opspace::PDTask Class Reference

Base class for tasks with proportional-derivative control. More...

#include <task_library.hpp>

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List of all members.

Public Member Functions
virtual Status	check (Vector const *param, Vector const &value) const
	Verifies that kp, kd, and maxvel are non-negative.
void	quickSetup (Vector const &kp, Vector const &kd, Vector const &maxvel)
Protected Types
enum	saturation_policy_t { SATURATION_OFF, SATURATION_COMPONENT_WISE, SATURATION_MAX_COMPONENT, SATURATION_NORM }
	Velocity saturation policy. More...
Protected Member Functions
	PDTask (std::string const &name, saturation_policy_t saturation_policy)
Status	initPDTask (Vector const &initpos)
	Initialize the goalpos to initpos and the goalvel to zero.
Status	computePDCommand (Vector const &curpos, Vector const &curvel, Vector &command)
	Compute PD command, with velocity saturation determined by the saturation_policy specified at construction time.
Protected Attributes
saturation_policy_t const	saturation_policy_
bool	initialized_
Vector	goalpos_
Vector	goalvel_
Vector	errpos_
Vector	errvel_
Vector	kp_
Vector	kd_
Vector	maxvel_

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Detailed Description

Base class for tasks with proportional-derivative control.

It provides a reusable implementation for the parameters and algorithm of a PD controller with velocity saturation.

Parameters:

• goalpos (vector): desired position
• goalvel (vector): desired velocity
• kp (vector): proportional gain
• kd (vector): derivative gain
• maxvel (vector): velocity saturation limit

Subclasses should call initPDTask() from within their init() method, and computePDCommand() from their computeCommand().

Definition at line 51 of file task_library.hpp.

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Member Enumeration Documentation

enum opspace::PDTask::saturation_policy_t [protected]

Velocity saturation policy.

• SATURATION_OFF: do not saturate commands (use with caution)
• SATURATION_COMPONENT_WISE: each component of the position-error is scaled according to an individual saturation term
• SATURATION_MAX_COMPONENT: similar to SATURATION_COMPONENT_WISE, but the most saturated component determines the overall scaling.
• SATURATION_NORM: the vector norm of the position error is used to determine the saturation factor (this only makes sense if kp, kd, and maxvel are one-dimensional values, so this constraint is enforced in other parts of the PDTask implementation as well)

Enumerator:

SATURATION_OFF
SATURATION_COMPONENT_WISE
SATURATION_MAX_COMPONENT
SATURATION_NORM

Reimplemented in opspace::TrajectoryTask.

Definition at line 88 of file task_library.hpp.

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Constructor & Destructor Documentation

opspace::PDTask::PDTask	(	std::string const &	name,
		saturation_policy_t	saturation_policy
	)			[protected]

Definition at line 35 of file task_library.cpp.

References opspace::ParameterReflection::declareParameter(), errpos_, errvel_, goalpos_, goalvel_, kd_, kp_, maxvel_, and opspace::PARAMETER_FLAG_NOLOG.

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Member Function Documentation

Status opspace::PDTask::check	(	Vector const *	param,
		Vector const &	value
	)			const [virtual]

Verifies that kp, kd, and maxvel are non-negative.

If initialized, also verifies the vector dimension for kp, kd, maxvel, goalpos, and goalvel.

Returns:

Failure if any of the mentioned checks fail, and success otherwise.

Reimplemented from opspace::ParameterReflection.

Reimplemented in opspace::DraftPIDTask, and opspace::TrajectoryTask.

Definition at line 52 of file task_library.cpp.

References errpos_, errvel_, goalpos_, goalvel_, initialized_, kd_, kp_, maxvel_, SATURATION_NORM, and saturation_policy_.

Referenced by opspace::TrajectoryTask::check().

void opspace::PDTask::quickSetup	(	Vector const &	kp,
		Vector const &	kd,
		Vector const &	maxvel
	)			[inline]

Definition at line 65 of file task_library.hpp.

References kd_, kp_, and maxvel_.

Referenced by opspace::CartPosTask::quickSetup().

Status opspace::PDTask::initPDTask

(

Vector const &

initpos

)

[protected]

Initialize the goalpos to initpos and the goalvel to zero.

