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 RRTNode::RRTNode()
  13 {
  14 }
  15
  16 RRTNode::RRTNode(const BicycleCar &bc) : BicycleCar(bc)
  17 {
  18 }
  19
  20 Obstacle::Obstacle()
  21 {
  22 }
  23
  24 // RRT procedures
  25 bool RRTS::collide(std::vector<std::tuple<double, double>> &poly)
  26 {
  27         for (auto &o: this->obstacles())
  28                 if (std::get<0>(::collide(poly, o.poly())))
  29                         return true;
  30         return false;
  31 }
  32
  33 bool RRTS::collide_steered_from(RRTNode &f)
  34 {
  35         std::vector<std::tuple<double, double>> s;
  36         s.push_back(std::make_tuple(f.x(), f.y()));
  37         for (auto &n: this->steered()) {
  38                 s.push_back(std::make_tuple(n.lfx(), n.lfy()));
  39                 s.push_back(std::make_tuple(n.lrx(), n.lry()));
  40                 s.push_back(std::make_tuple(n.rrx(), n.rry()));
  41                 s.push_back(std::make_tuple(n.rfx(), n.rfy()));
  42         }
  43         return this->collide(s);
  44 }
  45
  46 bool RRTS::collide_two_nodes(RRTNode &f, RRTNode &t)
  47 {
  48         std::vector<std::tuple<double, double>> p;
  49         p.push_back(std::make_tuple(f.lfx(), f.lfy()));
  50         p.push_back(std::make_tuple(f.lrx(), f.lry()));
  51         p.push_back(std::make_tuple(f.rrx(), f.rry()));
  52         p.push_back(std::make_tuple(f.rfx(), f.rfy()));
  53         p.push_back(std::make_tuple(t.lfx(), t.lfy()));
  54         p.push_back(std::make_tuple(t.lrx(), t.lry()));
  55         p.push_back(std::make_tuple(t.rrx(), t.rry()));
  56         p.push_back(std::make_tuple(t.rfx(), t.rfy()));
  57         return this->collide(p);
  58 }
  59
  60 double RRTS::cost(RRTNode &f, RRTNode &t)
  61 {
  62         double cost = 0;
  63         cost = sqrt(pow(t.y() - f.y(), 2) + pow(t.x() - f.x(), 2));
  64         return cost;
  65 }
  66
  67 double RRTS::cost_build(RRTNode &f, RRTNode &t)
  68 {
  69         double q0[] = {f.x(), f.y(), f.h()};
  70         double q1[] = {t.x(), t.y(), t.h()};
  71         ReedsSheppStateSpace rsss(f.mtr());
  72         return rsss.distance(q0, q1);
  73 }
  74
  75 double RRTS::cost_search(RRTNode &f, RRTNode &t)
  76 {
  77         double cost = 0;
  78         cost = sqrt(pow(t.y() - f.y(), 2) + pow(t.x() - f.x(), 2));
  79         double heur = std::min(
  80                 std::abs(t.h() - f.h()),
  81                 2 * M_PI - std::abs(t.h() - f.h())
  82         );
  83         heur *= f.mtr();
  84         cost = std::max(cost, heur);
  85         return cost;
  86 }
  87
  88 void RRTS::sample()
  89 {
  90         double x = this->ndx_(this->gen_);
  91         double y = this->ndy_(this->gen_);
  92         double h = this->ndh_(this->gen_);
  93         this->samples().push_back(RRTNode());
  94         this->samples().back().x(x);
  95         this->samples().back().y(y);
  96         this->samples().back().h(h);
  97 }
  98
  99 RRTNode *RRTS::nn(RRTNode &t)
 100 {
 101         RRTNode *nn = &this->nodes().front();
 102         double cost = this->cost(*nn, t);
 103         for (auto &f: this->nodes()) {
 104                 if (this->cost(f, t) < cost) {
 105                         nn = &f;
 106                         cost = this->cost(f, t);
 107                 }
 108         }
 109         return nn;
 110 }
 111
 112 std::vector<RRTNode *> RRTS::nv(RRTNode &t)
 113 {
 114         std::vector<RRTNode *> nv;
 115         double cost = std::min(GAMMA(this->nodes().size()), ETA);
 116         for (auto &f: this->nodes())
 117                 if (this->cost(f, t) < cost)
 118                         nv.push_back(&f);
 119         return nv;
 120 }
 121
 122 int cb_rs_steer(double q[3], void *user_data)
 123 {
 124         std::vector<RRTNode> *nodes = (std::vector<RRTNode> *) user_data;
 125         nodes->push_back(RRTNode());
 126         nodes->back().x(q[0]);
 127         nodes->back().y(q[1]);
 128         nodes->back().h(q[2]);
 129         return 0;
 130 }
 131
 132 void RRTS::steer(RRTNode &f, RRTNode &t)
 133 {
 134         this->steered().clear();
 135         double q0[] = {f.x(), f.y(), f.h()};
 136         double q1[] = {t.x(), t.y(), t.h()};
 137         ReedsSheppStateSpace rsss(f.mtr());
 138         rsss.sample(q0, q1, 0.5, cb_rs_steer, &this->steered());
 139 }
 140
 141 // RRT* procedures
 142 bool RRTS::connect()
 143 {
 144         bool conn = false;
 145         RRTNode *t = &this->steered().front();
 146         RRTNode *f = this->nn(this->samples().back());
 147         double cost = this->cost(*f, *t);
 148         for (auto n: this->nv(*t)) {
 149                 if (
 150                         !this->collide_two_nodes(*n, *t)
 151                         && this->cost(*n, *t) < cost
 152                 ) {
 153                         f = n;
 154                         cost = this->cost(*n, *t);
 155                 }
 156         }
 157         this->nodes().push_back(this->steered().front());
 158         t = &this->nodes().back();
 159         t->p(f);
 160         t->c(this->cost(*f, *t));
 161         conn = true;
 162         return conn;
 163 }
 164
 165 void RRTS::rewire()
 166 {
 167         RRTNode *f = &this->nodes().back();
 168         for (auto n: this->nv(*f)) {
 169                 if (
 170                         !this->collide_two_nodes(*f, *n)
 171                         && cc(*f) + this->cost(*f, *n) < cc(*n)
 172                 )
 173                         n->p(f);
 174         }
 175 }
 176
 177 // API
 178 std::vector<RRTNode *> RRTS::path()
 179 {
 180         std::vector<RRTNode *> path;
 181         if (this->goals().size() == 0)
 182                 return path;
 183         RRTNode *goal = &this->goals().front();
 184         for (auto &n: this->goals()) {
 185                 if (
 186                         n.p() != nullptr
 187                         && (n.c() < goal->c() || goal->p() == nullptr)
 188                 ) {
 189                         goal = &n;
 190                 }
 191         }
 192         if (goal->p() == nullptr)
 193                 return path;
 194         while (goal != nullptr) {
 195                 path.push_back(goal);
 196                 goal = goal->p();
 197         }
 198         std::reverse(path.begin(), path.end());
 199         return path;
 200 }
 201
 202 bool RRTS::next()
 203 {
 204         bool next = true;
 205         this->icnt_++;
 206         this->sample();
 207         this->steer(
 208                 *this->nn(this->samples().back()),
 209                 this->samples().back()
 210         );
 211         if (this->collide_steered_from(*this->nn(this->samples().back())))
 212                 return next;
 213         if (!this->connect())
 214                 return next;
 215         this->rewire();
 216         unsigned scnt = this->steered().size();
 217         this->steered().erase(this->steered().begin());
 218         while (this->steered().size() > 0) {
 219                 RRTNode *f = &this->nodes().back();
 220                 this->nodes().push_back(this->steered().front());
 221                 RRTNode *t = &this->nodes().back();
 222                 t->p(f);
 223                 t->c(this->cost(*f, *t));
 224                 this->steered().erase(this->steered().begin());
 225         }
 226         RRTNode *just_added = &this->nodes().back();
 227         while (scnt > 0) {
 228                 scnt--;
 229                 for (auto &g: this->goals()) {
 230                         this->steer(*just_added, g);
 231                         if (this->collide_steered_from(*just_added))
 232                                 continue;
 233                         RRTNode *f = just_added;
 234                         while (this->steered().size() > 0) {
 235                                 RRTNode s = this->steered().front();
 236                                 this->nodes().push_back(s);
 237                                 RRTNode *t = &this->nodes().back();
 238                                 t->p(f);
 239                                 t->c(this->cost(*f, *t));
 240                                 this->steered().erase(this->steered().begin());
 241                                 f = t;
 242                         }
 243                 }
 244                 just_added = just_added->p();
 245         }
 246         for (auto &g: this->goals()) {
 247                 double cost = this->cost(this->nodes().back(), g);
 248                 double edist = sqrt(
 249                         pow(this->nodes().back().x() - g.x(), 2)
 250                         + pow(this->nodes().back().y() - g.y(), 2)
 251                 );
 252                 double adist = std::abs(this->nodes().back().h() - g.h());
 253                 if (edist < 0.05 && adist < M_PI / 32) {
 254                         next = false;
 255                         if (
 256                                 g.p() == nullptr
 257                                 || cc(this->nodes().back()) + cost < cc(g)
 258                         ) {
 259                                 g.p(&this->nodes().back());
 260                                 g.c(cost);
 261                         }
 262                 }
 263         }
 264         if (this->icnt_ > 999)
 265                 next = false;
 266         return next;
 267 }
 268
 269 void RRTS::set_sample(
 270         double mx, double dx,
 271         double my, double dy,
 272         double mh, double dh
 273 )
 274 {
 275         this->ndx_ = std::normal_distribution<double>(mx, dx);
 276         this->ndy_ = std::normal_distribution<double>(my, dy);
 277         this->ndh_ = std::normal_distribution<double>(mh, dh);
 278 }
 279
 280 RRTS::RRTS()
 281         : gen_(std::random_device{}())
 282 {
 283         this->goals().reserve(1);
 284         this->nodes().reserve(40000);
 285         this->samples().reserve(1000);
 286         this->steered().reserve(200);
 287         this->nodes().push_back(RRTNode()); // root
 288 }
 289
 290 double cc(RRTNode &t)
 291 {
 292         RRTNode *n = &t;
 293         double cost = 0;
 294         while (n != nullptr) {
 295                 cost += n->c();
 296                 n = n->p();
 297         }
 298         return cost;
 299 }