support publishing of partial trees. Ticket #4464

robot_state_publisher/include/robot_state_publisher/joint_state_listener.h

@@ -62,11 +62,14 @@ public:
 
 private:
   void callbackJointState(const JointStateConstPtr& state);
+  void callbackFixedJoint(const ros::TimerEvent& e);
 
-  NodeHandle n_, n_tilde_;
-  Rate publish_rate_;
+  Duration publish_interval_;
   robot_state_publisher::RobotStatePublisher state_publisher_;
   Subscriber joint_state_sub_;
+  ros::Timer timer_;
+  ros::Time last_publish_time_;
+
 };
 }
 

robot_state_publisher/include/robot_state_publisher/robot_state_publisher.h

@@ -41,10 +41,23 @@
 #include <boost/scoped_ptr.hpp>
 #include <tf/tf.h>
 #include <tf/transform_broadcaster.h>
-#include "robot_state_publisher/treefksolverposfull_recursive.hpp"
+#include <kdl/frames.hpp>
+#include <kdl/segment.hpp>
+#include <kdl/tree.hpp>
 
 namespace robot_state_publisher{
 
+class SegmentPair
+{
+public:
+  SegmentPair(const KDL::Segment& p_segment, const std::string& p_root, const std::string& p_tip):
+    segment(p_segment), root(p_root), tip(p_tip){}
+
+  KDL::Segment segment;
+  std::string root, tip;
+};
+
+
 class RobotStatePublisher
 {
 public:
@@ -62,21 +75,14 @@ public:
    * returns true on success; return false when the robot model is empty or not all the joints in the robot model are specified in the joint map.
    */
   bool publishTransforms(const std::map<std::string, double>& joint_positions, const ros::Time& time);
+  void publishFixedTransforms();
 
 private:
-  ros::Publisher tf_publisher_;
-  bool flatten_tree_;
-  KDL::Tree tree_;
-  boost::scoped_ptr<KDL::TreeFkSolverPosFull_recursive> solver_;
-  std::string root_;
-  std::vector<tf::StampedTransform> transforms_;
-  tf::TransformBroadcaster tf_broadcaster_;
+  void addChildren(const KDL::SegmentMap::const_iterator segment);
 
-  class empty_tree_exception: public std::exception{
-    virtual const char* what() const throw(){
-      return "Tree is empty";}
-  } empty_tree_ex;
 
+  std::map<std::string, SegmentPair> segments_, segments_fixed_;
+  tf::TransformBroadcaster tf_broadcaster_, tf_broadcaster_fixed_;
 };
 
 

robot_state_publisher/src/joint_state_listener.cpp

@@ -48,25 +48,24 @@ using namespace robot_state_publisher;
 
 
 JointStateListener::JointStateListener(const KDL::Tree& tree)
-  : n_tilde_("~"), publish_rate_(0.0), state_publisher_(tree)
+  : state_publisher_(tree)
 {
+  ros::NodeHandle n_tilde("~");
+  ros::NodeHandle n;
+
   // set publish frequency
   double publish_freq;
-  n_tilde_.param("publish_frequency", publish_freq, 50.0);
-  publish_rate_ = Rate(publish_freq);
+  n_tilde.param("publish_frequency", publish_freq, 50.0);
+  publish_interval_ = ros::Duration(1.0/max(publish_freq,1.0));
+  
+
+  // subscribe to joint state
+  joint_state_sub_ = n.subscribe("joint_states", 1, &JointStateListener::callbackJointState, this);
+
+  // trigger to publish fixed joints
+  last_publish_time_ = ros::Time();
+  timer_ = n_tilde.createTimer(publish_interval_, &JointStateListener::callbackFixedJoint, this);
 
-  if (tree.getNrOfJoints() == 0){
-    boost::shared_ptr<sensor_msgs::JointState> empty_state(new sensor_msgs::JointState);
-    while (ros::ok()){
-      empty_state->header.stamp = ros::Time::now();
-      this->callbackJointState(empty_state);
-      publish_rate_.sleep();
-    }
-  }
-  else{
-    // subscribe to mechanism state
-    joint_state_sub_ = n_.subscribe("joint_states", 1, &JointStateListener::callbackJointState, this);
-  }
 };
 
 
@@ -74,6 +73,11 @@ JointStateListener::~JointStateListener()
 {};
 
 
+void JointStateListener::callbackFixedJoint(const ros::TimerEvent& e)
+{
+  state_publisher_.publishFixedTransforms();
+}
+
 void JointStateListener::callbackJointState(const JointStateConstPtr& state)
 {
   if (state->name.size() != state->position.size()){
@@ -81,12 +85,15 @@ void JointStateListener::callbackJointState(const JointStateConstPtr& state)
     return;
   }
 
+  // check if we need to publish
+  if (state->header.stamp >= last_publish_time_ + publish_interval_){
     // get joint positions from state message
     map<string, double> joint_positions;
     for (unsigned int i=0; i<state->name.size(); i++)
       joint_positions.insert(make_pair(state->name[i], state->position[i]));
     state_publisher_.publishTransforms(joint_positions, state->header.stamp);
-  publish_rate_.sleep();
+    last_publish_time_ = state->header.stamp;
+  }
 }
 
