init_joint_trajectory.h

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// Copyright (C) 2013, PAL Robotics S.L.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
//   * Neither the name of PAL Robotics S.L. nor the names of its
//     contributors may be used to endorse or promote products derived from
//     this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// POSSIBILITY OF SUCH DAMAGE.


#ifndef JOINT_TRAJECTORY_CONTROLLER_INIT_JOINT_TRAJECTORY_H
#define JOINT_TRAJECTORY_CONTROLLER_INIT_JOINT_TRAJECTORY_H

// C++ standard
#include <algorithm>
#include <iomanip>
#include <sstream>
#include <stdexcept>
#include <vector>

// Boost
#include <boost/shared_ptr.hpp>

// ROS messages
#include <control_msgs/FollowJointTrajectoryAction.h>
#include <trajectory_msgs/JointTrajectoryPoint.h>

// ros_controls
#include <realtime_tools/realtime_server_goal_handle.h>

// Project
#include <joint_trajectory_controller/joint_trajectory_msg_utils.h>
#include <joint_trajectory_controller/joint_trajectory_segment.h>

namespace joint_trajectory_controller
{

namespace internal
{
template <class T>
inline std::vector<unsigned int> mapping(const T& t1, const T& t2)
{
  typedef unsigned int SizeType;

  // t1 must be a subset of t2
  if (t1.size() > t2.size()) {return std::vector<SizeType>();}

  std::vector<SizeType> mapping_vector(t1.size()); // Return value
  for (typename T::const_iterator t1_it = t1.begin(); t1_it != t1.end(); ++t1_it)
  {
    typename T::const_iterator t2_it = std::find(t2.begin(), t2.end(), *t1_it);
    if (t2.end() == t2_it) {return std::vector<SizeType>();}
    else
    {
      const SizeType t1_dist = std::distance(t1.begin(), t1_it);
      const SizeType t2_dist = std::distance(t2.begin(), t2_it);
      mapping_vector[t1_dist] = t2_dist;
    }
  }
  return mapping_vector;
}

} // namespace

template <class Trajectory>
struct InitJointTrajectoryOptions
{
  typedef realtime_tools::RealtimeServerGoalHandle<control_msgs::FollowJointTrajectoryAction> RealtimeGoalHandle;
  typedef boost::shared_ptr<RealtimeGoalHandle>                                               RealtimeGoalHandlePtr;
  typedef typename Trajectory::value_type                                                     TrajectoryPerJoint;
  typedef typename TrajectoryPerJoint::value_type                                             Segment;
  typedef typename Segment::Scalar                                                            Scalar;

  InitJointTrajectoryOptions()
    : current_trajectory(0),
      joint_names(0),
      angle_wraparound(0),
      rt_goal_handle(),
      default_tolerances(0),
      other_time_base(0),
      allow_partial_joints_goal(false),
      error_string(0)
  {}

  Trajectory*                current_trajectory;
  std::vector<std::string>*  joint_names;
  std::vector<bool>*         angle_wraparound;
  RealtimeGoalHandlePtr      rt_goal_handle;
  SegmentTolerances<Scalar>* default_tolerances;
  ros::Time*                 other_time_base;
  bool                       allow_partial_joints_goal;
  std::string*               error_string;

  void setErrorString(const std::string &msg) const
  {
    if(error_string)
    {
      *error_string = msg;
    }
  }
};

template <class Trajectory>
bool isNotEmpty(typename Trajectory::value_type trajPerJoint)
{
  return !trajPerJoint.empty();
};

// TODO: Return useful bits of current trajectory if input msg is useless?
template <class Trajectory>
Trajectory initJointTrajectory(const trajectory_msgs::JointTrajectory&       msg,
                               const ros::Time&                              time,
                               const InitJointTrajectoryOptions<Trajectory>& options =
                               InitJointTrajectoryOptions<Trajectory>())
{
  typedef typename Trajectory::value_type TrajectoryPerJoint;
  typedef typename TrajectoryPerJoint::value_type Segment;
  typedef typename Segment::Scalar Scalar;
  typedef typename TrajectoryPerJoint::const_iterator TrajIter;

  const unsigned int n_joints = msg.joint_names.size();

  const ros::Time msg_start_time = internal::startTime(msg, time); // Message start time

  ROS_DEBUG_STREAM("Figuring out new trajectory starting at time "
                   << std::fixed << std::setprecision(3) << msg_start_time.toSec());

  std::string error_string;

  // Empty trajectory
  if (msg.points.empty())
  {
    error_string = "Trajectory message contains empty trajectory. Nothing to convert.";
    ROS_DEBUG_STREAM(error_string);
    options.setErrorString(error_string);
    return Trajectory();
  }

