pycram.external_interfaces.ik

Functions

_make_request_msg(→ moveit_msgs.msg.PositionIKRequest)	Generates an ik request message for the kdl_ik_service. The message is
call_ik(→ typing_extensions.List[float])	Sends a request to the kdl_ik_service and returns the solution.
try_to_reach_with_grasp(...)	Checks if the robot can reach a given position with a specific grasp orientation.
apply_grasp_orientation_to_pose(...)	Applies the orientation of a grasp to a given pose. This is done by using the grasp orientation
try_to_reach(...)	Tries to reach a given position with a given robot. This is done by calculating the inverse kinematics.
request_ik(...)	Top-level method to request ik solution for a given pose. This method will check if the giskard node is running
request_kdl_ik(→ typing_extensions.Dict[str, float])	Top-level method to request ik solution for a given pose. Before calling the ik service the links directly before
request_giskard_ik(...)	Calls giskard in projection mode and queries the ik solution for a full body ik solution. This method will
request_pinocchio_ik(→ typing_extensions.Dict[str, float])	Calls the pinocchio ik solver to calculate the ik solution for a given target link and pose.

Module Contents

pycram.external_interfaces.ik._make_request_msg(root_link: str, tip_link: str, target_pose: pycram.datastructures.pose.PoseStamped, robot_object: pycram.world_concepts.world_object.Object, joints: typing_extensions.List[str]) → moveit_msgs.msg.PositionIKRequest

Generates an ik request message for the kdl_ik_service. The message is of the type moveit_msgs/PositionIKRequest and contains all information contained in the parameter.

Parameters:

• root_link – The first link of the chain of joints to be altered

• tip_link – The last link of the chain of joints to be altered

• target_pose – Target pose for which the message should be created

• robot_object – The robot for which the ik should be generated

• joints – A list of joint names between the root_link and tip_link that should be altered.

Returns:

A moveit_msgs/PositionIKRequest message containing all the information from the parameter

pycram.external_interfaces.ik.call_ik(root_link: str, tip_link: str, target_pose: pycram.datastructures.pose.PoseStamped, robot_object: pycram.world_concepts.world_object.Object, joints: typing_extensions.List[str]) → typing_extensions.List[float]

Sends a request to the kdl_ik_service and returns the solution. Note that the robot in robot_object should be identical to the robot description uploaded to the parameter server. Furthermore, note that the root_link and tip_link are the links attached to the first and last joints in the joints list.

Parameters:

• root_link – The first link of the chain of joints to be altered

• tip_link – The last link in the chain of joints to be altered

• target_pose – The target pose in frame of root link second is the orientation as quaternion in world coordinate frame

• robot_object – The robot object for which the ik solution should be generated

• joints – A list of joint name that should be altered

Returns:

The solution that was generated as a list of joint values corresponding to the order of joints given

pycram.external_interfaces.ik.try_to_reach_with_grasp(pose_or_object: typing_extensions.Union[pycram.datastructures.pose.PoseStamped, pycram.world_concepts.world_object.Object], prospection_robot: pycram.world_concepts.world_object.Object, gripper_name: str, grasp_quaternion: typing_extensions.List[float]) → typing_extensions.Union[pycram.datastructures.pose.PoseStamped, None]

Checks if the robot can reach a given position with a specific grasp orientation. To determine this the inverse kinematics are calculated and applied.

Parameters:

• pose_or_object – The position and rotation or Object for which reachability should be checked or an Object

• prospection_robot – The robot that should reach for the position

• gripper_name – The name of the end effector

• grasp_quaternion – The orientation of the grasp

pycram.external_interfaces.ik.apply_grasp_orientation_to_pose(grasp_orientation: typing_extensions.List[float], pose: pycram.datastructures.pose.PoseStamped) → pycram.datastructures.pose.PoseStamped

Applies the orientation of a grasp to a given pose. This is done by using the grasp orientation of the given grasp and applying it to the given pose.

