ompl::geometric::pSBL Class Reference

Parallel Single-query Bi-directional Lazy collision checking planner. More...

#include <pSBL.h>

Inheritance diagram for ompl::geometric::pSBL:

Classes
class	Motion
struct	MotionsToBeRemoved
struct	PendingRemoveMotion
struct	SolutionInfo
struct	TreeData
Public Member Functions
virtual void	clear (void)
	Clear all internal datastructures. Planner settings are not affected. Subsequent calls to solve() will ignore all previous work.
virtual void	getPlannerData (base::PlannerData &data) const
	Get information about the current run of the motion planner. Repeated calls to this function will update data (only additions are made). This is useful to see what changed in the exploration datastructure, between calls to solve(), for example (without calling clear() in between).
const base::ProjectionEvaluatorPtr &	getProjectionEvaluator (void) const
	Get the projection evaluator.
double	getRange (void) const
	Get the range the planner is using.
unsigned int	getThreadCount (void) const
	Get the thread count.
	pSBL (const base::SpaceInformationPtr &si)
void	setProjectionEvaluator (const std::string &name)
	Set the projection evaluator (select one from the ones registered with the state space).
void	setProjectionEvaluator (const base::ProjectionEvaluatorPtr &projectionEvaluator)
	Set the projection evaluator. This class is able to compute the projection of a given state.
void	setRange (double distance)
	Set the range the planner is supposed to use.
void	setThreadCount (unsigned int nthreads)
	Set the number of threads the planner should use. Default is 2.
virtual void	setup (void)
	Perform extra configuration steps, if needed. This call will also issue a call to ompl::base::SpaceInformation::setup() if needed. This must be called before solving.
virtual bool	solve (const base::PlannerTerminationCondition &ptc)
	Function that can solve the motion planning problem. This function can be called multiple times on the same problem, without calling clear() in between. This allows the planner to continue work more time on an unsolved problem, for example. If this option is used, it is assumed the problem definition is not changed (unpredictable results otherwise). The only change in the problem definition that is accounted for is the addition of starting or goal states (but not changing previously added start/goal states). The function terminates if the call to ptc returns true.
virtual	~pSBL (void)
Protected Types
typedef std::vector< Motion * >	MotionSet
Protected Member Functions
void	addMotion (TreeData &tree, Motion *motion)
bool	checkSolution (RNG &rng, bool start, TreeData &tree, TreeData &otherTree, Motion motion, std::vector< Motion > &solution)
void	freeGridMotions (Grid< MotionSet > &grid)
void	freeMemory (void)
bool	isPathValid (TreeData &tree, Motion *motion)
void	removeMotion (TreeData &tree, Motion motion, std::map< Motion , bool > &seen)
Motion *	selectMotion (RNG &rng, TreeData &tree)
void	threadSolve (unsigned int tid, const base::PlannerTerminationCondition &ptc, SolutionInfo *sol)
Protected Attributes
unsigned int	loopCounter_
boost::mutex	loopLock_
boost::mutex	loopLockCounter_
double	maxDistance_
base::ProjectionEvaluatorPtr	projectionEvaluator_
MotionsToBeRemoved	removeList_
base::StateSamplerArray < base::ValidStateSampler >	samplerArray_
TreeData	tGoal_
unsigned int	threadCount_
TreeData	tStart_

Detailed Description

Parallel Single-query Bi-directional Lazy collision checking planner.

Short description: SBL is a tree-based motion planner that attempts to grow two trees at once: one grows from the starting state and the other from the goal state. The tree expansion strategy is the same as for EST. Attempts are made to connect these trees at every step of the expansion. If they are connected, a solution path is obtained. However, this solution path is not certain to be valid (the lazy part of the algorithm) so it is checked for validity. If invalid parts are found, they are removed from the tree and exploration of the state space continues until a solution is found. To guide the exploration, an additional grid data structure is maintained. Grid cells contain states that have been previously visited. When deciding which state to use for further expansion, this grid is used; least-filled grid cells have most chances of being selected. The grid is usually imposed on a projection of the state space. This projection needs to be set before using the planner (setProjectionEvaluator() function). Connection of states in different trees is attempted if they fall in the same grid cell. If no projection is set, the planner will attempt to use the default projection associated to the state space. An exception is thrown if no default projection is available either.

