joint_trajectory_action_controller.cpp

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/*
 * Copyright (c) 2008, Willow Garage, Inc.
 * All rights reserved.
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 * 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.
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 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 */

/*
 * Author: Stuart Glaser
 */

#include "robot_mechanism_controllers/joint_trajectory_action_controller.h"
#include <sstream>
#include "angles/angles.h"
#include "pluginlib/class_list_macros.h"

PLUGINLIB_EXPORT_CLASS( controller::JointTrajectoryActionController, pr2_controller_interface::Controller)

namespace controller {

// These functions are pulled from the spline_smoother package.
// They've been moved here to avoid depending on packages that aren't
// mature yet.


static inline void generatePowers(int n, double x, double* powers)
{
  powers[0] = 1.0;
  for (int i=1; i<=n; i++)
  {
    powers[i] = powers[i-1]*x;
  }
}

static void getQuinticSplineCoefficients(double start_pos, double start_vel, double start_acc,
    double end_pos, double end_vel, double end_acc, double time, std::vector<double>& coefficients)
{
  coefficients.resize(6);

  if (time == 0.0)
  {
    coefficients[0] = end_pos;
    coefficients[1] = end_vel;
    coefficients[2] = 0.5*end_acc;
    coefficients[3] = 0.0;
    coefficients[4] = 0.0;
    coefficients[5] = 0.0;
  }
  else
  {
    double T[6];
    generatePowers(5, time, T);

    coefficients[0] = start_pos;
    coefficients[1] = start_vel;
    coefficients[2] = 0.5*start_acc;
    coefficients[3] = (-20.0*start_pos + 20.0*end_pos - 3.0*start_acc*T[2] + end_acc*T[2] -
                       12.0*start_vel*T[1] - 8.0*end_vel*T[1]) / (2.0*T[3]);
    coefficients[4] = (30.0*start_pos - 30.0*end_pos + 3.0*start_acc*T[2] - 2.0*end_acc*T[2] +
                       16.0*start_vel*T[1] + 14.0*end_vel*T[1]) / (2.0*T[4]);
    coefficients[5] = (-12.0*start_pos + 12.0*end_pos - start_acc*T[2] + end_acc*T[2] -
                       6.0*start_vel*T[1] - 6.0*end_vel*T[1]) / (2.0*T[5]);
  }
}

static void sampleQuinticSpline(const std::vector<double>& coefficients, double time,
    double& position, double& velocity, double& acceleration)
{
  // create powers of time:
  double t[6];
  generatePowers(5, time, t);

  position = t[0]*coefficients[0] +
      t[1]*coefficients[1] +
      t[2]*coefficients[2] +
      t[3]*coefficients[3] +
      t[4]*coefficients[4] +
      t[5]*coefficients[5];

  velocity = t[0]*coefficients[1] +
      2.0*t[1]*coefficients[2] +
      3.0*t[2]*coefficients[3] +
      4.0*t[3]*coefficients[4] +
      5.0*t[4]*coefficients[5];

  acceleration = 2.0*t[0]*coefficients[2] +
      6.0*t[1]*coefficients[3] +
      12.0*t[2]*coefficients[4] +
      20.0*t[3]*coefficients[5];
}

static void getCubicSplineCoefficients(double start_pos, double start_vel,
    double end_pos, double end_vel, double time, std::vector<double>& coefficients)
{
  coefficients.resize(4);

  if (time == 0.0)
  {
    coefficients[0] = end_pos;
    coefficients[1] = end_vel;
    coefficients[2] = 0.0;
    coefficients[3] = 0.0;
  }
  else
  {
    double T[4];
    generatePowers(3, time, T);

    coefficients[0] = start_pos;
    coefficients[1] = start_vel;
    coefficients[2] = (-3.0*start_pos + 3.0*end_pos - 2.0*start_vel*T[1] - end_vel*T[1]) / T[2];
    coefficients[3] = (2.0*start_pos - 2.0*end_pos + start_vel*T[1] + end_vel*T[1]) / T[3];
  }
}


JointTrajectoryActionController::JointTrajectoryActionController()
  : loop_count_(0), robot_(NULL)
{
}

JointTrajectoryActionController::~JointTrajectoryActionController()
{
  sub_command_.shutdown();
  serve_query_state_.shutdown();
  action_server_.reset();
  action_server_follow_.reset();
}

bool JointTrajectoryActionController::init(pr2_mechanism_model::RobotState *robot, ros::NodeHandle &n)
{
  using namespace XmlRpc;
  node_ = n;
  robot_ = robot;

  // Gets all of the joints
  XmlRpc::XmlRpcValue joint_names;
  if (!node_.getParam("joints", joint_names))
  {
    ROS_ERROR("No joints given. (namespace: %s)", node_.getNamespace().c_str());
    return false;
  }
  if (joint_names.getType() != XmlRpc::XmlRpcValue::TypeArray)
  {
    ROS_ERROR("Malformed joint specification.  (namespace: %s)", node_.getNamespace().c_str());
    return false;
  }
  for (int i = 0; i < joint_names.size(); ++i)
  {
    XmlRpcValue &name_value = joint_names[i];
    if (name_value.getType() != XmlRpcValue::TypeString)
    {
      ROS_ERROR("Array of joint names should contain all strings.  (namespace: %s)",
                node_.getNamespace().c_str());
      return false;
    }

    pr2_mechanism_model::JointState *j = robot->getJointState((std::string)name_value);
    if (!j) {
      ROS_ERROR("Joint not found: %s. (namespace: %s)",
                ((std::string)name_value).c_str(), node_.getNamespace().c_str());
      return false;
    }
    joints_.push_back(j);
  }

