fetch

Fetch

Bases: ManipulationRobot, TwoWheelRobot, ActiveCameraRobot

Fetch Robot Reference: https://fetchrobotics.com/robotics-platforms/fetch-mobile-manipulator/

Source code in omnigibson/robots/fetch.py

class Fetch(ManipulationRobot, TwoWheelRobot, ActiveCameraRobot):
    """
    Fetch Robot
    Reference: https://fetchrobotics.com/robotics-platforms/fetch-mobile-manipulator/
    """

    def __init__(
        self,
        # Shared kwargs in hierarchy
        name,
        prim_path=None,
        uuid=None,
        scale=None,
        visible=True,
        visual_only=False,
        self_collisions=False,
        load_config=None,
        fixed_base=False,

        # Unique to USDObject hierarchy
        abilities=None,

        # Unique to ControllableObject hierarchy
        control_freq=None,
        controller_config=None,
        action_type="continuous",
        action_normalize=True,
        reset_joint_pos=None,

        # Unique to BaseRobot
        obs_modalities="all",
        proprio_obs="default",
        sensor_config=None,

        # Unique to ManipulationRobot
        grasping_mode="physical",
        disable_grasp_handling=False,

        # Unique to Fetch
        rigid_trunk=False,
        default_trunk_offset=0.365,
        default_reset_mode="untuck",
        default_arm_pose="vertical",
        **kwargs,
    ):
        """
        Args:
            name (str): Name for the object. Names need to be unique per scene
            prim_path (None or str): global path in the stage to this object. If not specified, will automatically be
                created at /World/<name>
            uuid (None or int): Unique unsigned-integer identifier to assign to this object (max 8-numbers).
                If None is specified, then it will be auto-generated
            scale (None or float or 3-array): if specified, sets either the uniform (float) or x,y,z (3-array) scale
                for this object. A single number corresponds to uniform scaling along the x,y,z axes, whereas a
                3-array specifies per-axis scaling.
            visible (bool): whether to render this object or not in the stage
            visual_only (bool): Whether this object should be visual only (and not collide with any other objects)
            self_collisions (bool): Whether to enable self collisions for this object
            load_config (None or dict): If specified, should contain keyword-mapped values that are relevant for
                loading this prim at runtime.
            abilities (None or dict): If specified, manually adds specific object states to this object. It should be
                a dict in the form of {ability: {param: value}} containing object abilities and parameters to pass to
                the object state instance constructor.
            control_freq (float): control frequency (in Hz) at which to control the object. If set to be None,
                simulator.import_object will automatically set the control frequency to be at the render frequency by default.
            controller_config (None or dict): nested dictionary mapping controller name(s) to specific controller
                configurations for this object. This will override any default values specified by this class.
            action_type (str): one of {discrete, continuous} - what type of action space to use
            action_normalize (bool): whether to normalize inputted actions. This will override any default values
                specified by this class.
            reset_joint_pos (None or n-array): if specified, should be the joint positions that the object should
                be set to during a reset. If None (default), self._default_joint_pos will be used instead.
                Note that _default_joint_pos are hardcoded & precomputed, and thus should not be modified by the user.
                Set this value instead if you want to initialize the robot with a different rese joint position.
            obs_modalities (str or list of str): Observation modalities to use for this robot. Default is "all", which
                corresponds to all modalities being used.
                Otherwise, valid options should be part of omnigibson.sensors.ALL_SENSOR_MODALITIES.
                Note: If @sensor_config explicitly specifies `modalities` for a given sensor class, it will
                    override any values specified from @obs_modalities!
            proprio_obs (str or list of str): proprioception observation key(s) to use for generating proprioceptive
                observations. If str, should be exactly "default" -- this results in the default proprioception
                observations being used, as defined by self.default_proprio_obs. See self._get_proprioception_dict
                for valid key choices
            sensor_config (None or dict): nested dictionary mapping sensor class name(s) to specific sensor
                configurations for this object. This will override any default values specified by this class.
            grasping_mode (str): One of {"physical", "assisted", "sticky"}.
                If "physical", no assistive grasping will be applied (relies on contact friction + finger force).
                If "assisted", will magnetize any object touching and within the gripper's fingers.
                If "sticky", will magnetize any object touching the gripper's fingers.
            disable_grasp_handling (bool): If True, will disable all grasp handling for this object. This means that
                sticky and assisted grasp modes will not work unless the connection/release methodsare manually called.
            rigid_trunk (bool) if True, will prevent the trunk from moving during execution.
            default_trunk_offset (float): sets the default height of the robot's trunk
            default_reset_mode (str): Default reset mode for the robot. Should be one of: {"tuck", "untuck"}
            If reset_joint_pos is not None, this will be ignored (since _default_joint_pos won't be used during initialization).
            default_arm_pose (str): Default pose for the robot arm. Should be one of:
                {"vertical", "diagonal15", "diagonal30", "diagonal45", "horizontal"}
                If either reset_joint_pos is not None or default_reset_mode is "tuck", this will be ignored. 
                Otherwise the reset_joint_pos will be initialized to the precomputed joint positions that represents default_arm_pose.
            kwargs (dict): Additional keyword arguments that are used for other super() calls from subclasses, allowing
                for flexible compositions of various object subclasses (e.g.: Robot is USDObject + ControllableObject).
        """
        # Store args
        self.rigid_trunk = rigid_trunk
        self.default_trunk_offset = default_trunk_offset
        assert_valid_key(key=default_reset_mode, valid_keys=RESET_JOINT_OPTIONS, name="default_reset_mode")
        self.default_reset_mode = default_reset_mode
        assert_valid_key(key=default_arm_pose, valid_keys=DEFAULT_ARM_POSES, name="default_arm_pose")
        self.default_arm_pose = default_arm_pose

