src/rrts.cc

   1 #include <algorithm>
   2 #include "rrts.h"
   3
   4 #include "reeds_shepp.h"
   5
   6 template <typename T> int sgn(T val) {
   7         return (T(0) < val) - (val < T(0));
   8 }
   9
  10 RRTNode::RRTNode()
  11 {
  12 }
  13
  14 RRTNode::RRTNode(const BicycleCar &bc) : BicycleCar(bc)
  15 {
  16 }
  17
  18 Obstacle::Obstacle()
  19 {
  20 }
  21
  22 double RRTS::elapsed()
  23 {
  24         std::chrono::duration<double> dt;
  25         dt = std::chrono::duration_cast<std::chrono::duration<double>>(
  26                 std::chrono::high_resolution_clock::now()
  27                 - this->tstart_
  28         );
  29         this->scnt_ = dt.count();
  30         return this->scnt_;
  31 }
  32
  33 bool RRTS::should_stop()
  34 {
  35         // the following counters must be updated, do not comment
  36         this->icnt_++;
  37         this->elapsed();
  38         // decide the stop conditions (maybe comment some lines)
  39         if (this->icnt_ > 999) return true;
  40         if (this->scnt_ > 10) return true;
  41         if (this->gf()) return true;
  42         // but continue by default
  43         return false;
  44 }
  45
  46 void RRTS::store_node(RRTNode n)
  47 {
  48         this->nodes().push_back(n);
  49 }
  50
  51 // RRT procedures
  52 std::tuple<bool, unsigned int, unsigned int>
  53 RRTS::collide(std::vector<std::tuple<double, double>> &poly)
  54 {
  55         for (auto &o: this->obstacles())
  56                 if (std::get<0>(::collide(poly, o.poly())))
  57                         return ::collide(poly, o.poly());
  58         return std::make_tuple(false, 0, 0);
  59 }
  60
  61 std::tuple<bool, unsigned int, unsigned int>
  62 RRTS::collide_steered_from(RRTNode &f)
  63 {
  64         std::vector<std::tuple<double, double>> s;
  65         s.push_back(std::make_tuple(f.x(), f.y()));
  66         for (auto &n: this->steered()) {
  67                 s.push_back(std::make_tuple(n.lfx(), n.lfy()));
  68                 s.push_back(std::make_tuple(n.lrx(), n.lry()));
  69                 s.push_back(std::make_tuple(n.rrx(), n.rry()));
  70                 s.push_back(std::make_tuple(n.rfx(), n.rfy()));
  71         }
  72         auto col = this->collide(s);
  73         auto strip_from = this->steered().size() - std::get<1>(col) / 4;
  74         if (std::get<0>(col) && strip_from > 0) {
  75                 while (strip_from-- > 0) {
  76                         this->steered().pop_back();
  77                 }
  78                 return this->collide_steered_from(f);
  79         }
  80         return col;
  81 }
  82
  83 std::tuple<bool, unsigned int, unsigned int>
  84 RRTS::collide_two_nodes(RRTNode &f, RRTNode &t)
  85 {
  86         std::vector<std::tuple<double, double>> p;
  87         p.push_back(std::make_tuple(f.lfx(), f.lfy()));
  88         p.push_back(std::make_tuple(f.lrx(), f.lry()));
  89         p.push_back(std::make_tuple(f.rrx(), f.rry()));
  90         p.push_back(std::make_tuple(f.rfx(), f.rfy()));
  91         p.push_back(std::make_tuple(t.lfx(), t.lfy()));
  92         p.push_back(std::make_tuple(t.lrx(), t.lry()));
  93         p.push_back(std::make_tuple(t.rrx(), t.rry()));
  94         p.push_back(std::make_tuple(t.rfx(), t.rfy()));
  95         return this->collide(p);
  96 }
  97
  98 double RRTS::cost_build(RRTNode &f, RRTNode &t)
  99 {
 100         double cost = 0;
 101         cost = sqrt(pow(t.y() - f.y(), 2) + pow(t.x() - f.x(), 2));
 102         return cost;
 103 }
 104
 105 double RRTS::cost_search(RRTNode &f, RRTNode &t)
 106 {
 107         double cost = 0;
 108         cost = sqrt(pow(t.y() - f.y(), 2) + pow(t.x() - f.x(), 2));
 109         return cost;
 110 }
 111
 112 void RRTS::sample()
 113 {
 114         double x = this->ndx_(this->gen_);
 115         double y = this->ndy_(this->gen_);
 116         double h = this->ndh_(this->gen_);