  // Ensures that all the joints are calibrated.
  for (size_t i = 0; i < joints_.size(); ++i)
  {
    if (!joints_[i]->calibrated_)
    {
      ROS_ERROR("Joint %s was not calibrated (namespace: %s)",
                joints_[i]->joint_->name.c_str(), node_.getNamespace().c_str());
      return false;
    }
  }

  // Sets up pid controllers for all of the joints
  std::string gains_ns;
  if (!node_.getParam("gains", gains_ns))
    gains_ns = node_.getNamespace() + "/gains";
  masses_.resize(joints_.size());
  pids_.resize(joints_.size());
  for (size_t i = 0; i < joints_.size(); ++i)
  {
    ros::NodeHandle joint_nh(gains_ns + "/" + joints_[i]->joint_->name);
    joint_nh.param("mass", masses_[i], 0.0);
    if (!pids_[i].init(joint_nh))
      return false;
  }

  // Sets up the proxy controllers for each joint
  proxies_enabled_.resize(joints_.size());
  proxies_.resize(joints_.size());
  for (size_t i = 0; i < joints_.size(); ++i)
  {
    ros::NodeHandle joint_nh(gains_ns + "/" + joints_[i]->joint_->name);
    if (joint_nh.hasParam("proxy")) {
      proxies_enabled_[i] = true;
      joint_nh.param("proxy/lambda", proxies_[i].lambda_proxy_, 1.0);
      joint_nh.param("proxy/acc_converge", proxies_[i].acc_converge_, 0.0);
      joint_nh.param("proxy/vel_limit", proxies_[i].vel_limit_, 0.0);
      joint_nh.param("proxy/effort_limit", proxies_[i].effort_limit_, 0.0);
      proxies_[i].mass_ = masses_[i];
      double _;
      pids_[i].getGains(proxies_[i].Kp_, proxies_[i].Ki_, proxies_[i].Kd_, proxies_[i].Ficl_, _);
    }
    else {
      proxies_enabled_[i] = false;
    }
  }

  // Trajectory and goal tolerances
  default_trajectory_tolerance_.resize(joints_.size());
  default_goal_tolerance_.resize(joints_.size());
  node_.param("joint_trajectory_action_node/constraints/goal_time", default_goal_time_constraint_, 0.0);
  double stopped_velocity_tolerance;
  node_.param("joint_trajectory_action_node/constraints/stopped_velocity_tolerance", stopped_velocity_tolerance, 0.01);
  for (size_t i = 0; i < default_goal_tolerance_.size(); ++i)
    default_goal_tolerance_[i].velocity = stopped_velocity_tolerance;
  for (size_t i = 0; i < joints_.size(); ++i)
  {
    std::string ns = std::string("joint_trajectory_action_node/constraints") + joints_[i]->joint_->name;
    node_.param(ns + "/goal", default_goal_tolerance_[i].position, 0.0);
    node_.param(ns + "/trajectory", default_trajectory_tolerance_[i].position, 0.0);
  }

  // Output filters
  output_filters_.resize(joints_.size());
  for (size_t i = 0; i < joints_.size(); ++i)
  {
    std::string p = "output_filters/" + joints_[i]->joint_->name;
    if (node_.hasParam(p))
    {
      output_filters_[i].reset(new filters::FilterChain<double>("double"));
      if (!output_filters_[i]->configure(node_.resolveName(p)))
        output_filters_[i].reset();
    }
  }

  // Creates a dummy trajectory
  boost::shared_ptr<SpecifiedTrajectory> traj_ptr(new SpecifiedTrajectory(1));
  SpecifiedTrajectory &traj = *traj_ptr;
  traj[0].start_time = robot_->getTime().toSec();
  traj[0].duration = 0.0;
  traj[0].splines.resize(joints_.size());
  for (size_t j = 0; j < joints_.size(); ++j)
    traj[0].splines[j].coef[0] = 0.0;
  current_trajectory_box_.set(traj_ptr);

  sub_command_ = node_.subscribe("command", 1, &JointTrajectoryActionController::commandCB, this);
  serve_query_state_ = node_.advertiseService(
    "query_state", &JointTrajectoryActionController::queryStateService, this);

  q.resize(joints_.size());
  qd.resize(joints_.size());
  qdd.resize(joints_.size());