        # Run super init
        super().__init__(
            prim_path=prim_path,
            name=name,
            uuid=uuid,
            scale=scale,
            visible=visible,
            fixed_base=fixed_base,
            visual_only=visual_only,
            self_collisions=self_collisions,
            load_config=load_config,
            abilities=abilities,
            control_freq=control_freq,
            controller_config=controller_config,
            action_type=action_type,
            action_normalize=action_normalize,
            reset_joint_pos=reset_joint_pos,
            obs_modalities=obs_modalities,
            proprio_obs=proprio_obs,
            sensor_config=sensor_config,
            grasping_mode=grasping_mode,
            disable_grasp_handling=disable_grasp_handling,
            **kwargs,
        )

    @property
    def model_name(self):
        return "Fetch"

    @property
    def tucked_default_joint_pos(self):
        return np.array(
            [
                0.0,
                0.0,  # wheels
                0.02,  # trunk
                0.0,
                1.1707963267948966,
                0.0,  # head
                1.4707963267948965,
                -0.4,
                1.6707963267948966,
                0.0,
                1.5707963267948966,
                0.0,  # arm
                0.05,
                0.05,  # gripper
            ]
        )

    @property
    def untucked_default_joint_pos(self):
        pos = np.zeros(self.n_joints)
        pos[self.base_control_idx] = 0.0
        pos[self.trunk_control_idx] = 0.02 + self.default_trunk_offset
        pos[self.camera_control_idx] = np.array([0.0, 0.45])
        pos[self.gripper_control_idx[self.default_arm]] = np.array([0.05, 0.05])  # open gripper

        # Choose arm based on setting
        if self.default_arm_pose == "vertical":
            pos[self.arm_control_idx[self.default_arm]] = np.array(
                [-0.94121, -0.64134, 1.55186, 1.65672, -0.93218, 1.53416, 2.14474]
            )
        elif self.default_arm_pose == "diagonal15":
            pos[self.arm_control_idx[self.default_arm]] = np.array(
                [-0.95587, -0.34778, 1.46388, 1.47821, -0.93813, 1.4587, 1.9939]
            )
        elif self.default_arm_pose == "diagonal30":
            pos[self.arm_control_idx[self.default_arm]] = np.array(
                [-1.06595, -0.22184, 1.53448, 1.46076, -0.84995, 1.36904, 1.90996]
            )
        elif self.default_arm_pose == "diagonal45":
            pos[self.arm_control_idx[self.default_arm]] = np.array(
                [-1.11479, -0.0685, 1.5696, 1.37304, -0.74273, 1.3983, 1.79618]
            )
        elif self.default_arm_pose == "horizontal":
            pos[self.arm_control_idx[self.default_arm]] = np.array(
                [-1.43016, 0.20965, 1.86816, 1.77576, -0.27289, 1.31715, 2.01226]
            )
        else:
            raise ValueError("Unknown default arm pose: {}".format(self.default_arm_pose))
        return pos

    def _post_load(self):
        super()._post_load()

