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falling

Falling

Bases: FailureCondition

Falling (failure condition) used for any navigation-type tasks Episode terminates if the robot falls out of the world (i.e.: falls below the floor height by at least @fall_height

Parameters:

Name Type Description Default
robot_idn int

robot identifier to evaluate condition with. Default is 0, corresponding to the first robot added to the scene

 0
fall_height float

distance (m) > 0 below the scene's floor height under which the the robot is considered to be falling out of the world

 0.03
topple bool

whether to also consider the robot to be falling if it is toppling over (i.e.: if it is no longer upright

 True
Source code in omnigibson/termination_conditions/falling.py 
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class Falling(FailureCondition):
    """
    Falling (failure condition) used for any navigation-type tasks
    Episode terminates if the robot falls out of the world (i.e.: falls below the floor height by at least
    @fall_height

    Args:
        robot_idn (int): robot identifier to evaluate condition with. Default is 0, corresponding to the first
            robot added to the scene
        fall_height (float): distance (m) > 0 below the scene's floor height under which the the robot is considered
            to be falling out of the world
        topple (bool): whether to also consider the robot to be falling if it is toppling over (i.e.: if it is
            no longer upright
    """

    def __init__(self, robot_idn=0, fall_height=0.03, topple=True, tilt_tolerance=0.75):
        # Store internal vars
        self._robot_idn = robot_idn
        self._fall_height = fall_height
        self._topple = topple
        self._tilt_tolerance = tilt_tolerance

        # Run super init
        super().__init__()

    def _step(self, task, env, action):
        # Terminate if the specified robot is falling out of the scene
        robot_z = env.scene.robots[self._robot_idn].get_position_orientation()[0][2]
        if robot_z < (env.scene.get_floor_height() - self._fall_height):
            return True

        # Terminate if the robot has toppled over
        if self._topple:
            robot_up = T.quat_apply(
                env.scene.robots[self._robot_idn].get_position_orientation()[1], th.tensor([0, 0, 1], dtype=th.float32)
            )
            if robot_up[2] < self._tilt_tolerance:
                return True

        return False