  controller_state_publisher_.reset(
    new realtime_tools::RealtimePublisher<pr2_controllers_msgs::JointTrajectoryControllerState>
    (node_, "state", 1));
  controller_state_publisher_->lock();
  for (size_t j = 0; j < joints_.size(); ++j)
    controller_state_publisher_->msg_.joint_names.push_back(joints_[j]->joint_->name);
  controller_state_publisher_->msg_.desired.positions.resize(joints_.size());
  controller_state_publisher_->msg_.desired.velocities.resize(joints_.size());
  controller_state_publisher_->msg_.desired.accelerations.resize(joints_.size());
  controller_state_publisher_->msg_.actual.positions.resize(joints_.size());
  controller_state_publisher_->msg_.actual.velocities.resize(joints_.size());
  controller_state_publisher_->msg_.error.positions.resize(joints_.size());
  controller_state_publisher_->msg_.error.velocities.resize(joints_.size());
  controller_state_publisher_->unlock();

  action_server_.reset(new JTAS(node_, "joint_trajectory_action",
                                boost::bind(&JointTrajectoryActionController::goalCB, this, _1),
                                boost::bind(&JointTrajectoryActionController::cancelCB, this, _1),
                                false));
  action_server_follow_.reset(new FJTAS(node_, "follow_joint_trajectory",
                                        boost::bind(&JointTrajectoryActionController::goalCBFollow, this, _1),
                                        boost::bind(&JointTrajectoryActionController::cancelCBFollow, this, _1),
                                        false));
  action_server_->start();
  action_server_follow_->start();

  return true;
}

void JointTrajectoryActionController::starting()
{
  last_time_ = robot_->getTime();

  for (size_t i = 0; i < pids_.size(); ++i) {
    pids_[i].reset();
    proxies_[i].reset(joints_[i]->position_, joints_[i]->velocity_);
  }

  // Creates a "hold current position" trajectory.
  boost::shared_ptr<SpecifiedTrajectory> hold_ptr(new SpecifiedTrajectory(1));
  SpecifiedTrajectory &hold = *hold_ptr;
  hold[0].start_time = last_time_.toSec() - 0.001;
  hold[0].duration = 0.0;
  hold[0].splines.resize(joints_.size());
  for (size_t j = 0; j < joints_.size(); ++j)
    hold[0].splines[j].coef[0] = joints_[j]->position_;

  current_trajectory_box_.set(hold_ptr);
}

void JointTrajectoryActionController::update()
{
  ros::Time time = robot_->getTime();
  ros::Duration dt = time - last_time_;
  last_time_ = time;

  boost::shared_ptr<RTGoalHandle> current_active_goal(rt_active_goal_);
  boost::shared_ptr<RTGoalHandleFollow> current_active_goal_follow(rt_active_goal_follow_);

  boost::shared_ptr<const SpecifiedTrajectory> traj_ptr;
  current_trajectory_box_.get(traj_ptr);
  if (!traj_ptr)
    ROS_FATAL("The current trajectory can never be null");

  // Only because this is what the code originally looked like.
  const SpecifiedTrajectory &traj = *traj_ptr;

  // ------ Finds the current segment

  // Determines which segment of the trajectory to use.  (Not particularly realtime friendly).
  int seg = -1;
  while (seg + 1 < (int)traj.size() &&
         traj[seg+1].start_time < time.toSec())
  {
    ++seg;
  }

  if (seg == -1)
  {
    if (traj.size() == 0)
      ROS_ERROR("No segments in the trajectory");
    else
      ROS_ERROR("No earlier segments.  First segment starts at %.3lf (now = %.3lf)", traj[0].start_time, time.toSec());
    return;
  }

  // ------ Trajectory Sampling

  for (size_t i = 0; i < q.size(); ++i)
  {
    sampleSplineWithTimeBounds(traj[seg].splines[i].coef, traj[seg].duration,
                               time.toSec() - traj[seg].start_time,
                               q[i], qd[i], qdd[i]);
  }

  // ------ Trajectory Following

  std::vector<double> error(joints_.size());
  std::vector<double> v_error(joints_.size());
  for (size_t i = 0; i < joints_.size(); ++i)
  {
    double effort;

    // Compute the errors with respect to the desired trajectory
    // (whether or not using the proxy controller).  They are also
    // used later to determine reaching the goal.
    error[i] = q[i] - joints_[i]->position_;
    v_error[i] = qd[i] - joints_[i]->velocity_;

    // Use the proxy controller (if enabled)
    if (proxies_enabled_[i]) {
      effort = proxies_[i].update(q[i], qd[i], qdd[i],
                                  joints_[i]->position_, joints_[i]->velocity_,
                                  dt.toSec());
    }
    else {
      effort = pids_[i].computeCommand(error[i], v_error[i], dt);

      double effort_unfiltered = effort;
      if (output_filters_[i])
        output_filters_[i]->update(effort_unfiltered, effort);
    }

    // Apply the effort.  WHY IS THIS ADDITIVE?
    joints_[i]->commanded_effort_ = effort;
  }

