move_base.cpp

Go to the documentation of this file.

/*********************************************************************
*
* Software License Agreement (BSD License)
*
*  Copyright (c) 2008, Willow Garage, Inc.
*  All rights reserved.
*
*  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 Willow Garage 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 SUBSTITUTE GOODS OR SERVICES;
*  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
*  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
*  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
*  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
*  POSSIBILITY OF SUCH DAMAGE.
*
* Author: Eitan Marder-Eppstein
*         Mike Phillips (put the planner in its own thread)
*********************************************************************/
#include <move_base/move_base.h>
#include <boost/algorithm/string.hpp>

namespace move_base {

  MoveBase::MoveBase(std::string name, tf::TransformListener& tf) :
    tf_(tf),
    as_(NULL),
    tc_(NULL), planner_costmap_ros_(NULL), controller_costmap_ros_(NULL),
    planner_(NULL), bgp_loader_("nav_core", "nav_core::BaseGlobalPlanner"),
    blp_loader_("nav_core", "nav_core::BaseLocalPlanner"), 
    recovery_loader_("nav_core", "nav_core::RecoveryBehavior"),
    planner_plan(NULL), latest_plan(NULL), controller_plan(NULL),
    runPlanner(false){

    as_ = new MoveBaseActionServer(ros::NodeHandle(), "move_base", boost::bind(&MoveBase::executeCb, this, _1), false);
    
    ros::NodeHandle private_nh("~");
    ros::NodeHandle nh;

    control_failure_recovery_ = false;

    //get some parameters that will be global to the move base node
    std::string global_planner, local_planner;
    private_nh.param("base_global_planner", global_planner, std::string("navfn/NavfnROS"));
    private_nh.param("base_local_planner", local_planner, std::string("base_local_planner/TrajectoryPlannerROS"));
    private_nh.param("global_costmap/robot_base_frame", robot_base_frame_, std::string("base_link"));
    private_nh.param("global_costmap/global_frame", global_frame_, std::string("/map"));
    private_nh.param("controller_frequency", controller_frequency_, 20.0);
    private_nh.param("controller_patience", controller_patience_, 15.0);
    private_nh.param("planner_frequency", planner_frequency_, 0.0);
    private_nh.param("planner_patience", planner_patience_, 5.0);


    //set up plan triple buffer
    planner_plan = new std::vector<geometry_msgs::PoseStamped>();
    latest_plan = new std::vector<geometry_msgs::PoseStamped>();
    controller_plan = new std::vector<geometry_msgs::PoseStamped>();

    //set up the planner's thread
    planner_lock = new boost::unique_lock<boost::mutex>(planner_mutex);
    planner_lock->unlock();
    
    planner_thread = new boost::thread(boost::bind(&MoveBase::planThread, this));


    //for comanding the base
    vel_pub_ = nh.advertise<geometry_msgs::Twist>("cmd_vel", 1);
    current_goal_pub_ = private_nh.advertise<geometry_msgs::PoseStamped>("current_goal", 0 );

    ros::NodeHandle action_nh("move_base");
    action_goal_pub_ = action_nh.advertise<move_base_msgs::MoveBaseActionGoal>("goal", 1);

    //we'll provide a mechanism for some people to send goals 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
    ros::NodeHandle simple_nh("move_base_simple");
    goal_sub_ = simple_nh.subscribe<geometry_msgs::PoseStamped>("goal", 1, boost::bind(&MoveBase::goalCB, this, _1));

    //we'll assume the radius of the robot to be consistent with what's specified for the costmaps
    private_nh.param("local_costmap/inscribed_radius", inscribed_radius_, 0.325);
    private_nh.param("local_costmap/circumscribed_radius", circumscribed_radius_, 0.46);
    private_nh.param("clearing_radius", clearing_radius_, circumscribed_radius_);
    private_nh.param("conservative_reset_dist", conservative_reset_dist_, 3.0);

    private_nh.param("shutdown_costmaps", shutdown_costmaps_, false);
    private_nh.param("clearing_roatation_allowed", clearing_roatation_allowed_, true);
    private_nh.param("recovery_behavior_enabled", recovery_behavior_enabled_, true);

    //create the ros wrapper for the planner's costmap... and initializer a pointer we'll use with the underlying map
    planner_costmap_ros_ = new costmap_2d::Costmap2DROS("global_costmap", tf_);
    planner_costmap_ros_->pause();

