flexiv::rdk::Model Class Reference

Interface to obtain certain model data of the robot, including kinematics and dynamics. More...

#include <model.hpp>

Public Member Functions
	Model (const Robot &robot, const Eigen::Vector3d &gravity_vector=Eigen::Vector3d(0.0, 0.0, -9.81))
	[Non-blocking] Instantiate the robot model interface. More...
std::vector< std::string >	link_names () const
	[Non-blocking] Names of all links in the robot model. More...
void	Reload ()
	[Blocking] Reload (refresh) parameters of the robot model stored locally in this class using the latest data synced from the connected robot. Tool model is also synced. More...
void	Update (const std::vector< double > &positions, const std::vector< double > &velocities)
	[Non-blocking] Update the configuration (posture) of the locally-stored robot model so that the locally computed functions return results based on the updated configuration. More...
Eigen::MatrixXd	dJ (const std::string &link_name)
	[Non-blocking] Compute the time derivative of Jacobian matrix at the specified frame w.r.t. world frame. More...
Eigen::MatrixXd	M ()
	[Non-blocking] Compute the mass matrix in generalized coordinates, i.e. joint space. More...
Eigen::MatrixXd	C ()
	[Non-blocking] Compute the Coriolis/centripetal matrix in generalized coordinates, i.e. joint space. More...
Eigen::VectorXd	g ()
	[Non-blocking] Compute the gravity force vector in generalized coordinates, i.e. joint space. More...
Eigen::VectorXd	c ()
	[Non-blocking] Compute the Coriolis force vector in generalized coordinates, i.e. joint space. More...
Eigen::MatrixXd	J (const std::string &link_name)
	[Non-blocking] Compute the Jacobian matrix at the specified frame w.r.t. world frame. More...
Eigen::Isometry3d	T (const std::string &link_name)
	[Non-blocking] Compute the transformation matrix of the specified frame w.r.t. world frame. More...
void	SyncURDF (const std::string &template_urdf_path)
	[Blocking] Sync the actual kinematic parameters of the connected robot into the template URDF. More...
std::pair< bool, std::vector< double > >	reachable (const std::array< double, kPoseSize > &pose, const std::vector< double > &seed_positions, bool free_orientation) const
	[Blocking] Check if a Cartesian pose is reachable. If yes, also return an IK solution of the corresponding joint positions. More...
std::pair< double, double >	configuration_score () const
	[Blocking] Score of the robot's current configuration (posture), calculated from the manipulability measurements. More...

Detailed Description

Interface to obtain certain model data of the robot, including kinematics and dynamics.

Definition at line 20 of file model.hpp.

Constructor & Destructor Documentation

Model()

flexiv::rdk::Model::Model	(	const Robot &	robot,
		const Eigen::Vector3d &	gravity_vector = Eigen::Vector3d(0.0, 0.0, -9.81)
	)

[Non-blocking] Instantiate the robot model interface.

Parameters

[in]	robot	Reference to the instance of flexiv::rdk::Robot.
[in]	gravity_vector	Earth's gravity vector in world frame. Default to \( [0.0, 0.0, -9.81]^T \). Unit: \( [m/s^2] \).

Exceptions

std::runtime_error	if the initialization sequence failed.
std::logic_error	if the connected robot does not have an RDK professional license; or the parsed robot model is not supported.

Member Function Documentation

C()

Eigen::MatrixXd flexiv::rdk::Model::C

(

)

[Non-blocking] Compute the Coriolis/centripetal matrix in generalized coordinates, i.e. joint space.

Returns

Coriolis/centripetal matrix: \( C(q,\dot{q}) \in \mathbb{R}^{n \times n} \).

Note

Call Update() before this function.

c()

Eigen::VectorXd flexiv::rdk::Model::c

(

)

[Non-blocking] Compute the Coriolis force vector in generalized coordinates, i.e. joint space.

Returns

Coriolis force vector: \( c(q,\dot{q}) \in \mathbb{R}^{n \times 1} \). Unit: \( [Nm] \).

Note

Call Update() before this function.

configuration_score()

std::pair<double, double> flexiv::rdk::Model::configuration_score

(

)

const

[Blocking] Score of the robot's current configuration (posture), calculated from the manipulability measurements.

Returns

A pair of {translation_score, orientation_score}. The quality of configuration based on score is mapped as: poor = [0, 20), medium = [20, 40), good = [40, 100].

Exceptions

std::runtime_error

if failed to get a reply from the connected robot.

Note

This function blocks until a reply is received.

Warning

A poor configuration score means the robot is near or at singularity, which can lead to degraded Cartesian performance. Use configuration with high scores for better manipulability and task results.

dJ()

Eigen::MatrixXd flexiv::rdk::Model::dJ

(

const std::string &

link_name

)

[Non-blocking] Compute the time derivative of Jacobian matrix at the specified frame w.r.t. world frame.

Parameters

[in]

link_name

Name of the link whose frame is the specified one.

Returns

Time derivative of the Jacobian matrix: \( ^{0}\dot{J_i} \in \mathbb{R}^{m \times n} \).

Exceptions

std::invalid_argument

if [link_name] does not exist.

Note

Call Update() before this function.

