nao_path_follower.cpp

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/*
 *
 * Copyright 2011-2014 Armin Hornung, Stefan Osswald, Daniel Maier
 * University of Freiburg
 * http://www.ros.org/wiki/nao
 *
 * 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 the University of Freiburg 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
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 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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#include <ros/ros.h>
#include <tf/transform_datatypes.h>
#include <tf/transform_listener.h>
#include <geometry_msgs/Transform.h>
#include <std_msgs/Bool.h>
#include <std_srvs/Empty.h>
#include <cmath>
#include <geometry_msgs/Pose2D.h>
#include <nav_msgs/Path.h>
#include <geometry_msgs/PoseStamped.h>
#include <move_base_msgs/MoveBaseAction.h>
#include <nao_msgs/FollowPathAction.h>
#include <actionlib/server/simple_action_server.h>
#include <angles/angles.h>
#include <assert.h>

class PathFollower
{
public:
        PathFollower();
        ~PathFollower();
        void goalActionCB(const move_base_msgs::MoveBaseGoalConstPtr &goal);
        void pathActionCB(const nao_msgs::FollowPathGoalConstPtr &goal);
        void goalCB(const geometry_msgs::PoseStampedConstPtr& goal);
        void pathCB(const nav_msgs::PathConstPtr& goal);
        bool getRobotPose( tf::StampedTransform & globalToBase, const std::string & global_frame_id);

private:
  bool getNextTarget(const nav_msgs::Path & path, const tf::Pose & robotPose,  const std::vector<geometry_msgs::PoseStamped>::const_iterator & currentPathPoseIt, tf::Stamped<tf::Transform> & targetPose, std::vector< geometry_msgs::PoseStamped>::const_iterator & targetPathPoseIt);
        void stopWalk();
        void setVelocity(const tf::Transform& relTarget);
        void publishTargetPoseVis(const tf::Stamped<tf::Pose>& targetPose);
        void footContactCallback(const std_msgs::BoolConstPtr& contact);
  void inhibitJoystick();

        ros::NodeHandle nh;
        ros::NodeHandle privateNh;
        ros::Subscriber m_simpleGoalSub, m_simplePathSub;
        ros::Publisher m_targetPub, m_velPub, m_actionGoalPub, m_visPub, m_actionPathPub;
        tf::TransformListener m_tfListener;
        actionlib::SimpleActionServer<move_base_msgs::MoveBaseAction> m_walkGoalServer;
        actionlib::SimpleActionServer<nao_msgs::FollowPathAction> m_walkPathServer;
        ros::ServiceClient m_inhibitWalkClient, m_uninhibitWalkClient;
        ros::Subscriber m_footContactSub;

        std::string m_baseFrameId;     
        double m_controllerFreq;       
        double m_targetDistThres;      
        double m_targetAngThres;       
        double m_waypointDistThres;    
        double m_waypointAngThres;     
        bool m_isJoystickInhibited;    
        bool m_useFootContactProtection;  
        bool m_footContact;            
        
        // Parameters for the velocity controller
        bool m_useVelocityController;  
        double m_maxVelFractionX;      
        double m_maxVelFractionY;      
        double m_maxVelFractionYaw;    
        double m_stepFreq;             
        double m_stepFactor;           
        const double m_maxVelXY;       
        const double m_maxVelYaw;      
        const double m_minStepFreq;    
        const double m_maxStepFreq;    
        double m_thresholdFar;         
        double m_thresholdRotate;      
        double m_thresholdDampXY;      
        double m_thresholdDampYaw;     
        // for path following
        double m_pathNextTargetDistance; 
        double m_pathStartMaxDistance;   
        double m_straightMaxRobotDev;     
        double m_straightMaxRobotYaw;     
        double m_straightMaxPathDev;      
        double m_straightThreshold;       
        double m_straightOffset;        
        bool m_straight;                
};

PathFollower::PathFollower()
  : privateNh("~"),
    m_walkGoalServer(nh, "walk_target", boost::bind(&PathFollower::goalActionCB, this, _1), false),
    m_walkPathServer(nh, "walk_path", boost::bind(&PathFollower::pathActionCB, this, _1), false),
    m_baseFrameId("base_footprint"), m_controllerFreq(10),
    m_targetDistThres(0.05), m_targetAngThres(angles::from_degrees(5.)),
    m_waypointDistThres(0.05), m_waypointAngThres(angles::from_degrees(45)),
    m_isJoystickInhibited(false), 
    m_useFootContactProtection(true), m_footContact(true),
    m_useVelocityController(false),
    m_maxVelFractionX(0.7), m_maxVelFractionY(0.7), m_maxVelFractionYaw(0.7), m_stepFreq(0.5),
    m_maxVelXY(0.0952), m_maxVelYaw(angles::from_degrees(47.6)), m_minStepFreq(1.667), m_maxStepFreq(2.381),    
    m_thresholdFar(0.20), m_thresholdRotate(angles::from_degrees(45.)),
    m_thresholdDampXY(0.20), m_thresholdDampYaw(angles::from_degrees(60.)), m_pathNextTargetDistance(0.1),
    m_pathStartMaxDistance(0.1),
    m_straightMaxRobotDev(0.1), m_straightMaxRobotYaw(0.25), m_straightMaxPathDev(0.1),
    m_straightThreshold(0.2), m_straightOffset(0.3), m_straight(false)
{