  // ------ Determines if the goal has failed or succeeded

  if ((traj[seg].gh && traj[seg].gh == current_active_goal) ||
      (traj[seg].gh_follow && traj[seg].gh_follow == current_active_goal_follow))
  {
    ros::Time end_time(traj[seg].start_time + traj[seg].duration);
    if (time <= end_time)
    {
      // Verifies trajectory tolerances
      for (size_t j = 0; j < joints_.size(); ++j)
      {
        if (traj[seg].trajectory_tolerance[j].violated(error[j], v_error[j]))
        {
          if (traj[seg].gh)
            traj[seg].gh->setAborted();
          else if (traj[seg].gh_follow) {
            traj[seg].gh_follow->preallocated_result_->error_code =
              control_msgs::FollowJointTrajectoryResult::PATH_TOLERANCE_VIOLATED;
            traj[seg].gh_follow->setAborted(traj[seg].gh_follow->preallocated_result_);
          }
          break;
        }
      }
    }
    else if (seg == (int)traj.size() - 1)
    {
      // Checks that we have ended inside the goal tolerances
      bool inside_goal_constraints = true;
      for (size_t i = 0; i < joints_.size() && inside_goal_constraints; ++i)
      {
        if (traj[seg].goal_tolerance[i].violated(error[i], v_error[i]))
          inside_goal_constraints = false;
      }

      if (inside_goal_constraints)
      {
        rt_active_goal_.reset();
        rt_active_goal_follow_.reset();
        if (traj[seg].gh)
          traj[seg].gh->setSucceeded();
        else if (traj[seg].gh_follow) {
          traj[seg].gh_follow->preallocated_result_->error_code = control_msgs::FollowJointTrajectoryResult::SUCCESSFUL;
          traj[seg].gh_follow->setSucceeded(traj[seg].gh_follow->preallocated_result_);
        }
        //ROS_ERROR("Success!  (%s)", traj[seg].gh->gh_.getGoalID().id.c_str());
      }
      else if (time < end_time + ros::Duration(traj[seg].goal_time_tolerance))
      {
        // Still have some time left to make it.
      }
      else
      {
        //ROS_WARN("Aborting because we wound up outside the goal constraints");
        rt_active_goal_.reset();
        rt_active_goal_follow_.reset();
        if (traj[seg].gh)
          traj[seg].gh->setAborted();
        else if (traj[seg].gh_follow) {
          traj[seg].gh_follow->preallocated_result_->error_code = control_msgs::FollowJointTrajectoryResult::GOAL_TOLERANCE_VIOLATED;
          traj[seg].gh_follow->setAborted(traj[seg].gh_follow->preallocated_result_);
        }
      }
    }
  }

  // ------ State publishing

  if (loop_count_ % 10 == 0)
  {
    if (controller_state_publisher_ && controller_state_publisher_->trylock())
    {
      controller_state_publisher_->msg_.header.stamp = time;
      for (size_t j = 0; j < joints_.size(); ++j)
      {
        controller_state_publisher_->msg_.desired.positions[j] = q[j];
        controller_state_publisher_->msg_.desired.velocities[j] = qd[j];
        controller_state_publisher_->msg_.desired.accelerations[j] = qdd[j];
        controller_state_publisher_->msg_.actual.positions[j] = joints_[j]->position_;
        controller_state_publisher_->msg_.actual.velocities[j] = joints_[j]->velocity_;
        controller_state_publisher_->msg_.error.positions[j] = error[j];
        controller_state_publisher_->msg_.error.velocities[j] = joints_[j]->velocity_ - qd[j];
      }
      controller_state_publisher_->unlockAndPublish();
    }
    if (current_active_goal_follow)
    {
      current_active_goal_follow->preallocated_feedback_->header.stamp = time;
      current_active_goal_follow->preallocated_feedback_->joint_names.resize(joints_.size());
      current_active_goal_follow->preallocated_feedback_->desired.positions.resize(joints_.size());
      current_active_goal_follow->preallocated_feedback_->desired.velocities.resize(joints_.size());
      current_active_goal_follow->preallocated_feedback_->desired.accelerations.resize(joints_.size());
      current_active_goal_follow->preallocated_feedback_->actual.positions.resize(joints_.size());
      current_active_goal_follow->preallocated_feedback_->actual.velocities.resize(joints_.size());
      current_active_goal_follow->preallocated_feedback_->error.positions.resize(joints_.size());
      current_active_goal_follow->preallocated_feedback_->error.velocities.resize(joints_.size());
      for (size_t j = 0; j < joints_.size(); ++j)
      {
        current_active_goal_follow->preallocated_feedback_->joint_names[j] = joints_[j]->joint_->name;
        current_active_goal_follow->preallocated_feedback_->desired.positions[j] = q[j];
        current_active_goal_follow->preallocated_feedback_->desired.velocities[j] = qd[j];
        current_active_goal_follow->preallocated_feedback_->desired.accelerations[j] = qdd[j];
        current_active_goal_follow->preallocated_feedback_->actual.positions[j] = joints_[j]->position_;
        current_active_goal_follow->preallocated_feedback_->actual.velocities[j] = joints_[j]->velocity_;
        current_active_goal_follow->preallocated_feedback_->error.positions[j] = error[j];
        current_active_goal_follow->preallocated_feedback_->error.velocities[j] = joints_[j]->velocity_ - qd[j];
      }
      const actionlib_msgs::GoalID goalID = current_active_goal_follow->gh_.getGoalID();
      ros::Duration time_from_start = time - goalID.stamp;
      current_active_goal_follow->preallocated_feedback_->desired.time_from_start = time_from_start;
      current_active_goal_follow->preallocated_feedback_->actual.time_from_start = time_from_start;
      current_active_goal_follow->preallocated_feedback_->error.time_from_start = time_from_start;
      current_active_goal_follow->gh_.publishFeedback(*current_active_goal_follow->preallocated_feedback_);