        # Set the wheels back to using sphere approximations
        for wheel_name in ["l_wheel_link", "r_wheel_link"]:
            log.warning(
                "Fetch wheel links are post-processed to use sphere approximation collision meshes."
                "Please ignore any previous errors about these collision meshes.")
            wheel_link = self.links[wheel_name]
            assert set(wheel_link.collision_meshes) == {"collisions"}, "Wheel link should only have 1 collision!"
            wheel_link.collision_meshes["collisions"].set_collision_approximation("boundingSphere")

        # Also apply a convex decomposition to the torso lift link
        torso_lift_link = self.links["torso_lift_link"]
        assert set(torso_lift_link.collision_meshes) == {"collisions"}, "Wheel link should only have 1 collision!"
        torso_lift_link.collision_meshes["collisions"].set_collision_approximation("convexDecomposition")

    @property
    def discrete_action_list(self):
        # Not supported for this robot
        raise NotImplementedError()

    def _create_discrete_action_space(self):
        # Fetch does not support discrete actions
        raise ValueError("Fetch does not support discrete actions!")

    def tuck(self):
        """
        Immediately set this robot's configuration to be in tucked mode
        """
        self.set_joint_positions(self.tucked_default_joint_pos)

    def untuck(self):
        """
        Immediately set this robot's configuration to be in untucked mode
        """
        self.set_joint_positions(self.untucked_default_joint_pos)

    def _initialize(self):
        # Run super method first
        super()._initialize()

        # Set the joint friction for EEF to be higher
        for arm in self.arm_names:
            for joint in self.finger_joints[arm]:
                if joint.joint_type != JointType.JOINT_FIXED:
                    joint.friction = 500

    def _postprocess_control(self, control, control_type):
        # Run super method first
        u_vec, u_type_vec = super()._postprocess_control(control=control, control_type=control_type)

        # Override trunk value if we're keeping the trunk rigid
        if self.rigid_trunk:
            u_vec[self.trunk_control_idx] = self.untucked_default_joint_pos[self.trunk_control_idx]
            u_type_vec[self.trunk_control_idx] = ControlType.POSITION

        # Return control
        return u_vec, u_type_vec

    def _get_proprioception_dict(self):
        dic = super()._get_proprioception_dict()

        # Add trunk info
        joint_positions = self.get_joint_positions(normalized=False)
        joint_velocities = self.get_joint_velocities(normalized=False)
        dic["trunk_qpos"] = joint_positions[self.trunk_control_idx]
        dic["trunk_qvel"] = joint_velocities[self.trunk_control_idx]

        return dic

    @property
    def default_proprio_obs(self):
        obs_keys = super().default_proprio_obs
        return obs_keys + ["trunk_qpos"]

    @property
    def controller_order(self):
        # Ordered by general robot kinematics chain
        return ["base", "camera", "arm_{}".format(self.default_arm), "gripper_{}".format(self.default_arm)]

    @property
    def _default_controllers(self):
        # Always call super first
        controllers = super()._default_controllers

        # We use multi finger gripper, differential drive, and IK controllers as default
        controllers["base"] = "DifferentialDriveController"
        controllers["camera"] = "JointController"
        controllers["arm_{}".format(self.default_arm)] = "InverseKinematicsController"
        controllers["gripper_{}".format(self.default_arm)] = "MultiFingerGripperController"

        return controllers

    @property
    def _default_controller_config(self):
        # Grab defaults from super method first
        cfg = super()._default_controller_config

        # Need to override joint idx being controlled to include trunk in default arm controller configs
        for arm_cfg in cfg[f"arm_{self.default_arm}"].values():
            arm_control_idx = np.concatenate([self.trunk_control_idx, self.arm_control_idx[self.default_arm]])
            arm_cfg["dof_idx"] = arm_control_idx

            # Need to modify the default joint positions also if this is a null joint controller
            if arm_cfg["name"] == "NullJointController":
                arm_cfg["default_command"] = self.reset_joint_pos[arm_control_idx]

