emig summer school - robotics - slideseitidaten.fh-pforzheim.de/daten/mitarbeiter/johannsen/... ·...

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Summer School EMIG – Engineers Made in Germany

Robotics – An Interactive Introduction to Programming Robots

Prof. Dr. Peer Johannsen

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• Prof. Dr. rer. nat. Peer Johannsen– Computer Science and Software-Engineering– School of Engineering– Department of Information Technology– Dean of Studies, Computer Engineering Degree Program– [email protected]

• Teaching and Research Interests– Applied and Theoretical Computer Science– Formal Logic– Software-Development, Programming Languages– Algorithms and Data Structures– Robotics and Robot Programming

• Certified Roberta Teacher– Fraunhofer IAIS Initiative „Roberta – Lernen mit Robotern“

(“Roberta – Learning with Robots”)

Who I am

Contact:

Pforzheim University School of Engineering

Department of Information TechnologyRoom T1.4.29

[email protected]

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• School of Engineering– Department of Information Technology

• Bachelor Degree Programs– Mechatronics, Computer Engineering,

Electrical Engineering, Medical Engineering• Master Degree Program

– Embedded Systems

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Computer Science and Robotics Lab

• 10 NAO H25 V4 Educational Humanoid Robots• Academic Cooperation with Aldebaran Robotics Paris• KUKA Youbot Omni Directional Mobile Platform• 5 DOF Manipulator with 2 Finger Gripper• LEGO Mindstorms NXT Robotics Kits• 3D Virtual Environment Simulator

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• Lab Activities– Introductory and advanced lectures– Programming languages and programming

techniques– Robotics and robot programming– Student projects– Research projects– Thesis projects–

• Objectives– Using robots to spike an interest in

Computer Science and programming– Giving students the possibility to work on a

real robot in the classroom

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Summer School EMIG – Engineers Made in Germany

Robotics – An Interactive Introduction to Programming Robots

or:How to think like an

Engineer

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Case Study – Mobile Robot Platform KUKA youBot

Case Study – Humanoid Robot NAO

Case Study – Cube Solving Robot

Algorithms

Flowcharts

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1. Grappler2. Platform3. Mobile unit with

four omniwheels

1. Clamps2. Gripper unit3. Rotating joint4. Upper arm5. Middle arm6. Lower arm7. Control unit8. Turntable

• Autonomous mobile robot platform withmounted Gripper

• Educational robot system modeled on real automotive robots

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• Mobile Platform• Maneuverable 0 – 360 degrees• 4 Mechanum-Wheels (Omniwheels)

– A turning wheel causes a propelling force at an angle of 45 degrees to its rotational axis

– Direction of platform is determined by the vectorialsum auf the propelling forces of all wheels

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• Moving forward or backward

– All 4 wheels turn in the same direction at the same speed

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• Moving sideways

– Neighboring wheels are counter-rotating– All wheels run at the same speed

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• Turning in place

– Left wheels are counter-rotating to right wheels– All wheels run at the same speed

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• Moving at arbitrary angles

– Two diagonal wheels are turning in the same direction, the other wheels are locked– Angle is determined by the ratio of all wheel speeds

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Algorithms

Flowcharts

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The NAO H25 V4 Robot

• Programable Humanoid Robot• 25 degrees of freedom• Lots of sensors and communication devices• Linux operating system• Manufactured by Aldebaran Robotics, Paris

– Start of development in 2006– First release version in 2008– V4 is the newest 2012 version

• Designed as an educational robotics systems• Used world-wide at universities and in research projects• Specialized in Man-Machine interaction• Own league in the Robot Soccer World Cup

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Infrared Sensors

HIFI Speakers

Microphone

Touch Sensors

HD Digital Cameras

Ultrasound Sensor

Graplers

Gyro

PressureSensors

Bumpers 25 electronicallydriven Joints

2 Intel Atom Processors

WLAN

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Algorithms

Flowcharts

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• Ernö Rubik– Hungarian designer an architect– Professor of Arts and Design at the University of Budapest