    //initialize the global planner
    try {
      //check if a non fully qualified name has potentially been passed in
      if(!bgp_loader_.isClassAvailable(global_planner)){
        std::vector<std::string> classes = bgp_loader_.getDeclaredClasses();
        for(unsigned int i = 0; i < classes.size(); ++i){
          if(global_planner == bgp_loader_.getName(classes[i])){
            //if we've found a match... we'll get the fully qualified name and break out of the loop
            ROS_WARN("Planner specifications should now include the package name. You are using a deprecated API. Please switch from %s to %s in your yaml file.",
                global_planner.c_str(), classes[i].c_str());
            global_planner = classes[i];
            break;
          }
        }
      }

      planner_ = bgp_loader_.createClassInstance(global_planner);
      planner_->initialize(bgp_loader_.getName(global_planner), planner_costmap_ros_);
    } catch (const pluginlib::PluginlibException& ex)
    {
      ROS_FATAL("Failed to create the %s planner, are you sure it is properly registered and that the containing library is built? Exception: %s", global_planner.c_str(), ex.what());
      exit(0);
    }

    ROS_INFO("MAP SIZE: %d, %d", planner_costmap_ros_->getSizeInCellsX(), planner_costmap_ros_->getSizeInCellsY());

    //create the ros wrapper for the controller's costmap... and initializer a pointer we'll use with the underlying map
    controller_costmap_ros_ = new costmap_2d::Costmap2DROS("local_costmap", tf_);
    controller_costmap_ros_->pause();

    //create a local planner
    try {
      //check if a non fully qualified name has potentially been passed in
      if(!blp_loader_.isClassAvailable(local_planner)){
        std::vector<std::string> classes = blp_loader_.getDeclaredClasses();
        for(unsigned int i = 0; i < classes.size(); ++i){
          if(local_planner == blp_loader_.getName(classes[i])){
            //if we've found a match... we'll get the fully qualified name and break out of the loop
            ROS_WARN("Planner specifications should now include the package name. You are using a deprecated API. Please switch from %s to %s in your yaml file.",
                local_planner.c_str(), classes[i].c_str());
            local_planner = classes[i];
            break;
          }
        }
      }

      tc_ = blp_loader_.createClassInstance(local_planner);
      tc_->initialize(blp_loader_.getName(local_planner), &tf_, controller_costmap_ros_);
    } catch (const pluginlib::PluginlibException& ex)
    {
      ROS_FATAL("Failed to create the %s planner, are you sure it is properly registered and that the containing library is built? Exception: %s", local_planner.c_str(), ex.what());
      exit(0);
    }

    // Start actively updating costmaps based on sensor data
    planner_costmap_ros_->start();
    controller_costmap_ros_->start();

    //advertise a service for getting a plan
    make_plan_srv_ = private_nh.advertiseService("make_plan", &MoveBase::planService, this);

    //advertise a service for clearing the costmaps
    clear_unknown_srv_ = private_nh.advertiseService("clear_unknown_space", &MoveBase::clearUnknownService, this);

    //initially clear any unknown space around the robot
    planner_costmap_ros_->clearNonLethalWindow(circumscribed_radius_ * 4, circumscribed_radius_ * 4);
    controller_costmap_ros_->clearNonLethalWindow(circumscribed_radius_ * 4, circumscribed_radius_ * 4);

    //if we shutdown our costmaps when we're deactivated... we'll do that now
    if(shutdown_costmaps_){
      ROS_DEBUG("Stopping costmaps initially");
      planner_costmap_ros_->stop();
      controller_costmap_ros_->stop();
    }

    //load any user specified recovery behaviors, and if that fails load the defaults
    if(!loadRecoveryBehaviors(private_nh)){
      loadDefaultRecoveryBehaviors();
    }

    //initially, we'll need to make a plan
    state_ = PLANNING;

    //we'll start executing recovery behaviors at the beginning of our list
    recovery_index_ = 0;

    //we're all set up now so we can start the action server
    as_->start();
  }

  void MoveBase::goalCB(const geometry_msgs::PoseStamped::ConstPtr& 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;

    action_goal_pub_.publish(action_goal);
  }

  void MoveBase::clearCostmapWindows(double size_x, double size_y){
    tf::Stamped<tf::Pose> global_pose;

