robot_trajectory.cpp

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/* Author: Ioan Sucan, Adam Leeper */

#include <moveit/robot_trajectory/robot_trajectory.h>
#include <moveit/robot_state/conversions.h>
#include <eigen_conversions/eigen_msg.h>
#include <boost/math/constants/constants.hpp>
#include <numeric>

namespace robot_trajectory
{
RobotTrajectory::RobotTrajectory(const robot_model::RobotModelConstPtr& robot_model, const std::string& group)
  : robot_model_(robot_model), group_(group.empty() ? nullptr : robot_model->getJointModelGroup(group))
{
}

RobotTrajectory::RobotTrajectory(const robot_model::RobotModelConstPtr& robot_model,
                                 const robot_model::JointModelGroup* group)
  : robot_model_(robot_model), group_(group)
{
}

void RobotTrajectory::setGroupName(const std::string& group_name)
{
  group_ = robot_model_->getJointModelGroup(group_name);
}

const std::string& RobotTrajectory::getGroupName() const
{
  if (group_)
    return group_->getName();
  static const std::string empty;
  return empty;
}

double RobotTrajectory::getAverageSegmentDuration() const
{
  if (duration_from_previous_.empty())
    return 0.0;
  else
    return std::accumulate(duration_from_previous_.begin(), duration_from_previous_.end(), 0.0) /
           (double)duration_from_previous_.size();
}

void RobotTrajectory::swap(RobotTrajectory& other)
{
  robot_model_.swap(other.robot_model_);
  std::swap(group_, other.group_);
  waypoints_.swap(other.waypoints_);
  duration_from_previous_.swap(other.duration_from_previous_);
}

void RobotTrajectory::append(const RobotTrajectory& source, double dt, size_t start_index, size_t end_index)
{
  end_index = std::min(end_index, source.waypoints_.size());
  if (start_index >= end_index)
    return;
  waypoints_.insert(waypoints_.end(), std::next(source.waypoints_.begin(), start_index),
                    std::next(source.waypoints_.begin(), end_index));
  std::size_t index = duration_from_previous_.size();
  duration_from_previous_.insert(duration_from_previous_.end(),
                                 std::next(source.duration_from_previous_.begin(), start_index),
                                 std::next(source.duration_from_previous_.begin(), end_index));
  if (duration_from_previous_.size() > index)
    duration_from_previous_[index] += dt;
}

void RobotTrajectory::reverse()
{
  std::reverse(waypoints_.begin(), waypoints_.end());
  for (robot_state::RobotStatePtr& waypoint : waypoints_)
  {
    // reversing the trajectory implies inverting the velocity profile
    waypoint->invertVelocity();
  }
  if (!duration_from_previous_.empty())
  {
    duration_from_previous_.push_back(duration_from_previous_.front());
    std::reverse(duration_from_previous_.begin(), duration_from_previous_.end());
    duration_from_previous_.pop_back();
  }
}

void RobotTrajectory::unwind()
{
  if (waypoints_.empty())
    return;

  const std::vector<const robot_model::JointModel*>& cont_joints =
      group_ ? group_->getContinuousJointModels() : robot_model_->getContinuousJointModels();

  for (std::size_t i = 0; i < cont_joints.size(); ++i)
  {
    // unwrap continuous joints
    double running_offset = 0.0;
    double last_value = waypoints_[0]->getJointPositions(cont_joints[i])[0];

    for (std::size_t j = 1; j < waypoints_.size(); ++j)
    {
      double current_value = waypoints_[j]->getJointPositions(cont_joints[i])[0];
      if (last_value > current_value + boost::math::constants::pi<double>())
        running_offset += 2.0 * boost::math::constants::pi<double>();
      else if (current_value > last_value + boost::math::constants::pi<double>())
        running_offset -= 2.0 * boost::math::constants::pi<double>();

      last_value = current_value;
      if (running_offset > std::numeric_limits<double>::epsilon() ||
          running_offset < -std::numeric_limits<double>::epsilon())
      {
        current_value += running_offset;
        waypoints_[j]->setJointPositions(cont_joints[i], &current_value);
      }
    }
  }
  for (std::size_t j = 0; j < waypoints_.size(); ++j)
    waypoints_[j]->update();
}

void RobotTrajectory::unwind(const robot_state::RobotState& state)
{
  if (waypoints_.empty())
    return;

  const std::vector<const robot_model::JointModel*>& cont_joints =
      group_ ? group_->getContinuousJointModels() : robot_model_->getContinuousJointModels();

  for (std::size_t i = 0; i < cont_joints.size(); ++i)
  {
    double reference_value0 = state.getJointPositions(cont_joints[i])[0];
    double reference_value = reference_value0;
    cont_joints[i]->enforcePositionBounds(&reference_value);

