constrained_goal_sampler.cpp

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/* Author: Ioan Sucan */
 
#include <moveit/ompl_interface/detail/constrained_goal_sampler.h>
#include <moveit/ompl_interface/model_based_planning_context.h>
#include <moveit/ompl_interface/detail/state_validity_checker.h>
#include <moveit/utils/logger.hpp>
 
#include <utility>
 
namespace ompl_interface
{
namespace
{
rclcpp::Logger getLogger()
{
  return moveit::getLogger("ompl_constrained_goal_sampler");
}
}  // namespace
 
ConstrainedGoalSampler::ConstrainedGoalSampler(const ModelBasedPlanningContext* pc,
                                               kinematic_constraints::KinematicConstraintSetPtr ks,
                                               constraint_samplers::ConstraintSamplerPtr cs)
  : ob::GoalLazySamples(
        pc->getOMPLSimpleSetup()->getSpaceInformation(),
        [this](const GoalLazySamples* gls, ompl::base::State* state) {
          return sampleUsingConstraintSampler(gls, state);
        },
        false)
  , planning_context_(pc)
  , kinematic_constraint_set_(std::move(ks))
  , constraint_sampler_(std::move(cs))
  , work_state_(pc->getCompleteInitialRobotState())
  , invalid_sampled_constraints_(0)
  , warned_invalid_samples_(false)
  , verbose_display_(0)
{
  if (!constraint_sampler_)
    default_sampler_ = si_->allocStateSampler();
  RCLCPP_DEBUG(getLogger(), "Constructed a ConstrainedGoalSampler instance at address %p", this);
  startSampling();
}
 
bool ConstrainedGoalSampler::checkStateValidity(ob::State* new_goal, const moveit::core::RobotState& state,
                                                bool verbose) const
{
  planning_context_->getOMPLStateSpace()->copyToOMPLState(new_goal, state);
  return static_cast<const StateValidityChecker*>(si_->getStateValidityChecker().get())->isValid(new_goal, verbose);
}
 
bool ConstrainedGoalSampler::stateValidityCallback(ob::State* new_goal, const moveit::core::RobotState* state,
                                                   const moveit::core::JointModelGroup* jmg, const double* jpos,
                                                   bool verbose) const
{
  // we copy the state to not change the seed state
  moveit::core::RobotState solution_state(*state);
  solution_state.setJointGroupPositions(jmg, jpos);
  solution_state.update();
  return checkStateValidity(new_goal, solution_state, verbose);
}
 
bool ConstrainedGoalSampler::sampleUsingConstraintSampler(const ob::GoalLazySamples* gls, ob::State* new_goal)
{
  unsigned int max_attempts = planning_context_->getMaximumGoalSamplingAttempts();
  unsigned int attempts_so_far = gls->samplingAttemptsCount();
 
  // terminate after too many attempts
  if (attempts_so_far >= max_attempts)
    return false;
 
  // terminate after a maximum number of samples
  if (gls->getStateCount() >= planning_context_->getMaximumGoalSamples())
    return false;
 
  // terminate the sampling thread when a solution has been found
  if (planning_context_->getOMPLSimpleSetup()->getProblemDefinition()->hasSolution())
    return false;
 
  unsigned int max_attempts_div2 = max_attempts / 2;
  for (unsigned int a = gls->samplingAttemptsCount(); a < max_attempts && gls->isSampling(); ++a)
  {
    bool verbose = false;
    if (gls->getStateCount() == 0 && a >= max_attempts_div2)
    {
      if (verbose_display_ < 1)
      {
        verbose = true;
        verbose_display_++;
      }
    }
 
    if (constraint_sampler_)
    {
      // makes the constraint sampler also perform a validity callback
      moveit::core::GroupStateValidityCallbackFn gsvcf = [this, new_goal,
                                                          verbose](moveit::core::RobotState* robot_state,
                                                                   const moveit::core::JointModelGroup* joint_group,
                                                                   const double* joint_group_variable_values) {
        return stateValidityCallback(new_goal, robot_state, joint_group, joint_group_variable_values, verbose);
      };
      constraint_sampler_->setGroupStateValidityCallback(gsvcf);
 
      if (constraint_sampler_->sample(work_state_, planning_context_->getMaximumStateSamplingAttempts()))
      {
        work_state_.update();
        if (kinematic_constraint_set_->decide(work_state_, verbose).satisfied)
        {
          if (checkStateValidity(new_goal, work_state_, verbose))
            return true;
        }
        else
        {
          invalid_sampled_constraints_++;
          if (!warned_invalid_samples_ && invalid_sampled_constraints_ >= (attempts_so_far * 8) / 10)
          {
            warned_invalid_samples_ = true;
            RCLCPP_WARN(getLogger(), "More than 80%% of the sampled goal states "
                                     "fail to satisfy the constraints imposed on the goal sampler. "
                                     "Is the constrained sampler working correctly?");
          }
        }
      }
    }
    else
    {
      default_sampler_->sampleUniform(new_goal);
      if (static_cast<const StateValidityChecker*>(si_->getStateValidityChecker().get())->isValid(new_goal, verbose))
      {
        planning_context_->getOMPLStateSpace()->copyToRobotState(work_state_, new_goal);
        if (kinematic_constraint_set_->decide(work_state_, verbose).satisfied)
          return true;
      }
    }
  }
  return false;
}
 
}  // namespace ompl_interface