Also performs sanity checks on kp, kd, and maxvel. If saturation policy is opspace::PDTask::SATURATION_NORM, then kp, kd, and maxvel must be single-dimensional. Otherwise, if they are single-dimensional, this method converts them to N-dimensional vectors by filling them with N copies of the value. E.g. if kp=[100.0] and initpos is 3-dimensional, kp would end up as [100.0, 100.0, 100.0].

Returns:

Success if everything went well, failure otherwise.

Definition at line 88 of file task_library.cpp.

References errpos_, errvel_, goalpos_, goalvel_, initialized_, kd_, kp_, maxvel_, SATURATION_NORM, and saturation_policy_.

Referenced by opspace::JPosTask::init(), opspace::CartPosTask::init(), opspace::DraftPIDTask::initDraftPIDTask(), and opspace::TrajectoryTask::initTrajectoryTask().

Status opspace::PDTask::computePDCommand	(	Vector const &	curpos,
		Vector const &	curvel,
		Vector &	command
	)			[protected]

Compute PD command, with velocity saturation determined by the saturation_policy specified at construction time.

This drives the task to achieving goalpos with goalvel.

Returns:

Success if everything went well, failure otherwise.

Definition at line 142 of file task_library.cpp.

References errpos_, jspace::Status::errstr, errvel_, goalpos_, goalvel_, initialized_, kd_, kp_, maxvel_, jspace::Status::ok, SATURATION_COMPONENT_WISE, SATURATION_MAX_COMPONENT, SATURATION_NORM, and saturation_policy_.

Referenced by opspace::DraftPIDTask::computeDraftPIDCommand(), opspace::TrajectoryTask::computeTrajectoryCommand(), opspace::JPosTask::update(), and opspace::CartPosTask::update().

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Member Data Documentation

saturation_policy_t const opspace::PDTask::saturation_policy_ [protected]

Definition at line 122 of file task_library.hpp.

Referenced by opspace::TrajectoryTask::check(), check(), computePDCommand(), initPDTask(), and opspace::TrajectoryTask::initTrajectoryTask().

bool opspace::PDTask::initialized_ [protected]

Definition at line 123 of file task_library.hpp.

Referenced by opspace::DraftPIDTask::check(), check(), computePDCommand(), and initPDTask().

Vector opspace::PDTask::goalpos_ [protected]

Definition at line 124 of file task_library.hpp.

Referenced by opspace::DraftPIDTask::check(), check(), computePDCommand(), opspace::TrajectoryTask::computeTrajectoryCommand(), initPDTask(), and PDTask().

Vector opspace::PDTask::goalvel_ [protected]

Definition at line 125 of file task_library.hpp.

Referenced by check(), computePDCommand(), opspace::TrajectoryTask::computeTrajectoryCommand(), initPDTask(), and PDTask().

Vector opspace::PDTask::errpos_ [protected]

Definition at line 126 of file task_library.hpp.

Referenced by check(), opspace::DraftPIDTask::computeDraftPIDCommand(), computePDCommand(), opspace::DraftPIDTask::dbg(), initPDTask(), and PDTask().

Vector opspace::PDTask::errvel_ [protected]

Definition at line 127 of file task_library.hpp.

Referenced by check(), opspace::DraftPIDTask::computeDraftPIDCommand(), computePDCommand(), initPDTask(), and PDTask().

Vector opspace::PDTask::kp_ [protected]

Definition at line 128 of file task_library.hpp.

Referenced by check(), computePDCommand(), initPDTask(), PDTask(), opspace::JPosTrjTask::quickSetup(), and quickSetup().

Vector opspace::PDTask::kd_ [protected]

Definition at line 129 of file task_library.hpp.

Referenced by check(), computePDCommand(), initPDTask(), PDTask(), opspace::JPosTrjTask::quickSetup(), and quickSetup().

Vector opspace::PDTask::maxvel_ [protected]

Definition at line 130 of file task_library.hpp.

Referenced by opspace::TrajectoryTask::check(), check(), computePDCommand(), initPDTask(), opspace::TrajectoryTask::initTrajectoryTask(), PDTask(), opspace::JPosTrjTask::quickSetup(), and quickSetup().

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

• opspace/include/opspace/task_library.hpp
• opspace/src/task_library.cpp

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