• Rubik‘s Cube– Invented in 1974– Means to train students in 3-dimensional thinking– World-wide commercial success from 1980 on

• Overall number of possible configurations:– 43.252.003.274.489.856.000 (ca. 43 * 1018)

• Overall number of humans who despaired:– Significantly higher…

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• mIQube - A cube solving robot• Used as introductory example in the Computer Science classes of the Bachelor of

Mechatronics degree program• Based on the „Tilted Twister“ robot by Hans Andersson

– Swedish software engineer– Construction plans available at www.tiltedtwister.com

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Color Sensor

DistanceSensor

3 Electric Motors

Turntable

Microcontroller

Grappler

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Scan upperSurface

Initialize Sensors

Please give me a Cube!

CubePresent?

yes

no

All 6 sidesscanned?

Turn Cube

no

ComputeSolution

(Sequence ofmoves)

All Moves done?

Execute Move

yes

Done!

no

yes

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• 3-Phase Algorithm

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• Sub-Procedures

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Quelle: Tom Werneck, der Zaubercube, Heyne

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• Algorithm implemented in C– Middle edge correction

void middle_edge_correction(int[] cube){

if (upper_layer_correct(cube)){

if ((cube[front][bottom][middle] == cube[front][middle][middle]) &&(cube[front][top][middle] == cube[front][middle][middle]) &&(cube[bottom][top][middle] == cube[right][middle][middle]))

{turn(bottom, left, 90);turn_column(right, down, 90);turn(bottom, right, 90);turn_column(right, up, 90);turn(bottom, right, 90);turn(front, right, 90);turn(bottom, left, 90);turn(front, left, 90);

}}

}

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• God‘s Algorithm– For each configuration, compute a solution of minimum length

• God‘s Number– Maximum number of moves that is sufficient for solving the cube from

an arbitrary starting configuration

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Algorithms

Flowcharts

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Algorithms

• Definition– An algorithm is an effective method for solving a specific problem, described by a finite set

of step-by-step operations to be performed.

• Essential Building Blocks of Algorithms– Sequences of Instructions

• Order is well defined– Branching Points

• Depending on the evaluation of a test condition different branches of instruction sequences aretakewn

– Conditional Loops• Conditional repetition of sequences of instructions

• Programming Language– A means to specify an algorithm in a way that it can be understood and executed by a

machine or computer

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Abu truefar Mohammed Ibn Musa Al-Khwarizmi

• Ca. 780 – 850 n. Chr.• Born presumably in the Persian town Khwarizm (now in

Usbekistan)• Scientist at the courtyard of caliph Harun al-Raschid in

Bagdad• Adoption of the East Indian numeral system (arabic

numerals)• Introduction of decimal notation of numbers• First usage of zero as a digit• „as-sifr“ (die Leere) („zero“, „chiffre“, „Ziffer“)• Most famous book: „Al Kitab al-muhtasar fi hisab al-gabr

w-almuqabala“• „A short book on computing by completion and

balancing“• Methods to solve linear and quadratic equations• „Al-gabr“, „to add sth., to complete sth.“, „Algebra“

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Variables in Algorithms

• Variable– symbolic storage (memory) of a specific value– has a name (unique Identifier)– has a current value (can change over time)

• Read / Write access– current value can be obtained (read)– current value can be replaced by a new value (write)

• Mathematics vs. Computer Science– in math x = x + 1 is an equation without a solution– in a program x = x + 1is an assignment (value update), meaning „the new value of x is

the sum of its old value and 1

x

8

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Algorithms

Flowcharts

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Flowcharts

• Graphical representation of Algorithms– Oval

• Start, Stop– Arrow

• Sequence– Rectangle

• Basic Operation– Diamond

• Branching Point– Parallelogram / Rhomboid

• Input / Output– Rectangle with bars

• Subroutine Call

• PAP-Designer, Free (Windows) Software– Download: http://friedrich-folkmann.de/papdesigner/Hauptseite.html

