Control of multiple robot models inside Rviz

asked 2019-02-22 07:18:47 -0600

Ravi Joshi gravatar image

updated 2019-02-22 19:58:45 -0600

I have the URDF file of my robot model. I am able to visualize it inside ROS using the following command:

roslaunch urdf_tutorial display.launch model:=my_robot.urdf

Please note that the above command was used when only one robot, i.e. my_robot is present. Inside the RViz, I can see my_robot after checking RobotModel and I can also see tf frames after adding TF inside the RViz.

Now, In order to move my_robot, I am providing joint angles by writing a joint state publisher in the following way:

#include <ros/ros.h>
#include <sensor_msgs/JointState.h>
#define TOTAL_JOINTS 8

int main(int argc, char** argv)
{
  ros::init(argc, argv, "my_robot_controller");
  ros::NodeHandle n;
  ros::Publisher joint_state_pub = n.advertise<sensor_msgs::JointState>("joint_states", 1);

  sensor_msgs::JointState joint_state;
  joint_state.position.resize(TOTAL_JOINTS);

  // the following joint names are taken from my_robot.urdf file
  joint_state.name = {
      "joint_1", "joint_2", "joint_3", "joint_4",
      "joint_5", "joint_6", "joint_7", "joint_8"};

  joint_state.header.frame_id = "my_robot_link_0";
  while (ros::ok())
  {
      // update the timestamp
      joint_state.header.stamp = ros::Time::now();

      for (int i = 0; i < TOTAL_JOINTS; i++)
        // here is some calculations for joint values
        joint_state.position[i] = joint_value * M_PI / 180.0f;

      joint_state_pub.publish(joint_state);
      ros::spinOnce();
  }
  return 0;
}

The above code works. However, I do have another robot, let say another_robot. This is a commercial robot and I have installed its SDK. Hence whenever I execute this SDK, I can see this robot inside RVIZ.

I want to know how to control and visualize multiple robots inside RViz?

Just for quick understanding, below is the code of display.launch which is inside urdf_tutorial package:

<launch>
  <arg name="model" default="$(find urdf_tutorial)/urdf/01-myfirst.urdf"/>
  <arg name="gui" default="true" />
  <arg name="rvizconfig" default="$(find urdf_tutorial)/rviz/urdf.rviz" />

  <param name="robot_description" command="$(find xacro)/xacro --inorder $(arg model)" />
  <param name="use_gui" value="$(arg gui)"/>

  <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" />
  <node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher" />
  <node name="rviz" pkg="rviz" type="rviz" args="-d $(arg rvizconfig)" required="true" />
</launch>

I want to know how to control and visualize multiple robots inside RViz?

There are the following constraints in this integration task:

  • I cannot change the topics (say joint state or robot state) for another_robot, i.e., a commercial robot.
  • However, I am allowed to configure my_robot in all possible way.

Following are the functionalities I am looking for my_robot:

  1. URDF visualization inside RViz
  2. Real-time motions of URDF structure by providing all joint values
  3. TF frames for all links
  4. 3D position of all links with respect to my_robot
  5. 3D position of all links with respect to another_robot

I have the transformation matrix of TF base frame of my_robot with respect to TF base frame of another_robot. So I think If I can attach TF to my_robot, point # 3, 4 and 5 should be easy! Any clue for point #1, 2 and 3, please?

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Comments

As an observation: I would call "publishing JointState msgs" and viewing the resulting motion in RViz not controlling, but animating a robot model. Control is typically done using msgs other than JointState, as the latter are used to convey state, not command it.

gvdhoorn gravatar imagegvdhoorn ( 2019-02-22 10:04:52 -0600 )edit

@gvdhoorn: Thank you very much. I have added the exact functionalities, I am looking to incorporate in my_robot. Can you please have a look again? Thank again for the help!

Ravi Joshi gravatar imageRavi Joshi ( 2019-02-22 20:00:12 -0600 )edit