 117         this->samples().push_back(RRTNode());
 118         this->samples().back().x(x);
 119         this->samples().back().y(y);
 120         this->samples().back().h(h);
 121 }
 122
 123 RRTNode *RRTS::nn(RRTNode &t)
 124 {
 125         RRTNode *nn = &this->nodes().front();
 126         double cost = this->cost_search(*nn, t);
 127         for (auto &f: this->nodes()) {
 128                 if (this->cost_search(f, t) < cost) {
 129                         nn = &f;
 130                         cost = this->cost_search(f, t);
 131                 }
 132         }
 133         return nn;
 134 }
 135
 136 std::vector<RRTNode *> RRTS::nv(RRTNode &t)
 137 {
 138         std::vector<RRTNode *> nv;
 139         double cost = std::min(GAMMA(this->nodes().size()), ETA);
 140         for (auto &f: this->nodes())
 141                 if (this->cost_search(f, t) < cost)
 142                         nv.push_back(&f);
 143         return nv;
 144 }
 145
 146 int cb_rs_steer(double q[4], void *user_data)
 147 {
 148         std::vector<RRTNode> *nodes = (std::vector<RRTNode> *) user_data;
 149         RRTNode *ln = nullptr;
 150         if (nodes->size() > 0)
 151                 ln = &nodes->back();
 152         nodes->push_back(RRTNode());
 153         nodes->back().x(q[0]);
 154         nodes->back().y(q[1]);
 155         nodes->back().h(q[2]);
 156         nodes->back().sp(q[3]);
 157         if (nodes->back().sp() == 0)
 158                 nodes->back().set_t(RRTNodeType::cusp);
 159         else if (ln != nullptr && sgn(ln->sp()) != sgn(nodes->back().sp()))
 160                 ln->set_t(RRTNodeType::cusp);
 161         return 0;
 162 }
 163
 164 void RRTS::steer(RRTNode &f, RRTNode &t)
 165 {
 166         this->steered().clear();
 167         double q0[] = {f.x(), f.y(), f.h()};
 168         double q1[] = {t.x(), t.y(), t.h()};
 169         ReedsSheppStateSpace rsss(f.mtr());
 170         rsss.sample(q0, q1, 0.5, cb_rs_steer, &this->steered());
 171 }
 172
 173 void RRTS::join_steered(RRTNode *f)
 174 {
 175         while (this->steered().size() > 0) {
 176                 this->store_node(this->steered().front());
 177                 RRTNode *t = &this->nodes().back();
 178                 t->p(f);
 179                 t->c(this->cost_build(*f, *t));
 180                 this->steered().erase(this->steered().begin());
 181                 f = t;
 182         }
 183 }
 184
 185 bool RRTS::goal_found(RRTNode &f)
 186 {
 187         bool found = false;
 188         for (auto &g: this->goals()) {
 189                 double cost = this->cost_build(f, g);
 190                 double edist = sqrt(
 191                         pow(f.x() - g.x(), 2)
 192                         + pow(f.y() - g.y(), 2)
 193                 );
 194                 double adist = std::abs(f.h() - g.h());
 195                 if (edist < 0.05 && adist < M_PI / 32) {
 196                         found = true;
 197                         if (g.p() == nullptr || cc(f) + cost < cc(g)) {
 198                                 g.p(&f);
 199                                 g.c(cost);
 200                         }
 201                 }
 202         }
 203         return found;
 204 }
 205
 206 // RRT* procedures
 207 bool RRTS::connect()
 208 {
 209         RRTNode *t = &this->steered().front();
 210         RRTNode *f = this->nn(this->samples().back());
 211         double cost = this->cost_search(*f, *t);
 212         for (auto n: this->nv(*t)) {
 213                 if (
 214                         !std::get<0>(this->collide_two_nodes(*n, *t))
 215                         && this->cost_search(*n, *t) < cost
 216                 ) {
 217                         f = n;
 218                         cost = this->cost_search(*n, *t);
 219                 }
 220         }
 221         this->store_node(this->steered().front());
 222         t = &this->nodes().back();
 223         t->p(f);
 224         t->c(this->cost_build(*f, *t));