    //clear the planner's costmap
    planner_costmap_ros_->getRobotPose(global_pose);

    std::vector<geometry_msgs::Point> clear_poly;
    double x = global_pose.getOrigin().x();
    double y = global_pose.getOrigin().y();
    geometry_msgs::Point pt;

    pt.x = x - size_x / 2;
    pt.y = y - size_x / 2;
    clear_poly.push_back(pt);

    pt.x = x + size_x / 2;
    pt.y = y - size_x / 2;
    clear_poly.push_back(pt);

    pt.x = x + size_x / 2;
    pt.y = y + size_x / 2;
    clear_poly.push_back(pt);

    pt.x = x - size_x / 2;
    pt.y = y + size_x / 2;
    clear_poly.push_back(pt);

    planner_costmap_ros_->setConvexPolygonCost(clear_poly, costmap_2d::FREE_SPACE);

    //clear the controller's costmap
    controller_costmap_ros_->getRobotPose(global_pose);

    clear_poly.clear();
    x = global_pose.getOrigin().x();
    y = global_pose.getOrigin().y();

    pt.x = x - size_x / 2;
    pt.y = y - size_x / 2;
    clear_poly.push_back(pt);

    pt.x = x + size_x / 2;
    pt.y = y - size_x / 2;
    clear_poly.push_back(pt);

    pt.x = x + size_x / 2;
    pt.y = y + size_x / 2;
    clear_poly.push_back(pt);

    pt.x = x - size_x / 2;
    pt.y = y + size_x / 2;
    clear_poly.push_back(pt);

    controller_costmap_ros_->setConvexPolygonCost(clear_poly, costmap_2d::FREE_SPACE);
  }

  bool MoveBase::clearUnknownService(std_srvs::Empty::Request &req, std_srvs::Empty::Response &resp){
    //clear any unknown space around the robot the same as we do on initialization
    planner_costmap_ros_->clearNonLethalWindow(circumscribed_radius_ * 4, circumscribed_radius_ * 4);
    controller_costmap_ros_->clearNonLethalWindow(circumscribed_radius_ * 4, circumscribed_radius_ * 4);
    return true;
  }

  bool MoveBase::planService(nav_msgs::GetPlan::Request &req, nav_msgs::GetPlan::Response &resp){
    if(as_->isActive()){
      ROS_ERROR("move_base must be in an inactive state to make a plan for an external user");
      return false;
    }

    //make sure we have a costmap for our planner
    if(planner_costmap_ros_ == NULL){
      ROS_ERROR("move_base cannot make a plan for you because it doesn't have a costmap");
      return false;
    }

    tf::Stamped<tf::Pose> global_pose;
    if(!planner_costmap_ros_->getRobotPose(global_pose)){
      ROS_ERROR("move_base cannot make a plan for you because it could not get the start pose of the robot");
      return false;
    }

    geometry_msgs::PoseStamped start;
    tf::poseStampedTFToMsg(global_pose, start);

    //update the copy of the costmap the planner uses
    clearCostmapWindows(2 * clearing_radius_, 2 * clearing_radius_);

    //if we have a tolerance on the goal point that is greater
    //than the resolution of the map... compute the full potential function
    double resolution = planner_costmap_ros_->getResolution();
    std::vector<geometry_msgs::PoseStamped> global_plan;
    geometry_msgs::PoseStamped p;
    p = req.goal;
    p.pose.position.y = req.goal.pose.position.y - req.tolerance;
    bool found_legal = false;
    while(!found_legal && p.pose.position.y <= req.goal.pose.position.y + req.tolerance){
      p.pose.position.x = req.goal.pose.position.x - req.tolerance;
      while(!found_legal && p.pose.position.x <= req.goal.pose.position.x + req.tolerance){
        if(planner_->makePlan(start, p, global_plan)){
          if(!global_plan.empty()){
            global_plan.push_back(p);
            found_legal = true;
          }
          else
            ROS_DEBUG("Failed to find a  plan to point (%.2f, %.2f)", p.pose.position.x, p.pose.position.y);
        }
        p.pose.position.x += resolution*3.0;
      }
      p.pose.position.y += resolution*3.0;
    }

