revolute_joint_model.cpp

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/* Author: Ioan Sucan */

#include <moveit/robot_model/revolute_joint_model.h>
#include <boost/math/constants/constants.hpp>
#include <limits>
#include <cmath>

robot_model::RevoluteJointModel::RevoluteJointModel(const std::string& name) : JointModel(name),
                                                                                   axis_(0.0, 0.0, 0.0), continuous_(false)
{
  type_ = REVOLUTE;
  variable_bounds_.push_back(std::make_pair(-boost::math::constants::pi<double>(), boost::math::constants::pi<double>()));
  variable_names_.push_back(name_);
}

unsigned int robot_model::RevoluteJointModel::getStateSpaceDimension() const
{
  return 1;
}

double robot_model::RevoluteJointModel::getMaximumExtent(const Bounds &other_bounds) const
{
  return other_bounds[0].second - other_bounds[0].first;
}

void robot_model::RevoluteJointModel::getVariableDefaultValues(std::vector<double> &values, const Bounds &bounds) const
{
  // if zero is a valid value
  if (bounds[0].first <= 0.0 && bounds[0].second >= 0.0)
    values.push_back(0.0);
  else
    values.push_back((bounds[0].first + bounds[0].second)/2.0);
}

void robot_model::RevoluteJointModel::getVariableRandomValues(random_numbers::RandomNumberGenerator &rng, std::vector<double> &values, const Bounds &bounds) const
{
  values.push_back(rng.uniformReal(bounds[0].first, bounds[0].second));
}

void robot_model::RevoluteJointModel::getVariableRandomValuesNearBy(random_numbers::RandomNumberGenerator &rng, std::vector<double> &values, const Bounds &bounds,
                                                                        const std::vector<double> &near, const double distance) const
{
  if (continuous_)
  {
    values.push_back(rng.uniformReal(near[values.size()] - distance, near[values.size()] + distance));
    enforceBounds(values, bounds);
  }
  else
    values.push_back(rng.uniformReal(std::max(bounds[0].first, near[values.size()] - distance),
                                     std::min(bounds[0].second, near[values.size()] + distance)));
}

void robot_model::RevoluteJointModel::interpolate(const std::vector<double> &from, const std::vector<double> &to, const double t, std::vector<double> &state) const
{
  if (continuous_)
  {
    double diff = to[0] - from[0];
    if (fabs(diff) <= boost::math::constants::pi<double>())
      state[0] = from[0] + diff * t;
    else
    {
      if (diff > 0.0)
        diff = 2.0 * boost::math::constants::pi<double>() - diff;
      else
        diff = -2.0 * boost::math::constants::pi<double>() - diff;
      state[0] = from[0] - diff * t;
      // input states are within bounds, so the following check is sufficient
      if (state[0] > boost::math::constants::pi<double>())
        state[0] -= 2.0 * boost::math::constants::pi<double>();
      else
        if (state[0] < -boost::math::constants::pi<double>())
          state[0] += 2.0 * boost::math::constants::pi<double>();
    }
  }
  else
    state[0] = from[0] + (to[0] - from[0]) * t;
}

double robot_model::RevoluteJointModel::distance(const std::vector<double> &values1, const std::vector<double> &values2) const
{
  assert(values1.size() == 1);
  assert(values2.size() == 1);
  if (continuous_)
  {
    double d = fabs(values1[0] - values2[0]);
    return (d > boost::math::constants::pi<double>()) ? 2.0 * boost::math::constants::pi<double>() - d : d;
  }
  else
    return fabs(values1[0] - values2[0]);
}

bool robot_model::RevoluteJointModel::satisfiesBounds(const std::vector<double> &values, const Bounds &bounds, double margin) const
{
  if (continuous_)
    return true;
  assert(bounds.size() > 0);
  if (values[0] < bounds[0].first - margin || values[0] > bounds[0].second + margin)
    return false;
  return true;
}

void robot_model::RevoluteJointModel::enforceBounds(std::vector<double> &values, const Bounds &bounds) const
{
  if (continuous_)
  {
    double &v = values[0];
    v = fmod(v, 2.0 * boost::math::constants::pi<double>());
    if (v < -boost::math::constants::pi<double>())
      v += 2.0 * boost::math::constants::pi<double>();
    else
      if (v > boost::math::constants::pi<double>())
        v -= 2.0 * boost::math::constants::pi<double>();
  }
  else
  {
    const std::pair<double, double> &b = bounds[0];
    if (values[0] < b.first)
      values[0] = b.first;
    else
      if (values[0] > b.second)
        values[0] = b.second;
  }
}

void robot_model::RevoluteJointModel::computeDefaultVariableLimits()
{
  JointModel::computeDefaultVariableLimits();
  if (continuous_)
    default_limits_[0].has_position_limits = false;
}

void robot_model::RevoluteJointModel::computeTransform(const std::vector<double>& joint_values, Eigen::Affine3d &transf) const
{
  updateTransform(joint_values, transf);
}

void robot_model::RevoluteJointModel::updateTransform(const std::vector<double>& joint_values, Eigen::Affine3d &transf) const
{
  transf = Eigen::Affine3d(Eigen::AngleAxisd(joint_values[0], axis_));
}

void robot_model::RevoluteJointModel::computeJointStateValues(const Eigen::Affine3d& transf, std::vector<double> &joint_values) const
{
  joint_values.resize(1);
  Eigen::Quaterniond q(transf.rotation());
  q.normalize();
  joint_values[0] = acos(q.w())*2.0f;
}