  // Non strictly-monotonic waypoints
  if (!isTimeStrictlyIncreasing(msg))
  {
    error_string = "Trajectory message contains waypoints that are not strictly increasing in time.";
    ROS_ERROR_STREAM(error_string);
    options.setErrorString(error_string);
    return Trajectory();
  }

  // Validate options
  const bool has_current_trajectory = options.current_trajectory && !options.current_trajectory->empty();
  const bool has_joint_names        = options.joint_names        && !options.joint_names->empty();
  const bool has_angle_wraparound   = options.angle_wraparound   && !options.angle_wraparound->empty();
  const bool has_rt_goal_handle     = options.rt_goal_handle != NULL;
  const bool has_other_time_base    = options.other_time_base != NULL;
  const bool has_default_tolerances = options.default_tolerances != NULL;

  if (!has_current_trajectory && has_angle_wraparound)
  {
    ROS_WARN("Vector specifying whether joints wrap around will not be used because no current trajectory was given.");
  }

  // Compute trajectory start time and data extraction time associated to the 'other' time base, if it applies
  // The o_ prefix indicates that time values are represented in this 'other' time base.
  ros::Time o_time;
  ros::Time o_msg_start_time;
  if (has_other_time_base)
  {
    ros::Duration msg_start_duration = msg_start_time - time;
    o_time = *options.other_time_base;
    o_msg_start_time = o_time + msg_start_duration;
    ROS_DEBUG_STREAM("Using alternate time base. In it, the new trajectory starts at time "
                     << std::fixed << std::setprecision(3) << o_msg_start_time.toSec());
  }
  else
  {
    o_time = time;
    o_msg_start_time = msg_start_time;
  }

  const std::vector<std::string> joint_names = has_joint_names ? *(options.joint_names) : msg.joint_names;

  if (has_angle_wraparound)
  {
    // Preconditions
    const unsigned int n_angle_wraparound = options.angle_wraparound->size();
    if (n_angle_wraparound != joint_names.size())
    {
      error_string = "Cannot create trajectory from message. "
                "Vector specifying whether joints wrap around has an invalid size.";
      ROS_ERROR_STREAM(error_string);
      options.setErrorString(error_string);
      return Trajectory();
    }
  }

  // If partial joints goals are not allowed, goal should specify all controller joints
  if (!options.allow_partial_joints_goal)
  {
    if (msg.joint_names.size() != joint_names.size())
    {
      error_string = "Cannot create trajectory from message. It does not contain the expected joints.";
      ROS_ERROR_STREAM(error_string);
      options.setErrorString(error_string);
      return Trajectory();
    }
  }

  // Mapping vector contains the map between the message joint order and the expected joint order
  // If unspecified, a trivial map is computed
  std::vector<unsigned int> mapping_vector = internal::mapping(msg.joint_names,joint_names);

  if (mapping_vector.empty())
  {
    error_string = "Cannot create trajectory from message. It does not contain the expected joints.";
    ROS_ERROR_STREAM(error_string);
    options.setErrorString(error_string);
    return Trajectory();
  }

  // Tolerances to be used in all new segments
  SegmentTolerances<Scalar> tolerances = has_default_tolerances ?
                                         *(options.default_tolerances) : SegmentTolerances<Scalar>(n_joints);

  if (has_rt_goal_handle && options.rt_goal_handle->gh_.getGoal())
  {
    updateSegmentTolerances<Scalar>(*(options.rt_goal_handle->gh_.getGoal()), joint_names, tolerances);
  }

  // Find first point of new trajectory occurring after current time
  // This point is used later on in this function, but is computed here, in advance because if the trajectory message
  // contains a trajectory in the past, we can quickly return without spending additional computational resources
  std::vector<trajectory_msgs::JointTrajectoryPoint>::const_iterator
  msg_it = findPoint(msg, time); // Points to last point occurring before current time (NOTE: Using time, not o_time)
  if (msg_it == msg.points.end())
  {
    msg_it = msg.points.begin();  // Entire trajectory is after current time
  }
  else
  {
    ++msg_it;                     // Points to first point after current time OR sequence end
    if (msg_it == msg.points.end())
    {
      ros::Duration last_point_dur = time - (msg_start_time + (--msg_it)->time_from_start);
      std::stringstream error_stringstream;
      error_stringstream << "Dropping all " << msg.points.size();
      error_stringstream << " trajectory point(s), as they occur before the current time.\n";
      error_stringstream << "Last point is " << last_point_dur.toSec();
      error_stringstream << "s in the past.";

