World

A World encompasses the simulation/reality of the experimental setup. Worlds contain specifications for the physics of simulation (gravity, timesteps, collisions.) Worlds contain arenas and interfaces to robots, objects and sensors. Worlds do not typically contain information relevant to the task(i.e. reward functions, observations, actions, terminations.) Environments take the state of the World to produce an observation, and apply actions to the world at each step.

Switching between sim and real worlds.

perls2 makes it easy to share the same code for simulation and real-world experimentation. Simply change the perls2 config world:type key from bullet to real. That’s it! When your environment is next created, a RealWorld will automatically be generated with the appropriate robots.

If you want to distinguish between code for simulation, just add

if self.world.is_sim:

to your environment.

Hierarchy:

Attributes:

-config: dict Config files contain parameters to create an arena, robot interface, sensor interface and object interface. They also contain specs for learning, simulation and experiment setup.

-arena: Arena Manages the sim by loading models (in both sim/real envs) and for simulations, randomizing objects and sensors parameters

-robot_interface: RobotInterface Communicates with robots and executes robot commands. Robot Interfaces are also typically constructed by the robot_factory.

-sensor_interface: SensorInterface Retrieves sensor info and executes changes to params

-object_interface: ObjectInterface Only for Sim environments– retrieves object info and excecutes changes to params