            # If using rigid trunk, we also clamp its limits
            if self.rigid_trunk:
                arm_cfg["control_limits"]["position"][0][self.trunk_control_idx] = \
                    self.untucked_default_joint_pos[self.trunk_control_idx]
                arm_cfg["control_limits"]["position"][1][self.trunk_control_idx] = \
                    self.untucked_default_joint_pos[self.trunk_control_idx]

        return cfg

    @property
    def _default_joint_pos(self):
        return self.tucked_default_joint_pos if self.default_reset_mode == "tuck" else self.untucked_default_joint_pos

    @property
    def wheel_radius(self):
        return 0.0613

    @property
    def wheel_axle_length(self):
        return 0.372

    @property
    def finger_lengths(self):
        return {self.default_arm: 0.1}

    @property
    def assisted_grasp_start_points(self):
        return {
            self.default_arm: [
                GraspingPoint(link_name="r_gripper_finger_link", position=[0.025, -0.012, 0.0]),
                GraspingPoint(link_name="r_gripper_finger_link", position=[-0.025, -0.012, 0.0]),
            ]
        }

    @property
    def assisted_grasp_end_points(self):
        return {
            self.default_arm: [
                GraspingPoint(link_name="l_gripper_finger_link", position=[0.025, 0.012, 0.0]),
                GraspingPoint(link_name="l_gripper_finger_link", position=[-0.025, 0.012, 0.0]),
            ]
        }

    @property
    def base_control_idx(self):
        """
        Returns:
            n-array: Indices in low-level control vector corresponding to [Left, Right] wheel joints.
        """
        return np.array([0, 1])

    @property
    def trunk_control_idx(self):
        """
        Returns:
            n-array: Indices in low-level control vector corresponding to trunk joint.
        """
        return np.array([2])

    @property
    def camera_control_idx(self):
        """
        Returns:
            n-array: Indices in low-level control vector corresponding to [tilt, pan] camera joints.
        """
        return np.array([3, 5])

    @property
    def arm_control_idx(self):
        return {self.default_arm: np.array([4, 6, 7, 8, 9, 10, 11])}

    @property
    def gripper_control_idx(self):
        return {self.default_arm: np.array([12, 13])}

    @property
    def disabled_collision_pairs(self):
        return [
            ["torso_lift_link", "shoulder_lift_link"],
            ["torso_lift_link", "torso_fixed_link"],
            ["torso_lift_link", "estop_link"],
            ["base_link", "laser_link"],
            ["base_link", "torso_fixed_link"],
            ["base_link", "l_wheel_link"],
            ["base_link", "r_wheel_link"],
            ["base_link", "estop_link"],
            ["torso_lift_link", "shoulder_pan_link"],
            ["torso_lift_link", "head_pan_link"],
            ["head_pan_link", "head_tilt_link"],
            ["shoulder_pan_link", "shoulder_lift_link"],
            ["shoulder_lift_link", "upperarm_roll_link"],
            ["upperarm_roll_link", "elbow_flex_link"],
            ["elbow_flex_link", "forearm_roll_link"],
            ["forearm_roll_link", "wrist_flex_link"],
            ["wrist_flex_link", "wrist_roll_link"],
            ["wrist_roll_link", "gripper_link"],
        ]

    @property
    def manipulation_link_names(self):
        return [
            "torso_lift_link", 
            "head_pan_link", 
            "head_tilt_link",  
            "shoulder_pan_link", 
            "shoulder_lift_link", 
            "upperarm_roll_link", 
            "elbow_flex_link", 
            "forearm_roll_link", 
            "wrist_flex_link", 
            "wrist_roll_link", 
            "gripper_link", 
            "l_gripper_finger_link", 
            "r_gripper_finger_link",
        ]

    @property
    def arm_link_names(self):
        return {self.default_arm: [
            "shoulder_pan_link",
            "shoulder_lift_link",
            "upperarm_roll_link",
            "elbow_flex_link",
            "forearm_roll_link",
            "wrist_flex_link",
            "wrist_roll_link",
        ]}