    }
  }

  ++loop_count_;
}

void JointTrajectoryActionController::commandCB(const trajectory_msgs::JointTrajectory::ConstPtr &msg)
{
  preemptActiveGoal();
  commandTrajectory(msg);
}

void JointTrajectoryActionController::commandTrajectory(const trajectory_msgs::JointTrajectory::ConstPtr &msg,
                                                        boost::shared_ptr<RTGoalHandle> gh,
                                                        boost::shared_ptr<RTGoalHandleFollow> gh_follow)
{
  assert(!gh || !gh_follow);
  ros::Time time = last_time_ + ros::Duration(0.01);
  ROS_DEBUG("Figuring out new trajectory at %.3lf, with data from %.3lf",
            time.toSec(), msg->header.stamp.toSec());

  boost::shared_ptr<SpecifiedTrajectory> new_traj_ptr(new SpecifiedTrajectory);
  SpecifiedTrajectory &new_traj = *new_traj_ptr;

  // ------ If requested, performs a stop

  if (msg->points.empty())
  {
    starting();
    return;
  }

  // ------ Computes the tolerances for following the trajectory
  
  std::vector<JointTolerance> trajectory_tolerance = default_trajectory_tolerance_;
  std::vector<JointTolerance> goal_tolerance = default_goal_tolerance_;
  double goal_time_tolerance = default_goal_time_constraint_;

  if (gh_follow)
  {
    for (size_t j = 0; j < joints_.size(); ++j)
    {
      // Extracts the path tolerance from the command
      for (size_t k = 0; k < gh_follow->gh_.getGoal()->path_tolerance.size(); ++k)
      {
        const control_msgs::JointTolerance &tol = gh_follow->gh_.getGoal()->path_tolerance[k];
        if (joints_[j]->joint_->name == tol.name)
        {
          // If the commanded tolerances are positive, overwrite the
          // existing tolerances.  If they are -1, remove any existing
          // tolerance.  If they are 0, leave the default tolerance in
          // place.
          
          if (tol.position > 0)
            trajectory_tolerance[j].position = tol.position;
          else if (tol.position < 0)
            trajectory_tolerance[j].position = 0.0;

          if (tol.velocity > 0)
            trajectory_tolerance[j].velocity = tol.velocity;
          else if (tol.velocity < 0)
            trajectory_tolerance[j].velocity = 0.0;

          if (tol.acceleration > 0)
            trajectory_tolerance[j].acceleration = tol.acceleration;
          else if (tol.acceleration < 0)
            trajectory_tolerance[j].acceleration = 0.0;
          
          break;
        }
      }

      // Extracts the goal tolerance from the command
      for (size_t k = 0; k < gh_follow->gh_.getGoal()->goal_tolerance.size(); ++k)
      {
        const control_msgs::JointTolerance &tol = gh_follow->gh_.getGoal()->goal_tolerance[k];
        if (joints_[j]->joint_->name == tol.name)
        {
          // If the commanded tolerances are positive, overwrite the
          // existing tolerances.  If they are -1, remove any existing
          // tolerance.  If they are 0, leave the default tolerance in
          // place.
          
          if (tol.position > 0)
            goal_tolerance[j].position = tol.position;
          else if (tol.position < 0)
            goal_tolerance[j].position = 0.0;

          if (tol.velocity > 0)
            goal_tolerance[j].velocity = tol.velocity;
          else if (tol.velocity < 0)
            goal_tolerance[j].velocity = 0.0;

          if (tol.acceleration > 0)
            goal_tolerance[j].acceleration = tol.acceleration;
          else if (tol.acceleration < 0)
            goal_tolerance[j].acceleration = 0.0;
          
          break;
        }
      }
    }
    
    const ros::Duration &tol = gh_follow->gh_.getGoal()->goal_time_tolerance;
    if (tol < ros::Duration(0.0))
      goal_time_tolerance = 0.0;
    else if (tol > ros::Duration(0.0))
      goal_time_tolerance = tol.toSec();
  }

  // ------ Correlates the joints we're commanding to the joints in the message

  std::vector<int> lookup(joints_.size(), -1);  // Maps from an index in joints_ to an index in the msg
  for (size_t j = 0; j < joints_.size(); ++j)
  {
    for (size_t k = 0; k < msg->joint_names.size(); ++k)
    {
      if (msg->joint_names[k] == joints_[j]->joint_->name)
      {
        lookup[j] = k;
        break;
      }
    }

    if (lookup[j] == -1)
    {
      ROS_ERROR("Unable to locate joint %s in the commanded trajectory.", joints_[j]->joint_->name.c_str());
      if (gh)
        gh->setAborted();
      else if (gh_follow) {
        gh_follow->preallocated_result_->error_code = control_msgs::FollowJointTrajectoryResult::INVALID_JOINTS;
        gh_follow->setAborted(gh_follow->preallocated_result_);
      }
      return;
    }
  }

  // ------ Grabs the trajectory that we're currently following.

  boost::shared_ptr<const SpecifiedTrajectory> prev_traj_ptr;
  current_trajectory_box_.get(prev_traj_ptr);
  if (!prev_traj_ptr)
  {
    ROS_FATAL("The current trajectory can never be null");
    return;
  }
  const SpecifiedTrajectory &prev_traj = *prev_traj_ptr;

  // ------ Copies over the segments from the previous trajectory that are still useful.

