constraint_sampler_manager.cpp

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/* Author: Ioan Sucan */

#include <moveit/constraint_samplers/constraint_sampler_manager.h>
#include <moveit/constraint_samplers/default_constraint_samplers.h>
#include <moveit/constraint_samplers/union_constraint_sampler.h>
#include <sstream>

constraint_samplers::ConstraintSamplerPtr
constraint_samplers::ConstraintSamplerManager::selectSampler(const planning_scene::PlanningSceneConstPtr& scene,
                                                             const std::string& group_name,
                                                             const moveit_msgs::Constraints& constr) const
{
  for (std::size_t i = 0; i < sampler_alloc_.size(); ++i)
    if (sampler_alloc_[i]->canService(scene, group_name, constr))
      return sampler_alloc_[i]->alloc(scene, group_name, constr);

  // if no default sampler was used, try a default one
  return selectDefaultSampler(scene, group_name, constr);
}

constraint_samplers::ConstraintSamplerPtr
constraint_samplers::ConstraintSamplerManager::selectDefaultSampler(const planning_scene::PlanningSceneConstPtr& scene,
                                                                    const std::string& group_name,
                                                                    const moveit_msgs::Constraints& constr)
{
  const robot_model::JointModelGroup* jmg = scene->getRobotModel()->getJointModelGroup(group_name);
  if (!jmg)
    return constraint_samplers::ConstraintSamplerPtr();
  std::stringstream ss;
  ss << constr;
  ROS_DEBUG_NAMED("constraint_samplers",
                  "Attempting to construct constrained state sampler for group '%s', using constraints:\n%s.\n",
                  jmg->getName().c_str(), ss.str().c_str());

  ConstraintSamplerPtr joint_sampler;  // location to put chosen joint sampler if needed
  // if there are joint constraints, we could possibly get a sampler from those
  if (!constr.joint_constraints.empty())
  {
    ROS_DEBUG_NAMED("constraint_samplers", "There are joint constraints specified. "
                                           "Attempting to construct a JointConstraintSampler for group '%s'",
                    jmg->getName().c_str());

    std::map<std::string, bool> joint_coverage;
    for (std::size_t i = 0; i < jmg->getVariableNames().size(); ++i)
      joint_coverage[jmg->getVariableNames()[i]] = false;

    // construct the constraints
    std::vector<kinematic_constraints::JointConstraint> jc;
    for (std::size_t i = 0; i < constr.joint_constraints.size(); ++i)
    {
      kinematic_constraints::JointConstraint j(scene->getRobotModel());
      if (j.configure(constr.joint_constraints[i]))
      {
        if (joint_coverage.find(j.getJointVariableName()) != joint_coverage.end())
        {
          joint_coverage[j.getJointVariableName()] = true;
          jc.push_back(j);
        }
      }
    }

    // check if every joint is covered (constrained) by just joint samplers
    bool full_coverage = true;
    for (std::map<std::string, bool>::iterator it = joint_coverage.begin(); it != joint_coverage.end(); ++it)
      if (!it->second)
      {
        full_coverage = false;
        break;
      }

    // if we have constrained every joint, then we just use a sampler using these constraints
    if (full_coverage)
    {
      JointConstraintSamplerPtr sampler(new JointConstraintSampler(scene, jmg->getName()));
      if (sampler->configure(jc))
      {
        ROS_DEBUG_NAMED("constraint_samplers", "Allocated a sampler satisfying joint constraints for group '%s'",
                        jmg->getName().c_str());
        return sampler;
      }
    }
    else
        // if a smaller set of joints has been specified, keep the constraint sampler around, but use it only if no IK
        // sampler has been specified.
        if (!jc.empty())
    {
      JointConstraintSamplerPtr sampler(new JointConstraintSampler(scene, jmg->getName()));
      if (sampler->configure(jc))
      {
        ROS_DEBUG_NAMED("constraint_samplers",
                        "Temporary sampler satisfying joint constraints for group '%s' allocated. "
                        "Looking for different types of constraints before returning though.",
                        jmg->getName().c_str());
        joint_sampler = sampler;
      }
    }
  }

  std::vector<ConstraintSamplerPtr> samplers;
  if (joint_sampler)  // Start making a union of constraint samplers
    samplers.push_back(joint_sampler);

  // read the ik allocators, if any
  const robot_model::JointModelGroup::KinematicsSolver& ik_alloc = jmg->getGroupKinematics().first;
  const robot_model::JointModelGroup::KinematicsSolverMap& ik_subgroup_alloc = jmg->getGroupKinematics().second;