    @property
    def arm_joint_names(self):
        return {self.default_arm: [
            "torso_lift_joint",
            "shoulder_pan_joint",
            "shoulder_lift_joint",
            "upperarm_roll_joint",
            "elbow_flex_joint",
            "forearm_roll_joint",
            "wrist_flex_joint",
            "wrist_roll_joint",
        ]}

    @property
    def eef_link_names(self):
        return {self.default_arm: "gripper_link"}

    @property
    def finger_link_names(self):
        return {self.default_arm: ["r_gripper_finger_link", "l_gripper_finger_link"]}

    @property
    def finger_joint_names(self):
        return {self.default_arm: ["r_gripper_finger_joint", "l_gripper_finger_joint"]}

    @property
    def usd_path(self):
        return os.path.join(gm.ASSET_PATH, "models/fetch/fetch/fetch.usd")

    @property
    def robot_arm_descriptor_yamls(self):
        return {self.default_arm: os.path.join(gm.ASSET_PATH, "models/fetch/fetch_descriptor.yaml")}

    @property
    def urdf_path(self):
        return os.path.join(gm.ASSET_PATH, "models/fetch/fetch.urdf")

    @property
    def arm_workspace_range(self):
        return {
            self.default_arm : [np.deg2rad(-45), np.deg2rad(45)]
        }

    @property
    def eef_usd_path(self):
        return {self.default_arm: os.path.join(gm.ASSET_PATH, "models/fetch/fetch/fetch_eef.usd")}

    @property
    def teleop_rotation_offset(self):
        return {self.default_arm: euler2quat([0, np.pi / 2, np.pi])}

base_control_idx property

Returns:

Type	Description
	n-array: Indices in low-level control vector corresponding to [Left, Right] wheel joints.

camera_control_idx property

Returns:

Type	Description
	n-array: Indices in low-level control vector corresponding to [tilt, pan] camera joints.

trunk_control_idx property

Returns:

Type	Description
	n-array: Indices in low-level control vector corresponding to trunk joint.

__init__(name, prim_path=None, uuid=None, scale=None, visible=True, visual_only=False, self_collisions=False, load_config=None, fixed_base=False, abilities=None, control_freq=None, controller_config=None, action_type='continuous', action_normalize=True, reset_joint_pos=None, obs_modalities='all', proprio_obs='default', sensor_config=None, grasping_mode='physical', disable_grasp_handling=False, rigid_trunk=False, default_trunk_offset=0.365, default_reset_mode='untuck', default_arm_pose='vertical', **kwargs)

Parameters:

Name	Type	Description	Default
name	str	Name for the object. Names need to be unique per scene	required
prim_path	None or str	global path in the stage to this object. If not specified, will automatically be created at /World/	None
uuid	None or int	Unique unsigned-integer identifier to assign to this object (max 8-numbers). If None is specified, then it will be auto-generated	None
scale	None or float or 3 - array	if specified, sets either the uniform (float) or x,y,z (3-array) scale for this object. A single number corresponds to uniform scaling along the x,y,z axes, whereas a 3-array specifies per-axis scaling.	None
visible	bool	whether to render this object or not in the stage	True
visual_only	bool	Whether this object should be visual only (and not collide with any other objects)	False
self_collisions	bool	Whether to enable self collisions for this object	False
load_config	None or dict	If specified, should contain keyword-mapped values that are relevant for loading this prim at runtime.	None
abilities	None or dict	If specified, manually adds specific object states to this object. It should be a dict in the form of {ability: {param: value}} containing object abilities and parameters to pass to the object state instance constructor.	None
control_freq	float	control frequency (in Hz) at which to control the object. If set to be None, simulator.import_object will automatically set the control frequency to be at the render frequency by default.	None
controller_config	None or dict	nested dictionary mapping controller name(s) to specific controller configurations for this object. This will override any default values specified by this class.	None
action_type	str	one of {discrete, continuous} - what type of action space to use	'continuous'
action_normalize	bool	whether to normalize inputted actions. This will override any default values specified by this class.	True
reset_joint_pos	None or n - array	if specified, should be the joint positions that the object should be set to during a reset. If None (default), self._default_joint_pos will be used instead. Note that _default_joint_pos are hardcoded & precomputed, and thus should not be modified by the user. Set this value instead if you want to initialize the robot with a different rese joint position.	None
obs_modalities	str or list of str	Observation modalities to use for this robot. Default is "all", which corresponds to all modalities being used. Otherwise, valid options should be part of omnigibson.sensors.ALL_SENSOR_MODALITIES. Note: If @sensor_config explicitly specifies modalities for a given sensor class, it will override any values specified from @obs_modalities!	'all'
proprio_obs	str or list of str	proprioception observation key(s) to use for generating proprioceptive observations. If str, should be exactly "default" -- this results in the default proprioception observations being used, as defined by self.default_proprio_obs. See self._get_proprioception_dict for valid key choices	'default'
sensor_config	None or dict	nested dictionary mapping sensor class name(s) to specific sensor configurations for this object. This will override any default values specified by this class.	None
grasping_mode	str	One of {"physical", "assisted", "sticky"}. If "physical", no assistive grasping will be applied (relies on contact friction + finger force). If "assisted", will magnetize any object touching and within the gripper's fingers. If "sticky", will magnetize any object touching the gripper's fingers.	'physical'
disable_grasp_handling	bool	If True, will disable all grasp handling for this object. This means that sticky and assisted grasp modes will not work unless the connection/release methodsare manually called.	False
default_trunk_offset	float	sets the default height of the robot's trunk	0.365
default_reset_mode	str	Default reset mode for the robot. Should be one of: {"tuck", "untuck"}	'untuck'
default_arm_pose	str	Default pose for the robot arm. Should be one of: {"vertical", "diagonal15", "diagonal30", "diagonal45", "horizontal"} If either reset_joint_pos is not None or default_reset_mode is "tuck", this will be ignored. Otherwise the reset_joint_pos will be initialized to the precomputed joint positions that represents default_arm_pose.	'vertical'
kwargs	dict	Additional keyword arguments that are used for other super() calls from subclasses, allowing for flexible compositions of various object subclasses (e.g.: Robot is USDObject + ControllableObject).	{}

Source code in omnigibson/robots/fetch.py

def __init__(
    self,
    # Shared kwargs in hierarchy
    name,
    prim_path=None,
    uuid=None,
    scale=None,
    visible=True,
    visual_only=False,
    self_collisions=False,
    load_config=None,
    fixed_base=False,

    # Unique to USDObject hierarchy
    abilities=None,

    # Unique to ControllableObject hierarchy
    control_freq=None,
    controller_config=None,
    action_type="continuous",
    action_normalize=True,
    reset_joint_pos=None,

