src/rrts.cc

   1 #include <algorithm>
   2 #include "rrts.h"
   3
   4 #include "reeds_shepp.h"
   5
   6 #define ETA 1.0 // for steer, nv
   7 #define GAMMA(cV) ({ \
   8         __typeof__ (cV) _cV = (cV); \
   9         pow(log(_cV) / _cV, 1.0 / 3.0); \
  10 })
  11
  12 template <typename T> int sgn(T val) {
  13         return (T(0) < val) - (val < T(0));
  14 }
  15
  16 RRTNode::RRTNode()
  17 {
  18 }
  19
  20 RRTNode::RRTNode(const BicycleCar &bc) : BicycleCar(bc)
  21 {
  22 }
  23
  24 Obstacle::Obstacle()
  25 {
  26 }
  27
  28 double RRTS::elapsed()
  29 {
  30         std::chrono::duration<double> dt;
  31         dt = std::chrono::duration_cast<std::chrono::duration<double>>(
  32                 std::chrono::high_resolution_clock::now()
  33                 - this->tstart_
  34         );
  35         this->scnt_ = dt.count();
  36         return this->scnt_;
  37 }
  38
  39 bool RRTS::should_stop()
  40 {
  41         // the following counters must be updated, do not comment
  42         this->icnt_++;
  43         this->elapsed();
  44         // decide the stop conditions (maybe comment some lines)
  45         if (this->icnt_ > 999) return true;
  46         if (this->scnt_ > 10) return true;
  47         if (this->gf()) return true;
  48         // but continue by default
  49         return false;
  50 }
  51
  52 // RRT procedures
  53 std::tuple<bool, unsigned int, unsigned int>
  54 RRTS::collide(std::vector<std::tuple<double, double>> &poly)
  55 {
  56         for (auto &o: this->obstacles())
  57                 if (std::get<0>(::collide(poly, o.poly())))
  58                         return ::collide(poly, o.poly());
  59         return std::make_tuple(false, 0, 0);
  60 }
  61
  62 std::tuple<bool, unsigned int, unsigned int>
  63 RRTS::collide_steered_from(RRTNode &f)
  64 {
  65         std::vector<std::tuple<double, double>> s;
  66         s.push_back(std::make_tuple(f.x(), f.y()));
  67         for (auto &n: this->steered()) {
  68                 s.push_back(std::make_tuple(n.lfx(), n.lfy()));
  69                 s.push_back(std::make_tuple(n.lrx(), n.lry()));
  70                 s.push_back(std::make_tuple(n.rrx(), n.rry()));
  71                 s.push_back(std::make_tuple(n.rfx(), n.rfy()));
  72         }
  73         auto col = this->collide(s);
  74         auto strip_from = this->steered().size() - std::get<1>(col) / 4;
  75         if (std::get<0>(col) && strip_from > 0) {
  76                 while (strip_from-- > 0) {
  77                         this->steered().pop_back();
  78                 }
  79                 return this->collide_steered_from(f);
  80         }
  81         return col;
  82 }
  83
  84 std::tuple<bool, unsigned int, unsigned int>
  85 RRTS::collide_two_nodes(RRTNode &f, RRTNode &t)
  86 {
  87         std::vector<std::tuple<double, double>> p;
  88         p.push_back(std::make_tuple(f.lfx(), f.lfy()));
  89         p.push_back(std::make_tuple(f.lrx(), f.lry()));
  90         p.push_back(std::make_tuple(f.rrx(), f.rry()));
  91         p.push_back(std::make_tuple(f.rfx(), f.rfy()));
  92         p.push_back(std::make_tuple(t.lfx(), t.lfy()));
  93         p.push_back(std::make_tuple(t.lrx(), t.lry()));
  94         p.push_back(std::make_tuple(t.rrx(), t.rry()));
  95         p.push_back(std::make_tuple(t.rfx(), t.rfy()));
  96         return this->collide(p);
  97 }
  98
  99 double RRTS::cost_build(RRTNode &f, RRTNode &t)
 100 {
 101         double cost = 0;
 102         cost = sqrt(pow(t.y() - f.y(), 2) + pow(t.x() - f.x(), 2));
 103         return cost;
 104 }
 105
 106 double RRTS::cost_search(RRTNode &f, RRTNode &t)
 107 {
 108         double cost = 0;
 109         cost = sqrt(pow(t.y() - f.y(), 2) + pow(t.x() - f.x(), 2));
 110         return cost;
 111 }
 112
 113 void RRTS::sample()
 114 {
 115         double x = this->ndx_(this->gen_);
 116         double y = this->ndy_(this->gen_);