  // if we have a means of computing complete states for the group using IK, then we try to see if any IK constraints
  // should be used
  if (ik_alloc)
  {
    ROS_DEBUG_NAMED("constraint_samplers", "There is an IK allocator for '%s'. "
                                           "Checking for corresponding position and/or orientation constraints",
                    jmg->getName().c_str());

    // keep track of which links we constrained
    std::map<std::string, IKConstraintSamplerPtr> usedL;

    // if we have position and/or orientation constraints on links that we can perform IK for,
    // we will use a sampleable goal region that employs IK to sample goals;
    // if there are multiple constraints for the same link, we keep the one with the smallest
    // volume for sampling
    for (std::size_t p = 0; p < constr.position_constraints.size(); ++p)
      for (std::size_t o = 0; o < constr.orientation_constraints.size(); ++o)
        if (constr.position_constraints[p].link_name == constr.orientation_constraints[o].link_name)
        {
          kinematic_constraints::PositionConstraintPtr pc(
              new kinematic_constraints::PositionConstraint(scene->getRobotModel()));
          kinematic_constraints::OrientationConstraintPtr oc(
              new kinematic_constraints::OrientationConstraint(scene->getRobotModel()));
          if (pc->configure(constr.position_constraints[p], scene->getTransforms()) &&
              oc->configure(constr.orientation_constraints[o], scene->getTransforms()))
          {
            IKConstraintSamplerPtr iks(new IKConstraintSampler(scene, jmg->getName()));
            if (iks->configure(IKSamplingPose(pc, oc)))
            {
              bool use = true;
              // Check if there already is a constraint on this link
              if (usedL.find(constr.position_constraints[p].link_name) != usedL.end())
                // If there is, check if the previous one has a smaller volume for sampling
                if (usedL[constr.position_constraints[p].link_name]->getSamplingVolume() < iks->getSamplingVolume())
                  use = false;  // only use new constraint if it has a smaller sampling volume
              if (use)
              {
                // assign the link to a new constraint sampler
                usedL[constr.position_constraints[p].link_name] = iks;
                ROS_DEBUG_NAMED("constraint_samplers", "Allocated an IK-based sampler for group '%s' "
                                                       "satisfying position and orientation constraints on link '%s'",
                                jmg->getName().c_str(), constr.position_constraints[p].link_name.c_str());
              }
            }
          }
        }

    // keep track of links constrained with a full pose
    std::map<std::string, IKConstraintSamplerPtr> usedL_fullPose = usedL;

    for (std::size_t p = 0; p < constr.position_constraints.size(); ++p)
    {
      // if we are constraining this link with a full pose, we do not attempt to constrain it with a position constraint
      // only
      if (usedL_fullPose.find(constr.position_constraints[p].link_name) != usedL_fullPose.end())
        continue;

      kinematic_constraints::PositionConstraintPtr pc(
          new kinematic_constraints::PositionConstraint(scene->getRobotModel()));
      if (pc->configure(constr.position_constraints[p], scene->getTransforms()))
      {
        IKConstraintSamplerPtr iks(new IKConstraintSampler(scene, jmg->getName()));
        if (iks->configure(IKSamplingPose(pc)))
        {
          bool use = true;
          if (usedL.find(constr.position_constraints[p].link_name) != usedL.end())
            if (usedL[constr.position_constraints[p].link_name]->getSamplingVolume() < iks->getSamplingVolume())
              use = false;
          if (use)
          {
            usedL[constr.position_constraints[p].link_name] = iks;
            ROS_DEBUG_NAMED("constraint_samplers", "Allocated an IK-based sampler for group '%s' "
                                                   "satisfying position constraints on link '%s'",
                            jmg->getName().c_str(), constr.position_constraints[p].link_name.c_str());
          }
        }
      }
    }

    for (std::size_t o = 0; o < constr.orientation_constraints.size(); ++o)
    {
      // if we are constraining this link with a full pose, we do not attempt to constrain it with an orientation
      // constraint only
      if (usedL_fullPose.find(constr.orientation_constraints[o].link_name) != usedL_fullPose.end())
        continue;

      kinematic_constraints::OrientationConstraintPtr oc(
          new kinematic_constraints::OrientationConstraint(scene->getRobotModel()));
      if (oc->configure(constr.orientation_constraints[o], scene->getTransforms()))
      {
        IKConstraintSamplerPtr iks(new IKConstraintSampler(scene, jmg->getName()));
        if (iks->configure(IKSamplingPose(oc)))
        {
          bool use = true;
          if (usedL.find(constr.orientation_constraints[o].link_name) != usedL.end())
            if (usedL[constr.orientation_constraints[o].link_name]->getSamplingVolume() < iks->getSamplingVolume())
              use = false;
          if (use)
          {
            usedL[constr.orientation_constraints[o].link_name] = iks;
            ROS_DEBUG_NAMED("constraint_samplers", "Allocated an IK-based sampler for group '%s' "
                                                   "satisfying orientation constraints on link '%s'",
                            jmg->getName().c_str(), constr.orientation_constraints[o].link_name.c_str());
          }
        }
      }
    }

