Webots

	Autonomous car in Webots
Developer(s)	Cyberbotics Ltd.
Stable release	Webots R2020b / July 29th, 2020
Repository	GitHub
Operating system	Windows 10, Linux 64 bit, Mac OS X 10.14, 10.13
Type	Robotics simulator
License	Apache 2
Website	Cyberbotics Web page

Webots is a free and open-source 3D robot simulator used in industry, education and research.

The Webots project started in 1996, initially developed by Dr. Olivier Michel at the Swiss Federal Institute of Technology (EPFL) in Lausanne, Switzerland and then from 1998 by Cyberbotics Ltd. as a proprietary licensed software. Since December 2018, it is released under the free and open-source Apache 2 license^[1].

Webots includes a large collection of freely modifiable models of robots, sensors, actuators and objects. In addition, it is also possible to build new models from scratch or import them from 3D CAD software. When designing a robot model, the user specifies both the graphical and the physical properties of the objects. The graphical properties include the shape, dimensions, position and orientation, colors, and texture of the object. The physical properties include the mass, friction factor, as well as the spring and damping constants. Simple fluid dynamics is present in the software.

Webots uses a fork of the ODE (Open Dynamics Engine) for detecting of collisions and simulating rigid body dynamics. The ODE library allows one to accurately simulate physical properties of objects such as velocity, inertia and friction.

Webots includes a set of sensors and actuators frequently used in robotic experiments, e.g. lidars, radars, proximity sensors, light sensors, touch sensors, GPS, accelerometers, cameras, emitters and receivers, servo motors (rotational & linear), position and force sensor, LEDs, grippers, gyros, compass, IMU, etc.

The robot controller programs can be written outside of Webots in C, C++, Python, ROS, Java and MATLAB using a simple API.

Webots offers the possibility to take screenshots and record simulations movies. Webots worlds are stored in cross-platform .wbt files which format is based on the VRML language. It is also possible to import and export Webots worlds or objects in the VRML format. Users can interact with a running simulation at any time, i.e., it is possible to move the robots and other object with the mouse while the simulation is running. Webots can stream a simulation on web browsers using WebGL.

Simulation of a Pioneer 3-AT (Adept Mobile Robots) mounted with a SICK LMS 291 in Webots

Simulation of a Pioneer 3-AT (Adept Mobile Robots) in Webots

A simulation model of the PR2 robot in Webots.

A simulation model of the Khepera III robot with gripper in Webots.

A simulation model of a salamander robot in Webots which has a deformable skin.

Web interface

Since August 18, 2017, the robotbenchmark.net website has offered free access to a series of robotics benchmarks based on Webots simulations through the Webots web interface. Webots instances are running in the cloud and the 3D views are displayed in the user browser. From this web interface, users can program robots in Python and learn robot control in a step-by-step procedure.

Controller programming example

This is a simple example of C/C++ controller programming with Webots: a trivial collision avoidance behavior. Initially, the robot runs forwards, then when an obstacle is detected it rotates around itself for a while and then resumes the forward motion.

#include <webots/robot.h>
#include <webots/differential_wheels.h>
#include <webots/distance_sensor.h>

#define TIME_STEP 64

int main() {
  // initialize Webots
  wb_robot_init();

  // get handle and enable distance sensor
  WbDeviceTag ds = wb_robot_get_device("ds");
  wb_distance_sensor_enable(ds, TIME_STEP);

  // control loop
  while (1) {
    // read sensors
    double v = wb_distance_sensor_get_value(ds);

    // if obstacle detected
    if (v > 512) {
      // turn around
      wb_differential_wheels_set_speed(-600, 600);
    }
    else {
      // go straight
      wb_differential_wheels_set_speed(600, 600);
    }
    
    // run a simulation step
    wb_robot_step(TIME_STEP);
  }

  return 0;
}

Main fields of application

Fast prototyping of wheeled and legged robots
Research on robot locomotion^[2]
Swarm intelligence (Multi-robot simulations)^[3]^[4]
Artificial life and evolutionary robotics
Simulation of adaptive behaviour^[5]^[6]
Self-Reconfiguring Modular Robotics^[7]
Experimental environment for computer vision
Teaching and robot programming contests

Included robot models

A complete and up-to-date list is provided in the Webots user guide.

