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fetch

Fetch

Bases: ManipulationRobot, TwoWheelRobot, ActiveCameraRobot

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

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

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

        # 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",

        # Unique to ManipulationRobot
        grasping_mode="physical",

        # Unique to Fetch
        rigid_trunk=False,
        default_trunk_offset=0.365,
        default_arm_pose="vertical",

        **kwargs,
    ):
        """
        Args:
            prim_path (str): global path in the stage to this object
            name (None or str): Name for the object. Names need to be unique per scene. If None, a name will be
                generated at the time the object is added to the scene, using the object's category.
            class_id (None or int): What class ID the object should be assigned in semantic segmentation rendering mode.
                If None, the ID will be inferred from this object's category.
            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
            fixed_base (bool): whether to fix the base of this object or not
            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 1 / render_timestep 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.
            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.
            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
            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.
            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_arm_pose (str): Default pose for the robot arm. Should be one of:
                {"vertical", "diagonal15", "diagonal30", "diagonal45", "horizontal"}
            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_arm_pose, valid_keys=DEFAULT_ARM_POSES, name="default_arm_pose")
        self.default_arm_pose = default_arm_pose

        # Parse reset joint pos if specifying special string
        if isinstance(reset_joint_pos, str):
            assert (
                reset_joint_pos in RESET_JOINT_OPTIONS
            ), "reset_joint_pos should be one of {} if using a string!".format(RESET_JOINT_OPTIONS)
            reset_joint_pos = (
                self.tucked_default_joint_pos if reset_joint_pos == "tuck" else self.untucked_default_joint_pos
            )

        # Run super init
        super().__init__(
            prim_path=prim_path,
            name=name,
            class_id=class_id,
            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,
            grasping_mode=grasping_mode,
            **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

    @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 _actions_to_control(self, action):
        # Run super method first
        u_vec, u_type_vec = super()._actions_to_control(action=action)

        # 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_cfg["dof_idx"] = np.concatenate([self.trunk_control_idx, self.arm_control_idx[self.default_arm]])

            # 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.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=[0.04, -0.012, 0.014]),
                GraspingPoint(link_name="r_gripper_finger_link", position=[0.04, -0.012, -0.014]),
                GraspingPoint(link_name="r_gripper_finger_link", position=[-0.04, -0.012, 0.014]),
                GraspingPoint(link_name="r_gripper_finger_link", position=[-0.04, -0.012, -0.014]),
            ]
        }

    @property
    def assisted_grasp_end_points(self):
        return {
            self.default_arm: [
                GraspingPoint(link_name="l_gripper_finger_link", position=[0.04, 0.012, 0.014]),
                GraspingPoint(link_name="l_gripper_finger_link", position=[0.04, 0.012, -0.014]),
                GraspingPoint(link_name="l_gripper_finger_link", position=[-0.04, 0.012, 0.014]),
                GraspingPoint(link_name="l_gripper_finger_link", position=[-0.04, 0.012, -0.014]),
            ]
        }

    @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"],
        ]

    @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(omnigibson.assets_path, "models/fetch/fetch/fetch.usd")

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

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

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

Parameters:

Name Type Description Default
prim_path str

global path in the stage to this object

required
name None or str

Name for the object. Names need to be unique per scene. If None, a name will be generated at the time the object is added to the scene, using the object's category.

None
class_id None or int

What class ID the object should be assigned in semantic segmentation rendering mode. If None, the ID will be inferred from this object's category.

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
fixed_base bool

whether to fix the base of this object or not

False
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 1 / render_timestep 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.

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.

'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'
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'
default_trunk_offset float

sets the default height of the robot's trunk

0.365
default_arm_pose str

Default pose for the robot arm. Should be one of:

'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 robots/fetch.py
def __init__(
    self,
    # Shared kwargs in hierarchy
    prim_path,
    name=None,
    class_id=None,
    uuid=None,
    scale=None,
    visible=True,
    fixed_base=False,
    visual_only=False,
    self_collisions=False,
    load_config=None,

    # 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",

    # Unique to ManipulationRobot
    grasping_mode="physical",

    # Unique to Fetch
    rigid_trunk=False,
    default_trunk_offset=0.365,
    default_arm_pose="vertical",

    **kwargs,
):
    """
    Args:
        prim_path (str): global path in the stage to this object
        name (None or str): Name for the object. Names need to be unique per scene. If None, a name will be
            generated at the time the object is added to the scene, using the object's category.
        class_id (None or int): What class ID the object should be assigned in semantic segmentation rendering mode.
            If None, the ID will be inferred from this object's category.
        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
        fixed_base (bool): whether to fix the base of this object or not
        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 1 / render_timestep 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.
        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.
        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
        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.
        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_arm_pose (str): Default pose for the robot arm. Should be one of:
            {"vertical", "diagonal15", "diagonal30", "diagonal45", "horizontal"}
        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_arm_pose, valid_keys=DEFAULT_ARM_POSES, name="default_arm_pose")
    self.default_arm_pose = default_arm_pose

    # Parse reset joint pos if specifying special string
    if isinstance(reset_joint_pos, str):
        assert (
            reset_joint_pos in RESET_JOINT_OPTIONS
        ), "reset_joint_pos should be one of {} if using a string!".format(RESET_JOINT_OPTIONS)
        reset_joint_pos = (
            self.tucked_default_joint_pos if reset_joint_pos == "tuck" else self.untucked_default_joint_pos
        )

    # Run super init
    super().__init__(
        prim_path=prim_path,
        name=name,
        class_id=class_id,
        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,
        grasping_mode=grasping_mode,
        **kwargs,
    )

tuck()

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

Source code in 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 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)