External documentation: G. Sánchez and J.-C. Latombe, A single-query bi-directional probabilistic roadmap planner with lazy collision checking, in The Tenth International Symposium on Robotics Research, pp. 403–417, 2001. DOI: 10.1007/3-540-36460-9_27
[PDF]

Definition at line 88 of file pSBL.h.

Member Typedef Documentation

typedef std::vector<Motion*> ompl::geometric::pSBL::MotionSet [protected]

Definition at line 160 of file pSBL.h.

Constructor & Destructor Documentation

ompl::geometric::pSBL::pSBL ( const base::SpaceInformationPtr & si ) [inline]

Definition at line 92 of file pSBL.h.

virtual ompl::geometric::pSBL::~pSBL ( void ) [inline, virtual]

Definition at line 100 of file pSBL.h.

Member Function Documentation

void ompl::geometric::pSBL::addMotion	(	TreeData &	tree,
		Motion *	motion
	)			`[protected]`

bool ompl::geometric::pSBL::checkSolution	(	RNG &	rng,
		bool	start,
		TreeData &	tree,
		TreeData &	otherTree,
		Motion *	motion,
		std::vector< Motion * > &	solution
	)			`[protected]`

virtual void ompl::geometric::pSBL::clear ( void ) [virtual]

Clear all internal datastructures. Planner settings are not affected. Subsequent calls to solve() will ignore all previous work.

Reimplemented from ompl::base::Planner.

void ompl::geometric::pSBL::freeGridMotions ( Grid< MotionSet > & grid ) [protected]

void ompl::geometric::pSBL::freeMemory ( void ) [inline, protected]

Definition at line 219 of file pSBL.h.

virtual void ompl::geometric::pSBL::getPlannerData ( base::PlannerData & data ) const [virtual]

Get information about the current run of the motion planner. Repeated calls to this function will update data (only additions are made). This is useful to see what changed in the exploration datastructure, between calls to solve(), for example (without calling clear() in between).

Reimplemented from ompl::base::Planner.

const base::ProjectionEvaluatorPtr& ompl::geometric::pSBL::getProjectionEvaluator ( void ) const [inline]

Get the projection evaluator.

Definition at line 120 of file pSBL.h.

double ompl::geometric::pSBL::getRange ( void ) const [inline]

Get the range the planner is using.

Definition at line 136 of file pSBL.h.

unsigned int ompl::geometric::pSBL::getThreadCount ( void ) const [inline]

Get the thread count.

Definition at line 145 of file pSBL.h.

bool ompl::geometric::pSBL::isPathValid	(	TreeData &	tree,
		Motion *	motion
	)			`[protected]`

void ompl::geometric::pSBL::removeMotion	(	TreeData &	tree,
		Motion *	motion,
		std::map< Motion *, bool > &	seen
	)			`[protected]`

Motion* ompl::geometric::pSBL::selectMotion	(	RNG &	rng,
		TreeData &	tree
	)			`[protected]`

void ompl::geometric::pSBL::setProjectionEvaluator ( const std::string & name ) [inline]

Set the projection evaluator (select one from the ones registered with the state space).

Definition at line 114 of file pSBL.h.

void ompl::geometric::pSBL::setProjectionEvaluator ( const base::ProjectionEvaluatorPtr & projectionEvaluator ) [inline]

Set the projection evaluator. This class is able to compute the projection of a given state.

Definition at line 107 of file pSBL.h.

void ompl::geometric::pSBL::setRange ( double distance ) [inline]

Set the range the planner is supposed to use.

This parameter greatly influences the runtime of the algorithm. It represents the maximum length of a motion to be added in the tree of motions.

Definition at line 130 of file pSBL.h.

void ompl::geometric::pSBL::setThreadCount ( unsigned int nthreads )

Set the number of threads the planner should use. Default is 2.

virtual void ompl::geometric::pSBL::setup ( void ) [virtual]

Perform extra configuration steps, if needed. This call will also issue a call to ompl::base::SpaceInformation::setup() if needed. This must be called before solving.

Reimplemented from ompl::base::Planner.

virtual bool ompl::geometric::pSBL::solve ( const base::PlannerTerminationCondition & ptc ) [virtual]

Function that can solve the motion planning problem. This function can be called multiple times on the same problem, without calling clear() in between. This allows the planner to continue work more time on an unsolved problem, for example. If this option is used, it is assumed the problem definition is not changed (unpredictable results otherwise). The only change in the problem definition that is accounted for is the addition of starting or goal states (but not changing previously added start/goal states). The function terminates if the call to ptc returns true.

Implements ompl::base::Planner.