Intermediate RoboticsGetting to the Next Level

Guiding Question: How might I move the robot consistently, accurately, and predictably?

– Review basics (consistent x-y movement)– Reference Points (mechanical stops, sensors)– Videos (examples)– Programming

• WAIT block (simple sensors)• Loop/Switch blocks• Advanced blocks (Motor/Sensor/Math/etc.)• MY Blocks

Reminder

• KIDS DO THE WORK!!!• Encourage kids to ask questions, do

research, experiment, discuss observations, etc.

• “Mentor with questions”

• Use simple exercises to demo key concepts/programming skills

• Have fun!!!

BOT BASICS(NXT Curriculum)

• Bot calibration– 5 rotation test n = D/C– 360° test n = (A/360)(2πd/C)

• Initial Placement– X - Y position– angle

• Mission mapping

Reference Points

• Final position error depends upon:– initial placement (x, y, angle)– distance/angle measurements– bot calibration

• Problem: long distances, multiple turns lead to large final position errors

2011 FLL Table

Angle Errors

2 Degrees Left 2 Degrees Right

Error = ± 1.5”@ 50”

Positional Error Reduction

Solution:

identify “intermediate reference points”

(keep MOVE distances short)

Use:

- mechanical stops (walls, other)

- sensors

Demo Videos(identifying reference points)

• 2011 SRES FLL - Supai

• Youtube (253 pts)

• ASU BEST

• Mohave Robotics Club

Simple Sensors

WAIT blocks (ultrasonic, light, sound, touch)

Basic operation: move unlimited until sensor is triggered and stop

SENSOR ISSUES: placement on bot limitations

Challenges/Exercises(WAIT Blocks)

• “closest to the wall” using ultrasonic– limitations???

• “find a line” (find multiple lines)– light sensor needs calibration– color sensor (no calibration

• FLL challenges– FLL table (issues??)– FLL/Avnet challenges

Discussion

• Learning??

Moving with LOOP Block(vs WAIT Block)

Sensors (ultrasonic)

Logic

Moving with LOOP Block II

Multiple Sensors (with COMPARE block)

Line Following(LOOP/SWITCH/SENSOR BLOCKS)

Challenges

• follow a line (or find a line and follow it)

• use touch sensor to “square up to a wall”

• FLL challenges (i.e. pill push)

• FLL table challenges

Discussion

• Learning??

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VARIABLE block•The variable block is a “bucket” where you can store information and retrieve it at a later time.•There are three types: Number, Text, and Logic

MATH block•The math block allows the addition, subtraction, division or multiplication of two numbers.

COMPARE block•The compare allows you to determine if one number is greater than, less than or equal to another number.

Input

Output

Output (True or False)

Input

Advanced Blocks

VARIABLES – how to create your own variables

• To create your own variables

1. Select “File” Menu and "Define Variables" option

2. Type the name of the variable, then select its type.

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Data Hubs and Data Wires• Data Hub is another way of providing input data

into a Block.

• Most blocks have a tab at the bottom and when clicked the block expands to show its data "hubs"

• The MOVE block has are several datahubs that correspond to its input fields

• Data wires connect data hubs; you create a data wire by “drawing it out” of a block’s data hub.

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Power

Direction

Duration degrees

Next Action (brake or coast)

Steering

Left Motor

Right Motor

Other Motor

Data Wire

Move Input Distance I(Variable & Math Blocks, Wiring)

Input distance

Convert distanceto degrees &

Input to MOVE block

Distance-Power Example II(Variable & Math Blocks, Wiring)

MY Blocks

Condenses multiple blocks to a single block (a sub-routine)

• multiple use of same coding sequence• reduces memory needed

MY Block Example

Select blocks

Create MY Block

Name Variables in MY Block

Name Values

Before

After

MY Block Use

• Use for repeated operations– find a line– line following– etc.

• Include variables into MY blocks(repeated operations with different parameters)

• Where ever

SCC Avnet Competition

Tasks (located at trigger points): - raise flag - pill push - grab “Trophy” Complete course

Issues: Line Geometry/Trigger Points are NOT predefined

SCC Avnet TechGames

• Show program build

• Show videos

Exercises

• Create a MY Block– follow line & find trigger points– design your own challenge

• Create MY block with 1 or more variables– follow line & use variable distance ultrasonic– design your own challenge

Reminder

• KIDS DO THE WORK!!!• Encourage kids to ask questions, do

research, experiment, discuss observations, etc.

• “Mentor with questions”

• Use simple exercises to demo key concepts/programming skills

• Have fun!!!

Info Sources

• http://engineering.asu.edu/k12outreach/fll/coaches– NXT Programs = Robot Building Instructions– Oregon FLL Video NXT Tutorial – Introductory Robotics Curriculum– Intermediate Robotics Instruction

• Youtube.com (NXT programming)

• books– Kelly, James “LEGO MINDSTORMS NXT-G Programming Guide”