BipedalLocomotion::IK::DistanceTask class
#include <BipedalLocomotion/IK/DistanceTask.h>

The DistanceTask class controls the distance of a frame with respect the world origin, or another frame.

The task assumes perfect control of the robot velocity that contains the base linear and angular velocity expressed in mixed representation and the joint velocities. The task represents the following equation

where is the position of the target frame wrt the base or world frame. is the current distance. is the linear part of the robot jacobian. is the controller gain and is the desired distance.

Base classes

struct IKLinearTask: IKLinearTask specializes a LinearTask in the case of Inverse Kinematics.

Public functions

auto initialize(std::weak_ptr<const ParametersHandler::IParametersHandler> paramHandler) -> bool override: Initialize the task.
auto setKinDyn(std::shared_ptr<iDynTree::KinDynComputations> kinDyn) -> bool override: Set the kinDynComputations object.
auto setVariablesHandler(const System::VariablesHandler& variablesHandler) -> bool override: Set the set of variables required by the task.
auto update() -> bool override: Update the content of the task.
auto setDesiredDistance(double desiredDistance) -> bool: setDesiredDistance Set the desired distance between the target and the reference frame
auto setSetPoint(double desiredDistance) -> bool: setSetPoint Set the desired distance between the target and the reference frame
auto getDistance() const -> double: Get the computed distance between the target frame and either the world origin, or the base origin.
auto size() const -> std::size_t override: Get the size of the task.
auto type() const -> Type override: The DistanceTask is an equality task.
auto isValid() const -> bool override: Determines the validity of the objects retrieved with getA() and getB()

Function documentation

bool BipedalLocomotion::IK::DistanceTask::initialize(std::weak_ptr<const ParametersHandler::IParametersHandler> paramHandler) override

Initialize the task.

Parameters
paramHandler	pointer to the parameters handler.
Returns	True in case of success, false otherwise.

Note

the following parameters are required by the class

Parameter Name	Type	Description	Mandatory
`robot_velocity_variable_name`	`string`	Name of the variable contained in `VariablesHandler` describing the robot velocity	Yes
`kp`	`double`	Gain of the distance controller	Yes
`target_frame_name`	`string`	Name of the frame of which computing the distance	Yes
`reference_frame_name`	`string`	Name of the frame with respect to which computing the distance. If empty, the world frame will be used (Default = "")	No
`distance_numeric_threshold`	`double`	Lowerbound for the computed distance when inverting it in the task Jacobian (Default = 0.001)	No

bool BipedalLocomotion::IK::DistanceTask::setKinDyn(std::shared_ptr<iDynTree::KinDynComputations> kinDyn) override

Set the kinDynComputations object.

Parameters
kinDyn	pointer to a kinDynComputations object.
Returns	True in case of success, false otherwise.

bool BipedalLocomotion::IK::DistanceTask::setVariablesHandler(const System::VariablesHandler& variablesHandler) override

Set the set of variables required by the task.

Parameters
variablesHandler	reference to a variables handler.
Returns	True in case of success, false otherwise.

The variables are stored in the System::VariablesHandler.

bool BipedalLocomotion::IK::DistanceTask::update() override

Update the content of the task.

Returns	True in case of success, false otherwise.

bool BipedalLocomotion::IK::DistanceTask::setDesiredDistance(double desiredDistance)

setDesiredDistance Set the desired distance between the target and the reference frame

Parameters
desiredDistance	The desired distance expressed in meters
Returns	True in case of success, false otherwise.

bool BipedalLocomotion::IK::DistanceTask::setSetPoint(double desiredDistance)

setSetPoint Set the desired distance between the target and the reference frame

Parameters
desiredDistance	The desired distance expressed in meters
Returns	True in case of success, false otherwise.

It is equivalent to setDesiredDistance

double BipedalLocomotion::IK::DistanceTask::getDistance() const

Get the computed distance between the target frame and either the world origin, or the base origin.

Returns	The computed distance

std::size_t BipedalLocomotion::IK::DistanceTask::size() const override

Get the size of the task.

Returns	the size of the task.

(I.e the number of rows of the vector b)

Type BipedalLocomotion::IK::DistanceTask::type() const override

The DistanceTask is an equality task.

Returns	the size of the task.

bool BipedalLocomotion::IK::DistanceTask::isValid() const override

Determines the validity of the objects retrieved with getA() and getB()

Returns	True if the objects are valid, false otherwise.