    if (usedL.size() == 1)
    {
      if (samplers.empty())
        return usedL.begin()->second;
      else
      {
        samplers.push_back(usedL.begin()->second);
        return ConstraintSamplerPtr(new UnionConstraintSampler(scene, jmg->getName(), samplers));
      }
    }
    else if (usedL.size() > 1)
    {
      ROS_DEBUG_NAMED("constraint_samplers",
                      "Too many IK-based samplers for group '%s'. Keeping the one with minimal sampling volume",
                      jmg->getName().c_str());
      // find the sampler with the smallest sampling volume; delete the rest
      IKConstraintSamplerPtr iks = usedL.begin()->second;
      double msv = iks->getSamplingVolume();
      for (std::map<std::string, IKConstraintSamplerPtr>::const_iterator it = ++usedL.begin(); it != usedL.end(); ++it)
      {
        double v = it->second->getSamplingVolume();
        if (v < msv)
        {
          iks = it->second;
          msv = v;
        }
      }
      if (samplers.empty())
      {
        return iks;
      }
      else
      {
        samplers.push_back(iks);
        return ConstraintSamplerPtr(new UnionConstraintSampler(scene, jmg->getName(), samplers));
      }
    }
  }

  // if we got to this point, we have not decided on a sampler.
  // we now check to see if we can use samplers from subgroups
  if (!ik_subgroup_alloc.empty())
  {
    ROS_DEBUG_NAMED("constraint_samplers", "There are IK allocators for subgroups of group '%s'. "
                                           "Checking for corresponding position and/or orientation constraints",
                    jmg->getName().c_str());

    bool some_sampler_valid = false;

    std::set<std::size_t> usedP, usedO;
    for (robot_model::JointModelGroup::KinematicsSolverMap::const_iterator it = ik_subgroup_alloc.begin();
         it != ik_subgroup_alloc.end(); ++it)
    {
      // construct a sub-set of constraints that operate on the sub-group for which we have an IK allocator
      moveit_msgs::Constraints sub_constr;
      for (std::size_t p = 0; p < constr.position_constraints.size(); ++p)
        if (it->first->hasLinkModel(constr.position_constraints[p].link_name))
          if (usedP.find(p) == usedP.end())
          {
            sub_constr.position_constraints.push_back(constr.position_constraints[p]);
            usedP.insert(p);
          }

      for (std::size_t o = 0; o < constr.orientation_constraints.size(); ++o)
        if (it->first->hasLinkModel(constr.orientation_constraints[o].link_name))
          if (usedO.find(o) == usedO.end())
          {
            sub_constr.orientation_constraints.push_back(constr.orientation_constraints[o]);
            usedO.insert(o);
          }

      // if some matching constraints were found, construct the allocator
      if (!sub_constr.orientation_constraints.empty() || !sub_constr.position_constraints.empty())
      {
        ROS_DEBUG_NAMED("constraint_samplers", "Attempting to construct a sampler for the '%s' subgroup of '%s'",
                        it->first->getName().c_str(), jmg->getName().c_str());
        ConstraintSamplerPtr cs = selectDefaultSampler(scene, it->first->getName(), sub_constr);
        if (cs)
        {
          ROS_DEBUG_NAMED("constraint_samplers", "Constructed a sampler for the joints corresponding to group '%s', "
                                                 "but part of group '%s'",
                          it->first->getName().c_str(), jmg->getName().c_str());
          some_sampler_valid = true;
          samplers.push_back(cs);
        }
      }
    }
    if (some_sampler_valid)
    {
      ROS_DEBUG_NAMED("constraint_samplers", "Constructing sampler for group '%s' as a union of %zu samplers",
                      jmg->getName().c_str(), samplers.size());
      return ConstraintSamplerPtr(new UnionConstraintSampler(scene, jmg->getName(), samplers));
    }
  }

  // if we've gotten here, just return joint sampler
  if (joint_sampler)
  {
    ROS_DEBUG_NAMED("constraint_samplers", "Allocated a sampler satisfying joint constraints for group '%s'",
                    jmg->getName().c_str());
    return joint_sampler;
  }

  ROS_DEBUG_NAMED("constraint_samplers", "No constraints sampler allocated for group '%s'", jmg->getName().c_str());

  return ConstraintSamplerPtr();
}