robot_state_publisher.cpp

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/* Author: Wim Meeussen */
 
#include <map>
#include <string>
 
#include <kdl/frames_io.hpp>
#include <geometry_msgs/TransformStamped.h>
#include <tf2_kdl/tf2_kdl.h>
 
#include "robot_state_publisher/robot_state_publisher.h"
 
namespace robot_state_publisher {
 
RobotStatePublisher::RobotStatePublisher() : RobotStatePublisher(KDL::Tree())
{
}
 
RobotStatePublisher::RobotStatePublisher(const KDL::Tree& tree, const urdf::Model& model)
  : model_(model)
{
  // 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 = GetTreeElementSegment(segment->second).getName();
 
  const std::vector<KDL::SegmentMap::const_iterator>& children = GetTreeElementChildren(segment->second);
  for (size_t i = 0; i < children.size(); ++i) {
    const KDL::Segment& child = GetTreeElementSegment(children[i]->second);
    SegmentPair s(GetTreeElementSegment(children[i]->second), root, child.getName());
    if (child.getJoint().getType() == KDL::Joint::None) {
      if (model_.getJoint(child.getJoint().getName()) && model_.getJoint(child.getJoint().getName())->type == urdf::Joint::FLOATING) {
        ROS_INFO("Floating joint. Not adding segment from %s to %s. This TF can not be published based on joint_states info", root.c_str(), child.getName().c_str());
      }
      else {
        segments_fixed_.insert(make_pair(child.getJoint().getName(), s));
        ROS_DEBUG("Adding fixed segment from %s to %s", root.c_str(), child.getName().c_str());
      }
    }
    else {
      segments_.insert(make_pair(child.getJoint().getName(), s));
      ROS_DEBUG("Adding moving segment from %s to %s", root.c_str(), child.getName().c_str());
    }
    addChildren(children[i]);
  }
}
 
std::string stripSlash(const std::string & in)
{
  if (in.size() && in[0] == '/')
  {
    return in.substr(1);
  }
  return in;
}
 
// Replicate behavior of tf 1 tf_prefix
std::string prefix_frame(const std::string & tf_prefix, const std::string & frame)
{
  // If the frame begins with a slash, remove the first slash and don't add prefix at all
  if (frame.size() && frame[0] == '/') {
    return frame.substr(1);
  }
 
  std::string prefixed_frame;
 
  // If the prefix begins with a slash, remove it
  if (tf_prefix.size() && tf_prefix[0] == '/') {
    prefixed_frame = tf_prefix.substr(1);
  } else {
    prefixed_frame = tf_prefix;
  }
 
  // Add a slash after a non-empty prefix
  if (!tf_prefix.empty()) {
    prefixed_frame += '/';
  }
 
  prefixed_frame += frame;
 
  return prefixed_frame;
}
 
// publish moving transforms
void RobotStatePublisher::publishTransforms(const std::map<std::string, double>& joint_positions, const ros::Time& time, const std::string & tf_prefix)
{
  ROS_DEBUG("Publishing transforms for moving joints");
  std::vector<geometry_msgs::TransformStamped> tf_transforms;
 
  // loop over all joints
  for (std::map<std::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()) {
      geometry_msgs::TransformStamped tf_transform = tf2::kdlToTransform(seg->second.segment.pose(jnt->second));
      tf_transform.header.stamp = time;
      tf_transform.header.frame_id = prefix_frame(tf_prefix, seg->second.root);
      tf_transform.child_frame_id = prefix_frame(tf_prefix, seg->second.tip);
      tf_transforms.push_back(tf_transform);
    }
    else {
      ROS_WARN_THROTTLE(10, "Joint state with name: \"%s\" was received but not found in URDF", jnt->first.c_str());
    }
  }
  tf_broadcaster_.sendTransform(tf_transforms);
}
 
// publish fixed transforms
void RobotStatePublisher::publishFixedTransforms(const std::string & tf_prefix, bool use_tf_static)
{
  ROS_DEBUG("Publishing transforms for fixed joints");
  std::vector<geometry_msgs::TransformStamped> tf_transforms;
  geometry_msgs::TransformStamped tf_transform;
 
  // loop over all fixed segments
  for (std::map<std::string, SegmentPair>::const_iterator seg = segments_fixed_.begin(); seg != segments_fixed_.end(); seg++) {
    geometry_msgs::TransformStamped tf_transform = tf2::kdlToTransform(seg->second.segment.pose(0));
    tf_transform.header.stamp = ros::Time::now();
    if (!use_tf_static) {
      tf_transform.header.stamp += ros::Duration(0.5);
    }
    tf_transform.header.frame_id = prefix_frame(tf_prefix, seg->second.root);
    tf_transform.child_frame_id = prefix_frame(tf_prefix, seg->second.tip);
    tf_transforms.push_back(tf_transform);
  }
  if (use_tf_static) {
    static_tf_broadcaster_.sendTransform(tf_transforms);
  }
  else {
    tf_broadcaster_.sendTransform(tf_transforms);
  }
}
 
void RobotStatePublisher::publishTransforms(const std::map<std::string, double>& joint_positions, const ros::Time& time)
{
  publishTransforms(joint_positions, time, "");
}
 
void RobotStatePublisher::publishFixedTransforms(bool use_tf_static)
{
  publishFixedTransforms("", use_tf_static);
}
 
}