Gazebo Physics Engine Wrapper

Current PR2 simulation is implemented through the Gazebo Project. Gazebo is a simulation interface wrapper around the physics engine (currently ODE) under the Player Project.

Simulation World

• Simulated world environments can be found in directory worlds under the ros package gazebo_worlds.

Simulating Robots

• We use URDF (uniform robot description format) to define objects and robots in simulation.

  • pr2_description contains the xacro-lized (an XML macro language) urdf definitions for the PR2 robot.

ROS Simulation Interface

• pr2_gazebo_plugins supports following functionalities on the PR2 robot:

  • prosilica_camera

  • pr2_controller_manager

    • Operating transparency between simulation and the actual hardware at actuators level.
    • Physics simulation of kinematics assumes:
      • exact torque production at actuated joints, i.e. torque constants are exact.
      • explicit joint damping applied, i.e. damping force = damping coefficient times joint velocity.
      • currently, joint friction, efficiency and motor inertias are not modeled.

    • Generic Robot Mechanism Controllers

    • PR2 specific Mechanism Controllers

  • power_monitor

• See ROS-Gazebo plugins for more details on Gazebo's ROS interface, and on how to extend Gazebo's functionality