        privateNh.param("base_frame_id", m_baseFrameId, m_baseFrameId);
        m_baseFrameId = m_tfListener.resolve(m_baseFrameId);
        privateNh.param("controller_frequency", m_controllerFreq, m_controllerFreq);
        privateNh.param("target_distance_threshold", m_targetDistThres, m_targetDistThres);
        privateNh.param("target_angle_threshold", m_targetAngThres, m_targetAngThres);
  privateNh.param("waypoint_distance_threshold", m_waypointDistThres, m_waypointDistThres);
  privateNh.param("waypoint_angle_threshold", m_waypointAngThres, m_waypointAngThres);
        privateNh.param("max_vel_x", m_maxVelFractionX, m_maxVelFractionX);
        privateNh.param("max_vel_y", m_maxVelFractionY, m_maxVelFractionY);
        privateNh.param("max_vel_yaw", m_maxVelFractionYaw, m_maxVelFractionYaw);
        privateNh.param("step_freq", m_stepFreq, m_stepFreq);
        privateNh.param("use_vel_ctrl", m_useVelocityController, m_useVelocityController);
        privateNh.param("use_foot_contact_protection", m_useFootContactProtection, m_useFootContactProtection);
        privateNh.param("path_next_target_distance", m_pathNextTargetDistance, m_pathNextTargetDistance);
  privateNh.param("path_max_start_distance", m_pathStartMaxDistance, m_pathStartMaxDistance);
        privateNh.param("threshold_damp_xy", m_thresholdDampXY, m_thresholdDampXY);
  privateNh.param("threshold_damp_yaw", m_thresholdDampYaw, m_thresholdDampYaw);
        
        privateNh.param("straight_max_robot_dev", m_straightMaxRobotDev, m_straightMaxRobotDev);
        privateNh.param("straight_max_robot_yaw", m_straightMaxRobotYaw, m_straightMaxRobotYaw);
        privateNh.param("straight_max_path_dev", m_straightMaxPathDev, m_straightMaxPathDev);
        privateNh.param("straight_threshold", m_straightThreshold, m_straightThreshold);
        privateNh.param("straight_offset", m_straightOffset, m_straightOffset);

        m_stepFactor = ((m_maxStepFreq - m_minStepFreq) * m_stepFreq + m_minStepFreq) / m_maxStepFreq;
        ROS_INFO("Using step factor of %4.2f",m_stepFactor);

        if(m_useVelocityController) {
            ROS_INFO("Using velocity controller");
            m_velPub = nh.advertise<geometry_msgs::Twist>("cmd_vel", 10);
        } else {
            ROS_INFO("Using target pose controller");
            m_targetPub = nh.advertise<geometry_msgs::Pose2D>("cmd_pose", 10);
        }

        m_actionGoalPub = nh.advertise<move_base_msgs::MoveBaseActionGoal>("walk_target/goal", 1);
        m_actionPathPub = nh.advertise<nao_msgs::FollowPathActionGoal>("walk_path/goal", 1);
        //we'll provide a mechanism for some people to send goals or paths as PoseStamped messages over a topic
        //they won't get any useful information back about its status, but this is useful for tools
        //like nav_view and rviz
        m_simpleGoalSub = nh.subscribe<geometry_msgs::PoseStamped>("walk_target_simple/goal", 1, boost::bind(&PathFollower::goalCB, this, _1));
        m_simplePathSub = nh.subscribe<nav_msgs::Path>("walk_path_simple/goal", 1, boost::bind(&PathFollower::pathCB, this, _1));
        
        if(m_useFootContactProtection) {
            m_footContactSub = nh.subscribe<std_msgs::Bool>("foot_contact", 1, &PathFollower::footContactCallback, this);
        }

        m_inhibitWalkClient = nh.serviceClient<std_srvs::Empty>("inhibit_walk");
        m_uninhibitWalkClient = nh.serviceClient<std_srvs::Empty>("uninhibit_walk");

        m_visPub = privateNh.advertise<geometry_msgs::PoseStamped>("target_pose", 1, true);

