Webots

About project

Webots is a professional robot simulator widely used for educational purposes. The Webots project started in 1996, initially developed by Dr. Olivier Michel at the Swiss Federal Institute of Technology (EPFL) in Lausanne, Switzerland. Webots uses 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. A large collection of freely modifiable robot models comes in the software distribution. In addition, it is also possible to build new models from scratch. 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. Webots includes a set of sensors and actuators frequently used in robotic experiments, e.g. proximity sensors, light sensors, touch sensors, GPS, accelerometers, cameras, emitters and receivers, servo motors (rotational & linear), position and force sensor, LEDs, grippers, gyros and compass. The robot controller programs can be written in C, C++, Java, Python and MATLAB. The AIBO, Nao and E-puck robot models can also be programmed with the URBI language (URBI license required). Webots offers the possibility to take PNG screen shots and to record the simulations as MPEG (Mac/Linux) and AVI (Windows) 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. Another useful feature is that the user can interact with a running simulation at any time, i.e. it possible to move the robots and other object with the mouse. Webots is used in several online robot programming contests. The Robotstadium[1] competition is a simulation of the RoboCup Standard Platform League. In this simulation two teams of Nao play soccer with rules similar to regular soccer. The robots use simulated cameras, ultrasound and pressure sensors. In the Rat's Life[2] competition two simulated e-puck robots compete for energy resources in a Lego maze. Matches are run on a daily basis and the results can be watched in online videos.

Example of source code

  wb_robot_keyboard_enable(TIME_STEP);
  
  do {
    sc_update();
    
    double speeds[2] = {0.0, 0.0};
    int c = wb_robot_keyboard_get_key();
    while (c) {
      switch (c) {
        case WB_ROBOT_KEYBOARD_UP:
          speeds[LEFT]  += MAX_SPEED;
          speeds[RIGHT] += MAX_SPEED;
          break;
        case WB_ROBOT_KEYBOARD_DOWN:
          speeds[LEFT]  -= MAX_SPEED;
          speeds[RIGHT] -= MAX_SPEED;
          break;
        case WB_ROBOT_KEYBOARD_LEFT:
          speeds[LEFT]  -= TURN_SPEED;
          speeds[RIGHT] += TURN_SPEED;
          break;
        case WB_ROBOT_KEYBOARD_RIGHT:
          speeds[LEFT]  += TURN_SPEED;
          speeds[RIGHT] -= TURN_SPEED;
          break;
      }
      c = wb_robot_keyboard_get_key();
    }
    wb_differential_wheels_set_speed(speeds[LEFT], speeds[RIGHT]);
    
  } while (wb_robot_step(TIME_STEP) != -1);

Screenshots

Workplace in Webots:

Sensor for new robot:

Moja púť

Pre rýchlo-kurz Webots, som sa držal základného Tutorialu priamo od výrobcu : http://www.cyberbotics.com/guide/chapter7.php
Čas v zátvorkách pri jednotlivých kapitolách, sedí skoro presne, skor by som povedal, že je stanoveny s miernou nadsázkou,
preto celá táto kapitola Vám nezabere viac ako 1,5-2h, čo je ukrutne málo, v pomere zábavy a novonadobudnutých znalostí.

Webots pracuje na základe knižnice ODE, čize je veľmi doležité, ako definujete objekty, ich hranice, fyziku a pod,
pri neopatrnosti , sa vám teda kludne može stať, že sa vám zhrúti celý svet, zmiznú objekty, prepadne zem pod kolieskami a pod.

Doležité upozornenia
-ukladajte po každom úkone (ak ste si istý, že je správny)
-sledujte či čas v pravom dolnom rohu sú samé 000.
-animácia musí byť zastavená ak niečo meníte.
-ak použivate DEF-USE, sledujte na čom DEF a čomu USE, neporiadok vedie k chaosu a čistej dezolácií.
-Ak mate projekt uložený mimo "materského" priečinka, je doležité prepísať cesty , poprípade prekopírovať potrebné priečinky.
-Sledujte či Robot_controller ,ktorý práve modifikujete je ten, ktorý ste priradili jeho uzlu.

Vysledok tutorialu. Robot sa vyhýba prekážkam.

V ĺavo stromová štruktura podlahy. V strede , okno pre výber textúry. V pravo ROBOT_Controller.

Chyba. Zrútenie zeme za pomoci, neuváženého pridania fyziky.

Links

http://www.cyberbotics.com/overview
http://en.wikipedia.org/wiki/Webots

ODE : http://ode.org/