    //copy the plan into a message to send out
    resp.plan.poses.resize(global_plan.size());
    for(unsigned int i = 0; i < global_plan.size(); ++i){
      resp.plan.poses[i] = global_plan[i];
    }



    return true;
  }

  MoveBase::~MoveBase(){
    recovery_behaviors_.clear();

    if(as_ != NULL)
      delete as_;

    if(planner_ != NULL)
      delete planner_;

    if(tc_ != NULL)
      delete tc_;

    if(planner_costmap_ros_ != NULL)
      delete planner_costmap_ros_;

    if(controller_costmap_ros_ != NULL)
      delete controller_costmap_ros_;

    planner_thread->join();

    delete planner_plan;
    delete latest_plan;
    delete controller_plan;
    delete planner_lock;
  }

  bool MoveBase::makePlan(const geometry_msgs::PoseStamped& goal, std::vector<geometry_msgs::PoseStamped>& plan){
    //make sure to set the plan to be empty initially
    plan.clear();

    //since this gets called on handle activate
    if(planner_costmap_ros_ == NULL)
      return false;

    //get the starting pose of the robot
    tf::Stamped<tf::Pose> global_pose;
    if(!planner_costmap_ros_->getRobotPose(global_pose))
      return false;

    geometry_msgs::PoseStamped start;
    tf::poseStampedTFToMsg(global_pose, start);

    //if the planner fails or returns a zero length plan, planning failed
    if(!planner_->makePlan(start, goal, plan) || plan.empty()){
      ROS_DEBUG("Failed to find a  plan to point (%.2f, %.2f)", goal.pose.position.x, goal.pose.position.y);
      return false;
    }

    return true;
  }

  void MoveBase::publishZeroVelocity(){
    geometry_msgs::Twist cmd_vel;
    cmd_vel.linear.x = 0.0;
    cmd_vel.linear.y = 0.0;
    cmd_vel.angular.z = 0.0;
    vel_pub_.publish(cmd_vel);

  }

  bool MoveBase::isQuaternionValid(const geometry_msgs::Quaternion& q){
    //first we need to check if the quaternion has nan's or infs
    if(!std::isfinite(q.x) || !std::isfinite(q.y) || !std::isfinite(q.z) || !std::isfinite(q.w)){
      ROS_ERROR("Quaternion has nans or infs... discarding as a navigation goal");
      return false;
    }

    tf::Quaternion tf_q(q.x, q.y, q.z, q.w);

    //next, we need to check if the length of the quaternion is close to zero
    if(tf_q.length2() < 1e-6){
      ROS_ERROR("Quaternion has length close to zero... discarding as navigation goal");
      return false;
    }

    //next, we'll normalize the quaternion and check that it transforms the vertical vector correctly
    tf_q.normalize();

    btVector3 up(0, 0, 1);

    double dot = up.dot(up.rotate(tf_q.getAxis(), tf_q.getAngle()));

    if(fabs(dot - 1) > 1e-3){
      ROS_ERROR("Quaternion is invalid... for navigation the z-axis of the quaternion must be close to vertical.");
      return false;
    }

    return true;
  }

  geometry_msgs::PoseStamped MoveBase::goalToGlobalFrame(const geometry_msgs::PoseStamped& goal_pose_msg){
    std::string global_frame = planner_costmap_ros_->getGlobalFrameID();
    tf::Stamped<tf::Pose> goal_pose, global_pose;
    poseStampedMsgToTF(goal_pose_msg, goal_pose);

    //just get the latest available transform... for accuracy they should send
    //goals in the frame of the planner
    goal_pose.stamp_ = ros::Time();

    try{
      tf_.transformPose(global_frame, goal_pose, global_pose);
    }
    catch(tf::TransformException& ex){
      ROS_WARN("Failed to transform the goal pose from %s into the %s frame: %s",
          goal_pose.frame_id_.c_str(), global_frame.c_str(), ex.what());
      return goal_pose_msg;
    }

    geometry_msgs::PoseStamped global_pose_msg;
    tf::poseStampedTFToMsg(global_pose, global_pose_msg);
    return global_pose_msg;

  }

  void MoveBase::planThread(){
    ROS_DEBUG("Starting planner thread...");
    ros::NodeHandle n;
    ros::Rate r(planner_frequency_);
    while(n.ok()){
      
      //check if we should run the planner
      planner_lock->lock();
      while(!runPlanner){
        //if we should not be running the planner then suspend this thread
        ROS_DEBUG("Planner thread is suspending");
        planner_cond.wait(*planner_lock);
      }
      planner_lock->unlock();
      ROS_DEBUG("Planning...");