    // unwrap continuous joints
    double running_offset = reference_value0 - reference_value;

    double last_value = waypoints_[0]->getJointPositions(cont_joints[i])[0];
    if (running_offset > std::numeric_limits<double>::epsilon() ||
        running_offset < -std::numeric_limits<double>::epsilon())
    {
      double current_value = last_value + running_offset;
      waypoints_[0]->setJointPositions(cont_joints[i], &current_value);
    }

    for (std::size_t j = 1; j < waypoints_.size(); ++j)
    {
      double current_value = waypoints_[j]->getJointPositions(cont_joints[i])[0];
      if (last_value > current_value + boost::math::constants::pi<double>())
        running_offset += 2.0 * boost::math::constants::pi<double>();
      else if (current_value > last_value + boost::math::constants::pi<double>())
        running_offset -= 2.0 * boost::math::constants::pi<double>();

      last_value = current_value;
      if (running_offset > std::numeric_limits<double>::epsilon() ||
          running_offset < -std::numeric_limits<double>::epsilon())
      {
        current_value += running_offset;
        waypoints_[j]->setJointPositions(cont_joints[i], &current_value);
      }
    }
  }
  for (std::size_t j = 0; j < waypoints_.size(); ++j)
    waypoints_[j]->update();
}

void RobotTrajectory::clear()
{
  waypoints_.clear();
  duration_from_previous_.clear();
}

void RobotTrajectory::getRobotTrajectoryMsg(moveit_msgs::RobotTrajectory& trajectory) const
{
  trajectory = moveit_msgs::RobotTrajectory();
  if (waypoints_.empty())
    return;
  const std::vector<const robot_model::JointModel*>& jnt =
      group_ ? group_->getActiveJointModels() : robot_model_->getActiveJointModels();

  std::vector<const robot_model::JointModel*> onedof;
  std::vector<const robot_model::JointModel*> mdof;
  trajectory.joint_trajectory.joint_names.clear();
  trajectory.multi_dof_joint_trajectory.joint_names.clear();

  for (std::size_t i = 0; i < jnt.size(); ++i)
    if (jnt[i]->getVariableCount() == 1)
    {
      trajectory.joint_trajectory.joint_names.push_back(jnt[i]->getName());
      onedof.push_back(jnt[i]);
    }
    else
    {
      trajectory.multi_dof_joint_trajectory.joint_names.push_back(jnt[i]->getName());
      mdof.push_back(jnt[i]);
    }
  if (!onedof.empty())
  {
    trajectory.joint_trajectory.header.frame_id = robot_model_->getModelFrame();
    trajectory.joint_trajectory.header.stamp = ros::Time(0);
    trajectory.joint_trajectory.points.resize(waypoints_.size());
  }

  if (!mdof.empty())
  {
    trajectory.multi_dof_joint_trajectory.header.frame_id = robot_model_->getModelFrame();
    trajectory.multi_dof_joint_trajectory.header.stamp = ros::Time(0);
    trajectory.multi_dof_joint_trajectory.points.resize(waypoints_.size());
  }

  static const ros::Duration zero_duration(0.0);
  double total_time = 0.0;
  for (std::size_t i = 0; i < waypoints_.size(); ++i)
  {
    if (duration_from_previous_.size() > i)
      total_time += duration_from_previous_[i];

    if (!onedof.empty())
    {
      trajectory.joint_trajectory.points[i].positions.resize(onedof.size());
      trajectory.joint_trajectory.points[i].velocities.reserve(onedof.size());

      for (std::size_t j = 0; j < onedof.size(); ++j)
      {
        trajectory.joint_trajectory.points[i].positions[j] =
            waypoints_[i]->getVariablePosition(onedof[j]->getFirstVariableIndex());
        // if we have velocities/accelerations/effort, copy those too
        if (waypoints_[i]->hasVelocities())
          trajectory.joint_trajectory.points[i].velocities.push_back(
              waypoints_[i]->getVariableVelocity(onedof[j]->getFirstVariableIndex()));
        if (waypoints_[i]->hasAccelerations())
          trajectory.joint_trajectory.points[i].accelerations.push_back(
              waypoints_[i]->getVariableAcceleration(onedof[j]->getFirstVariableIndex()));
        if (waypoints_[i]->hasEffort())
          trajectory.joint_trajectory.points[i].effort.push_back(
              waypoints_[i]->getVariableEffort(onedof[j]->getFirstVariableIndex()));
      }
      // clear velocities if we have an incomplete specification
      if (trajectory.joint_trajectory.points[i].velocities.size() != onedof.size())
        trajectory.joint_trajectory.points[i].velocities.clear();
      // clear accelerations if we have an incomplete specification
      if (trajectory.joint_trajectory.points[i].accelerations.size() != onedof.size())
        trajectory.joint_trajectory.points[i].accelerations.clear();
      // clear effort if we have an incomplete specification
      if (trajectory.joint_trajectory.points[i].effort.size() != onedof.size())
        trajectory.joint_trajectory.points[i].effort.clear();