    # Unique to BaseRobot
    obs_modalities="all",
    proprio_obs="default",
    sensor_config=None,

    # Unique to ManipulationRobot
    grasping_mode="physical",
    disable_grasp_handling=False,

    # Unique to Fetch
    rigid_trunk=False,
    default_trunk_offset=0.365,
    default_reset_mode="untuck",
    default_arm_pose="vertical",
    **kwargs,
):
    """
    Args:
        name (str): Name for the object. Names need to be unique per scene
        prim_path (None or str): global path in the stage to this object. If not specified, will automatically be
            created at /World/<name>
        uuid (None or int): Unique unsigned-integer identifier to assign to this object (max 8-numbers).
            If None is specified, then it will be auto-generated
        scale (None or float or 3-array): if specified, sets either the uniform (float) or x,y,z (3-array) scale
            for this object. A single number corresponds to uniform scaling along the x,y,z axes, whereas a
            3-array specifies per-axis scaling.
        visible (bool): whether to render this object or not in the stage
        visual_only (bool): Whether this object should be visual only (and not collide with any other objects)
        self_collisions (bool): Whether to enable self collisions for this object
        load_config (None or dict): If specified, should contain keyword-mapped values that are relevant for
            loading this prim at runtime.
        abilities (None or dict): If specified, manually adds specific object states to this object. It should be
            a dict in the form of {ability: {param: value}} containing object abilities and parameters to pass to
            the object state instance constructor.
        control_freq (float): control frequency (in Hz) at which to control the object. If set to be None,
            simulator.import_object will automatically set the control frequency to be at the render frequency by default.
        controller_config (None or dict): nested dictionary mapping controller name(s) to specific controller
            configurations for this object. This will override any default values specified by this class.
        action_type (str): one of {discrete, continuous} - what type of action space to use
        action_normalize (bool): whether to normalize inputted actions. This will override any default values
            specified by this class.
        reset_joint_pos (None or n-array): if specified, should be the joint positions that the object should
            be set to during a reset. If None (default), self._default_joint_pos will be used instead.
            Note that _default_joint_pos are hardcoded & precomputed, and thus should not be modified by the user.
            Set this value instead if you want to initialize the robot with a different rese joint position.
        obs_modalities (str or list of str): Observation modalities to use for this robot. Default is "all", which
            corresponds to all modalities being used.
            Otherwise, valid options should be part of omnigibson.sensors.ALL_SENSOR_MODALITIES.
            Note: If @sensor_config explicitly specifies `modalities` for a given sensor class, it will
                override any values specified from @obs_modalities!
        proprio_obs (str or list of str): proprioception observation key(s) to use for generating proprioceptive
            observations. If str, should be exactly "default" -- this results in the default proprioception
            observations being used, as defined by self.default_proprio_obs. See self._get_proprioception_dict
            for valid key choices
        sensor_config (None or dict): nested dictionary mapping sensor class name(s) to specific sensor
            configurations for this object. This will override any default values specified by this class.
        grasping_mode (str): One of {"physical", "assisted", "sticky"}.
            If "physical", no assistive grasping will be applied (relies on contact friction + finger force).
            If "assisted", will magnetize any object touching and within the gripper's fingers.
            If "sticky", will magnetize any object touching the gripper's fingers.
        disable_grasp_handling (bool): If True, will disable all grasp handling for this object. This means that
            sticky and assisted grasp modes will not work unless the connection/release methodsare manually called.
        rigid_trunk (bool) if True, will prevent the trunk from moving during execution.
        default_trunk_offset (float): sets the default height of the robot's trunk
        default_reset_mode (str): Default reset mode for the robot. Should be one of: {"tuck", "untuck"}
        If reset_joint_pos is not None, this will be ignored (since _default_joint_pos won't be used during initialization).
        default_arm_pose (str): Default pose for the robot arm. Should be one of:
            {"vertical", "diagonal15", "diagonal30", "diagonal45", "horizontal"}
            If either reset_joint_pos is not None or default_reset_mode is "tuck", this will be ignored. 
            Otherwise the reset_joint_pos will be initialized to the precomputed joint positions that represents default_arm_pose.
        kwargs (dict): Additional keyword arguments that are used for other super() calls from subclasses, allowing
            for flexible compositions of various object subclasses (e.g.: Robot is USDObject + ControllableObject).
    """
    # Store args
    self.rigid_trunk = rigid_trunk
    self.default_trunk_offset = default_trunk_offset
    assert_valid_key(key=default_reset_mode, valid_keys=RESET_JOINT_OPTIONS, name="default_reset_mode")
    self.default_reset_mode = default_reset_mode
    assert_valid_key(key=default_arm_pose, valid_keys=DEFAULT_ARM_POSES, name="default_arm_pose")
    self.default_arm_pose = default_arm_pose

    # Run super init
    super().__init__(
        prim_path=prim_path,
        name=name,
        uuid=uuid,
        scale=scale,
        visible=visible,
        fixed_base=fixed_base,
        visual_only=visual_only,
        self_collisions=self_collisions,
        load_config=load_config,
        abilities=abilities,
        control_freq=control_freq,
        controller_config=controller_config,
        action_type=action_type,
        action_normalize=action_normalize,
        reset_joint_pos=reset_joint_pos,
        obs_modalities=obs_modalities,
        proprio_obs=proprio_obs,
        sensor_config=sensor_config,
        grasping_mode=grasping_mode,
        disable_grasp_handling=disable_grasp_handling,
        **kwargs,
    )

tuck()

Immediately set this robot's configuration to be in tucked mode

Source code in omnigibson/robots/fetch.py

def tuck(self):
    """
    Immediately set this robot's configuration to be in tucked mode
    """
    self.set_joint_positions(self.tucked_default_joint_pos)

untuck()

Immediately set this robot's configuration to be in untucked mode

Source code in omnigibson/robots/fetch.py

def untuck(self):
    """
    Immediately set this robot's configuration to be in untucked mode
    """
    self.set_joint_positions(self.untucked_default_joint_pos)