  // Useful segments are still relevant after the current time.
  int first_useful = -1;
  while (first_useful + 1 < (int)prev_traj.size() &&
         prev_traj[first_useful + 1].start_time <= time.toSec())
  {
    ++first_useful;
  }

  // Useful segments are not going to be completely overwritten by the message's splines.
  int last_useful = -1;
  double msg_start_time;
  if (msg->header.stamp == ros::Time(0.0))
    msg_start_time = time.toSec();
  else
    msg_start_time = msg->header.stamp.toSec();
  /*
  if (msg->points.size() > 0)
    msg_start_time += msg->points[0].time_from_start.toSec();
  */

  while (last_useful + 1 < (int)prev_traj.size() &&
         prev_traj[last_useful + 1].start_time < msg_start_time)
  {
    ++last_useful;
  }

  if (last_useful < first_useful)
    first_useful = last_useful;

  // Copies over the old segments that were determined to be useful.
  for (int i = std::max(first_useful,0); i <= last_useful; ++i)
  {
    new_traj.push_back(prev_traj[i]);
  }

  // We always save the last segment so that we know where to stop if
  // there are no new segments.
  if (new_traj.size() == 0)
    new_traj.push_back(prev_traj[prev_traj.size() - 1]);

  // ------ Determines when and where the new segments start

  // Finds the end conditions of the final segment
  Segment &last = new_traj[new_traj.size() - 1];
  std::vector<double> prev_positions(joints_.size());
  std::vector<double> prev_velocities(joints_.size());
  std::vector<double> prev_accelerations(joints_.size());

  double t = (msg->header.stamp == ros::Time(0.0) ? time.toSec() : msg->header.stamp.toSec())
    - last.start_time;
  ROS_DEBUG("Initial conditions at %.3f for new set of splines:", t);
  for (size_t i = 0; i < joints_.size(); ++i)
  {
    sampleSplineWithTimeBounds(last.splines[i].coef, last.duration,
                               t,
                               prev_positions[i], prev_velocities[i], prev_accelerations[i]);
    ROS_DEBUG("    %.2lf, %.2lf, %.2lf  (%s)", prev_positions[i], prev_velocities[i],
              prev_accelerations[i], joints_[i]->joint_->name.c_str());
  }

  // ------ Tacks on the new segments

  std::vector<double> positions;
  std::vector<double> velocities;
  std::vector<double> accelerations;

  std::vector<double> durations(msg->points.size());
  if (msg->points.size() > 0)
    durations[0] = msg->points[0].time_from_start.toSec();
  for (size_t i = 1; i < msg->points.size(); ++i)
    durations[i] = (msg->points[i].time_from_start - msg->points[i-1].time_from_start).toSec();

  // Checks if we should wrap
  std::vector<double> wrap(joints_.size(), 0.0);
  assert(!msg->points[0].positions.empty());
  for (size_t j = 0; j < joints_.size(); ++j)
  {
    if (joints_[j]->joint_->type == urdf::Joint::CONTINUOUS)
    {
      double dist = angles::shortest_angular_distance(prev_positions[j], msg->points[0].positions[lookup[j]]);
      wrap[j] = (prev_positions[j] + dist) - msg->points[0].positions[lookup[j]];
    }
  }

  for (size_t i = 0; i < msg->points.size(); ++i)
  {
    Segment seg;

    if (msg->header.stamp == ros::Time(0.0))
      seg.start_time = (time + msg->points[i].time_from_start).toSec() - durations[i];
    else
      seg.start_time = (msg->header.stamp + msg->points[i].time_from_start).toSec() - durations[i];
    seg.duration = durations[i];
    seg.gh = gh;
    seg.gh_follow = gh_follow;
    seg.splines.resize(joints_.size());

    // Checks that the incoming segment has the right number of elements.

    if (msg->points[i].accelerations.size() != 0 && msg->points[i].accelerations.size() != joints_.size())
    {
      ROS_ERROR("Command point %d has %d elements for the accelerations", (int)i, (int)msg->points[i].accelerations.size());
      return;
    }
    if (msg->points[i].velocities.size() != 0 && msg->points[i].velocities.size() != joints_.size())
    {
      ROS_ERROR("Command point %d has %d elements for the velocities", (int)i, (int)msg->points[i].velocities.size());
      return;
    }
    if (msg->points[i].positions.size() != joints_.size())
    {
      ROS_ERROR("Command point %d has %d elements for the positions", (int)i, (int)msg->points[i].positions.size());
      return;
    }

    // Re-orders the joints in the command to match the internal joint order.

    accelerations.resize(msg->points[i].accelerations.size());
    velocities.resize(msg->points[i].velocities.size());
    positions.resize(msg->points[i].positions.size());
    for (size_t j = 0; j < joints_.size(); ++j)
    {
      if (!accelerations.empty()) accelerations[j] = msg->points[i].accelerations[lookup[j]];
      if (!velocities.empty()) velocities[j] = msg->points[i].velocities[lookup[j]];
      if (!positions.empty()) positions[j] = msg->points[i].positions[lookup[j]] + wrap[j];
    }

