move_base列印輸出LOG如下：

//進入planThread
[ INFO] [1533878479.616677684]: MOVE_BASE makeplan ............//進入makePlan
[ WARN] [1533878479.616771892]: Unable to get starting pose of robot, unable to create global plan
[ INFO] [1533878479.616850642]: move_base_plan_thread No Plan...
[ INFO] [1533878479.616929100]: move_base plan_thread temp_goal:2.127500,0.136710 ////step1
[ INFO] [1533878479.617001725]: MOVE_BASE makeplan ............//進入makePlan//step2
[ WARN] [1533878479.617083684]: Unable to get starting pose of robot, unable to create global plan //進入makePlan//step2
[ INFO] [1533878479.617222225]: move_base_plan_thread No Plan...//退出至planThread//step3
[ INFO] [1533878479.617307100]: move_base plan_thread temp_goal:2.127500,0.136710 //step1
[ INFO] [1533878479.617379142]: MOVE_BASE makeplan ............//進入makePlan//step2
[ WARN] [1533878479.617462850]: Unable to get starting pose of robot, unable to create global plan
......
process[move_base-1]: started with pid [3033]
[ INFO] [1533885354.818131879]: move_base plan_thread //進入planThread
[ INFO] [1533885356.529799005]: Created local_planner base_local_planner/TrajectoryPlannerROS  //建立一個區域性規劃器
[ WARN] [1533885604.047814331]: Costmap2DROS transform timeout. Current time: 1533885604.0476, global_pose stamp: 1533885602.5442, tolerance: 1.5000
[ WARN] [1533885604.076749998]: Could not get robot pose, cancelling reconfiguration
 

現象描述：

在專案中設定的流程為先執行move_base，到達目標後執行沿邊清掃程式，以上故障會導致定點移動失敗！且沿邊時會碰撞障礙物並不停止。

“Unable to get starting pose of robot, unable to create global plan”

逐本溯源：

逐本1層，以上log源於move_base.cpp函式，以上log是在執行planTread執行緒，進行規劃makePlan並不斷失敗，重新規劃的過程！細節見下：

bool MoveBase::makePlan(const geometry_msgs::PoseStamped& goal, std::vector<geometry_msgs::PoseStamped>& plan){
    boost::unique_lock<costmap_2d::Costmap2D::mutex_t> lock(*(planner_costmap_ros_->getCostmap()->getMutex()));

    //make sure to set the plan to be empty initially
    plan.clear();

    //since this gets called on handle activate
    if(planner_costmap_ros_ == NULL) { //全域性導航的地圖
      ROS_ERROR("Planner costmap ROS is NULL, unable to create global plan");
      return false;
    }

    //get the starting pose of the robot
    tf::Stamped<tf::Pose> global_pose;
    if(!planner_costmap_ros_->getRobotPose(global_pose)) {
      ROS_WARN("Unable to get starting pose of robot, unable to create global plan");
      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_NAMED("move_base","Failed to find a  plan to point (%.2f, %.2f)", goal.pose.position.x,               goal.pose.position.y);
      return false;
    }

    return true;
  }
 

bool MoveBase::makePlan(const geometry_msgs::PoseStamped& goal, std::vector<geometry_msgs::PoseStamped>& plan)中,該函式①清除了規劃器plan --->②全域性導航的地圖是否為空--->③獲取裝置在全域性導航地圖中的座標--->④將該座標轉換為move_base中的座標geometry_msgs::PoseStamped作為起點--->⑤根據起點和目標點規劃plan;

根據log可知，排除了全域性導航的地圖為空的可能性，問題在於getRobotPose失敗！當且僅當planner_costmap_ros_->getRobotPose(global_pose)值為0時。

if(!planner_costmap_ros_->getRobotPose(global_pose)) {
      ROS_WARN("Unable to get starting pose of robot, unable to create global plan");
      return false;

逐本2層，etRobotPose這個函式是costmap_2d包中costmap_2d_ros.cpp，原始碼如下：

bool Costmap2DROS::getRobotPose(tf::Stamped<tf::Pose>& global_pose) const
{
  global_pose.setIdentity();
  tf::Stamped < tf::Pose > robot_pose;
  robot_pose.setIdentity();
  robot_pose.frame_id_ = robot_base_frame_;
  robot_pose.stamp_ = ros::Time();
  ros::Time current_time = ros::Time::now();  // save time for checking tf delay later

  // get the global pose of the robot
  try
  {
    tf_.transformPose(global_frame_, robot_pose, global_pose);
  }
  catch (tf::LookupException& ex)
  {
    ROS_ERROR_THROTTLE(1.0, "No Transform available Error looking up robot pose: %s\n", ex.what());
    return false;
  }
  catch (tf::ConnectivityException& ex)
  {
    ROS_ERROR_THROTTLE(1.0, "Connectivity Error looking up robot pose: %s\n", ex.what());
    return false;
  }
  catch (tf::ExtrapolationException& ex)
  {
    ROS_ERROR_THROTTLE(1.0, "Extrapolation Error looking up robot pose: %s\n", ex.what());
    return false;
  }
  // check global_pose timeout
  if (current_time.toSec() - global_pose.stamp_.toSec() > transform_tolerance_)
  {
    ROS_WARN_THROTTLE(1.0,
                      "Costmap2DROS transform timeout. Current time: %.4f, global_pose stamp: %.4f, tolerance: %.4f",
                      current_time.toSec(), global_pose.stamp_.toSec(), transform_tolerance_);
    return false;
  }

  return true;
}

這是一個函式實現了座標的tf轉換，並且進行了異常處理（作者早期的原始碼只有左邊轉換，無異常處理）；

有四種情況下會輸出false,分別是LookupException、ConnectivityException、ExtrapolationException、global_pose timeout；

其中前三個是由異常導致！！！最後一個是由於當前時間和global_pose時間差大於容忍轉換時間導致！！！

從try程式塊tf_.transformPose()可知，getRobotPose進行的工作是tf轉換！！！

將robot_pose轉換成global_pose，根據我們對tf轉換的瞭解可知，這兩者資料型別相同；（下面有分析均為Stamped<tf::Pose>）

因此造成以上失敗的原因，可能有兩種！

• tf_.transformPose轉換異常
• tf_.transformPose超時

以上兩種情況，按理論上應該是有列印輸出，通過檢視列印就能知道是哪種原因造成的。但實際執行時，由於日誌級別設定問題，不會輸出ROS_WARN_THROTTLE相關資訊！（此處有坑，理論上warn和error級別高於info，應該有列印輸出，實際輸出的log並未看見相關資訊）。正常情況下，如果有以上四種LOG中的任意一個就可以定位問題是轉換異常還是轉換超時，但是目前我們缺乏資訊，只能進一步深挖了！

補充資訊：tf_.transformPose轉換異常的型別彙總

tf/include/tf/exceptioms.h

#ifndef TF_EXCEPTIONS_H
#define TF_EXCEPTIONS_H

#include <stdexcept>
#include <tf2/exceptions.h>

namespace tf{

// Pass through exceptions from tf2
typedef tf2::TransformException TransformException;
typedef tf2::LookupException LookupException;
typedef tf2::ConnectivityException ConnectivityException;
typedef tf2::ExtrapolationException ExtrapolationException;
typedef tf2::InvalidArgumentException InvalidArgument; 
}
#endif //TF_EXCEPTIONS_H

逐本3層，如果是tf_.transformPose轉換異常，查詢tf_.transformPose具體內容：

那麼我們查詢下函式transformPose的位置在tf包中(有兩處):

• 第一處位於：

tf/include/tf.h描述了函式的作用和用法：

/** \brief Transform a Stamped Pose into the target frame 
   * This can throw anything a lookupTransform can throw as well as tf::InvalidArgument.*/
  void transformPose(const std::string& target_frame, const Stamped<tf::Pose>& stamped_in, Stamped<tf::Pose>& stamped_out) const;

tf/src/tf.cpp對函式進行了實體化

void Transformer::transformPose(const std::string& target_frame, const Stamped<Pose>& stamped_in, Stamped<Pose>& stamped_out) const
{
  StampedTransform transform;
  lookupTransform(target_frame, stamped_in.frame_id_, stamped_in.stamp_, transform);

  stamped_out.setData(transform * stamped_in);
  stamped_out.stamp_ = transform.stamp_;
  stamped_out.frame_id_ = target_frame;
};

• 第二處位於：

tf/include/tf/transform_listener.h描述了函式的作用和用法：

/** \brief Transform a Stamped Pose Message into the target frame 
   * This can throw all that lookupTransform can throw as well as tf::InvalidTransform */
  void transformPose(const std::string& target_frame, const geometry_msgs::PoseStamped& stamped_in, geometry_msgs::PoseStamped& stamped_out) const;

tf/src/transform_listener.cpp對函式進行了實體化

void TransformListener::transformPose(const std::string& target_frame,
    const geometry_msgs::PoseStamped& msg_in,
    geometry_msgs::PoseStamped& msg_out) const
{
  tf::assertQuaternionValid(msg_in.pose.orientation);

  Stamped<Pose> pin, pout;
  poseStampedMsgToTF(msg_in, pin);
  transformPose(target_frame, pin, pout); //
  poseStampedTFToMsg(pout, msg_out);
}

兩處函式名雖然相同，形參的資料型別不同，根據檢視我們的程式碼中形參的資料型別(tf::Stamped<tf::Pose>& global_pose) 可知，使用的是前者！transformPose中實際處理資料的函式是lookupTransform和setData；

逐本4層，什麼情況下導致以上提到的異常呢？lookupTransform()函式定義

 /*********** Accessors *************/

  /** \brief Get the transform between two frames by frame ID.
   * \param target_frame The frame to which data should be transformed
   * \param source_frame The frame where the data originated
   * \param time The time at which the value of the transform is desired. (0 will get the latest)
   * \param transform The transform reference to fill.  
   *
   * Possible exceptions tf::LookupException, tf::ConnectivityException,
   * tf::MaxDepthException, tf::ExtrapolationException
   */
  void lookupTransform(const std::string& target_frame, const std::string& source_frame,
                       const ros::Time& time, StampedTransform& transform) const;

void Transformer::lookupTransform(const std::string& target_frame, const std::string& source_frame,
                     const ros::Time& time, StampedTransform& transform) const
{
  geometry_msgs::TransformStamped output = 
    tf2_buffer_ptr_->lookupTransform(strip_leading_slash(target_frame),
                                strip_leading_slash(source_frame), time);
  transformStampedMsgToTF(output, transform);
  return;
};

tf2_buffer_ptr_結合tf_.transformPose轉換異常的型別#include <tf2/exceptions.h>可知，lookupTransform依賴於tf2包！說實在的我都快暈了，戰線越來越長！

<留坑符>暫時跳出來，分析超時問題！

2.轉換超時該如何處理？

答案：增大transform_tolerance_

costmap_2d_ros.cpp中對transform_tolerance_引數的預設設定為0.3;

transform_tolerance_(0.3),

如何修改transform_tolerance_呢？兩種方式一種，一種通過yaml更新節點引數，一種通過cfg動態調參；

第一種方法：

修改local_costmap_params.yaml中引數transform_tolerance的值

local_costmap:
  # global_frame: /odom
   global_frame: /odom_combined
   #global_frame: /map
   robot_base_frame: /base_footprint
   update_frequency: 5.0
   publish_frequency: 2.0
   static_map: false
   rolling_window: true
   width: 3.0
   height: 3.0
   resolution: 0.05
   transform_tolerance: 3 //transform_tolerance的調參範圍0.3~10，由1.5改為3
   map_type: costmap

再通過roslaunch引數配置rosparam載入load進去

<?xml version="1.0"?>

<launch>

<node pkg="move_base" type="move_base" respawn="false" name="move_base" output="screen">
    <rosparam file="$(find atrobot_nav)/config/lqc_test/costmap_common_params.yaml" command="load" ns="global_costmap" />
    <rosparam file="$(find atrobot_nav)/config/lqc_test/costmap_common_params.yaml" command="load" ns="local_costmap" />  
    <rosparam file="$(find atrobot_nav)/config/lqc_test/local_costmap_params.yaml" command="load" />  
    <rosparam file="$(find atrobot_nav)/config/lqc_test/global_costmap_params.yaml" command="load" /> 
    <rosparam file="$(find atrobot_nav)/config/lqc_test/base_local_planner_params.yaml" command="load" />
    <rosparam file="$(find atrobot_nav)/config/lqc_test/dwa_local_planner_params.yaml" command="load" />
    <rosparam file="$(find atrobot_nav)/config/lqc_test/base_global_planner_params.yaml" command="load" />
  </node>

</launch>

如何檢視是否修改成功？在終端通過rosparam指令檢視！《Using rosparam檢視和設定引數》

rosparam list

rosparam get /move_base/global_costmap/transform_tolerance

這兩個結果分別說明修改生效了!~（從以上程式碼也可以看出gloal_costmap和local_costmap都呼叫的同一段程式！）

第二種方法：動態調參

// Else neither param was found anywhere this knows about, so
  // defaults will come from dynamic_reconfigure stuff, set in
  // cfg/Costmap2D.cfg and read in this file in reconfigureCB().

當引數伺服器得到重新配置引數的請求，就會呼叫回撥函式。即需要動態調參客戶端client,傳送重新配置引數的請求時，才會從cfg中載入配置引數！

兩種的差別：

參考文獻：

move_base warning: "Unable to get starting pose of robot, unable to create global plan"

ROS naviagtion analysis: costmap_2d--Costmap2DROS

Costmap2DROS transform timeout.Could not get robot pose, cancelling reconfiguration

ROS naviagtion analysis: costmap_2d--Costmap2DROS

ROS動態調參(dynamic reconfigure)客戶端服務端之C++ Python實現

ROS_Dynamic Reconfig 動態引數調節

ROS與C++入門教程-Logging(日誌)

使用rosconsole和設定顯示級別