 
@@ -109,14 +116,8 @@ int main(int argc, char** argv)
     return -1;
   }
 
-  if (tree.getNrOfSegments() == 0){
-    ROS_WARN("Robot state publisher got an empty tree and cannot publish any state to tf");
-    ros::spin();
-  }
-  else{
   JointStateListener state_publisher(tree);
   ros::spin();
-  }
 
   return 0;
 }

robot_state_publisher/src/robot_state_publisher.cpp

@@ -40,59 +40,83 @@
 
 using namespace std;
 using namespace ros;
-using namespace KDL;
 
 
 
 namespace robot_state_publisher{
 
-RobotStatePublisher::RobotStatePublisher(const Tree& tree)
-   :tree_(tree)
+  RobotStatePublisher::RobotStatePublisher(const KDL::Tree& tree)
   {
-  // build tree solver
-  solver_.reset(new TreeFkSolverPosFull_recursive(tree_));
-
-  // get parameter to flatter tree or not
-  ros::NodeHandle n_private("~");
-  n_private.param("flatten_tree", flatten_tree_, false);
-
-  // advertise tf message
-  NodeHandle n;
-  tf_publisher_ = n.advertise<tf::tfMessage>("/tf", 5);
-
-  // get the root segment of the tree
-  SegmentMap::const_iterator root = tree.getRootSegment();
-  root_ = root->first;
+    // walk the tree and add segments to segments_
+    addChildren(tree.getRootSegment());
   }
 
 
+  // add children to correct maps
+  void RobotStatePublisher::addChildren(const KDL::SegmentMap::const_iterator segment)
+  {
+    const std::string& root = segment->second.segment.getName();
 
+    const std::vector<KDL::SegmentMap::const_iterator>& children = segment->second.children;
+    for (unsigned int i=0; i<children.size(); i++){
+      const KDL::Segment& child = children[i]->second.segment;
+      SegmentPair s(children[i]->second.segment, root, child.getName());
+      if (child.getJoint().getType() == KDL::Joint::None){
+        segments_fixed_.insert(make_pair(child.getJoint().getName(), s));
+        ROS_INFO("Adding fixed segment from %s to %s", root.c_str(), child.getName().c_str());
+      }
+      else{
+        segments_.insert(make_pair(child.getJoint().getName(), s));
+        ROS_INFO("Adding moving segment from %s to %s", root.c_str(), child.getName().c_str());
+      }
+      addChildren(children[i]);
+    }
+  }
+
+
+  // publish moving transforms
   bool RobotStatePublisher::publishTransforms(const map<string, double>& joint_positions, const Time& time)
   {
-  // calculate transforms 
-  map<string, tf::Stamped<Frame> > link_poses;
-  solver_->JntToCart(joint_positions, link_poses, flatten_tree_);
+    std::vector<tf::StampedTransform> tf_transforms;
 
-  if (link_poses.empty()){
-    ROS_ERROR("Could not compute link poses. The tree or the state is invalid.");
-    return false;
+    tf::StampedTransform tf_transform;
+    tf_transform.stamp_ = time;
+
+    // loop over all joints
+    for (map<string, double>::const_iterator jnt=joint_positions.begin(); jnt != joint_positions.end(); jnt++){
+      std::map<std::string, SegmentPair>::const_iterator seg = segments_.find(jnt->first);
+      if (seg != segments_.end()){
+        tf::TransformKDLToTF(seg->second.segment.pose(jnt->second), tf_transform);    
+        tf_transform.frame_id_ = seg->second.root;
+        tf_transform.child_frame_id_ = seg->second.tip;
+        tf_transforms.push_back(tf_transform);
       }
-  transforms_.resize(link_poses.size());
-
-  unsigned int i = 0;
-  tf::Transform tf_frame;
-  for (map<string, tf::Stamped<Frame> >::const_iterator f=link_poses.begin(); f!=link_poses.end(); f++){
-    tf::TransformKDLToTF(f->second, transforms_[i]);
-    transforms_[i].stamp_ = time;
-    transforms_[i].frame_id_ = f->second.frame_id_;
-    transforms_[i].child_frame_id_ = f->first;
-    i++;
     }
 
-  tf_broadcaster_.sendTransform(transforms_);
+    tf_broadcaster_.sendTransform(tf_transforms);
 
     return true;
   }
+
+
+  // publish fixed transforms
+  void RobotStatePublisher::publishFixedTransforms()
+  {
+    std::vector<tf::StampedTransform> tf_transforms;
+
+    tf::StampedTransform tf_transform;
+    tf_transform.stamp_ = ros::Time::now()+ros::Duration(0.5);  // future publish by 0.5 seconds
+
+    // loop over all fixed segments
+    for (map<string, SegmentPair>::const_iterator seg=segments_fixed_.begin(); seg != segments_fixed_.end(); seg++){
+      tf::TransformKDLToTF(seg->second.segment.pose(0), tf_transform);    
+      tf_transform.frame_id_ = seg->second.root;
+      tf_transform.child_frame_id_ = seg->second.tip;
+      tf_transforms.push_back(tf_transform);
+    }
+    tf_broadcaster_fixed_.sendTransform(tf_transforms);
+  }
+
 }