Parameters:

• grasp_orientation – The orientation of the grasp

• pose – The pose to which the grasp orientation should be applied

pycram.external_interfaces.ik.try_to_reach(pose_or_object: typing_extensions.Union[pycram.datastructures.pose.PoseStamped, pycram.world_concepts.world_object.Object], prospection_robot: pycram.world_concepts.world_object.Object, gripper_name: str) → typing_extensions.Union[pycram.datastructures.pose.PoseStamped, None]

Tries to reach a given position with a given robot. This is done by calculating the inverse kinematics.

Parameters:

• pose_or_object – The position and rotation or Object for which reachability should be checked.

• prospection_robot – The robot that should be used to check for reachability, should be the one in the prospection world

• gripper_name – Name of the gripper tool frame

Returns:

The pose at which the robot should stand or None if the target is not reachable

pycram.external_interfaces.ik.request_ik(target_pose: pycram.datastructures.pose.PoseStamped, robot: pycram.world_concepts.world_object.Object, joints: typing_extensions.List[str], gripper: str) → typing_extensions.Tuple[pycram.datastructures.pose.PoseStamped, typing_extensions.Dict[str, float]]

Top-level method to request ik solution for a given pose. This method will check if the giskard node is running and if so will call the giskard service. If the giskard node is not running the kdl_ik_service will be called.

Parameters:

• target_pose – Pose of the end-effector for which an ik solution should be found

• robot – The robot object which should be used

• joints – A list of joints that should be used in computation, this is only relevant for the kdl_ik_service

• gripper – Name of the tool frame which should grasp, this should be at the end of the given joint chain

Returns:

A Pose at which the robt should stand as well as a dictionary of joint values

pycram.external_interfaces.ik.request_kdl_ik(target_pose: pycram.datastructures.pose.PoseStamped, robot: pycram.world_concepts.world_object.Object, joints: typing_extensions.List[str], gripper: str) → typing_extensions.Dict[str, float]

Top-level method to request ik solution for a given pose. Before calling the ik service the links directly before and after the joint chain will be queried and the target_pose will be transformed into the frame of the root_link. Afterward, the offset between the tip_link and end effector will be calculated and taken into account. Lastly the ik service is called and the result returned

Parameters:

• target_pose – Pose for which an ik solution should be found

• robot – Robot object which should be used

• joints – List of joints that should be used in computation

• gripper – Name of the gripper which should grasp, this should be at the end of the given joint chain

Returns:

A list of joint values

pycram.external_interfaces.ik.request_giskard_ik(target_pose: pycram.datastructures.pose.PoseStamped, robot: pycram.world_concepts.world_object.Object, gripper: str) → typing_extensions.Tuple[pycram.datastructures.pose.PoseStamped, typing_extensions.Dict[str, float]]

Calls giskard in projection mode and queries the ik solution for a full body ik solution. This method will try to drive the robot directly to a pose from which the target_pose is reachable for the end effector. If there are obstacles in the way this method will fail. In this case please use the GiskardLocation designator.

Parameters:

• target_pose – Pose at which the end effector should be moved.

• robot – Robot object which should be used.

• gripper – Name of the tool frame which should grasp, this should be at the end of the given joint chain.

Returns:

A list of joint values.

pycram.external_interfaces.ik.request_pinocchio_ik(target_pose: pycram.datastructures.pose.PoseStamped, robot: pycram.world_concepts.world_object.Object, target_link: str, joints: typing_extensions.List[str]) → typing_extensions.Dict[str, float]

Calls the pinocchio ik solver to calculate the ik solution for a given target link and pose.

Parameters:

• target_link – The target link for which the ik solution should be calculated

• target_pose – The target pose for which the ik solution should be calculated

• robot – The robot object for which the ik solution should be calculated

• joints – The joints that should be used in the calculation

Returns:

A dictionary containing the joint names and joint values