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• Basic Operations

• Sequence of Operations

Flowchart

Flowchart

Operation

Operation 1

Operation 3

Operation 2

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Flowchart

• Conditional Branching Point with Boolean Condition

Test Condition

Operation A Operation B

false

true

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Flowchart

• Conditional Branching with multiple Cases

Test Condition

Operation B

Operation A1

Case 1

Operation A2

Operation An

Operation A3

Case 2

Case 3

Case n

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• Conditional Branching Boolean Branching is sufficient

Operation B

Test resultequals case 1? Operation A1

true

false


true

false


true

false

Test resultequals case n? Operation An

true

false

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Flowchart

• While Loop

Flowchart

• Do Loop

?

Operations

false

true

?

Operations

false

true

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• Loop with Counter

i = 10 ?

Operations

false

true

i = 1

i = i + 1

Flowchart

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Flowchart

• Special Case: Endless Loop

Operations

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Flowchart

• Call Subroutine

Flowchart

• Return from Subroutine

Name (Parameter)

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• Example

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C-Program Flowchart

• Basic Operationens (Instructions)

C-Program Flowchart

• Sequences

Instruction

Instruction 1

Instruction 3

Instruction 2

<C-Instruction>;

<C-Instruction 1>;<C-Instruction 2>;<C-Instruction 3>;

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C-Program Flowchart

• Blocks

Instruction 1Instruction 2Instruction 3

{<C-Instruction 1>;<C-Instruction 2>;<C-Instruction 3>;

}

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Flowchart

• Branching Points (Conditional Execution of Instructions)

TestCondition

Instruction A1Instruction A2

…

Instruction B1Instruction B2

…

false

true

C-Program

if (<Test>){<C-Instruction A1>;<C-Instruction A2>;...

}else{<C-Instruction B1>;<C-Instruction B2>;...

}

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Flowchart

• Conditional Skipping of Instructions

TestCondition

Instruction A1Instruction A2

…

false

true

C-Program

if (<Test>){<C-Instruction A1>;<C-Instruction A2>;...

}

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Flowchart

• Case Selection

TestWelcher Case

liegt vor?

Instruction B

Instruction A1

Case 1

Instruction A2

Instruction An

Instruction A3

Case 2

Case 3

Case n

C-Program

switch (<Test>){

case <Case 1>:<C-Instruction A1>;break;



...case <Case n>:

<C-Instruction An>;break;

default:<C-Instruction B>;

...}

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• Case Selection Binary Branching Points are always sufficient

Instruction B

Test resultequals Case 1? Instruction A1

true

false


true

false


true

false

Test resultequals Case n? Instruction An

true

false

if (<TestTest = Case 1>){<C-Instruction A1>;

}else if (<TestTest = Case 2>){<C-Instruction A2>;

}else if (<TestTest = Case 3>){<C-Instruction A3>;

}else if (<...>){

...

}else{<C-Instruction B>;

}

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Flowchart

• While Loop

Flowchart

• Do Loop

B?

Instruction A

false

true

B?

Instruction A

true

false

C-Program

C-Program

while (<Test B>){<C-Instruction A>;

}

do {<C-Instruction A>;

}while (<Test B>);

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Flowchart

• Loop with Counter

C-Program

for (<Variable = Anfangswert>;<Variable ≠ Endwert>;<Variable weiterzählen>)

{<C-Instruction>;

}

i = 10 ?

Operations

false

true

i = 1

i = i + 1

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Flowchart

• Subroutine Call (Function)

Flowchart

• Return from Subroutine

Prozedurname(Parameter)

C-Program

C-Program

main(){

ggT(44, 12);}

ggT(<Parameter A>, <Parameter B>){

<C-Instruction 1>;<C-Instruction 1>;... return;

}

emig summer school - robotics - slideseitidaten.fh-pforzheim.de/daten/mitarbeiter/johannsen/... ·...

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