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Added Tf publisher #30

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Added Tf publisher #30

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91dcbc7
Added Tf publisher in a thread and corrected transform initialization.
vikcp Jun 7, 2019
a0a3e4d
Issues from PR solved. Added mutex, changed function and new thread d…
vikcp Jul 29, 2019
901f7a4
Added debugging tools
vikcp Aug 6, 2019
076117f
before refactoring
vikcp Sep 20, 2019
257a5cf
logs and refactoring of merging_pipeline
vikcp Sep 25, 2019
586d9e0
Before not needing orgin at (0,0)
vikcp Oct 10, 2019
31c2585
no need to modify map origin
vikcp Oct 10, 2019
d4d548d
clean few last ros_debugs
vikcp Nov 11, 2019
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16 changes: 16 additions & 0 deletions map_merge/include/map_merge/map_merge.h
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Original file line number Diff line number Diff line change
Expand Up @@ -45,8 +45,10 @@

#include <combine_grids/merging_pipeline.h>
#include <geometry_msgs/Pose.h>
#include <geometry_msgs/TransformStamped.h>
#include <map_msgs/OccupancyGridUpdate.h>
#include <nav_msgs/OccupancyGrid.h>
#include <tf2_ros/transform_broadcaster.h>
#include <ros/ros.h>
#include <boost/thread.hpp>

Expand All @@ -56,6 +58,7 @@ struct MapSubscription {
// protects consistency of writable_map and readonly_map
// also protects reads and writes of shared_ptrs
std::mutex mutex;
std::string map_frame;

geometry_msgs::Transform initial_pose;
nav_msgs::OccupancyGrid::Ptr writable_map;
Expand All @@ -80,6 +83,7 @@ class MapMerge
std::string robot_namespace_;
std::string world_frame_;
bool have_initial_poses_;
bool publish_tf = true;

// publishing
ros::Publisher merged_map_publisher_;
Expand All @@ -92,6 +96,18 @@ class MapMerge
combine_grids::MergingPipeline pipeline_;
std::mutex pipeline_mutex_;

// publishing tfs
std::vector<std::string> map_frames_;
std::vector<geometry_msgs::TransformStamped> tf_transforms_;
tf2_ros::TransformBroadcaster tf_publisher_;
std::thread tf_thread_; // tf needs it own thread
std::atomic_flag tf_current_flag_; // whether tf_transforms_ are up to date
// with transforms_


void publishTF();
std::vector<geometry_msgs::TransformStamped> StampTransforms(const std::vector<geometry_msgs::Transform>, const std::string& frame);

std::string robotNameFromTopic(const std::string& topic);
bool isRobotMapTopic(const ros::master::TopicInfo& topic);
bool getInitPose(const std::string& name, geometry_msgs::Transform& pose);
Expand Down
5 changes: 4 additions & 1 deletion map_merge/src/combine_grids/merging_pipeline.cpp
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Expand Up @@ -214,9 +214,12 @@ std::vector<geometry_msgs::Transform> MergingPipeline::getTransforms() const
std::vector<geometry_msgs::Transform> result;
result.reserve(transforms_.size());

geometry_msgs::Transform identity_quaternion;
identity_quaternion.rotation.w = 1;

for (auto& transform : transforms_) {
if (transform.empty()) {
result.emplace_back();
result.emplace_back(identity_quaternion);
continue;
}

Expand Down
59 changes: 57 additions & 2 deletions map_merge/src/map_merge.cpp
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Expand Up @@ -60,11 +60,14 @@ MapMerge::MapMerge() : subscriptions_size_(0)
robot_map_updates_topic_, "map_updates");
private_nh.param<std::string>("robot_namespace", robot_namespace_, "");
private_nh.param<std::string>("merged_map_topic", merged_map_topic, "map");
private_nh.param<std::string>("world_frame", world_frame_, "world");
private_nh.param<std::string>("world_frame", world_frame_, "map");
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is this intended?