 117         double h = this->ndh_(this->gen_);
 118         this->samples().push_back(RRTNode());
 119         this->samples().back().x(x);
 120         this->samples().back().y(y);
 121         this->samples().back().h(h);
 122 }
 123
 124 RRTNode *RRTS::nn(RRTNode &t)
 125 {
 126         RRTNode *nn = &this->nodes().front();
 127         double cost = this->cost_search(*nn, t);
 128         for (auto &f: this->nodes()) {
 129                 if (this->cost_search(f, t) < cost) {
 130                         nn = &f;
 131                         cost = this->cost_search(f, t);
 132                 }
 133         }
 134         return nn;
 135 }
 136
 137 std::vector<RRTNode *> RRTS::nv(RRTNode &t)
 138 {
 139         std::vector<RRTNode *> nv;
 140         double cost = std::min(GAMMA(this->nodes().size()), ETA);
 141         for (auto &f: this->nodes())
 142                 if (this->cost_search(f, t) < cost)
 143                         nv.push_back(&f);
 144         return nv;
 145 }
 146
 147 int cb_rs_steer(double q[4], void *user_data)
 148 {
 149         std::vector<RRTNode> *nodes = (std::vector<RRTNode> *) user_data;
 150         RRTNode *ln = nullptr;
 151         if (nodes->size() > 0)
 152                 ln = &nodes->back();
 153         nodes->push_back(RRTNode());
 154         nodes->back().x(q[0]);
 155         nodes->back().y(q[1]);
 156         nodes->back().h(q[2]);
 157         nodes->back().sp(q[3]);
 158         if (nodes->back().sp() == 0)
 159                 nodes->back().set_t(RRTNodeType::cusp);
 160         else if (ln != nullptr && sgn(ln->sp()) != sgn(nodes->back().sp()))
 161                 ln->set_t(RRTNodeType::cusp);
 162         return 0;
 163 }
 164
 165 void RRTS::steer(RRTNode &f, RRTNode &t)
 166 {
 167         this->steered().clear();
 168         double q0[] = {f.x(), f.y(), f.h()};
 169         double q1[] = {t.x(), t.y(), t.h()};
 170         ReedsSheppStateSpace rsss(f.mtr());
 171         rsss.sample(q0, q1, 0.5, cb_rs_steer, &this->steered());
 172 }
 173
 174 void RRTS::join_steered(RRTNode *f)
 175 {
 176         while (this->steered().size() > 0) {
 177                 this->nodes().push_back(this->steered().front());
 178                 RRTNode *t = &this->nodes().back();
 179                 t->p(f);
 180                 t->c(this->cost_build(*f, *t));
 181                 this->steered().erase(this->steered().begin());
 182                 f = t;
 183         }
 184 }
 185
 186 bool RRTS::goal_found(RRTNode &f)
 187 {
 188         bool found = false;
 189         for (auto &g: this->goals()) {
 190                 double cost = this->cost_build(f, g);
 191                 double edist = sqrt(
 192                         pow(f.x() - g.x(), 2)
 193                         + pow(f.y() - g.y(), 2)
 194                 );
 195                 double adist = std::abs(f.h() - g.h());
 196                 if (edist < 0.05 && adist < M_PI / 32) {
 197                         found = true;
 198                         if (g.p() == nullptr || cc(f) + cost < cc(g)) {
 199                                 g.p(&f);
 200                                 g.c(cost);
 201                         }
 202                 }
 203         }
 204         return found;
 205 }
 206
 207 // RRT* procedures
 208 bool RRTS::connect()
 209 {
 210         RRTNode *t = &this->steered().front();
 211         RRTNode *f = this->nn(this->samples().back());
 212         double cost = this->cost_search(*f, *t);
 213         for (auto n: this->nv(*t)) {
 214                 if (
 215                         !std::get<0>(this->collide_two_nodes(*n, *t))
 216                         && this->cost_search(*n, *t) < cost
 217                 ) {
 218                         f = n;
 219                         cost = this->cost_search(*n, *t);
 220                 }
 221         }
 222         this->nodes().push_back(this->steered().front());
