Class RRTConnect

Nested Relationships

Nested Types

Inheritance Relationships

Base Type

Class Documentation

class RRTConnect : public ompl::base::Planner

RRT-Connect (RRTConnect)

Short description

The basic idea is to grow two RRTs, one from the start and one from the goal, and attempt to connect them.

External documentation

J. Kuffner and S.M. LaValle, RRT-connect: An efficient approach to single-query path planning, in Proc. 2000 IEEE Intl. Conf. on Robotics and Automation, pp. 995–1001, Apr. 2000. DOI: 10.1109/ROBOT.2000.844730[PDF] [more]

Public Functions

RRTConnect(const base::SpaceInformationPtr &si, bool addIntermediateStates = false)

Constructor.

~RRTConnect() override
virtual void getPlannerData(base::PlannerData &data) const override

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).

virtual base::PlannerStatus solve(const base::PlannerTerminationCondition &ptc) override

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 for 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). If clearQuery() is called, the planner may retain prior datastructures generated from a previous query on a new problem definition. The function terminates if the call to ptc returns true.

virtual void clear() override

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

inline bool getIntermediateStates() const

Return true if the intermediate states generated along motions are to be added to the tree itself.

inline void setIntermediateStates(bool addIntermediateStates)

Specify whether the intermediate states generated along motions are to be added to the tree itself.

inline void setRange(double distance)

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.

inline double getRange() const

Get the range the planner is using.

template<template<typename T> class NN>
inline void setNearestNeighbors()

Set a different nearest neighbors datastructure.

virtual void setup() override

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.

Protected Types

enum GrowState

The state of the tree after an attempt to extend it.

Values:

enumerator TRAPPED

no progress has been made

enumerator ADVANCED

progress has been made towards the randomly sampled state

enumerator REACHED

the randomly sampled state was reached

using TreeData = std::shared_ptr<NearestNeighbors<Motion*>>

A nearest-neighbor datastructure representing a tree of motions.

Protected Functions

void freeMemory()

Free the memory allocated by this planner.

inline double distanceFunction(const Motion *a, const Motion *b) const

Compute distance between motions (actually distance between contained states)

GrowState growTree(TreeData &tree, TreeGrowingInfo &tgi, Motion *rmotion)

Grow a tree towards a random state.

Protected Attributes

base::StateSamplerPtr sampler_

State sampler.

TreeData tStart_

The start tree.

TreeData tGoal_

The goal tree.

bool startTree_ = {true}

A flag that toggles between expanding the start tree (true) or goal tree (false).

double maxDistance_ = {0.}

The maximum length of a motion to be added to a tree.

bool addIntermediateStates_

Flag indicating whether intermediate states are added to the built tree of motions.

RNG rng_

The random number generator.

std::pair<base::State*, base::State*> connectionPoint_

The pair of states in each tree connected during planning. Used for PlannerData computation.

double distanceBetweenTrees_

Distance between the nearest pair of start tree and goal tree nodes.

class Motion

Representation of a motion.

Public Functions

Motion() = default
inline Motion(const base::SpaceInformationPtr &si)
~Motion() = default

Public Members

const base::State *root = {nullptr}
base::State *state = {nullptr}
Motion *parent = {nullptr}
struct TreeGrowingInfo

Information attached to growing a tree of motions (used internally)

Public Members

base::State *xstate
Motion *xmotion
bool start