 225         t->set_t(RRTNodeType::connected);
 226         return true;
 227 }
 228
 229 void RRTS::rewire()
 230 {
 231         RRTNode *f = &this->nodes().back();
 232         for (auto n: this->nv(*f)) {
 233                 if (
 234                         !std::get<0>(this->collide_two_nodes(*f, *n))
 235                         && cc(*f) + this->cost_search(*f, *n) < cc(*n)
 236                 ) {
 237                         n->p(f);
 238                         n->c(this->cost_build(*f, *n));
 239                 }
 240         }
 241 }
 242
 243 // API
 244 void RRTS::init()
 245 {
 246 }
 247
 248 void RRTS::deinit()
 249 {
 250 }
 251
 252 std::vector<RRTNode *> RRTS::path()
 253 {
 254         std::vector<RRTNode *> path;
 255         if (this->goals().size() == 0)
 256                 return path;
 257         RRTNode *goal = &this->goals().front();
 258         for (auto &n: this->goals()) {
 259                 if (
 260                         n.p() != nullptr
 261                         && (n.c() < goal->c() || goal->p() == nullptr)
 262                 ) {
 263                         goal = &n;
 264                 }
 265         }
 266         if (goal->p() == nullptr)
 267                 return path;
 268         while (goal != nullptr) {
 269                 path.push_back(goal);
 270                 goal = goal->p();
 271         }
 272         std::reverse(path.begin(), path.end());
 273         return path;
 274 }
 275
 276 bool RRTS::next()
 277 {
 278         if (this->icnt_ == 0)
 279                 this->tstart_ = std::chrono::high_resolution_clock::now();
 280         bool next = true;
 281         if (this->should_stop())
 282                 return false;
 283         this->sample();
 284         this->steer(
 285                 *this->nn(this->samples().back()),
 286                 this->samples().back()
 287         );
 288         if (std::get<0>(this->collide_steered_from(
 289                 *this->nn(this->samples().back())
 290         )))
 291                 return next;
 292         if (!this->connect())
 293                 return next;
 294         this->rewire();
 295         unsigned scnt = this->steered().size();
 296         this->steered().erase(this->steered().begin());
 297         this->join_steered(&this->nodes().back());
 298         RRTNode *just_added = &this->nodes().back();
 299         while (scnt > 0) {
 300                 scnt--;
 301                 for (auto &g: this->goals()) {
 302                         this->steer(*just_added, g);
 303                         if (std::get<0>(this->collide_steered_from(
 304                                 *just_added
 305                         )))
 306                                 continue;
 307                         this->join_steered(just_added);
 308                 }
 309                 this->gf(this->goal_found(this->nodes().back()));
 310                 just_added = just_added->p();
 311         }
 312         return next;
 313 }
 314
 315 void RRTS::set_sample(
 316         double mx, double dx,
 317         double my, double dy,
 318         double mh, double dh
 319 )
 320 {
 321         this->ndx_ = std::normal_distribution<double>(mx, dx);
 322         this->ndy_ = std::normal_distribution<double>(my, dy);
 323         this->ndh_ = std::normal_distribution<double>(mh, dh);
 324 }
 325
 326 RRTS::RRTS()
 327         : gen_(std::random_device{}())
 328 {
 329         this->goals().reserve(100);
 330         this->nodes().reserve(4000000);
 331         this->samples().reserve(1000);
 332         this->steered().reserve(20000);
 333         this->store_node(RRTNode()); // root
 334 }
 335
 336 double cc(RRTNode &t)
 337 {
 338         RRTNode *n = &t;
 339         double cost = 0;
 340         while (n != nullptr) {
 341                 cost += n->c();
 342                 n = n->p();
 343         }
 344         return cost;
 345 }