        // start up action server now:
        m_walkGoalServer.start();
        m_walkPathServer.start();
}

PathFollower::~PathFollower(){
   std::cerr << "Quitting PathFollower.." << std::endl;
   // TODO: stopWalk is not completed if ctrl+c is hit FIX THIS!
   stopWalk();
   std::cout << ".. stopWalk() called before quitting" << std::endl;

}

void PathFollower::publishTargetPoseVis(const tf::Stamped<tf::Pose>& targetPose) {
    geometry_msgs::PoseStamped targetPoseMsg;
    tf::poseStampedTFToMsg(targetPose, targetPoseMsg);
    m_visPub.publish(targetPoseMsg);
}

void PathFollower::goalCB(const geometry_msgs::PoseStampedConstPtr& goal) {
        ROS_DEBUG("In ROS goal callback, wrapping the PoseStamped in the action message and re-sending to the server.");
        move_base_msgs::MoveBaseActionGoal action_goal;
        action_goal.header.stamp = ros::Time::now();
        action_goal.goal.target_pose = *goal;
        m_actionGoalPub.publish(action_goal);
}

void PathFollower::pathCB(const nav_msgs::PathConstPtr& goal) {
   ROS_INFO("Simple Path callback");
        ROS_DEBUG("In ROS path callback, wrapping the Path in the action message and re-sending to the server.");
        nao_msgs::FollowPathActionGoal action_goal;
        action_goal.header = goal->header;
        action_goal.goal.path = *goal;
        m_actionPathPub.publish(action_goal);
}

void PathFollower::footContactCallback(const std_msgs::BoolConstPtr& contact) {
  m_footContact = contact->data;
}

void PathFollower::inhibitJoystick(){
  if(!m_isJoystickInhibited) {
    std_srvs::Empty e;
    if(m_inhibitWalkClient.call(e)) {
      ROS_INFO("Joystick inhibited");
      m_isJoystickInhibited = true;
    } else {
      ROS_WARN_ONCE("Could not inhibit joystick walk");
    }
  }  
}


bool hasOrientation(const geometry_msgs::Pose & pose)
{
   double eps = 1e-5;
   if ( fabs(pose.orientation.x) < eps && fabs(pose.orientation.y) < eps && fabs(pose.orientation.z) < eps && fabs(pose.orientation.w) < eps )
      return false;
   geometry_msgs::Quaternion q = pose.orientation;
   if ( fabs(q.x*q.x + q.y*q.y + q.z*q.z + q.w*q.w -1 ) > eps)
         return false;
   return true;
         
}

bool PathFollower::getRobotPose( tf::StampedTransform & globalToBase, const std::string & global_frame_id)
{
   try
   {
      // this causes a segfault when shutting down, move_base also doesn't have it?
      //                        m_tfListener.waitForTransform(targetPose.frame_id_, m_baseFrameId, ros::Time(), ros::Duration(0.1));
      m_tfListener.lookupTransform(global_frame_id, m_baseFrameId, ros::Time(), globalToBase);
      //ROS_INFO("ros::Time() is %f, ros::Time::now() is %f, delta is %f", globalToBase.stamp_.toSec(), ros::Time::now().toSec(), ros::Duration(ros::Time::now() - globalToBase.stamp_).toSec());
   }
   catch(const tf::TransformException& e)
   {
      ROS_WARN("Failed to obtain tf to base (%s)", e.what());
      return false;
   }
   //make sure base footprint is on the floor:
   globalToBase.getOrigin().setZ(0.0);
   double roll, pitch, yaw;
   globalToBase.getBasis().getRPY(roll, pitch, yaw);
   globalToBase.setRotation(tf::createQuaternionFromYaw(yaw));
   return true;
}

double poseDist(const tf::Pose& p1, const tf::Pose& p2)
{
  return (p1.getOrigin() - p2.getOrigin()).length();
}

double poseDist(const geometry_msgs::Pose& p1, const geometry_msgs::Pose& p2){
  tf::Vector3 p1_tf, p2_tf;
  tf::pointMsgToTF(p1.position, p1_tf);
  tf::pointMsgToTF(p2.position, p2_tf);

  return (p1_tf - p2_tf).length();
}

void print_transform(const tf::Transform & t)
{
   geometry_msgs::Pose m;
   tf::poseTFToMsg(t, m);
   std::cout << m;
}

double getYawBetween(const geometry_msgs::Pose& p1, const geometry_msgs::Pose& p2){
   tf::Vector3 o1, o2;
   tf::pointMsgToTF(p1.position, o1);
   tf::pointMsgToTF(p2.position, o2);