Available links can be found in the provided URDF. They are {"base_link", "link1", "link2", "link3", "link4", "link5", "link6", "link7", "flange"}, plus "tool" if any flange tool is mounted.

g()

Eigen::VectorXd flexiv::rdk::Model::g

(

)

[Non-blocking] Compute the gravity force vector in generalized coordinates, i.e. joint space.

Returns

Gravity force vector: \( g(q) \in \mathbb{R}^{n \times 1} \). Unit: \( [Nm] \).

Note

Call Update() before this function.

J()

Eigen::MatrixXd flexiv::rdk::Model::J

(

const std::string &

link_name

)

[Non-blocking] Compute the Jacobian matrix at the specified frame w.r.t. world frame.

Parameters

[in]

link_name

Name of the link whose frame is the specified one.

Returns

Jacobian matrix: \( ^{0}J_i \in \mathbb{R}^{m \times n} \).

Exceptions

std::invalid_argument

if [link_name] does not exist.

Note

Call Update() before this function.

Available links can be found in the provided URDF. They are {"base_link", "link1", "link2", "link3", "link4", "link5", "link6", "link7", "flange"}, plus "tool" if any flange tool is mounted.

link_names()

std::vector<std::string> flexiv::rdk::Model::link_names

(

)

const

[Non-blocking] Names of all links in the robot model.

Returns

Names vector in the same order as the robot's kinematic chain.

M()

Eigen::MatrixXd flexiv::rdk::Model::M

(

)

[Non-blocking] Compute the mass matrix in generalized coordinates, i.e. joint space.

Returns

Symmetric positive definite mass matrix: \( M(q) \in \mathbb{S}^{n \times n}_{++} \). Unit: \( [kgm^2] \).

Note

Call Update() before this function.

reachable()

std::pair<bool, std::vector<double> > flexiv::rdk::Model::reachable	(	const std::array< double, kPoseSize > &	pose,
		const std::vector< double > &	seed_positions,
		bool	free_orientation
	)		const

[Blocking] Check if a Cartesian pose is reachable. If yes, also return an IK solution of the corresponding joint positions.

Parameters

[in]	pose	Cartesian pose to be checked.
[in]	seed_positions	Joint positions to be used as the seed for solving IK.
[in]	free_orientation	Only constrain position and allow orientation to move freely.

Returns

A pair of {is_reachable, ik_solution}.

Exceptions

std::invalid_argument	if size of [seed_positions] does not match robot DoF.
std::runtime_error	if failed to get a reply from the connected robot.

Note

This function blocks until a reply is received.

Reload()

void flexiv::rdk::Model::Reload

(

)

[Blocking] Reload (refresh) parameters of the robot model stored locally in this class using the latest data synced from the connected robot. Tool model is also synced.

Exceptions

std::runtime_error	if failed to sync model data.
std::logic_error	if the synced robot model contains invalid data.

Note

This function blocks until the model parameters are synced and reloaded.

This function does not affect the kinematics functions.

Warning

Parameters of the locally-stored robot model must be manually refreshed using this function whenever a physical change is made to the connected robot (e.g. a tool is added or changed). Otherwise the locally computed functions will return incorrect results.

SyncURDF()

void flexiv::rdk::Model::SyncURDF

(

const std::string &

template_urdf_path

)

[Blocking] Sync the actual kinematic parameters of the connected robot into the template URDF.

Parameters

[in]

template_urdf_path

Path to the template URDF in [flexiv_rdk/resources] directory. This template URDF will be updated when the sync is finished.

Exceptions

std::invalid_argument	if failed to load the template URDF.
std::runtime_error	if failed to sync the URDF.

Note

This function blocks until the URDF syncing is finished.

Why is this function needed?

The URDFs in [flexiv_rdk/resources] directory contain kinematic parameters of the latest robot hardware version, which might be different from older versions. This function is therefore provided to sync the actual kinematic parameters of the connected robot into the template URDF.

T()

Eigen::Isometry3d flexiv::rdk::Model::T

(

const std::string &

link_name

)

[Non-blocking] Compute the transformation matrix of the specified frame w.r.t. world frame.

Parameters

[in]

link_name

Name of the link whose frame is the specified one.

Returns

Jacobian matrix: \( ^{0}J_i \in \mathbb{R}^{m \times n} \).

Exceptions

std::invalid_argument

if [link_name] does not exist.

Note

Call Update() before this function.

Available links can be found in the provided URDF. They are {"base_link", "link1", "link2", "link3", "link4", "link5", "link6", "link7", "flange"}, plus "tool" if any flange tool is mounted.

Update()

void flexiv::rdk::Model::Update	(	const std::vector< double > &	positions,
		const std::vector< double > &	velocities
	)

[Non-blocking] Update the configuration (posture) of the locally-stored robot model so that the locally computed functions return results based on the updated configuration.

Parameters

[in]	positions	Current joint positions: \( q \in \mathbb{R}^{n \times 1} \). Unit: \( [rad] \).
[in]	velocities	Current joint velocities: \( \dot{q} \in \mathbb{R}^{n \times 1} \). Unit: \( [rad/s] \).

Exceptions

std::invalid_argument

if size of any input vector does not match robot DoF.

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The documentation for this class was generated from the following file:

• include/flexiv/rdk/model.hpp