All Classes Namespaces Functions Variables Typedefs Enumerations Enumerator
RRT.cpp
00001 /*********************************************************************
00002 * Software License Agreement (BSD License)
00003 *
00004 *  Copyright (c) 2008, Willow Garage, Inc.
00005 *  All rights reserved.
00006 *
00007 *  Redistribution and use in source and binary forms, with or without
00008 *  modification, are permitted provided that the following conditions
00009 *  are met:
00010 *
00011 *   * Redistributions of source code must retain the above copyright
00012 *     notice, this list of conditions and the following disclaimer.
00013 *   * Redistributions in binary form must reproduce the above
00014 *     copyright notice, this list of conditions and the following
00015 *     disclaimer in the documentation and/or other materials provided
00016 *     with the distribution.
00017 *   * Neither the name of the Willow Garage nor the names of its
00018 *     contributors may be used to endorse or promote products derived
00019 *     from this software without specific prior written permission.
00020 *
00021 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00022 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00023 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00024 *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
00025 *  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00026 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00027 *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00028 *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00029 *  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00030 *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00031 *  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00032 *  POSSIBILITY OF SUCH DAMAGE.
00033 *********************************************************************/
00034 
00035 /* Author: Ioan Sucan */
00036 
00037 #include "ompl/control/planners/rrt/RRT.h"
00038 #include "ompl/base/GoalSampleableRegion.h"
00039 #include "ompl/datastructures/NearestNeighborsGNAT.h"
00040 #include <limits>
00041 
00042 ompl::control::RRT::RRT(const SpaceInformationPtr &si) : base::Planner(si, "RRT")
00043 {
00044     specs_.approximateSolutions = true;
00045     siC_ = si.get();
00046     addIntermediateStates_ = false;
00047 
00048     goalBias_ = 0.05;
00049 
00050     Planner::declareParam<double>("goal_bias", this, &RRT::setGoalBias, &RRT::getGoalBias);
00051     Planner::declareParam<bool>("intermediate_states", this, &RRT::setIntermediateStates, &RRT::getIntermediateStates);
00052 }
00053 
00054 ompl::control::RRT::~RRT(void)
00055 {
00056     freeMemory();
00057 }
00058 
00059 void ompl::control::RRT::setup(void)
00060 {
00061     base::Planner::setup();
00062     if (!nn_)
00063         nn_.reset(new NearestNeighborsGNAT<Motion*>());
00064     nn_->setDistanceFunction(boost::bind(&RRT::distanceFunction, this, _1, _2));
00065 }
00066 
00067 void ompl::control::RRT::clear(void)
00068 {
00069     Planner::clear();
00070     sampler_.reset();
00071     controlSampler_.reset();
00072     freeMemory();
00073     if (nn_)
00074         nn_->clear();
00075 }
00076 
00077 void ompl::control::RRT::freeMemory(void)
00078 {
00079     if (nn_)
00080     {
00081         std::vector<Motion*> motions;
00082         nn_->list(motions);
00083         for (unsigned int i = 0 ; i < motions.size() ; ++i)
00084         {
00085             if (motions[i]->state)
00086                 si_->freeState(motions[i]->state);
00087             if (motions[i]->control)
00088                 siC_->freeControl(motions[i]->control);
00089             delete motions[i];
00090         }
00091     }
00092 }
00093 
00094 bool ompl::control::RRT::solve(const base::PlannerTerminationCondition &ptc)
00095 {
00096     checkValidity();
00097     base::Goal                   *goal = pdef_->getGoal().get();
00098     base::GoalSampleableRegion *goal_s = dynamic_cast<base::GoalSampleableRegion*>(goal);
00099 
00100     while (const base::State *st = pis_.nextStart())
00101     {
00102         Motion *motion = new Motion(siC_);
00103         si_->copyState(motion->state, st);
00104         siC_->nullControl(motion->control);
00105         nn_->add(motion);
00106     }
00107 
00108     if (nn_->size() == 0)
00109     {
00110         msg_.error("There are no valid initial states!");
00111         return false;
00112     }
00113 
00114     if (!sampler_)
00115         sampler_ = si_->allocStateSampler();
00116     if (!controlSampler_)
00117         controlSampler_ = siC_->allocDirectedControlSampler();
00118 
00119     msg_.inform("Starting with %u states", nn_->size());
00120 
00121     Motion *solution  = NULL;
00122     Motion *approxsol = NULL;
00123     double  approxdif = std::numeric_limits<double>::infinity();
00124 
00125     Motion      *rmotion = new Motion(siC_);
00126     base::State  *rstate = rmotion->state;
00127     Control       *rctrl = rmotion->control;
00128     base::State  *xstate = si_->allocState();
00129 
00130     while (ptc() == false)
00131     {
00132         /* sample random state (with goal biasing) */
00133         if (goal_s && rng_.uniform01() < goalBias_ && goal_s->canSample())
00134             goal_s->sampleGoal(rstate);
00135         else
00136             sampler_->sampleUniform(rstate);
00137 
00138         /* find closest state in the tree */
00139         Motion *nmotion = nn_->nearest(rmotion);
00140 
00141         /* sample a random control that attempts to go towards the random state, and also sample a control duration */
00142         unsigned int cd = controlSampler_->sampleTo(rctrl, nmotion->control, nmotion->state, rmotion->state);
