obstacle_cost_function.cpp

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#include <base_local_planner/obstacle_cost_function.h>
#include <cmath>
#include <Eigen/Core>
#include <ros/console.h>
 
namespace base_local_planner {
 
ObstacleCostFunction::ObstacleCostFunction(costmap_2d::Costmap2D* costmap) 
    : costmap_(costmap), sum_scores_(false) {
  if (costmap != NULL) {
    world_model_ = new base_local_planner::CostmapModel(*costmap_);
  }
}
 
ObstacleCostFunction::~ObstacleCostFunction() {
  if (world_model_ != NULL) {
    delete world_model_;
  }
}
 
 
void ObstacleCostFunction::setParams(double max_trans_vel, double max_scaling_factor, double scaling_speed) {
  // TODO: move this to prepare if possible
  max_trans_vel_ = max_trans_vel;
  max_scaling_factor_ = max_scaling_factor;
  scaling_speed_ = scaling_speed;
}
 
void ObstacleCostFunction::setFootprint(std::vector<geometry_msgs::Point> footprint_spec) {
  footprint_spec_ = footprint_spec;
}
 
bool ObstacleCostFunction::prepare() {
  return true;
}
 
double ObstacleCostFunction::scoreTrajectory(Trajectory &traj) {
  double cost = 0;
  double scale = getScalingFactor(traj, scaling_speed_, max_trans_vel_, max_scaling_factor_);
  double px, py, pth;
  if (footprint_spec_.size() == 0) {
    // Bug, should never happen
    ROS_ERROR("Footprint spec is empty, maybe missing call to setFootprint?");
    return -9;
  }
 
  for (unsigned int i = 0; i < traj.getPointsSize(); ++i) {
    traj.getPoint(i, px, py, pth);
    double f_cost = footprintCost(px, py, pth,
        scale, footprint_spec_,
        costmap_, world_model_);
 
    if(f_cost < 0){
        return f_cost;
    }
 
    // Count cell costs instead of footprint costs for optimization
    unsigned int cell_x, cell_y;
    costmap_->worldToMap(px, py, cell_x, cell_y);
    double c_cost = double(costmap_->getCost(cell_x, cell_y));
 
    if(sum_scores_)
        cost +=  c_cost;
    else
        cost = std::max(cost, c_cost);
  }
  return cost;
}
 
double ObstacleCostFunction::getScalingFactor(Trajectory &traj, double scaling_speed, double max_trans_vel, double max_scaling_factor) {
  double vmag = hypot(traj.xv_, traj.yv_);
 
  //if we're over a certain speed threshold, we'll scale the robot's
  //footprint to make it either slow down or stay further from walls
  double scale = 1.0;
  if (vmag > scaling_speed) {
    //scale up to the max scaling factor linearly... this could be changed later
    double ratio = (vmag - scaling_speed) / (max_trans_vel - scaling_speed);
    scale = max_scaling_factor * ratio + 1.0;
  }
  return scale;
}
 
double ObstacleCostFunction::footprintCost (
    const double& x,
    const double& y,
    const double& th,
    double scale,
    std::vector<geometry_msgs::Point> footprint_spec,
    costmap_2d::Costmap2D* costmap,
    base_local_planner::WorldModel* world_model) {
 
  std::vector<geometry_msgs::Point> scaled_footprint;
  for(unsigned int i  = 0; i < footprint_spec.size(); ++i) {
    geometry_msgs::Point new_pt;
    new_pt.x = scale * footprint_spec[i].x;
    new_pt.y = scale * footprint_spec[i].y;
    scaled_footprint.push_back(new_pt);
  }
 
  //check if the footprint is legal
  // TODO: Cache inscribed radius
  double footprint_cost = world_model->footprintCost(x, y, th, scaled_footprint);
 
  if (footprint_cost < 0) {
    return -6.0;
  }
  unsigned int cell_x, cell_y;
 
  //we won't allow trajectories that go off the map... shouldn't happen that often anyways
  if ( ! costmap->worldToMap(x, y, cell_x, cell_y)) {
    return -7.0;
  }
 
  double occ_cost = std::max(std::max(0.0, footprint_cost), double(costmap->getCost(cell_x, cell_y)));
 
  return occ_cost;
}
 
} /* namespace base_local_planner */