Some Robotic STEM Ideas Craig Shelden craig.shelden@comcast.net 202-251-7578 Science and Engineering Festival.

Some Robotic STEM Ideas

Craig Sheldencraig.shelden@comcast.net

202-251-7578

Science and Engineering Festival

Robot Connections with STEM

Combines disciplines• Engineering• Math• Technology• Scientific Method

Makes abstract ideas real.

3

Thoughts on Programming

Clear Problem Statement

Pseudocode Draw out what’s being attempted Words First.

Program – Test – Program – Test ---> Repeat

Value of default settings… ? Make things easier to program… Make students think through every block they program

Approaches vary with goals and Team choices

WeDo Programming

Sailor Max

Basic boat movement

Basic boat movement with sound effects

basic_boat.wedoboat_sounds.wedo

WeDo – Complex Capability with Sailor Max

storm.wedo

Motion and sound with tilt sensor

Motion and sound with tilt triggered by proximity sensor

WeDo – NXT-G ConnectionSimilar: • Syntax• Coloring• Left – to – right

program flow

NXT-G Simple Area Measurement

Given a circle… How to measure its area using a robot?

Circumference = 2πr

Area = π r2

r

Pause Here…

NXT-G Simple Area Measurement

Given a circle… How to measure its area using a robot?

Circumference = 2πr

Area = π r2

One approach might be to:• measure all the way around

the circle• calculate the radius• calculate the area

Area = C2/(4 π)

r

One Circle Measuring Solution

NXT-G Simple Area Measurement

Given a circle… How to measure its area using a robot?Other ways….

Circumference = 2πr

Area = π r2

r

Are there other ways?

NXT-G Simple Area Measurement

Given a circle… How to measure its area using a robot?Other ways….

Circumference = 2πr

Area = π r2

Cross on a diameter and determine measurement….

r

NXT-G Complex Robotic Behavior - Sumo

Consider This Program Architecture

Define Variables

Monitor Sensor # 1 Variable # 1Monitor Sensor # 2 Variable # 2

Act

Record desired data

…

Act (Values) Act

See one of the sumo programs

Subsumptive Programming Architecture

Source: Brooks: A Robust Layered Control System for a Mobile Robothttp://people.csail.mit.edu/brooks/papers/AIM-864.pdf

See one of the sumo programs

NXT-G – Data Collection and AnalysisArea Measurement

NXT-G – Data Collection and AnalysisArea Measurement

How to measure the perimeter and area of an arbitrary closed shape?

Pause Here…

NXT-G – Data Collection and AnalysisArea Measurement

How to measure the perimeter and area of an arbitrary closed shape?

Consider Descartes’ method:

Could we do this by driving a robot around the shape?

From Area the Easy Way

INSTRUCTIONS

1. Beginning with any vertex, list the coordinates of the vertices in order, moving counter-clockwise around the polygon. List the first pair again at the end.

2. Find the diagonal products from left to right.

3. Find the diagonal products from right to left.

4. Sum each column of products.5. Find their difference and divide by

2.

This is the polygon’s area.

NXT-G – Data Collection and AnalysisArea Measurement

Need to generate (x, y) pairs as the robot follows the line around…

But unlike the plotted curve, the robot does not know what the next pair will be.

Need to find a way to remember the last point and calculate the next one.

Just a little trigonometry…

and a compass.

Inspired by Area the Easy Way

(X old, Y old)

North

Distance

(X new, Y new)

Heading

ΔX

ΔY

X new = X old + ΔX

Y new = Y old + ΔY

ΔX = Dist *Sine (Hdg)

ΔY = Dist *Cosine (Hdg)

NXT-G – Data Collection and AnalysisArea Measurement

Need to generate (x, y) pairs as the robot follows the line around…

But unlike the plotted curve, the robot does not know what the next pair will be.

Need to find a way to remember the last point and calculate the next one.

Just a little trigonometry…

and a compass.