00143 
00144         if (addIntermediateStates_)
00145         {
00146             // this code is contributed by Jennifer Barry
00147             std::vector<base::State *> pstates;
00148             cd = siC_->propagateWhileValid(nmotion->state, rctrl, cd, pstates, true);
00149 
00150             if (cd >= siC_->getMinControlDuration())
00151             {
00152                 Motion *lastmotion = nmotion;
00153                 bool solved = false;
00154                 size_t p = 0;
00155                 for ( ; p < pstates.size(); ++p)
00156                 {
00157                     /* create a motion */
00158                     Motion *motion = new Motion();
00159                     motion->state = pstates[p];
00160                     //we need multiple copies of rctrl
00161                     motion->control = siC_->allocControl();
00162                     siC_->copyControl(motion->control, rctrl);
00163                     motion->steps = 1;
00164                     motion->parent = lastmotion;
00165                     lastmotion = motion;
00166                     nn_->add(motion);
00167                     double dist = 0.0;
00168                     solved = goal->isSatisfied(motion->state, &dist);
00169                     if (solved)
00170                     {
00171                         approxdif = dist;
00172                         solution = motion;
00173                         break;
00174                     }
00175                     if (dist < approxdif)
00176                     {
00177                         approxdif = dist;
00178                         approxsol = motion;
00179                     }
00180                 }
00181 
00182                 //free any states after we hit the goal
00183                 while (++p < pstates.size())
00184                     si_->freeState(pstates[p]);
00185                 if (solved)
00186                     break;
00187             }
00188             else
00189                 for (size_t p = 0 ; p < pstates.size(); ++p)
00190                     si_->freeState(pstates[p]);
00191         }
00192         else
00193         {
00194             cd = siC_->propagateWhileValid(nmotion->state, rctrl, cd, xstate);
00195 
00196             if (cd >= siC_->getMinControlDuration())
00197             {
00198                 /* create a motion */
00199                 Motion *motion = new Motion(siC_);
00200                 si_->copyState(motion->state, xstate);
00201                 siC_->copyControl(motion->control, rctrl);
00202                 motion->steps = cd;
00203                 motion->parent = nmotion;
00204 
00205                 nn_->add(motion);
00206                 double dist = 0.0;
00207                 bool solv = goal->isSatisfied(motion->state, &dist);
00208                 if (solv)
00209                 {
00210                     approxdif = dist;
00211                     solution = motion;
00212                     break;
00213                 }
00214                 if (dist < approxdif)
00215                 {
00216                     approxdif = dist;
00217                     approxsol = motion;
00218                 }
00219             }
00220         }
00221     }
00222 
00223     bool solved = false;
00224     bool approximate = false;
00225     if (solution == NULL)
00226     {
00227         solution = approxsol;
00228         approximate = true;
00229     }
00230 
00231     if (solution != NULL)
00232     {
00233         /* construct the solution path */
00234         std::vector<Motion*> mpath;
00235         while (solution != NULL)
00236         {
00237             mpath.push_back(solution);
00238             solution = solution->parent;
00239         }
00240 
00241         /* set the solution path */
00242         PathControl *path = new PathControl(si_);
00243         for (int i = mpath.size() - 1 ; i >= 0 ; --i)
00244             if (mpath[i]->parent)
00245                 path->append(mpath[i]->state, mpath[i]->control, mpath[i]->steps * siC_->getPropagationStepSize());
00246             else
00247                 path->append(mpath[i]->state);
00248         solved = true;
00249         goal->addSolutionPath(base::PathPtr(path), approximate, approxdif);
00250     }
00251 
00252     if (rmotion->state)
00253         si_->freeState(rmotion->state);
00254     if (rmotion->control)
00255         siC_->freeControl(rmotion->control);
00256     delete rmotion;
00257     si_->freeState(xstate);
00258 
00259     msg_.inform("Created %u states", nn_->size());
00260 
00261     return solved;
00262 }
00263 
00264 void ompl::control::RRT::getPlannerData(base::PlannerData &data) const
00265 {
00266     Planner::getPlannerData(data);
00267 
00268     std::vector<Motion*> motions;
00269     if (nn_)
00270         nn_->list(motions);
00271 
00272     if (PlannerData *cpd = dynamic_cast<control::PlannerData*>(&data))
00273     {
00274         double delta = siC_->getPropagationStepSize();
00275 
00276         for (unsigned int i = 0 ; i < motions.size() ; ++i)
00277         {
00278             const Motion* m = motions[i];
00279             if (m->parent)
00280                 cpd->recordEdge(m->parent->state, m->state, m->control, m->steps * delta);
00281             else
00282                 cpd->recordEdge(NULL, m->state, NULL, 0.);
00283         }
00284     }
00285     else
00286     {
00287         for (unsigned int i = 0 ; i < motions.size() ; ++i)
00288         {
00289             const Motion* m = motions[i];
00290             data.recordEdge(m->parent ? m->parent->state : NULL, m->state);
00291         }
00292     }
00293 }
 All Classes Namespaces Functions Variables Typedefs Enumerations Enumerator Friends