    // Converts the boundary conditions to splines.

    for (size_t j = 0; j < joints_.size(); ++j)
    {
      if (prev_accelerations.size() > 0 && accelerations.size() > 0)
      {
        getQuinticSplineCoefficients(
          prev_positions[j], prev_velocities[j], prev_accelerations[j],
          positions[j], velocities[j], accelerations[j],
          durations[i],
          seg.splines[j].coef);
      }
      else if (prev_velocities.size() > 0 && velocities.size() > 0)
      {
        getCubicSplineCoefficients(
          prev_positions[j], prev_velocities[j],
          positions[j], velocities[j],
          durations[i],
          seg.splines[j].coef);
        seg.splines[j].coef.resize(6, 0.0);
      }
      else
      {
        seg.splines[j].coef[0] = prev_positions[j];
        if (durations[i] == 0.0)
          seg.splines[j].coef[1] = 0.0;
        else
          seg.splines[j].coef[1] = (positions[j] - prev_positions[j]) / durations[i];
        seg.splines[j].coef[2] = 0.0;
        seg.splines[j].coef[3] = 0.0;
        seg.splines[j].coef[4] = 0.0;
        seg.splines[j].coef[5] = 0.0;
      }
    }

    // Writes the tolerances into the segment
    seg.trajectory_tolerance = trajectory_tolerance;
    seg.goal_tolerance = goal_tolerance;
    seg.goal_time_tolerance = goal_time_tolerance;

    // Pushes the splines onto the end of the new trajectory.

    new_traj.push_back(seg);

    // Computes the starting conditions for the next segment

    prev_positions = positions;
    prev_velocities = velocities;
    prev_accelerations = accelerations;
  }

  //ROS_ERROR("Last segment goal id: %s", new_traj[new_traj.size()-1].gh->gh_.getGoalID().id.c_str());

  // ------ Commits the new trajectory

  if (!new_traj_ptr)
  {
    ROS_ERROR("The new trajectory was null!");
    return;
  }

  current_trajectory_box_.set(new_traj_ptr);
  ROS_DEBUG("The new trajectory has %d segments", (int)new_traj.size());
#if 0
  for (size_t i = 0; i < std::min((size_t)20,new_traj.size()); ++i)
  {
    ROS_DEBUG("Segment %2d: %.3lf for %.3lf", i, new_traj[i].start_time, new_traj[i].duration);
    for (size_t j = 0; j < new_traj[i].splines.size(); ++j)
    {
      ROS_DEBUG("    %.2lf  %.2lf  %.2lf  %.2lf , %.2lf  %.2lf(%s)",
                new_traj[i].splines[j].coef[0],
                new_traj[i].splines[j].coef[1],
                new_traj[i].splines[j].coef[2],
                new_traj[i].splines[j].coef[3],
                new_traj[i].splines[j].coef[4],
                new_traj[i].splines[j].coef[5],
                joints_[j]->joint_->name_.c_str());
    }
  }
#endif
}

bool JointTrajectoryActionController::queryStateService(
  pr2_controllers_msgs::QueryTrajectoryState::Request &req,
  pr2_controllers_msgs::QueryTrajectoryState::Response &resp)
{
  boost::shared_ptr<const SpecifiedTrajectory> traj_ptr;
  current_trajectory_box_.get(traj_ptr);
  if (!traj_ptr)
  {
    ROS_FATAL("The current trajectory can never be null");
    return false;
  }
  const SpecifiedTrajectory &traj = *traj_ptr;

  // Determines which segment of the trajectory to use
  int seg = -1;
  while (seg + 1 < (int)traj.size() &&
         traj[seg+1].start_time < req.time.toSec())
  {
    ++seg;
  }
  if (seg == -1)
    return false;

  for (size_t i = 0; i < q.size(); ++i)
  {
  }


  resp.name.resize(joints_.size());
  resp.position.resize(joints_.size());
  resp.velocity.resize(joints_.size());
  resp.acceleration.resize(joints_.size());
  for (size_t j = 0; j < joints_.size(); ++j)
  {
    resp.name[j] = joints_[j]->joint_->name;
    sampleSplineWithTimeBounds(traj[seg].splines[j].coef, traj[seg].duration,
                               req.time.toSec() - traj[seg].start_time,
                               resp.position[j], resp.velocity[j], resp.acceleration[j]);
  }

  return true;
}

void JointTrajectoryActionController::sampleSplineWithTimeBounds(
  const std::vector<double>& coefficients, double duration, double time,
  double& position, double& velocity, double& acceleration)
{
  if (time < 0)
  {
    double _;
    sampleQuinticSpline(coefficients, 0.0, position, _, _);
    velocity = 0;
    acceleration = 0;
  }
  else if (time > duration)
  {
    double _;
    sampleQuinticSpline(coefficients, duration, position, _, _);
    velocity = 0;
    acceleration = 0;
  }
  else
  {
    sampleQuinticSpline(coefficients, time,
                        position, velocity, acceleration);
  }
}

static bool setsEqual(const std::vector<std::string> &a, const std::vector<std::string> &b)
{
  if (a.size() != b.size())
    return false;

  for (size_t i = 0; i < a.size(); ++i)
  {
    if (count(b.begin(), b.end(), a[i]) != 1)
      return false;
  }
  for (size_t i = 0; i < b.size(); ++i)
  {
    if (count(a.begin(), a.end(), b[i]) != 1)
      return false;
  }

  return true;
}

void JointTrajectoryActionController::preemptActiveGoal()
{
  boost::shared_ptr<RTGoalHandle> current_active_goal(rt_active_goal_);
  boost::shared_ptr<RTGoalHandleFollow> current_active_goal_follow(rt_active_goal_follow_);
  