Inspired by Area the Easy Way

(X new, Y new)

Distance

(X old, Y old)

North

Heading

ΔX

ΔY

X new = X old + ΔX

Y new = Y old + ΔY

ΔX = Dist *Sine (Hdg)

ΔY = Dist *Cosine (Hdg)

Sine and cosine provide positive and negative factors that scale the sides of the right triangle.

NXT-G – Data Collection and AnalysisArea Measurement

Show development of the path as the robot follows along the orange curve.

Inspired by Area the Easy Way

X new = X old + ΔX

Y new = Y old + ΔY

ΔX = Dist *Sine (Hdg)

ΔY = Dist *Cosine (Hdg)

Sine and cosine provide positive and negative factors that scale the sides of the right triangle.

NXT-G – Data Collection and AnalysisArea Measurement

Show development of the path as the robot follows along the orange curve.

Inspired by Area the Easy Way

X new = X old + ΔX

Y new = Y old + ΔY

ΔX = Dist *Sine (Hdg)

ΔY = Dist *Cosine (Hdg)

Sine and cosine provide positive and negative factors that scale the sides of the right triangle.

ΔX

ΔY

(X1, Y1)

(X0, Y0)

North

ΔX

ΔY

(X2, Y2)

NXT-G – Data Collection and AnalysisArea Measurement

Example path showing generated (x, y) pairs as the robot follows the line around.

Inspired by Area the Easy Way

X new = X old + ΔX

Y new = Y old + ΔY

ΔX = Dist *Sine (Hdg)

ΔY = Dist *Cosine (Hdg)

Sine and cosine provide positive and negative factors that scale the sides of the right triangle.

(X1, Y1)

(X0, Y0)

North

ΔX

ΔY

(X2, Y2)

(X3, Y3) (X4, Y4)

(X5, Y5)

NXT-G – Data Collection and AnalysisArea Measurement

Example path showing generated (x, y) pairs as the robot follows the line around.

Inspired by Area the Easy Way

X new = X old + ΔX

Y new = Y old + ΔY

ΔX = Dist *Sine (Hdg)

ΔY = Dist *Cosine (Hdg)

Sine and cosine provide positive and negative factors that scale the sides of the right triangle.

NXT-G – Data Collection and AnalysisArea Measurement – two plots

Circle with Distance = 1 inch

Inspired by Area the Easy Way

Rectangle with Distance = 1 inch

NXT-G – Data Collection and AnalysisArea Measurement – two plots

Circle with Distance = 1 inch

Inspired by Area the Easy Way

Rectangle with Distance = 1 inch

Red arrows indicate error accumulated through each run.

Mapping with More Sensors

Mapping with More Sensors

NXT-G – Data Collection and AnalysisPendulum Motion

30

Data Logging

See Pendulum Program pendulum.rbtx

Application• Measuring period of a pendulum

common exercise for students

• Period = 2π √(L/g)

84 ½ inches 12 ½ inches

Pendulum Data

84 ½ inches

Ultrasonic sensor

Pendulum Data

84 ½ inches

Ultrasonic sensor

Pendulum Data

84 ½ inches

Light sensor

Pendulum Data

84 ½ inches

Light sensor

Pendulum Data

84 ½ inches

Acceleration sensor

Pendulum Data

84 ½ inches

Acceleration sensor

Pendulum Relationships

Pendulum Relationships

Maximum Negative Acceleration

Maximum Light

Minimum Ultrasonic Range

40

Math Excursion

See Pendulum Program pendulum.rbtx

Lower the sample Frequency to

Something near thePendulum period.

41

Simple Data Logging

See Pendulum Program pendulum.rbtx

50

Thoughts on Programming

Clear Problem Statement

Pseudocode Draw out what’s being attempted Words First.

Program – Test – Program – Test ---> Repeat

Value of default settings… ? Make things easier to program… Make students think through every block they program

Approaches vary with goals and Team choices

Robot Connections with STEM

Combines disciplines• Engineering• Math• Technology• Scientific Method

Makes abstract ideas real.

Some Robotic STEM Ideas

Craig Sheldencraig.shelden@comcast.net

202-251-7578

Science and Engineering Festival