      if (duration_from_previous_.size() > i)
        trajectory.joint_trajectory.points[i].time_from_start = ros::Duration(total_time);
      else
        trajectory.joint_trajectory.points[i].time_from_start = zero_duration;
    }
    if (!mdof.empty())
    {
      trajectory.multi_dof_joint_trajectory.points[i].transforms.resize(mdof.size());
      for (std::size_t j = 0; j < mdof.size(); ++j)
      {
        tf::transformEigenToMsg(waypoints_[i]->getJointTransform(mdof[j]),
                                trajectory.multi_dof_joint_trajectory.points[i].transforms[j]);
        // TODO: currently only checking for planar multi DOF joints / need to add check for floating
        if (waypoints_[i]->hasVelocities() && (mdof[j]->getType() == robot_model::JointModel::JointType::PLANAR))
        {
          const std::vector<std::string> names = mdof[j]->getVariableNames();
          const double* velocities = waypoints_[i]->getJointVelocities(mdof[j]);

          geometry_msgs::Twist point_velocity;

          for (std::size_t k = 0; k < names.size(); ++k)
          {
            if (names[k].find("/x") != std::string::npos)
            {
              point_velocity.linear.x = velocities[k];
            }
            else if (names[k].find("/y") != std::string::npos)
            {
              point_velocity.linear.y = velocities[k];
            }
            else if (names[k].find("/z") != std::string::npos)
            {
              point_velocity.linear.z = velocities[k];
            }
            else if (names[k].find("/theta") != std::string::npos)
            {
              point_velocity.angular.z = velocities[k];
            }
          }
          trajectory.multi_dof_joint_trajectory.points[i].velocities.push_back(point_velocity);
        }
      }
      if (duration_from_previous_.size() > i)
        trajectory.multi_dof_joint_trajectory.points[i].time_from_start = ros::Duration(total_time);
      else
        trajectory.multi_dof_joint_trajectory.points[i].time_from_start = zero_duration;
    }
  }
}

void RobotTrajectory::setRobotTrajectoryMsg(const robot_state::RobotState& reference_state,
                                            const trajectory_msgs::JointTrajectory& trajectory)
{
  // make a copy just in case the next clear() removes the memory for the reference passed in
  robot_state::RobotState copy = reference_state;
  clear();
  std::size_t state_count = trajectory.points.size();
  ros::Time last_time_stamp = trajectory.header.stamp;
  ros::Time this_time_stamp = last_time_stamp;

  for (std::size_t i = 0; i < state_count; ++i)
  {
    this_time_stamp = trajectory.header.stamp + trajectory.points[i].time_from_start;
    robot_state::RobotStatePtr st(new robot_state::RobotState(copy));
    st->setVariablePositions(trajectory.joint_names, trajectory.points[i].positions);
    if (!trajectory.points[i].velocities.empty())
      st->setVariableVelocities(trajectory.joint_names, trajectory.points[i].velocities);
    if (!trajectory.points[i].accelerations.empty())
      st->setVariableAccelerations(trajectory.joint_names, trajectory.points[i].accelerations);
    if (!trajectory.points[i].effort.empty())
      st->setVariableEffort(trajectory.joint_names, trajectory.points[i].effort);
    addSuffixWayPoint(st, (this_time_stamp - last_time_stamp).toSec());
    last_time_stamp = this_time_stamp;
  }
}

void RobotTrajectory::setRobotTrajectoryMsg(const robot_state::RobotState& reference_state,
                                            const moveit_msgs::RobotTrajectory& trajectory)
{
  // make a copy just in case the next clear() removes the memory for the reference passed in
  robot_state::RobotState copy = reference_state;
  clear();