   return  std::atan2(o2.getY() - o1.getY(), o2.getX() - o1.getX());
}

double getYawBetween(const tf::Transform & p1, const tf::Transform & p2){
  tf::Vector3 o1 = p1.getOrigin();
  tf::Vector3 o2 = p2.getOrigin();
  return  std::atan2( o2.getY() - o1.getY(), o2.getX() - o1.getX());
}

tf::Quaternion getOrientationBetween(const tf::Transform & p1, const tf::Transform & p2)
{
   double yaw = getYawBetween(p1, p2);
   return (tf::createQuaternionFromYaw(yaw));
}

tf::Quaternion getOrientationBetween(const geometry_msgs::Pose& p1, const geometry_msgs::Pose& p2)
{
  double yaw = getYawBetween(p1, p2);
  return (tf::createQuaternionFromYaw(yaw));
}


typedef std::vector< geometry_msgs::PoseStamped>::const_iterator PathIterator;

double moveAlongPathByDistance( const PathIterator & start, PathIterator & end, double targetDistance)
{
   PathIterator iter = start;
   double dist = 0.0;
   while(iter+1 != end ){

      double d = poseDist(iter->pose, (iter+1)->pose);
      if (dist + d > targetDistance )
         break;
      dist += d;
      ++iter;
   }
   end = iter;
   return dist;
}

// this function assumes that robotPose is close (< robot_start_path_threshold) to *currentPathPoseIt 
bool PathFollower::getNextTarget(const nav_msgs::Path& path, const tf::Pose& robotPose,  const std::vector<geometry_msgs::PoseStamped>::const_iterator & currentPathPoseIt, tf::Stamped<tf::Transform> & targetPose, std::vector< geometry_msgs::PoseStamped>::const_iterator & targetPathPoseIt)
{

   // current state in  path unclear: cannot go further, end of path reached
   if( path.poses.empty() || currentPathPoseIt == path.poses.end() ) // past-the-end of path
   {
      ROS_ERROR("Path does not have successors for currentPathPoseIt (i.e. currentPathPoseIt pointing to past-the-end or is empty)");
      return true;
      // TODO: Throw something
   }

   
   // no successors in path: last pose or only one pose in path
   if( currentPathPoseIt+1 == path.poses.end() )
   {
      // this can happen, if we are close to the final goal or the path only has one pose
      // => just keep targetPose until reached
      ROS_DEBUG("Goal almost reached! Keeping targetPose. ");

      // ensure that the orientation is valid
      if (!hasOrientation(targetPathPoseIt->pose)){
        // best guess: current rotation
        targetPose.setRotation(robotPose.getRotation());
      }
      return true;
   }

   // TODO: check if successor exists, otherwise go to target pose with orientation
   // or ignore orientation if there is none (take current)


   
   // Check if the robot encounters a straight line in the path, where it can walk faster.
   // The straight/remaining path has to have a minimum length of m_straightThreshold.
   m_straight = false;
   std::vector< geometry_msgs::PoseStamped>::const_iterator farIter = currentPathPoseIt;
   tf::Stamped<tf::Transform> currentPose, nearPose, farPose;
   tf::poseStampedMsgToTF(*(currentPathPoseIt), currentPose);
   double straightDist = 0.0;
   bool nearEnd = true;
   while(farIter+1 != path.poses.end()){
     tf::poseStampedMsgToTF(*farIter, farPose);
     if(straightDist <= m_straightThreshold/4)
       tf::poseStampedMsgToTF(*farIter, nearPose);
     straightDist += poseDist(farIter->pose, (farIter+1)->pose);
     if(straightDist > m_straightThreshold){
       nearEnd = false;
       break;
     }
     ++farIter;
   }
   // actually check if the path is straight, if the robot is within a certain distance of the straight, and if the robot faces the straight
   if(!nearEnd){
     double robotYaw = tf::getYaw(robotPose.getRotation());
     double robotToFar = getYawBetween(robotPose, farPose);
     double currentToNear = getYawBetween(currentPose, nearPose);
     double currentToFar = getYawBetween(currentPose, farPose);
     bool robot_on_straight = (poseDist(robotPose, currentPose) < m_straightMaxRobotDev);
     bool path_is_straight = std::abs(angles::shortest_angular_distance(currentToNear,currentToFar)) < m_straightMaxPathDev;
     bool robot_faces_straight = std::abs(angles::shortest_angular_distance(robotYaw,robotToFar)) < m_straightMaxRobotYaw;

     m_straight = (robot_on_straight && path_is_straight && robot_faces_straight);
     //ROS_DEBUG_STREAM("Straight path: " << robot_on_straight << " " << path_is_straight << " " << robot_faces_straight);
     if(m_straight)
       ROS_DEBUG("Robot is walking on a straight path.");

