Transition-based Rapidly-exploring Random Trees. More...
#include <ompl/geometric/planners/rrt/TRRT.h>

Classes | |
class | Motion |
Representation of a motion. More... | |
Public Member Functions | |
TRRT (const base::SpaceInformationPtr &si) | |
Constructor. | |
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). | |
virtual base::PlannerStatus | solve (const base::PlannerTerminationCondition &plannerTerminationCondition) |
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). The function terminates if the call to ptc returns true. | |
virtual void | clear () |
Clear all internal datastructures. Planner settings are not affected. Subsequent calls to solve() will ignore all previous work. | |
void | setGoalBias (double goalBias) |
Set the goal bias. | |
double | getGoalBias () const |
Get the goal bias the planner is using. | |
void | setRange (double distance) |
Set the range the planner is supposed to use. | |
double | getRange () const |
Get the range the planner is using. | |
void | setMaxStatesFailed (double maxStatesFailed) |
Set the maximum number of states that can be rejected before the temperature starts to rise. | |
double | getMaxStatesFailed (void) const |
Get the maximum number of states that can be rejected before the temperature starts to rise. | |
void | setTempChangeFactor (double tempChangeFactor) |
Set the factor by which the temperature rises or falls based on current acceptance/rejection rate. | |
double | getTempChangeFactor (void) const |
Get the factor by which the temperature rises or falls based on current acceptance/rejection rate. | |
void | setMinTemperature (double minTemperature) |
Set the minimum the temperature can drop to before being floored at that value. | |
double | getMinTemperature (void) const |
Get the minimum the temperature can drop to before being floored at that value. | |
void | setInitTemperature (double initTemperature) |
Set the initial temperature at the beginning of the algorithm. Should be low. | |
double | getInitTemperature (void) const |
Get the initial temperature at the beginning of the algorithm. Should be low. | |
void | setFrontierThreshold (double frontier_threshold) |
Set the distance between a new state and the nearest neighbor that qualifies that state as being a frontier. | |
double | getFrontierThreshold (void) const |
Get the distance between a new state and the nearest neighbor that qualifies that state as being a frontier. | |
void | setFrontierNodeRatio (double frontierNodeRatio) |
Set the ratio between adding nonfrontier nodes to frontier nodes, for example .1 is 1/10 or one nonfrontier node for every 10 frontier nodes added. | |
double | getFrontierNodeRatio (void) const |
Get the ratio between adding nonfrontier nodes to frontier nodes, for example .1 is 1/10 or one nonfrontier node for every 10 frontier nodes added. | |
void | setKConstant (double kConstant) |
Set the constant value used to normalize the expression. | |
double | getKConstant (void) const |
Get the constant value used to normalize the expression. | |
template<template< typename T > class NN> | |
void | setNearestNeighbors () |
Set a different nearest neighbors datastructure. | |
virtual void | setup () |
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 Member Functions | |
void | freeMemory () |
Free the memory allocated by this planner. | |
double | distanceFunction (const Motion *a, const Motion *b) const |
Compute distance between motions (actually distance between contained states) | |
bool | transitionTest (double childCost, double parentCost, double distance) |
Filter irrelevant configuration regarding the search of low-cost paths before inserting into tree. | |
bool | minExpansionControl (double randMotionDistance) |
Use ratio to prefer frontier nodes to nonfrontier ones. | |
Protected Attributes | |
base::StateSamplerPtr | sampler_ |
State sampler. | |
boost::shared_ptr < NearestNeighbors< Motion * > > | nearestNeighbors_ |
A nearest-neighbors datastructure containing the tree of motions. | |
double | goalBias_ |
The fraction of time the goal is picked as the state to expand towards (if such a state is available) | |
double | maxDistance_ |
The maximum length of a motion to be added to a tree. | |
RNG | rng_ |
The random number generator. | |
Motion * | lastGoalMotion_ |
The most recent goal motion. Used for PlannerData computation. | |
bool | verbose_ |
Output debug info. | |
double | temp_ |
Temperature parameter used to control the difficulty level of transition tests. Low temperatures limit the expansion to a slightly positive slopes, high temps enable to climb the steeper slopes. Dynamically tuned according to the information acquired during exploration. | |
double | kConstant_ |
Constant value used to normalize expression. Based on order of magnitude of the considered costs. Average cost of the query configurtaions since they are the only cost values known at the beginning of the search process. | |
unsigned int | maxStatesFailed_ |
Max number of rejections allowed. | |
double | tempChangeFactor_ |
Failure temperature factor used when max_num_failed_ failures occur. | |
double | minTemperature_ |
Prevent temperature from dropping too far. | |
double | initTemperature_ |
A very low value at initialization to authorize very easy positive slopes. | |
unsigned int | numStatesFailed_ |
Failure counter for states that are rejected. | |
double | nonfrontierCount_ |
Ratio counters for nodes that expand the search space versus those that do not. | |
double | frontierCount_ |
double | frontierThreshold_ |
The distance between an old state and a new state that qualifies it as a frontier state. | |
double | frontierNodeRatio_ |
Target ratio of nonfrontier nodes to frontier nodes. rho. | |
ompl::base::OptimizationObjectivePtr | opt_ |
The optimization objective being optimized by TRRT. |
Detailed Description
Transition-based Rapidly-exploring Random Trees.
- Short description
- T-RRT is an RRT variant and tree-based motion planner that takes into consideration state costs to compute low-cost paths that follow valleys and saddle points of the configuration-space costmap. It uses transition tests from stoachastic optimization methods to accept or reject new potential sates.
- Example usage
- Please see [Dave Coleman's example](https://github.com/davetcoleman/ompl_rviz_viewer/) to see how TRRT can be used.
- External documentation
- L. Jaillet, J. Cortés, T. Siméon, Sampling-Based Path Planning on Configuration-Space Costmaps, in IEEE TRANSACTIONS ON ROBOTICS, VOL. 26, NO. 4, AUGUST 2010. DOI: [10.1109/TRO.2010.2049527](http://dx.doi.org/10.1109/TRO.2010.2049527)
[[PDF]](http://homepages.laas.fr/nic/Papers/10TRO.pdf)
Member Function Documentation
void ompl::geometric::TRRT::setGoalBias | ( | double | goalBias | ) | [inline] |
Set the goal bias.
In the process of randomly selecting states in the state space to attempt to go towards, the algorithm may in fact choose the actual goal state, if it knows it, with some probability. This probability is a real number between 0.0 and 1.0; its value should usually be around 0.05 and should not be too large. It is probably a good idea to use the default value.
void ompl::geometric::TRRT::setRange | ( | double | distance | ) | [inline] |
ompl::base::PlannerStatus ompl::geometric::TRRT::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 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). The function terminates if the call to ptc returns true.
bool checkMotion(const State *s1, const State *s2, std::pair<State*, double> &lastValid) const Incrementally check if the path between two motions is valid. Also compute the last state that was valid and the time of that state. The time is used to parametrize the motion from s1 to s2, s1 being at t = 0 and s2 being at t = 1. This function assumes s1 is valid.
- Parameters:
-
s1 start state of the motion to be checked (assumed to be valid) s2 final state of the motion to be checked
Implements base::Planner.
bool ompl::geometric::TRRT::transitionTest | ( | double | childCost, |
double | parentCost, | ||
double | distance | ||
) | [protected] |
The documentation for this class was generated from the following files: