pyrcf.utils.frame_transforms

Utility functions to help with coordinate frame transforms.

Attributes

QuatType	Numpy array representating quaternion in format [x,y,z,w]
Vector3D	Numpy array representating 3D cartesian vector in format [x,y,z]

Classes

PoseTrasfrom

Transform a pose (point and orientation) between PyRCF coordinate frames.

Functions

transform_pose_to_frame(→ Tuple[Vector3D, QuatType])	Transform a pose from a global frame to a local frame.
twist_transform(→ numpy.ndarray)	Transform a twist screw (linear velocity & angular velocity) to another coordinate frame.
get_relative_pose_between_vectors(→ Tuple[Vector3D, ...)	Given two frame poses in the same coordinate frame, return the pose of

Module Contents

pyrcf.utils.frame_transforms.QuatType: TypeAlias = np.ndarray

Numpy array representating quaternion in format [x,y,z,w]

pyrcf.utils.frame_transforms.Vector3D: TypeAlias = np.ndarray

Numpy array representating 3D cartesian vector in format [x,y,z]

pyrcf.utils.frame_transforms.transform_pose_to_frame(pos_in_frame_1: Vector3D, quat_in_frame_1: QuatType, frame_2_pos_in_frame_1: Vector3D, frame_2_quat_in_frame_1: QuatType) → Tuple[Vector3D, QuatType]

Transform a pose from a global frame to a local frame.

Both the input pose and the local frame’s pose should be described in a common global frame.

Parameters:

• pos_in_frame_1 (Vector3D) – The position of the input pose object to be transformed in a common global frame.

• quat_in_frame_1 (QuatType) – The orientation of the input pose object to be transformed in a common global frame (quaternion: [x,y,z,w]).

• frame_2_pos_in_frame_1 (Vector3D) – Position of the origin of the target coordinate frame with respect to the common global frame.

• frame_2_quat_in_frame_1 (QuatType) – The orientation of the target frame in the global frame.

Returns:

Position and orientation of the input pose in the new target

frame.

Return type:

Tuple[Vector3D, QuatType]

pyrcf.utils.frame_transforms.twist_transform(twist_a: numpy.ndarray, frame_b_in_a: numpy.ndarray) → numpy.ndarray

Transform a twist screw (linear velocity & angular velocity) to another coordinate frame.

Parameters:

• twist_a (np.ndarray) – 6D twist screw (linear x, linear y, linear z, angular x, angular y, angular z)

• frame_b_in_a (np.ndarray) – Transformation matrix of the pose of the new frame in the old frame.

Returns:

Twist screw in the new frame (linear x, linear y, linear z, angular x,

angular y, angular z).

Return type:

np.ndarray

pyrcf.utils.frame_transforms.get_relative_pose_between_vectors(pos1: Vector3D, quat1: QuatType, pos2: Vector3D, quat2: QuatType) → Tuple[Vector3D, QuatType]

Given two frame poses in the same coordinate frame, return the pose of the second frame with respect to the first.

Parameters:

• pos1 (Vector3D) – Position of the first frame in a global frame.

• quat1 (QuatType) – Orientation quaternion of the first frame.

• pos2 (Vector3D) – Position of the second frame in the same global frame.

• quat2 (QuatType) – Orientation of the second frame.

Returns:

Position and orientation of the second frame

with respect to the first.

Return type:

Tuple[Vector3D, QuatType]

class pyrcf.utils.frame_transforms.PoseTrasfrom

Transform a pose (point and orientation) between PyRCF coordinate frames.

static TELEOP_FRAME_POSE_IN_WORLD(base_pos_in_world: Vector3D, base_ori_in_world: QuatType) → Tuple[Vector3D, QuatType]

This is the definition of the teleop frame.

static BASE_FRAME_POSE_IN_TELEOP(base_pos_in_world: Vector3D, base_ori_in_world: QuatType) → Tuple[Vector3D, QuatType]

This is the definition of the teleop frame.

static teleop2base(p_in_teleop: Vector3D, q_in_teleop: QuatType, base_pos_in_world: Vector3D, base_ori_in_world: QuatType) → Tuple[Vector3D, QuatType]

Transform a pose in teleop frame to base frame.

static base2teleop(p_in_base: Vector3D, q_in_base: QuatType, base_pos_in_world: Vector3D, base_ori_in_world: QuatType) → Tuple[Vector3D, QuatType]

Transform a pose in base frame to teleop frame.

static teleop2world(p_in_teleop: Vector3D, q_in_teleop: QuatType, base_pos_in_world: Vector3D, base_ori_in_world: QuatType) → Tuple[Vector3D, QuatType]

Transform a pose in teleop frame to world frame.

static world2teleop(p_in_world: Vector3D, q_in_world: QuatType, base_pos_in_world: Vector3D, base_ori_in_world: QuatType) → Tuple[Vector3D, QuatType]

Transform a pose in world frame to teleop frame.