   }
   
   
   // rewrite
   std::vector< geometry_msgs::PoseStamped>::const_iterator iter = currentPathPoseIt+1;
   tf::Stamped<tf::Transform> tfPose;
   tf::poseStampedMsgToTF( *iter, tfPose);
   double dist = poseDist( robotPose, tfPose);
   bool targetIsEndOfPath = true;
   while(iter+1 != path.poses.end() )
   {
      double d = poseDist(iter->pose, (iter+1)->pose);
      if (dist + d > m_pathNextTargetDistance )
      {
         targetIsEndOfPath = false;
         break;
      }
      dist += d;
      ++iter;
   }

   targetPathPoseIt = iter;
   tf::poseStampedMsgToTF(*iter, targetPose);
   

   // if no orientation, then compute from  waypoint
   if ( !hasOrientation (iter->pose) )
   {

      tf::Quaternion orientation;
      assert(iter != currentPathPoseIt);
      if (targetIsEndOfPath) // path length >= 2 and iter points to end of path
      {
        orientation = getOrientationBetween( (iter-1)->pose, targetPathPoseIt->pose);
      }
      else // iter has at least one succesor
      {
         // set Orientation so that successor of targetPose is faced        
         double yaw =  getYawBetween(targetPathPoseIt->pose, (targetPathPoseIt+1)->pose);
         if (targetPathPoseIt-1 != path.poses.begin() && targetPathPoseIt + 2 != path.poses.end() ){
           double yaw1 = getYawBetween((targetPathPoseIt-2)->pose, targetPathPoseIt->pose);
           double yaw2 = getYawBetween(targetPathPoseIt->pose, (targetPathPoseIt+2)->pose);
           yaw = atan2( sin(yaw1)+sin(yaw2), cos(yaw1) + cos(yaw2) );
         }
         orientation = tf::createQuaternionFromYaw(yaw);


      }
      targetPose.setRotation(orientation);

      //ROS_INFO_STREAM("..computed orientation" << basis << std::endl);
   }

   return targetIsEndOfPath;

}


void PathFollower::pathActionCB(const nao_msgs::FollowPathGoalConstPtr &goal){
   ROS_INFO("path action starting...");

   nav_msgs::Path path = goal->path;
   nao_msgs::FollowPathFeedback feedback;
   
   if( path.poses.empty() )
   {
      ROS_INFO("Stop requested by sending empty path.");
      stopWalk();
      m_walkPathServer.setSucceeded(nao_msgs::FollowPathResult(),"Stop succeeed");
      return;
   }

   ros::Rate r(m_controllerFreq);

   ros::Time lastTfSuccessTime = ros::Time::now();
   tf::StampedTransform globalToBase;
   double tfLookupTimeThresh = 1.0; // TODO: param
   std::string global_frame_id = path.header.frame_id;
   while (! getRobotPose(globalToBase, global_frame_id) )
   {
      if ( (ros::Time::now() - lastTfSuccessTime ).toSec() > tfLookupTimeThresh )
      {
         ROS_ERROR("Could not get robot pose. Stopping robot");
         stopWalk();
         m_walkPathServer.setAborted(nao_msgs::FollowPathResult(),"Aborted");
         return;
      }
      else
      {
         r.sleep();
         continue;
      }
   }
   //lastTfSuccessTime = globalToBase.stamp_;
   lastTfSuccessTime = ros::Time::now();

   // Check if start of path is consistent with current robot pose, otherwise abort
   std::vector< geometry_msgs::PoseStamped>::const_iterator currentPathPoseIt, targetPathPoseIt;
   currentPathPoseIt = path.poses.begin();
   targetPathPoseIt = currentPathPoseIt;
   // This is where Nao is currently walking to (current sub goal)
   tf::Stamped<tf::Transform> targetPose;
   
   tf::poseStampedMsgToTF( *currentPathPoseIt, targetPose);

   if (poseDist(targetPose, globalToBase)> m_pathStartMaxDistance)
   {
      ROS_ERROR("Robot is too far away from start of plan. aborting");
      stopWalk();
      m_walkPathServer.setAborted(nao_msgs::FollowPathResult(),"Aborted");
      return;
   }


   bool targetIsEndOfPath = getNextTarget(path, globalToBase, currentPathPoseIt, targetPose, targetPathPoseIt );
   publishTargetPoseVis(targetPose);
   inhibitJoystick();
   
   while(ros::ok()){
      if (! getRobotPose(globalToBase, global_frame_id) )
      {
         if ( (ros::Time::now() - lastTfSuccessTime ).toSec() > tfLookupTimeThresh )
         {
            ROS_ERROR("Could not get robot pose. Stopping robot");
            stopWalk();
            m_walkPathServer.setAborted(nao_msgs::FollowPathResult(),"Aborted");
            return;
         }
         else
         {
            r.sleep();
            continue;
         }
      }
      //lastTfSuccessTime = globalToBase.stamp_;
      lastTfSuccessTime = ros::Time::now();
      double dt = (lastTfSuccessTime - globalToBase.stamp_).toSec();
      if ( dt > tfLookupTimeThresh )
      {
         ROS_WARN("TF transforms are behind current clock by %4.2f", dt);
         //TODO do something here..
      }