      //run planner
      ROS_DEBUG("In planning state");
      planner_plan->clear();
      bool gotPlan = n.ok() && makePlan(planner_goal, *planner_plan);

      if(gotPlan){
        ROS_DEBUG("Got Plan!");
        //pointer swap the plans under mutex (the controller will pull from latest_plan)
        std::vector<geometry_msgs::PoseStamped>* temp_plan = planner_plan;
        plan_lock.lock();
        planner_plan = latest_plan;
        latest_plan = temp_plan;
        plan_lock.unlock();

        last_valid_plan_ = ros::Time::now();

        ROS_DEBUG("Generated a plan from the base_global_planner");
        
        //make sure we only start the controller if we still haven't reached the goal
        if(runPlanner)
          state_ = CONTROLLING;
        if(planner_frequency_ <= 0)
          runPlanner = false;

      }
      //if we didn't get a plan and we are in the planning state (the robot isn't moving)
      else if(state_==PLANNING){
        ROS_DEBUG("No Plan...");
        ros::Time attempt_end = last_valid_plan_ + ros::Duration(planner_patience_);

        //check if we've tried to make a plan for over our time limit
        if(ros::Time::now() > attempt_end){
          //we'll move into our obstacle clearing mode
          state_ = CLEARING;
          publishZeroVelocity();

        }
      }

      if(planner_frequency_ > 0)
        r.sleep();
    }
  }

  void MoveBase::executeCb(const move_base_msgs::MoveBaseGoalConstPtr& move_base_goal)
  {
    if(!isQuaternionValid(move_base_goal->target_pose.pose.orientation)){
      as_->setAborted(move_base_msgs::MoveBaseResult(), "Aborting on goal because it was sent with an invalid quaternion");
      return;
    }

    geometry_msgs::PoseStamped goal = goalToGlobalFrame(move_base_goal->target_pose);
    //we have a goal so start the planner
    planner_goal = goal;
    runPlanner = true;
    planner_cond.notify_one();

    current_goal_pub_.publish(goal);
    std::vector<geometry_msgs::PoseStamped> global_plan;

    ros::Rate r(controller_frequency_);
    if(shutdown_costmaps_){
      ROS_DEBUG("Starting up costmaps that were shut down previously");
      planner_costmap_ros_->start();
      controller_costmap_ros_->start();
    }

    //we want to make sure that we reset the last time we had a valid plan and control
    last_valid_control_ = ros::Time::now();
    last_valid_plan_ = ros::Time::now();
    last_plan_swap_ = ros::Time::now();

    ros::NodeHandle n;
    while(n.ok())
    {
      if(as_->isPreemptRequested()){
        if(as_->isNewGoalAvailable()){
          //if we're active and a new goal is available, we'll accept it, but we won't shut anything down
          move_base_msgs::MoveBaseGoal new_goal = *as_->acceptNewGoal();

          if(!isQuaternionValid(new_goal.target_pose.pose.orientation)){
            as_->setAborted(move_base_msgs::MoveBaseResult(), "Aborting on goal because it was sent with an invalid quaternion");
            return;
          }

          goal = goalToGlobalFrame(new_goal.target_pose);

          //we'll make sure that we reset our state for the next execution cycle
          recovery_index_ = 0;
          state_ = PLANNING;
          //we have a new goal so make sure the planner is awake
          planner_goal = goal;
          runPlanner = true;
          planner_cond.notify_one();

          //publish the goal point to the visualizer
          ROS_DEBUG("move_base has received a goal of x: %.2f, y: %.2f", goal.pose.position.x, goal.pose.position.y);
          current_goal_pub_.publish(goal);

          //make sure to reset our timeouts
          last_valid_control_ = ros::Time::now();
          last_valid_plan_ = ros::Time::now();
          last_plan_swap_ = ros::Time::now();
        }
        else {
          //if we've been preempted explicitly we need to shut things down
          resetState();

          //notify the ActionServer that we've successfully preempted
          ROS_DEBUG("Move base preempting the current goal");
          as_->setPreempted();

          //we'll actually return from execute after preempting
          return;
        }
      }

      //for timing that gives real time even in simulation
      ros::WallTime start = ros::WallTime::now();

