Getting Started with Webots

S FT COMPUTING @ YONSEI UNIV . KOREA 16

Webots?

• Webots is a professional mobile robot simulation software package.

• Offers a rapid prototyping environment, that allows the user to crea

te 3D virtual worlds with physics properties such as mass, joints, fricti

on coefficients, etc.

• User can add simple passive objects or active objects called mobile r

obots. They may be equipped with a number of sensor and actuat

or devices, such as distance sensors, drive wheels, cameras, servos,

touch sensors, emitters, receivers, etc.

• Finally, the user can program each robot individually to exhibit th

e desired behavior. Webots contains a large number of robot models

and controller program examples to help users get started.

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Features

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Features

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Features

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What can I do with Webots?

• Mobile robot prototyping

– academic research, the automotive industry, aeronautics, the vacuum cle

aner industry, the toy industry, hobbyists, etc.

• Robot locomotion research

– Legged, humanoids, quadrupeds robots, etc.

• Multi-agent research

– swarm intelligence, collaborative mobile robots groups, etc.

• Adaptive behavior research

– genetic algorithm, neural networks, AI, etc.

• Teaching robotics

– Robotics lectures, C/C++/Java/Python programming lectures, etc.

• Robot contests

– e.g. www.robotstadium.org1 or www.ratslife.org2

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What do I need to know to use Webots?

• A minimal amount of technical knowledge is Needed

• A basic knowledge of the C, C++, Java, Python, Matlab or URBI progr

amming language is necessary. (Just Single language)

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Simulation

• A Webots simulation is composed of following items:

1. A Webots world file (.wbt) that defines one or several robots and their en

vironment. The .wbt file does sometime depend on external prototypes fi

les (.proto) and textures.

2. One or several controller programs for the above robots(in C/C++/Java/

Python/Matlab/URBI).

3. An optional physics plugin that can be used to modify Webots regular ph

ysics behavior (in C/C++).

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What is World?

• A 3D description of the properties of robots and of their environment.

– Organized as hierarchical structures

– Position, orientation, geometry, appearance (like color or brightness),

physical properties, type of object, etc

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• A world file doesn’t contain the con-

troller code of the robots; it only sp-

ecifies the name of the controller

that is required for each robot.

• Worlds are saved in .wbt files. The

.wbt files are stored in the worlds s

ubdirectory of each Webots project.

Scene tree


What is Controller?

• Controls a robot specified in a world file. Controllers can be written in

any of the programming languages supported by Webots

– C, C++, Java, URBI, Python or MATLABTM

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• When simulation starts, the specifie

d controllers launched, each as a se

parate process, it associates the con

troller processes with the simulated

robots. -Note that several robots can use the

same controller code, however a distin

ct process will be launched for each

robot.

Control window


What is Supervisor? (Only in Professional ver.)

• A privileged type of Robot

– can execute operations that can normally only be carried out by a human

operator and not by a real robot.

• The Supervisor is normally associated with a controller program that c

an also be written in any of the above mentioned programming langua

ges.

• In contrast with a regular Robot controller, the Supervisor controller wi

ll have access to privileged operations. The privileged operations incl

ude simulation control, for example, moving the robots to a random po

sition, making a video capture of the simulation, etc.

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Webots installation

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Download the Webots. And Run. http://www.cyberbotics.com/windows


How to run the Webots in Matlab?

• On Windows, Webots comes only in 32-bit flavour and therefore it can

only inter-operate with a 32 bit version of MATLAB. (!!!!!!!)

• However, On Mac OS X, there is only one version of Webots but that

version is compatible with both 32-bit and 64-bit installations of MATL

AB.

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윈도우에서 64bit은 안됩니다. 절대!



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At first, Run CMD.



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Type Path=C:\Program Files (x86)\MATLAB\R2010a\bin



• Open the world file

– c:\program files (x64)\webots\projects/languages/matlab/worlds/ e-puck_

matlab.wbt or

– the world file c:\program files (x64)\webotsprojects/contests/nao_robocup/

worlds/nao2_matlab.wbt

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Open this file and wait until webots & matlab opens.



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Well done.


Webots guided tour – Control Nao

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Click play button. We can see the Nao walks.

And you can control it with your keyboard.



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Click Nao and,

Shift + click ->Move Nao

Shift + click ->Lift

Ctrl + click ->Rotate

In the same way, you can also move all the

element in this room.

Enjoy it!

Getting Started with Webots -...

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