      if (m_walkPathServer.isPreemptRequested()){
         if(m_walkPathServer.isNewGoalAvailable()){
            ROS_INFO("walk_path ActionServer: new goal available");
            nao_msgs::FollowPathGoal newGoal = *m_walkPathServer.acceptNewGoal();
            path = newGoal.path;
            // Check if path is not empty, otherwise abort
            if( path.poses.empty() )
            {
               ROS_INFO("Stop requested by sending empty path.");
               stopWalk();
               m_walkPathServer.setSucceeded(nao_msgs::FollowPathResult(),"Stop succeeed");
               return;
            }

            // Check if start of path is consistent with current robot pose, otherwise abort
            currentPathPoseIt = path.poses.begin();
            tf::poseStampedMsgToTF( *currentPathPoseIt, targetPose);
            if (poseDist(targetPose, globalToBase)> m_pathStartMaxDistance )
            {
               ROS_ERROR("Robot is too far away from start of plan. aborting");
               stopWalk();
               m_walkPathServer.setAborted(nao_msgs::FollowPathResult(),"Aborted");
               return;
            }

            // set targetPose, this will not change until we reached it
            targetIsEndOfPath = getNextTarget(path, globalToBase, currentPathPoseIt, targetPose, targetPathPoseIt );
            publishTargetPoseVis(targetPose);
            inhibitJoystick();
            
         } else {
            ROS_INFO("walk_path ActionServer preempted");
            // anything to cleanup?
            stopWalk();

            m_walkPathServer.setPreempted();
            return;
         }
      }

      if(m_useFootContactProtection && !m_footContact) {
         ROS_WARN("Lost foot contact, abort walk");
         stopWalk();
         m_walkPathServer.setAborted(nao_msgs::FollowPathResult(), "Aborting on the goal because the robot lost foot contact with the ground");
         return;
      }

      // TODO: publish feedback
      /*
         move_base_msgs::MoveBaseFeedback feedback;
         feedback.base_position.header.stamp = globalToBase.stamp_;
         feedback.base_position.header.frame_id = globalToBase.frame_id_;
         tf::poseTFToMsg(globalToBase, feedback.base_position.pose);
         m_walkGoalServer.publishFeedback(feedback);
         */


      double roll, pitch, yaw;
      tf::Transform relTarget = globalToBase.inverseTimes(targetPose);
      relTarget.getBasis().getRPY(roll, pitch, yaw);


      // treat last targetPose different from other waypoints on path
      if (targetIsEndOfPath && relTarget.getOrigin().length()< m_targetDistThres && std::abs(yaw) < m_targetAngThres){
         ROS_INFO("Target (%f %f %F) reached", targetPose.getOrigin().x(), targetPose.getOrigin().y(),
               tf::getYaw(targetPose.getRotation()));

         stopWalk();

         m_walkPathServer.setSucceeded(nao_msgs::FollowPathResult(), "Target reached");
         return;
      } else if (!targetIsEndOfPath && relTarget.getOrigin().length()< m_waypointDistThres && std::abs(yaw) < m_waypointAngThres){
         // update currentPathPoseIt to point to waypoint corresponding to  targetPose
         currentPathPoseIt = targetPathPoseIt;
         // update targetPose, targetPathPoseIt
         targetIsEndOfPath = getNextTarget(path, globalToBase, currentPathPoseIt, targetPose, targetPathPoseIt );
         publishTargetPoseVis(targetPose);
         // update relTarget
         relTarget = globalToBase.inverseTimes(targetPose);
      }
      

      // walk to targetPose (relTarget)
      // if the robot is walking on a straight line, set the target point further ahead (by m_straightOffset)
      tf::Transform relTargetStraight = relTarget;
      if(m_straight){
        std::vector< geometry_msgs::PoseStamped>::const_iterator targetIter = currentPathPoseIt;
        tf::Stamped<tf::Transform> targetPose, iterPose;
        double straightDist = 0.0;
        while(targetIter+1 != path.poses.end()){
          tf::poseStampedMsgToTF(*targetIter, targetPose);
          tf::poseStampedMsgToTF(*(targetIter+1), iterPose);
          straightDist += poseDist(targetPose, iterPose);
          if(straightDist > m_straightOffset)
            break;
          ++targetIter;
        }
        tf::Stamped<tf::Transform> straightTargetPose;
        tf::poseStampedMsgToTF(*targetIter, straightTargetPose);
        relTargetStraight = globalToBase.inverseTimes(straightTargetPose);
        relTargetStraight.setRotation(relTarget.getRotation());
      }
      if(m_useVelocityController) {
         setVelocity(relTargetStraight);
      } else {
         geometry_msgs::Pose2D target;
         target.x = relTargetStraight.getOrigin().x();
         target.y = relTargetStraight.getOrigin().y();
         target.theta = tf::getYaw(relTargetStraight.getRotation());