      error_string = error_stringstream.str();
      ROS_WARN_STREAM(error_string);
      options.setErrorString(error_string);
      return Trajectory();
    }
    else if ( // If the first point is at time zero and no start time is set in the header, skip it silently
              msg.points.begin()->time_from_start.isZero() &&
              msg.header.stamp.isZero() &&
              std::distance(msg.points.begin(), msg_it) == 1
              )
    {
      ROS_DEBUG_STREAM("Dropping first trajectory point at time=0. " <<
                       "First valid point will be reached at time_from_start " <<
                       std::fixed << std::setprecision(3) << msg_it->time_from_start.toSec() << "s.");
    }
    else
    {
      ros::Duration next_point_dur = msg_start_time + msg_it->time_from_start - time;
      ROS_WARN_STREAM("Dropping first " << std::distance(msg.points.begin(), msg_it) <<
                      " trajectory point(s) out of " << msg.points.size() <<
                      ", as they occur before the current time.\n" <<
                      "First valid point will be reached in " << std::fixed << std::setprecision(3) <<
                      next_point_dur.toSec() << "s.");
    }
  }

  // Initialize result trajectory: combination of:
  // - Useful segments of currently followed trajectory
  // - Useful segments of new trajectory (contained in ROS message)
  Trajectory result_traj; // Currently empty

  // Set active goal to segments after current time
  if (has_current_trajectory)
  {
    result_traj = *(options.current_trajectory);

    //Iterate to all segments after current time to set the new goal handler
    for (unsigned int joint_id=0; joint_id < joint_names.size();joint_id++)
    {
      const TrajectoryPerJoint& curr_joint_traj = result_traj[joint_id];
      TrajIter active_seg = findSegment(curr_joint_traj, o_time.toSec());   // Currently active segment

      while (std::distance(active_seg, curr_joint_traj.end())>=1)
      {
        (result_traj[joint_id])[std::distance(curr_joint_traj.begin(),active_seg)].setGoalHandle(options.rt_goal_handle);
        ++active_seg;
      }
    }
  }
  else
    result_traj.resize(joint_names.size());

  //Iterate through the joints that are in the message, in the order of the mapping vector
  //for (unsigned int joint_id=0; joint_id < joint_names.size();joint_id++)
  for (unsigned int msg_joint_it=0; msg_joint_it < mapping_vector.size();msg_joint_it++)
  {
    std::vector<trajectory_msgs::JointTrajectoryPoint>::const_iterator it = msg_it;
    if (!isValid(*it, it->positions.size()))
      throw(std::invalid_argument("Size mismatch in trajectory point position, velocity or acceleration data."));

    TrajectoryPerJoint result_traj_per_joint; // Currently empty
    unsigned int joint_id = mapping_vector[msg_joint_it];

    // Initialize offsets due to wrapping joints to zero
    std::vector<Scalar> position_offset(1, 0.0);

    //Initialize segment tolerance per joint
    SegmentTolerancesPerJoint<Scalar> tolerances_per_joint;
    tolerances_per_joint.state_tolerance = tolerances.state_tolerance[joint_id];
    tolerances_per_joint.goal_state_tolerance = tolerances.goal_state_tolerance[joint_id];
    tolerances_per_joint.goal_time_tolerance = tolerances.goal_time_tolerance;

    // Bridge current trajectory to new one
    if (has_current_trajectory)
    {
      const TrajectoryPerJoint& curr_joint_traj = (*options.current_trajectory)[joint_id];

      // Get the last time and state that will be executed from the current trajectory
      const typename Segment::Time last_curr_time = std::max(o_msg_start_time.toSec(), o_time.toSec()); // Important!
      typename Segment::State last_curr_state;
      sample(curr_joint_traj, last_curr_time, last_curr_state);

      // Get the first time and state that will be executed from the new trajectory
      trajectory_msgs::JointTrajectoryPoint point_per_joint;
      if (!it->positions.empty())     {point_per_joint.positions.resize(1, it->positions[msg_joint_it]);}
      if (!it->velocities.empty())    {point_per_joint.velocities.resize(1, it->velocities[msg_joint_it]);}
      if (!it->accelerations.empty()) {point_per_joint.accelerations.resize(1, it->accelerations[msg_joint_it]);}
      point_per_joint.time_from_start = it->time_from_start;

      const typename Segment::Time first_new_time = o_msg_start_time.toSec() + (it->time_from_start).toSec();
      typename Segment::State first_new_state(point_per_joint); // Here offsets are not yet applied

      // Compute offsets due to wrapping joints
      if (has_angle_wraparound)
      {
        position_offset[0] = wraparoundJointOffset(last_curr_state.position[0],
                                                first_new_state.position[0],
                                                (*options.angle_wraparound)[joint_id]);
      }