      //the real work on pursuing a goal is done here
      bool done = executeCycle(goal, global_plan);

      //if we're done, then we'll return from execute
      if(done)
        return;

      //check if execution of the goal has completed in some way

      ros::WallDuration t_diff = ros::WallTime::now() - start;
      ROS_DEBUG("Full control cycle time: %.9f\n", t_diff.toSec());

      r.sleep();
      //make sure to sleep for the remainder of our cycle time
      if(r.cycleTime() > ros::Duration(1 / controller_frequency_) && state_ == CONTROLLING)
        ROS_WARN("Control loop missed its desired rate of %.4fHz... the loop actually took %.4f seconds", controller_frequency_, r.cycleTime().toSec());
    }
    runPlanner = true;
    planner_cond.notify_one();

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

  bool MoveBase::executeCycle(geometry_msgs::PoseStamped& goal, std::vector<geometry_msgs::PoseStamped>& global_plan){
    ROS_DEBUG("executeCycle");
    //we need to be able to publish velocity commands
    geometry_msgs::Twist cmd_vel;

    //update feedback to correspond to our curent position
    tf::Stamped<tf::Pose> global_pose;
    planner_costmap_ros_->getRobotPose(global_pose);
    geometry_msgs::PoseStamped current_position;
    tf::poseStampedTFToMsg(global_pose, current_position);

    //push the feedback out
    move_base_msgs::MoveBaseFeedback feedback;
    feedback.base_position = current_position;
    as_->publishFeedback(feedback);

    //check that the observation buffers for the costmap are current, we don't want to drive blind
    if(!controller_costmap_ros_->isCurrent()){
      ROS_WARN("[%s]:Sensor data is out of date, we're not going to allow commanding of the base for safety",ros::this_node::getName().c_str());
      publishZeroVelocity();
      return false;
    }

    //if we have a new plan then grab it and give it to the controller
    ROS_DEBUG("time compare");
    if(last_valid_plan_.toSec() > last_plan_swap_.toSec()){
      ROS_DEBUG("new plan...swap pointers");

      //do a pointer swap under mutex
      last_plan_swap_ = ros::Time::now();
      std::vector<geometry_msgs::PoseStamped>* temp_plan = controller_plan;
      plan_lock.lock();
      controller_plan = latest_plan;
      latest_plan = temp_plan;
      plan_lock.unlock();
      ROS_DEBUG("pointers swapped!");

      if(!tc_->setPlan(*controller_plan)){
        //ABORT and SHUTDOWN COSTMAPS
        ROS_ERROR("Failed to pass global plan to the controller, aborting.");
        resetState();

        //disable the planner thread
        runPlanner = false;

        as_->setAborted(move_base_msgs::MoveBaseResult(), "Failed to pass global plan to the controller.");
        return true;
      }

      //make sure to reset recovery_index_ since we were able to find a valid plan
      if(!control_failure_recovery_)
        recovery_index_ = 0;
    }
    ROS_DEBUG("past time compare");

    //the move_base state machine, handles the control logic for navigation
    switch(state_){
      //if we are in a planning state, then we'll attempt to make a plan
      case PLANNING:
        ROS_DEBUG("Waiting for plan...");
        //we don't want to attempt to control if planning failed
        break;

      //if we're controlling, we'll attempt to find valid velocity commands
      case CONTROLLING:
        ROS_DEBUG("In controlling state");

        //check to see if we've reached our goal
        if(tc_->isGoalReached()){
          ROS_DEBUG("Goal reached!");
          resetState();

          //disable the planner thread
          runPlanner = false;

          as_->setSucceeded(move_base_msgs::MoveBaseResult(), "Goal reached.");
          return true;
        }

        if(tc_->computeVelocityCommands(cmd_vel)){
          last_valid_control_ = ros::Time::now();
          //make sure that we send the velocity command to the base
          vel_pub_.publish(cmd_vel);
          control_failure_recovery_ = false;
          recovery_index_ = 0;
        }
        else {
          ros::Time attempt_end = last_valid_control_ + ros::Duration(controller_patience_);

          //check if we've tried to find a valid control for longer than our time limit
          if(ros::Time::now() > attempt_end){
            //we'll move into our obstacle clearing mode
            publishZeroVelocity();
            state_ = CLEARING;
            control_failure_recovery_ = true;
          }
          else{
            //otherwise, if we can't find a valid control, we'll go back to planning
            last_valid_plan_ = ros::Time::now();
            state_ = PLANNING;
            publishZeroVelocity();