         m_targetPub.publish(target);
      }

      r.sleep();
      //make sure to sleep for the remainder of our cycle time
      if(r.cycleTime() > ros::Duration(1 / m_controllerFreq))
         ROS_WARN("Control loop missed its desired rate of %.4fHz... the loop actually took %.4f seconds", m_controllerFreq, r.cycleTime().toSec());

   }

   //if the node is killed then we'll abort and return

   // TODO: stopWalk is not completed if ctrl+c is hit FIX THIS!
   stopWalk();
   m_walkPathServer.setAborted(nao_msgs::FollowPathResult(), "Aborting on the goal because the node has been killed");



   std::cout << ("... path action ending") << std::endl;
}


void PathFollower::goalActionCB(const move_base_msgs::MoveBaseGoalConstPtr &goal){
        tf::Stamped<tf::Transform> targetPose;
        tf::poseStampedMsgToTF(goal->target_pose, targetPose);

        publishTargetPoseVis(targetPose);

        ros::Rate r(m_controllerFreq);
  inhibitJoystick();


        while(nh.ok()){
                if (m_walkGoalServer.isPreemptRequested()){
                        if(m_walkGoalServer.isNewGoalAvailable()){
                                ROS_INFO("walk_target ActionServer: new goal available");
                                move_base_msgs::MoveBaseGoal newGoal = *m_walkGoalServer.acceptNewGoal();
                                tf::poseStampedMsgToTF(newGoal.target_pose, targetPose);
                                publishTargetPoseVis(targetPose);
        inhibitJoystick();
        
                        } else {
                                ROS_INFO("walk_target ActionServer preempted");
                                // anything to cleanup?
                                stopWalk();

                                m_walkGoalServer.setPreempted();
                                return;
                        }
                }

                if(m_useFootContactProtection && !m_footContact) {
                    ROS_WARN("Lost foot contact, abort walk");
                    stopWalk();
                    m_walkGoalServer.setAborted(move_base_msgs::MoveBaseResult(), "Aborting on the goal because the robot lost foot contact with the ground");
                    return;
                }


                //tf::Stamped<tf::Transform> odomToTarget;
                tf::StampedTransform globalToBase;
                try
                {
                        // this causes a segfault when shutting down, move_base also doesn't have it?
//                      m_tfListener.waitForTransform(targetPose.frame_id_, m_baseFrameId, ros::Time(), ros::Duration(0.1));
                        m_tfListener.lookupTransform(targetPose.frame_id_, m_baseFrameId, ros::Time(), globalToBase);
                }
                catch(const tf::TransformException& e)
                {
                        ROS_WARN("Failed to obtain tf to base (%s)", e.what());
                        r.sleep();
                        continue;
                }
                //make sure base footprint is on the floor:
                globalToBase.getOrigin().setZ(0.0);
                double roll, pitch, yaw;
                globalToBase.getBasis().getRPY(roll, pitch, yaw);
                globalToBase.setRotation(tf::createQuaternionFromYaw(yaw));

                move_base_msgs::MoveBaseFeedback feedback;
                feedback.base_position.header.stamp = globalToBase.stamp_;
                feedback.base_position.header.frame_id = globalToBase.frame_id_;
                tf::poseTFToMsg(globalToBase, feedback.base_position.pose);
                m_walkGoalServer.publishFeedback(feedback);


                tf::Transform relTarget = globalToBase.inverseTimes(targetPose);
                relTarget.getBasis().getRPY(roll, pitch, yaw);

        // target reached:
        if (relTarget.getOrigin().length()< m_targetDistThres && std::abs(yaw) < m_targetAngThres){
            ROS_INFO("Target (%f %f %F) reached", targetPose.getOrigin().x(), targetPose.getOrigin().y(),
                    tf::getYaw(targetPose.getRotation()));

            stopWalk();

            m_walkGoalServer.setSucceeded(move_base_msgs::MoveBaseResult(), "Target reached");
            return;
        } else {
            if(m_useVelocityController) {
                setVelocity(relTarget);
            } else {
                geometry_msgs::Pose2D target;
                // workaround for NaoQI API (stay on the straight line connection facing towards goal)
                if (relTarget.getOrigin().length() > 0.2){
                    relTarget.setOrigin(0.2* relTarget.getOrigin().normalized());
                    yaw = atan2(relTarget.getOrigin().y(), relTarget.getOrigin().x());
                }
                target.x = relTarget.getOrigin().x();
                target.y = relTarget.getOrigin().y();
                target.theta = yaw;

                m_targetPub.publish(target);
            }
        }

            r.sleep();
            //make sure to sleep for the remainder of our cycle time
            if(r.cycleTime() > ros::Duration(1 / m_controllerFreq))
              ROS_WARN("Control loop missed its desired rate of %.4fHz... the loop actually took %.4f seconds", m_controllerFreq, r.cycleTime().toSec());