AIBO ERS7 and ERS210,^[8] Sony Corporation
BIOLOID (dog), Robotis^[9]
Boe-Bot
DARwIn-OP, Robotis
E-puck
Hemisson
HOAP-2, Fujitsu Limited
iCub, RobotCub Consortium
iRobot Create, iRobot
Katana IPR, Neuronics AG
Khepera mobile robot I, II, III, K-Team Corporation
KHR-2HV, KHR-3HV, Kondo
Koala, K-Team Corporation
Lego Mindstorms (RCX Rover model)
Magellan
Nao V2, V3, Aldebaran Robotics
MobileRobots Inc Pioneer 2, Pioneer 3-DX, Pioneer 3-AT
Puma 560, Unimate
Scout 2
Shrimp III, BlueBotics SA
Surveyor SRV-1, Surveyor Corporation
youBot, KUKA

Cross compilation and remote control support

E-puck
DARwIn-OP and Robotis OP2
NAO
Thymio II

References

^ "Version R2019a - Webots Goes Open Source" (HTML). Cyberbotics. 2018.
^ "Hand placement during quadruped locomotion in a humanoid robot: A dynamical system approach" (PDF). Biologically Inspired Robotics Group. 2007.
^ "Distributed Adaptation in Multi-Robot Search using Particle Swarm Optimization". Swarm-Intelligent Systems Group. 2008.
^ "Assembly of Configurations in a Networked Robotic System: A Case Study on a Reconfigurable Interactive Table Lamp" (PDF). DISAL - Distributed Intelligent Systems and Algorithms Laboratory. 2008.
^ Louis-Emmanuel Martinet, Denis Sheynikhovich, Karim Benchenane, and Angelo Arleo (2011) Spatial Learning and Action Planning in a Prefrontal Cortical Network Model, PLoS Comput Biol 7(5): e1002045. doi:10.1371/journal.pcbi.1002045
^ Mannella F., Mirolli M., Baldassarre G., A computational model of the amygdala nuclei's role in second order conditioning. In M. Asada et al. (eds.), From Animals to Animats 10: Proceedings of the Tenth International Conference on the Simulation of Adaptive Behavior (SAB2008), pp. 321-330. LNAI 5040 Berlin: Springer.
^ "An active connection mechanism for modular self-reconfigurable robotic systems based on physical latching" (PDF). Biologically Inspired Robotics Group. 2008.
^ "Aibo and webots: Simulation, wireless remote control and controller transfer" (PDF). Biologically Inspired Robotics Group. 2006.
^ Bioloid

External links

Cyberbotics

[openSourceAnnounce-1] "Version R2019a - Webots Goes Open Source" (HTML). Cyberbotics. 2018.

[sDegallier07-2] "Hand placement during quadruped locomotion in a humanoid robot: A dynamical system approach" (PDF). Biologically Inspired Robotics Group. 2007.

[jPugh08-3] "Distributed Adaptation in Multi-Robot Search using Particle Swarm Optimization". Swarm-Intelligent Systems Group. 2008.

[cCianci08-4] "Assembly of Configurations in a Networked Robotic System: A Case Study on a Reconfigurable Interactive Table Lamp" (PDF). DISAL - Distributed Intelligent Systems and Algorithms Laboratory. 2008.

[leMartinet11-5] Louis-Emmanuel Martinet, Denis Sheynikhovich, Karim Benchenane, and Angelo Arleo (2011) Spatial Learning and Action Planning in a Prefrontal Cortical Network Model, PLoS Comput Biol 7(5): e1002045. doi:10.1371/journal.pcbi.1002045

[fManella08-6] Mannella F., Mirolli M., Baldassarre G., A computational model of the amygdala nuclei's role in second order conditioning. In M. Asada et al. (eds.), From Animals to Animats 10: Proceedings of the Tenth International Conference on the Simulation of Adaptive Behavior (SAB2008), pp. 321-330. LNAI 5040 Berlin: Springer.

[aSproewitz08-7] "An active connection mechanism for modular self-reconfigurable robotic systems based on physical latching" (PDF). Biologically Inspired Robotics Group. 2008.

[hohl06-8] "Aibo and webots: Simulation, wireless remote control and controller transfer" (PDF). Biologically Inspired Robotics Group. 2006.

[9] Bioloid

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