  std::size_t state_count =
      std::max(trajectory.joint_trajectory.points.size(), trajectory.multi_dof_joint_trajectory.points.size());
  ros::Time last_time_stamp = trajectory.joint_trajectory.points.empty() ?
                                  trajectory.multi_dof_joint_trajectory.header.stamp :
                                  trajectory.joint_trajectory.header.stamp;
  ros::Time this_time_stamp = last_time_stamp;

  for (std::size_t i = 0; i < state_count; ++i)
  {
    robot_state::RobotStatePtr st(new robot_state::RobotState(copy));
    if (trajectory.joint_trajectory.points.size() > i)
    {
      st->setVariablePositions(trajectory.joint_trajectory.joint_names,
                               trajectory.joint_trajectory.points[i].positions);
      if (!trajectory.joint_trajectory.points[i].velocities.empty())
        st->setVariableVelocities(trajectory.joint_trajectory.joint_names,
                                  trajectory.joint_trajectory.points[i].velocities);
      if (!trajectory.joint_trajectory.points[i].accelerations.empty())
        st->setVariableAccelerations(trajectory.joint_trajectory.joint_names,
                                     trajectory.joint_trajectory.points[i].accelerations);
      if (!trajectory.joint_trajectory.points[i].effort.empty())
        st->setVariableEffort(trajectory.joint_trajectory.joint_names, trajectory.joint_trajectory.points[i].effort);
      this_time_stamp =
          trajectory.joint_trajectory.header.stamp + trajectory.joint_trajectory.points[i].time_from_start;
    }
    if (trajectory.multi_dof_joint_trajectory.points.size() > i)
    {
      for (std::size_t j = 0; j < trajectory.multi_dof_joint_trajectory.joint_names.size(); ++j)
      {
        Eigen::Affine3d t;
        tf::transformMsgToEigen(trajectory.multi_dof_joint_trajectory.points[i].transforms[j], t);
        st->setJointPositions(trajectory.multi_dof_joint_trajectory.joint_names[j], t);
      }
      this_time_stamp = trajectory.multi_dof_joint_trajectory.header.stamp +
                        trajectory.multi_dof_joint_trajectory.points[i].time_from_start;
    }

    addSuffixWayPoint(st, (this_time_stamp - last_time_stamp).toSec());
    last_time_stamp = this_time_stamp;
  }
}

void RobotTrajectory::setRobotTrajectoryMsg(const robot_state::RobotState& reference_state,
                                            const moveit_msgs::RobotState& state,
                                            const moveit_msgs::RobotTrajectory& trajectory)
{
  robot_state::RobotState st(reference_state);
  robot_state::robotStateMsgToRobotState(state, st);
  setRobotTrajectoryMsg(st, trajectory);
}

void RobotTrajectory::findWayPointIndicesForDurationAfterStart(const double& duration, int& before, int& after,
                                                               double& blend) const
{
  if (duration < 0.0)
  {
    before = 0;
    after = 0;
    blend = 0;
    return;
  }

  // Find indicies
  std::size_t index = 0, num_points = waypoints_.size();
  double running_duration = 0.0;
  for (; index < num_points; ++index)
  {
    running_duration += duration_from_previous_[index];
    if (running_duration >= duration)
      break;
  }
  before = std::max<int>(index - 1, 0);
  after = std::min<int>(index, num_points - 1);

  // Compute duration blend
  double before_time = running_duration - duration_from_previous_[index];
  if (after == before)
    blend = 1.0;
  else
    blend = (duration - before_time) / duration_from_previous_[index];
}

double RobotTrajectory::getWayPointDurationFromStart(std::size_t index) const
{
  if (duration_from_previous_.empty())
    return 0.0;
  if (index >= duration_from_previous_.size())
    index = duration_from_previous_.size() - 1;

  double time = 0.0;
  for (std::size_t i = 0; i <= index; ++i)
    time += duration_from_previous_[i];
  return time;
}

double RobotTrajectory::getWaypointDurationFromStart(std::size_t index) const
{
  return getWayPointDurationFromStart(index);
}

bool RobotTrajectory::getStateAtDurationFromStart(const double request_duration,
                                                  robot_state::RobotStatePtr& output_state) const
{
  // If there are no waypoints we can't do anything
  if (getWayPointCount() == 0)
    return false;

  int before = 0, after = 0;
  double blend = 1.0;
  findWayPointIndicesForDurationAfterStart(request_duration, before, after, blend);
  // ROS_DEBUG_NAMED("robot_trajectory", "Interpolating %.3f of the way between index %d and %d.", blend, before,
  // after);
  waypoints_[before]->interpolate(*waypoints_[after], blend, *output_state);
  return true;
}

}  // end of namespace robot_trajectory