            //enable the planner thread in case it isn't running on a clock
            runPlanner = true;
            planner_cond.notify_one();
          }
        }

        break;

      //we'll try to clear out space with any user-provided recovery behaviors
      case CLEARING:
        ROS_DEBUG("In clearing/recovery state");
        //we'll invoke whatever recovery behavior we're currently on if they're enabled
        if(recovery_behavior_enabled_ && recovery_index_ < recovery_behaviors_.size()){
          recovery_behaviors_[recovery_index_]->runBehavior();

          //we'll check if the recovery behavior actually worked
          state_ = PLANNING;

          //update the index of the next recovery behavior that we'll try
          recovery_index_++;
        }
        else{
          if(control_failure_recovery_){
            ROS_ERROR("Aborting because a valid control could not be found. Even after executing all recovery behaviors");

            //disable the planner thread
            runPlanner = false;

            as_->setAborted(move_base_msgs::MoveBaseResult(), "Failed to find a valid control. Even after executing recovery behaviors.");
          }
          else{
            ROS_ERROR("Aborting because a valid plan could not be found. Even after executing all recovery behaviors");

            //disable the planner thread
            runPlanner = false;

            as_->setAborted(move_base_msgs::MoveBaseResult(), "Failed to find a valid plan. Even after executing recovery behaviors.");
          }
          resetState();
          return true;
        }
        break;
      default:
        ROS_ERROR("This case should never be reached, something is wrong, aborting");
        resetState();

        //disable the planner thread
        runPlanner = false;

        as_->setAborted(move_base_msgs::MoveBaseResult(), "Reached a case that should not be hit in move_base. This is a bug, please report it.");
        return true;
    }

    //we aren't done yet
    return false;
  }

  bool MoveBase::loadRecoveryBehaviors(ros::NodeHandle node){
    XmlRpc::XmlRpcValue behavior_list;
    if(node.getParam("recovery_behaviors", behavior_list)){
      if(behavior_list.getType() == XmlRpc::XmlRpcValue::TypeArray){
        for(int i = 0; i < behavior_list.size(); ++i){
          if(behavior_list[i].getType() == XmlRpc::XmlRpcValue::TypeStruct){
            if(behavior_list[i].hasMember("name") && behavior_list[i].hasMember("type")){
              //check for recovery behaviors with the same name
              for(int j = i + 1; j < behavior_list.size(); j++){
                if(behavior_list[j].getType() == XmlRpc::XmlRpcValue::TypeStruct){
                  if(behavior_list[j].hasMember("name") && behavior_list[j].hasMember("type")){
                    std::string name_i = behavior_list[i]["name"];
                    std::string name_j = behavior_list[j]["name"];
                    if(name_i == name_j){
                      ROS_ERROR("A recovery behavior with the name %s already exists, this is not allowed. Using the default recovery behaviors instead.", 
                          name_i.c_str());
                      return false;
                    }
                  }
                }
              }
            }
            else{
              ROS_ERROR("Recovery behaviors must have a name and a type and this does not. Using the default recovery behaviors instead.");
              return false;
            }
          }
          else{
            ROS_ERROR("Recovery behaviors must be specified as maps, but they are XmlRpcType %d. We'll use the default recovery behaviors instead.",
                behavior_list[i].getType());
            return false;
          }
        }

        //if we've made it to this point, we know that the list is legal so we'll create all the recovery behaviors
        for(int i = 0; i < behavior_list.size(); ++i){
          try{
            //check if a non fully qualified name has potentially been passed in
            if(!recovery_loader_.isClassAvailable(behavior_list[i]["type"])){
              std::vector<std::string> classes = recovery_loader_.getDeclaredClasses();
              for(unsigned int i = 0; i < classes.size(); ++i){
                if(behavior_list[i]["type"] == recovery_loader_.getName(classes[i])){
                  //if we've found a match... we'll get the fully qualified name and break out of the loop
                  ROS_WARN("Recovery behavior specifications should now include the package name. You are using a deprecated API. Please switch from %s to %s in your yaml file.",
                      std::string(behavior_list[i]["type"]).c_str(), classes[i].c_str());
                  behavior_list[i]["type"] = classes[i];
                  break;
                }
              }
            }

            boost::shared_ptr<nav_core::RecoveryBehavior> behavior(recovery_loader_.createClassInstance(behavior_list[i]["type"]));

