treefksolverjointposaxis.cpp

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#include <collision_proximity_planner/treefksolverjointposaxis.hpp>
#include <iostream>

using namespace std;

namespace KDL {

TreeFkSolverJointPosAxis::TreeFkSolverJointPosAxis(const Tree& tree, const std::string& reference_frame):
  tree_(tree),
  reference_frame_(reference_frame)
{
  segment_names_.clear();
  assignSegmentNumber(tree_.getRootSegment());
  std::map<std::string, int>::iterator reference_frame_it = segment_name_to_index_.find(reference_frame);
  if (reference_frame_it == segment_name_to_index_.end())
  {
    cout << "TreeFkSolverJointPosAxis: Reference frame " << reference_frame << " could not be found! Forward kinematics will be performed in world frame.";
  }
  else
  {
    reference_frame_index_ = reference_frame_it->second;
  }
  num_segments_ = segment_names_.size();
  num_joints_ = tree_.getNrOfJoints();
}

TreeFkSolverJointPosAxis::~TreeFkSolverJointPosAxis()
{
}

int TreeFkSolverJointPosAxis::JntToCart(const JntArray& q_in, std::vector<Vector>& joint_pos, std::vector<Vector>& joint_axis, std::vector<Frame>& segment_frames) const
{
  joint_pos.resize(num_joints_);
  joint_axis.resize(num_joints_);
  segment_frames.resize(num_segments_);

  // start the recursion
  treeRecursiveFK(q_in, joint_pos, joint_axis, segment_frames, Frame::Identity(), tree_.getRootSegment(), 0);

  // get the inverse reference frame:
  Frame inv_ref_frame = segment_frames[reference_frame_index_].Inverse();

  // convert all the frames into the reference frame:
  for (int i=0; i<num_segments_; i++)
  {
    segment_frames[i] = inv_ref_frame * segment_frames[i];
  }

  // convert all joint positions and axes into reference frame:
  for (int i=0; i<num_joints_; i++)
  {
    joint_axis[i] = inv_ref_frame * joint_axis[i];
    joint_pos[i] = inv_ref_frame * joint_pos[i];
  }

  return 0;
}

int TreeFkSolverJointPosAxis::treeRecursiveFK(const JntArray& q_in, std::vector<Vector>& joint_pos, std::vector<Vector>& joint_axis, std::vector<Frame>& segment_frames,
    const Frame& previous_frame, const SegmentMap::const_iterator this_segment, int segment_nr) const
{
  Frame this_frame = previous_frame;

  // get the joint angle:
  double jnt_p = 0;
  if (this_segment->second.segment.getJoint().getType() != Joint::None)
  {
    int q_nr = this_segment->second.q_nr;
    jnt_p = q_in(q_nr);
    joint_pos[q_nr] = this_frame * this_segment->second.segment.getJoint().JointOrigin();
    joint_axis[q_nr] = this_frame.M * this_segment->second.segment.getJoint().JointAxis();
  }

  // do the FK:
  this_frame = this_frame * this_segment->second.segment.pose(jnt_p);
  segment_frames[segment_nr] = this_frame;
  segment_nr++;

  // get poses of child segments
  for (vector<SegmentMap::const_iterator>::const_iterator child=this_segment->second.children.begin(); child !=this_segment->second.children.end(); child++)
    segment_nr = treeRecursiveFK(q_in, joint_pos, joint_axis, segment_frames, this_frame, *child, segment_nr);
  return segment_nr;
}

void TreeFkSolverJointPosAxis::assignSegmentNumber(const SegmentMap::const_iterator this_segment)
{
  int num = segment_names_.size();
  segment_names_.push_back(this_segment->first);
  segment_name_to_index_[this_segment->first] = num;

  // add the child segments recursively
  for (vector<SegmentMap::const_iterator>::const_iterator child=this_segment->second.children.begin(); child !=this_segment->second.children.end(); child++)
  {
    assignSegmentNumber(*child);
  }
}

const std::vector<std::string> TreeFkSolverJointPosAxis::getSegmentNames() const
{
  return segment_names_;
}

const std::map<std::string, int> TreeFkSolverJointPosAxis::getSegmentNameToIndex() const
{
  return segment_name_to_index_;
}

int TreeFkSolverJointPosAxis::segmentNameToIndex(std::string name) const
{
  return segment_name_to_index_.find(name)->second;
}

} // namespace KDL