 223         t = &this->nodes().back();
 224         t->p(f);
 225         t->c(this->cost_build(*f, *t));
 226         t->set_t(RRTNodeType::connected);
 227         return true;
 228 }
 229
 230 void RRTS::rewire()
 231 {
 232         RRTNode *f = &this->nodes().back();
 233         for (auto n: this->nv(*f)) {
 234                 if (
 235                         !std::get<0>(this->collide_two_nodes(*f, *n))
 236                         && cc(*f) + this->cost_search(*f, *n) < cc(*n)
 237                 ) {
 238                         n->p(f);
 239                         n->c(this->cost_build(*f, *n));
 240                 }
 241         }
 242 }
 243
 244 // API
 245 std::vector<RRTNode *> RRTS::path()
 246 {
 247         std::vector<RRTNode *> path;
 248         if (this->goals().size() == 0)
 249                 return path;
 250         RRTNode *goal = &this->goals().front();
 251         for (auto &n: this->goals()) {
 252                 if (
 253                         n.p() != nullptr
 254                         && (n.c() < goal->c() || goal->p() == nullptr)
 255                 ) {
 256                         goal = &n;
 257                 }
 258         }
 259         if (goal->p() == nullptr)
 260                 return path;
 261         while (goal != nullptr) {
 262                 path.push_back(goal);
 263                 goal = goal->p();
 264         }
 265         std::reverse(path.begin(), path.end());
 266         return path;
 267 }
 268
 269 bool RRTS::next()
 270 {
 271         if (this->icnt_ == 0)
 272                 this->tstart_ = std::chrono::high_resolution_clock::now();
 273         bool next = true;
 274         if (this->should_stop())
 275                 return false;
 276         this->sample();
 277         this->steer(
 278                 *this->nn(this->samples().back()),
 279                 this->samples().back()
 280         );
 281         if (std::get<0>(this->collide_steered_from(
 282                 *this->nn(this->samples().back())
 283         )))
 284                 return next;
 285         if (!this->connect())
 286                 return next;
 287         this->rewire();
 288         unsigned scnt = this->steered().size();
 289         this->steered().erase(this->steered().begin());
 290         this->join_steered(&this->nodes().back());
 291         RRTNode *just_added = &this->nodes().back();
 292         while (scnt > 0) {
 293                 scnt--;
 294                 for (auto &g: this->goals()) {
 295                         this->steer(*just_added, g);
 296                         if (std::get<0>(this->collide_steered_from(
 297                                 *just_added
 298                         )))
 299                                 continue;
 300                         this->join_steered(just_added);
 301                 }
 302                 this->gf(this->goal_found(this->nodes().back()));
 303                 just_added = just_added->p();
 304         }
 305         return next;
 306 }
 307
 308 void RRTS::set_sample(
 309         double mx, double dx,
 310         double my, double dy,
 311         double mh, double dh
 312 )
 313 {
 314         this->ndx_ = std::normal_distribution<double>(mx, dx);
 315         this->ndy_ = std::normal_distribution<double>(my, dy);
 316         this->ndh_ = std::normal_distribution<double>(mh, dh);
 317 }
 318
 319 RRTS::RRTS()
 320         : gen_(std::random_device{}())
 321 {
 322         this->goals().reserve(100);
 323         this->nodes().reserve(4000000);
 324         this->samples().reserve(1000);
 325         this->steered().reserve(20000);
 326         this->nodes().push_back(RRTNode()); // root
 327 }
 328
 329 double cc(RRTNode &t)
 330 {
 331         RRTNode *n = &t;
 332         double cost = 0;
 333         while (n != nullptr) {
 334                 cost += n->c();
 335                 n = n->p();
 336         }
 337         return cost;
 338 }