How to make ekf localization node for multiple ridgeback robots

edit

Hi all, Now I'm running with Ubuntu 16.04, ROS kinetic (ROS1) I also working with my Gazebo multi ridgeback robots by modifying the ridgeback_simulation But the problem is I don't know how to let EKF localization node works for multiple robots. The similar question has mentioned here since 2016 similar_q. From my understanding, to make multiple EKF localization node we have to edit frameID from gazebo xacro file and put name space, tf_prefix for them. But finally, I still cannot do it with my ridgeback. The problem is it show that

Could not obtain transform from robot_1/base_link to /base_link. Error was "robot_1/base_link" passed to lookupTransform argument target_frame does not exist

Finally, I have found that someone can do it with multiple Husky robots simulation.multi_husky_explanation and the git repo here multi_husky_git_repo. So, I have downloaded the original Husky package and try to run the multihusky launch file. And found that

1. The kinect URDF file locazation was changed. So I have edit the mhusky.gazebo.xacro only one line as following
   <xacro:include filename="$(find husky_description)/urdf/accessories/kinect_camera.urdf.xacro"/>
2. When I launch the multihusky.launch. I have found the error below re/src/nre_simmultihusky/xacro/mhusky.gazebo.xacro' laser_enabled:=true ur5_enabled:=false kinect_enabled:=false nsp:=h1 tfpre:=h1_tf ] returned with code [2]. Param xml is <param command="$(find xacro)/xacro.py --inorder '$(find nre_simmu ltihusky)/xacro/mhusky.gazebo.xacro' laser_enabled:=$(arg laser_enabled ) ur5_enabled:=$(arg ur5_enabled) kinect_enabled:=$(arg kinect_ enabled) nsp:=$(arg namespace) tfpre:=$(arg tfpre) " na me="robot_description"/> The traceback for the exception was written to the log file

According to the multihusky repo, they give TF tree shown that multiple EKF nodes can work properly here nre_simmultihusky wiki. So my question is how I can run this file to understand how they create multiple EKF localization node. Please help me!!