        }

        //if the node is killed then we'll abort and return
    stopWalk();
        m_walkGoalServer.setAborted(move_base_msgs::MoveBaseResult(), "Aborting on the goal because the node has been killed");

}

void PathFollower::stopWalk(){
        std_srvs::Empty::Request req;
        std_srvs::Empty::Response resp;
        if (!ros::service::call("stop_walk_srv", req, resp)){
           if(m_useVelocityController) {
              ROS_WARN("Call to stop_walk_srv Service failed, falling back to velocity=0,0,0");
              geometry_msgs::Twist twist;
              twist.linear.x = 0.0;
              twist.linear.y = 0.0;
              twist.angular.z = 0.0;
              m_velPub.publish(twist);
           }
           else
           {
              ROS_WARN("Call to stop_walk_srv Service failed, falling back to target=0,0,0");
              geometry_msgs::Pose2D target;
              target.x = 0.0;
              target.y = 0.0;
              target.theta = 0.0;
              m_targetPub.publish(target);
           }
        }
        if(m_isJoystickInhibited) {
            std_srvs::Empty e;
                if(m_uninhibitWalkClient.call(e)) {
                    ROS_INFO("Joystick uninhibited");
                        m_isJoystickInhibited = false;
                } else {
                        ROS_WARN("Could not uninhibit joystick walk");
                }
        }
}

void PathFollower::setVelocity(const tf::Transform& relTarget) {
        double dx, dy, yaw;
        bool rotateOnSpot;
        const double dist = relTarget.getOrigin().length();
        if(dist > m_thresholdFar) {
            // Far away: Orient towards the target point
            yaw = atan2(relTarget.getOrigin().y(), relTarget.getOrigin().x());
            rotateOnSpot = (std::abs(yaw) > m_thresholdRotate);
        } else {
            // Near: Orient towards the final angle
            yaw = tf::getYaw(relTarget.getRotation());
            rotateOnSpot = (std::abs(yaw) > m_thresholdRotate);
            if(dist < m_targetDistThres && std::abs(yaw) < m_targetAngThres) {
                geometry_msgs::Twist twist;
                twist.linear.x = 0.0;
                twist.linear.y = 0.0;
                twist.angular.z = 0.0;
                m_velPub.publish(twist);
                return;
            }
        }

        // Normalize angle between -180° and +180°
        yaw = angles::normalize_angle(yaw);

        // Reduce velocity near target
        const double dampXY = std::min(dist / m_thresholdDampXY, 1.0);
        const double dampYaw = std::min(std::abs(yaw) / m_thresholdDampYaw, 1.0);

        if(rotateOnSpot) {
            dx = 0.0;
            dy = 0.0;
        } else {
            dx = relTarget.getOrigin().x();
            dy = relTarget.getOrigin().y();
        }

        const double times[] = {
        std::abs(dx)  / ((dampXY * m_maxVelFractionX)    * m_maxVelXY  * m_stepFactor),
        std::abs(dy)  / ((dampXY * m_maxVelFractionY)    * m_maxVelXY  * m_stepFactor),
        std::abs(yaw) / ((dampYaw * m_maxVelFractionYaw) * m_maxVelYaw * m_stepFactor),
        1. / m_controllerFreq
    };
    const double maxtime = *std::max_element(times, times + 4);

    geometry_msgs::Twist twist;
    twist.linear.x  = dx  / (maxtime * m_maxVelXY  * m_stepFactor);
    twist.linear.y  = dy  / (maxtime * m_maxVelXY  * m_stepFactor);
    twist.angular.z = yaw / (maxtime * m_maxVelYaw * m_stepFactor);

    ROS_DEBUG("setVelocity: target %f %f %f --> velocity %f %f %f",
          relTarget.getOrigin().x(), relTarget.getOrigin().y(), yaw,
          twist.linear.x, twist.linear.y, twist.angular.z);
    m_velPub.publish(twist);
}

int main(int argc, char** argv){
   ros::init(argc, argv, "nao_path_follower");
   PathFollower follower;

   ros::spin();

   return 0;
}