  // Cancels the currently active goal.
  if (current_active_goal)
  {
    // Marks the current goal as canceled.
    rt_active_goal_.reset();
    current_active_goal->gh_.setCanceled();
  }
  if (current_active_goal_follow)
  {
    rt_active_goal_follow_.reset();
    current_active_goal_follow->gh_.setCanceled();
  }
}


template <class Enclosure, class Member>
static boost::shared_ptr<Member> share_member(boost::shared_ptr<Enclosure> enclosure, Member &member)
{
  actionlib::EnclosureDeleter<Enclosure> d(enclosure);
  boost::shared_ptr<Member> p(&member, d);
  return p;
}

void JointTrajectoryActionController::goalCB(GoalHandle gh)
{
  std::vector<std::string> joint_names(joints_.size());
  for (size_t j = 0; j < joints_.size(); ++j)
    joint_names[j] = joints_[j]->joint_->name;

  // Ensures that the joints in the goal match the joints we are commanding.
  if (!setsEqual(joint_names, gh.getGoal()->trajectory.joint_names))
  {
    ROS_ERROR("Joints on incoming goal don't match our joints");
    gh.setRejected();
    return;
  }

  preemptActiveGoal();

  gh.setAccepted();
  boost::shared_ptr<RTGoalHandle> rt_gh(new RTGoalHandle(gh));

  // Sends the trajectory along to the controller
  goal_handle_timer_ = node_.createTimer(ros::Duration(0.01), &RTGoalHandle::runNonRT, rt_gh);
  commandTrajectory(share_member(gh.getGoal(), gh.getGoal()->trajectory), rt_gh);
  rt_active_goal_ = rt_gh;
  goal_handle_timer_.start();
}

void JointTrajectoryActionController::goalCBFollow(GoalHandleFollow gh)
{
  std::vector<std::string> joint_names(joints_.size());
  for (size_t j = 0; j < joints_.size(); ++j)
    joint_names[j] = joints_[j]->joint_->name;

  // Ensures that the joints in the goal match the joints we are commanding.
  if (!setsEqual(joint_names, gh.getGoal()->trajectory.joint_names))
  {
    ROS_ERROR("Joints on incoming goal don't match our joints");
    control_msgs::FollowJointTrajectoryResult result;
    result.error_code = control_msgs::FollowJointTrajectoryResult::INVALID_JOINTS;
    gh.setRejected(result);
    return;
  }

  preemptActiveGoal();

  gh.setAccepted();
  boost::shared_ptr<RTGoalHandleFollow> rt_gh(new RTGoalHandleFollow(gh));

  // Sends the trajectory along to the controller
  goal_handle_timer_ = node_.createTimer(ros::Duration(0.01), &RTGoalHandleFollow::runNonRT, rt_gh);
  commandTrajectory(share_member(gh.getGoal(), gh.getGoal()->trajectory),
                    boost::shared_ptr<RTGoalHandle>((RTGoalHandle*)NULL),
                    rt_gh);
  rt_active_goal_follow_ = rt_gh;
  goal_handle_timer_.start();
}

void JointTrajectoryActionController::cancelCB(GoalHandle gh)
{
  boost::shared_ptr<RTGoalHandle> current_active_goal(rt_active_goal_);
  if (current_active_goal && current_active_goal->gh_ == gh)
  {
    rt_active_goal_.reset();

    trajectory_msgs::JointTrajectory::Ptr empty(new trajectory_msgs::JointTrajectory);
    empty->joint_names.resize(joints_.size());
    for (size_t j = 0; j < joints_.size(); ++j)
      empty->joint_names[j] = joints_[j]->joint_->name;
    commandTrajectory(empty);

    // Marks the current goal as canceled.
    current_active_goal->gh_.setCanceled();
  }
}

void JointTrajectoryActionController::cancelCBFollow(GoalHandleFollow gh)
{
  boost::shared_ptr<RTGoalHandleFollow> current_active_goal(rt_active_goal_follow_);
  if (current_active_goal && current_active_goal->gh_ == gh)
  {
    rt_active_goal_follow_.reset();

    trajectory_msgs::JointTrajectory::Ptr empty(new trajectory_msgs::JointTrajectory);
    empty->joint_names.resize(joints_.size());
    for (size_t j = 0; j < joints_.size(); ++j)
      empty->joint_names[j] = joints_[j]->joint_->name;
    commandTrajectory(empty);

    // Marks the current goal as canceled.
    current_active_goal->gh_.setCanceled();
  }
}
}