobility Control Team

Date __09/20/2010__________

Subject _Determine best compromise for speed and maneuverability in wheel diameter____

Game Box Dimensions:

Length: 20 feet Width: 10 feet

Drive Motors:

Specifications:

Speed: 42 rpm

Control:

Forward: 0 to 127 (max. 42 rpm) in increments of 1

Reverse: 0 to -127 (max. 42 rpm) in increments of 1

Maximum revolutions per second: 42 rpm / 60 sec yields ~ 2/3 of one revolution

Digital Resolution: 127 / 42 rpm yields ~ 3 increments / rpm

~ 1 /3 rpm / digital increment

Wheel Speed and Maneuverability Table: (diameter x pi (3.14) = circumference of wheel)

Size

Rounded

Circumference

Maximum

ft/sec

Minimum

inches/sec

Travel

Time(1)

Round Trip

Time(2)

Maximum

Trips

6 ” 19 ” 1.0 0.11 20 s 40 s 4.5

7 ” 22 “ 1.2 0.12 17 s 34 s 5.3

8 ” 25 “ 1.4 0.14 14 s 28 s 6.0

9 ” 28 “ 1.6 0.15 13 s 26 s 6.5

10 ” 31 “ 1.7 0.17 12 s 24 s 7.5

11 ” 35 “ 1.9 0.19 11 s 22 s 8.2

12 ” 38 “ 2.1 0.21 10 s 20 s 9.0

13 ” 41 “ 2.3 0.23 9 s 18 s 10.0

14 ” 44 “ 2.4 0.24 8 s 16 s 11.2

15 ” 47 “ 2.6 0.26 7.5 s 15 s 12.0

16 ” 50 “ 2.8 0.28 7 s 14 s 12.8




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Controller Configuration

DIGITAL IN/OUT:

Input #1 Data Port Bit 0 - Bad Gadget Color Select

Input #2 Data Port Bit 1 - Bad Gadget Color Select

Input #3 Data Port bit 2 - Gizmo Type Select

Input #4 Gripper Left Rotate Limit Switch (Optional)

Input #5 Gripper Right Rotate Limit Switch (Optional)

Input #6 Arm Up Limit Switch (Optional)

Input #7 Arm Down Limit Switch (Optional)

Input #12 Reed Switch Magnetic Detector Switch (Optional)

MOTORS:

Output #1 Left-Side Drive Wheel Motor Control

Output #2 Gripper Arm Up/Down Motor Control

Output #3 Gripper Left-Hand Servo Control

Output #4 Gripper Right-Hand Servo Control

Output #7 Swept Arm Servo Control

Output #8 Color/Magnetic Indicator Servo Control

Output #9 Gripper Rotation Motor Control

Output #10 Right-Side Drive Wheel Motor Control




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Appendix D

Engineering Meeting Notes and

Drawings

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Notes from the interview with Mr. George Huttick

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Original Chassis Design

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Strategy for scoring points

Preliminary robot design idea

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The above design is the original claw idea that used the golf ball and egg pickup tube idea as

drawn below.

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Drawings were created to help with the SolidWorks CAD design. Drawings were made by

Ryan Cripps.

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Documents

Central Magnet Robotics