            //shouldn't be possible, but it won't hurt to check
            if(behavior.get() == NULL){
              ROS_ERROR("The ClassLoader returned a null pointer without throwing an exception. This should not happen");
              return false;
            }

            //initialize the recovery behavior with its name
            behavior->initialize(behavior_list[i]["name"], &tf_, planner_costmap_ros_, controller_costmap_ros_);
            recovery_behaviors_.push_back(behavior);
          }
          catch(pluginlib::PluginlibException& ex){
            ROS_ERROR("Failed to load a plugin. Using default recovery behaviors. Error: %s", ex.what());
            return false;
          }
        }
      }
      else{
        ROS_ERROR("The recovery behavior specification must be a list, but is of XmlRpcType %d. We'll use the default recovery behaviors instead.", 
            behavior_list.getType());
        return false;
      }
    }
    else{
      //if no recovery_behaviors are specified, we'll just load the defaults
      return false;
    }

    //if we've made it here... we've constructed a recovery behavior list successfully
    return true;
  }

  //we'll load our default recovery behaviors here
  void MoveBase::loadDefaultRecoveryBehaviors(){
    recovery_behaviors_.clear();
    try{
      //we need to set some parameters based on what's been passed in to us to maintain backwards compatibility
      ros::NodeHandle n("~");
      n.setParam("conservative_reset/reset_distance", conservative_reset_dist_);
      n.setParam("aggressive_reset/reset_distance", circumscribed_radius_ * 4);

      //first, we'll load a recovery behavior to clear the costmap
      boost::shared_ptr<nav_core::RecoveryBehavior> cons_clear(recovery_loader_.createClassInstance("clear_costmap_recovery/ClearCostmapRecovery"));
      cons_clear->initialize("conservative_reset", &tf_, planner_costmap_ros_, controller_costmap_ros_);
      recovery_behaviors_.push_back(cons_clear);

      //next, we'll load a recovery behavior to rotate in place
      boost::shared_ptr<nav_core::RecoveryBehavior> rotate(recovery_loader_.createClassInstance("rotate_recovery/RotateRecovery"));
      if(clearing_roatation_allowed_){
        boost::shared_ptr<nav_core::RecoveryBehavior> rotate(recovery_loader_.createClassInstance("rotate_recovery/RotateRecovery"));
        rotate->initialize("rotate_recovery", &tf_, planner_costmap_ros_, controller_costmap_ros_);
        recovery_behaviors_.push_back(rotate);
      }

      //next, we'll load a recovery behavior that will do an aggressive reset of the costmap
      boost::shared_ptr<nav_core::RecoveryBehavior> ags_clear(recovery_loader_.createClassInstance("clear_costmap_recovery/ClearCostmapRecovery"));
      ags_clear->initialize("aggressive_reset", &tf_, planner_costmap_ros_, controller_costmap_ros_);
      recovery_behaviors_.push_back(ags_clear);

      //we'll rotate in-place one more time
      if(clearing_roatation_allowed_){
        recovery_behaviors_.push_back(rotate);
      }
    }
    catch(pluginlib::PluginlibException& ex){
      ROS_FATAL("Failed to load a plugin. This should not happen on default recovery behaviors. Error: %s", ex.what());
    }

    return;
  }

  void MoveBase::resetState(){
    state_ = PLANNING;
    recovery_index_ = 0;
    control_failure_recovery_ = false;
    publishZeroVelocity();

    //if we shutdown our costmaps when we're deactivated... we'll do that now
    if(shutdown_costmaps_){
      ROS_DEBUG("Stopping costmaps");
      planner_costmap_ros_->stop();
      controller_costmap_ros_->stop();
    }
  }

};

int main(int argc, char** argv){
  ros::init(argc, argv, "move_base_node");
  tf::TransformListener tf(ros::Duration(10));

  move_base::MoveBase move_base("move_base", tf);

  //ros::MultiThreadedSpinner s;
  ros::spin();

  return(0);

}

---

parallel_move_base
Author(s): Eitan Marder-Eppstein, Mike Phillips
autogenerated on Fri Jan 11 09:12:29 2013