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Yes, but it is because in my opinion each robot map should have the namespace of the robot, and then, the global map, just be called map.
But it is just how I imagine it. I can revert this change before the pull request.

private_nh.param("publish_tf", publish_tf, true);

/* publishing */
merged_map_publisher_ =
node_.advertise<nav_msgs::OccupancyGrid>(merged_map_topic, 50, true);
tf_current_flag_.clear();

}

/*
Expand Down Expand Up @@ -186,22 +189,29 @@ void MapMerge::mapMerging()

void MapMerge::poseEstimation()
{
bool new_transform = false;
ROS_DEBUG("Grid pose estimation started.");
std::vector<nav_msgs::OccupancyGridConstPtr> grids;

grids.reserve(subscriptions_size_);
{
map_frames_.clear();
boost::shared_lock<boost::shared_mutex> lock(subscriptions_mutex_);
for (auto& subscription : subscriptions_) {
std::lock_guard<std::mutex> s_lock(subscription.mutex);
grids.push_back(subscription.readonly_map);
map_frames_.push_back(subscription.map_frame);
}
}

std::lock_guard<std::mutex> lock(pipeline_mutex_);
pipeline_.feed(grids.begin(), grids.end());
// TODO allow user to change feature type
pipeline_.estimateTransforms(combine_grids::FeatureType::AKAZE,
new_transform = pipeline_.estimateTransforms(combine_grids::FeatureType::AKAZE,
confidence_threshold_);
if (new_transform){
tf_current_flag_.clear();
}
}

void MapMerge::fullMapUpdate(const nav_msgs::OccupancyGrid::ConstPtr& msg,
Expand All @@ -215,6 +225,7 @@ void MapMerge::fullMapUpdate(const nav_msgs::OccupancyGrid::ConstPtr& msg,
return;
}

subscription.map_frame = msg->header.frame_id;
subscription.readonly_map = msg;
subscription.writable_map = nullptr;
}
Expand Down Expand Up @@ -378,6 +389,41 @@ void MapMerge::executeposeEstimation()
}
}

void MapMerge::publishTF()
{
if (!tf_current_flag_.test_and_set()) {
// need to recalculate stored transforms
auto transforms = pipeline_.getTransforms(); // this is thread-safe access
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this is not a thread-safe access AFAIK

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It think this may be the cause of the crash you experienced.

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Ok! I'll have a look to this.

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I have checked with TSan, and as you said, there was an issue there.
I have added a mutex to protect it.
With TSan I still have other warnings, however, I can't find the issue and I haven't experienced any other crashes.

//auto maps = getMaps();
tf_transforms_ = StampTransforms(transforms, world_frame_);
}
if (tf_transforms_.empty()) {
return;
}

// no locking. tf_transforms_ is always accessed only from tf thread
for (auto& transform : tf_transforms_) {
tf_publisher_.sendTransform(transform);
}
}

std::vector<geometry_msgs::TransformStamped> MapMerge::StampTransforms(const std::vector<geometry_msgs::Transform> transforms_, const std::string& frame)
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functions start with lowercase letter. this function should be static inline non-member or static member as it does not access any member variables. names with trailing underscore indicate member variables and should not be used as arguments.

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This function actually uses two member variables, which allow proper map naming. I changed the name of the transforms parameter not to confuse.
So should I leave this function as a member function as it uses two member variables or should I keep it static and pass the variables as parameters?

{
std::vector<geometry_msgs::TransformStamped> output;
output.reserve(transforms_.size());
int ii = 0;
for (auto transform : transforms_){
geometry_msgs::TransformStamped tf_stamped;
tf_stamped.transform = transform;
tf_stamped.child_frame_id = map_frames_[ii];
tf_stamped.header.frame_id = "world_frame_";
tf_stamped.header.stamp = ros::Time::now();
output.push_back(tf_stamped);
ii++;
}
return output;
}

/*
* spin()
*/
Expand All @@ -387,6 +433,15 @@ void MapMerge::spin()
std::thread merging_thr([this]() { executemapMerging(); });
std::thread subscribing_thr([this]() { executetopicSubscribing(); });
std::thread estimation_thr([this]() { executeposeEstimation(); });
if (publish_tf) {
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could we make this similar to those above?

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Done, I should have done it your way since the beginning.

tf_thread_ = std::thread([this]() {
ros::Rate rate(30.0);
while (node_.ok()) {
publishTF();
rate.sleep();
}
});
}
ros::spin();
estimation_thr.join();
merging_thr.join();
Expand Down