In my project, I am able to obtain a special pose (a future pose based on prediction) of a robot, and I need to publish the pose as tf from `map` to `odom_future` frame (my new frame). I know that amcl has provided such a tf publishing code. Therefore, I try to use the AMCL code to write a publisher that convert a pose and publish tf like amcl. However, I encountered some difficulties.
In the amcl_node.cpp file, it contains the following lines:
// subtracting base to odom from map to base and send map to odom instead
geometry_msgs::PoseStamped odom_to_map;
...
tf2::Quaternion q;
q.setRPY(0, 0, hyps[max_weight_hyp].pf_pose_mean.v[2]);
tf2::Transform tmp_tf(q, tf2::Vector3(hyps[max_weight_hyp].pf_pose_mean.v[0],
hyps[max_weight_hyp].pf_pose_mean.v[1],
0.0));
geometry_msgs::PoseStamped tmp_tf_stamped;
tmp_tf_stamped.header.frame_id = base_frame_id_;
tmp_tf_stamped.header.stamp = laser_scan->header.stamp;
tf2::toMsg(tmp_tf.inverse(), tmp_tf_stamped.pose); //invert the given pose
this->tf_->transform(tmp_tf_stamped, odom_to_map, odom_frame_id_); ///subtraction occurs here
...
I tried to use this snippet to help build my tf broadcaster, but it gives the error:
"Do not call canTransform or lookupTransform with a timeout unless you are using another thread for populating data. Without a dedicated thread it will always timeout. If you have a seperate thread servicing tf messages, call setUsingDedicatedThread(true) on your Buffer instance.";
My only major modification is the time stamp, because my node does not subscribe a laser scan (I also tried to subscribe a laser scan, and use the timestamp, but it doesn't work as well):
tmp_tf_stamped.header.stamp = ros::Time::now();
I've also tried `setUsingDedicatedThread(true)`. The error disappears, but the node doesn't do anything.
Questions:
1. What exactly does `tf_->transform(...)` do? I couldn't find any documentation about this function.
2. Does the error originated from the timestamp?
3. Is there any other elegant way to compute the tf between `map` and `odom_future` from pose? (in the same way of `odom` frame).
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