goal_position.cpp

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#include "constrained_ik/constrained_ik.h"
#include "constrained_ik/constraints/goal_position.h"
#include <ros/assert.h>
#include <pluginlib/class_list_macros.h>
PLUGINLIB_EXPORT_CLASS(constrained_ik::constraints::GoalPosition, constrained_ik::Constraint)

const double DEFAULT_POSITION_TOLERANCE = 0.001; 
namespace constrained_ik
{
namespace constraints
{

using namespace Eigen;

// initialize limits/tolerances to default values
GoalPosition::GoalPosition() : Constraint(), pos_err_tol_(DEFAULT_POSITION_TOLERANCE), weight_(Vector3d::Ones())
{
}

constrained_ik::ConstraintResults GoalPosition::evalConstraint(const SolverState &state) const
{
  constrained_ik::ConstraintResults output;
  GoalPosition::GoalPositionData cdata(state);

  output.error = calcError(cdata);
  output.jacobian = calcJacobian(cdata);
  output.status = checkStatus(cdata);

  return output;
}

Eigen::VectorXd GoalPosition::calcError(const GoalPosition::GoalPositionData &cdata) const
{
  Vector3d goalPos = cdata.state_.goal.translation();
  Vector3d estPos  = cdata.state_.pose_estimate.translation();
  Vector3d err = (goalPos - estPos).cwiseProduct(weight_);

  ROS_ASSERT( err.rows() == 3 );
  return err;
}

// translate cartesian errors into joint-space errors
Eigen::MatrixXd GoalPosition::calcJacobian(const GoalPosition::GoalPositionData &cdata) const
{
  MatrixXd tmpJ;
  if (!ik_->getKin().calcJacobian(cdata.state_.joints, tmpJ))
    throw std::runtime_error("Failed to calculate Jacobian");
  MatrixXd  J = tmpJ.topRows(3);

  // weight each row of J
  for (size_t ii=0; ii<3; ++ii)
      J.row(ii) *= weight_(ii);

  ROS_ASSERT( J.rows() == 3);
  return J;
}

double GoalPosition::calcDistance(const Eigen::Affine3d &p1, const Eigen::Affine3d &p2)
{
  return (p2.translation() - p1.translation()).norm();
}

bool GoalPosition::checkStatus(const GoalPosition::GoalPositionData &cdata) const
{
  // check to see if we've reached the goal position
  if (cdata.pos_err_ < pos_err_tol_)
    return true;

  return false;
}

void GoalPosition::loadParameters(const XmlRpc::XmlRpcValue &constraint_xml)
{
  XmlRpc::XmlRpcValue local_xml = constraint_xml;
  double pos_tol;
  if (getParam(local_xml, "position_tolerance", pos_tol))
  {
    setTolerance(pos_tol);
  }
  else
  {
    ROS_WARN("Goal Position: Unable to retrieve position_tolerance member, default parameter will be used.");
  }

  Eigen::VectorXd weights;
  if (getParam(local_xml, "weights", weights))
  {
    if (weights.size() == 3)
    {
      setWeight(weights);
    }
    else
    {
      ROS_WARN("Gool Position: Unable to add weights member, value must be a array of size 3.");
    }
  }
  else
  {
    ROS_WARN("Gool Position: Unable to retrieve weights member, default parameter will be used.");
  }

  bool debug;
  if (getParam(local_xml, "debug", debug))
  {
    setDebug(debug);
  }
  else
  {
    ROS_WARN("Goal Position: Unable to retrieve debug member, default parameter will be used.");
  }
}

GoalPosition::GoalPositionData::GoalPositionData(const SolverState &state): ConstraintData(state)
{
  pos_err_ = calcDistance(state.goal, state.pose_estimate);
}

} // namespace constraints
} // namespace constrained_ik