      // Apply offset to first state that will be executed from the new trajectory
      first_new_state = typename Segment::State(point_per_joint, position_offset); // Now offsets are applied

      // Add useful segments of current trajectory to result
      {
        TrajIter first = findSegment(curr_joint_traj, o_time.toSec());   // Currently active segment
        TrajIter last  = findSegment(curr_joint_traj, last_curr_time); // Segment active when new trajectory starts
        if (first == curr_joint_traj.end() || last == curr_joint_traj.end())
        {
          error_string = "Unexpected error: Could not find segments in current trajectory. Please contact the package maintainer.";
          ROS_ERROR_STREAM(error_string);
          options.setErrorString(error_string);
          return Trajectory();
        }
        result_traj_per_joint.insert(result_traj_per_joint.begin(), first, ++last); // Range [first,last) will still be executed
      }

      // Add segment bridging current and new trajectories to result
      Segment bridge_seg(last_curr_time, last_curr_state,
                         first_new_time, first_new_state);
      bridge_seg.setGoalHandle(options.rt_goal_handle);
      if (has_rt_goal_handle) {bridge_seg.setTolerances(tolerances_per_joint);}
      result_traj_per_joint.push_back(bridge_seg);
    }

    // Constants used in log statement at the end
    const unsigned int num_old_segments = result_traj_per_joint.size() -1;
    const unsigned int num_new_segments = std::distance(it, msg.points.end()) -1;

    // Add useful segments of new trajectory to result
    // - Construct all trajectory segments occurring after current time
    // - As long as there remain two trajectory points we can construct the next trajectory segment
    while (std::distance(it, msg.points.end()) >= 2)
    {
      std::vector<trajectory_msgs::JointTrajectoryPoint>::const_iterator next_it = it; ++next_it;

      trajectory_msgs::JointTrajectoryPoint it_point_per_joint, next_it_point_per_joint;

      if (!isValid(*it, it->positions.size()))
            throw(std::invalid_argument("Size mismatch in trajectory point position, velocity or acceleration data."));
      if (!it->positions.empty())     {it_point_per_joint.positions.resize(1, it->positions[msg_joint_it]);}
      if (!it->velocities.empty())    {it_point_per_joint.velocities.resize(1, it->velocities[msg_joint_it]);}
      if (!it->accelerations.empty()) {it_point_per_joint.accelerations.resize(1, it->accelerations[msg_joint_it]);}
      it_point_per_joint.time_from_start = it->time_from_start;

      if (!isValid(*next_it, next_it->positions.size()))
            throw(std::invalid_argument("Size mismatch in trajectory point position, velocity or acceleration data."));
      if (!next_it->positions.empty()) {next_it_point_per_joint.positions.resize(1, next_it->positions[msg_joint_it]);}
      if (!next_it->velocities.empty()) {next_it_point_per_joint.velocities.resize(1, next_it->velocities[msg_joint_it]);}
      if (!next_it->accelerations.empty()) {next_it_point_per_joint.accelerations.resize(1, next_it->accelerations[msg_joint_it]);}
      next_it_point_per_joint.time_from_start = next_it->time_from_start;

      Segment segment(o_msg_start_time, it_point_per_joint, next_it_point_per_joint, position_offset);
      segment.setGoalHandle(options.rt_goal_handle);
      if (has_rt_goal_handle) {segment.setTolerances(tolerances_per_joint);}
      result_traj_per_joint.push_back(segment);
      ++it;
    }

    // Useful debug info
    std::stringstream log_str;
    log_str << "Trajectory of joint " << joint_names[joint_id] << "has " << result_traj_per_joint.size() << " segments";
    if (has_current_trajectory)
    {
      log_str << ":";
      log_str << "\n- " << num_old_segments << " segment(s) will still be executed from previous trajectory.";
      log_str << "\n- 1 segment added for transitioning between the current trajectory and first point of the input message.";
      if (num_new_segments > 0) {log_str << "\n- " << num_new_segments << " new segments (" << (num_new_segments + 1) <<
                                 " points) taken from the input trajectory.";}
    }
    else {log_str << ".";}
    ROS_DEBUG_STREAM(log_str.str());

    if (result_traj_per_joint.size() > 0)
      result_traj[joint_id] = result_traj_per_joint;
  }

  // If the trajectory for all joints is empty, empty the trajectory vector
  typename Trajectory::const_iterator trajIter = std::find_if (result_traj.begin(), result_traj.end(), isNotEmpty<Trajectory>);
  if (trajIter == result_traj.end())
  {
    result_traj.clear();
  }

  return result_traj;
}

} // namespace

#endif // header guard