set_positions service: service not available if the server is executed before the client

[cosmac]

Hey guys,

I recently installed the tmr_ros2 drivers and experimented with the available demos. All good so far, except that the "set_position" demo does not behave as I would expect. Here is the summary:

• Scenario#1 (Successful) Step#1: Run demo (set_positions node) $ ros2 run demo demo_set_positions Step#2: Next, run the TM driver $ ros2 run tm_driver tm_driver ip:=192.168.1.92 In this case, as soon as the drivers are online, the request to move the joints is received and executed. The demo script finishes successful:

  $ ros2 run demo demo_set_positions 
  [INFO] [1638581348.011573916] [rclcpp]: service not available, waiting again...
  ...........
  [INFO] [1638581355.014004046] [rclcpp]: service not available, waiting again...

• Scenario#2 (service not available) Step#1: Run TM driver $ ros2 run tm_driver tm_driver ip:=192.168.1.92 Step#2: Next, run demo $ ros2 run demo demo_set_positions In this case, the demo script never finds the service available and gets stuck in the loop that waits for the service: while (!client->wait_for_service(1s)) From terminal I check that the service exists:

  $ ros2 service list -t
  /ask_item [tm_msgs/srv/AskItem]
  /ask_sta [tm_msgs/srv/AskSta]
  /connect_tmsct [tm_msgs/srv/ConnectTM]
  /connect_tmsvr [tm_msgs/srv/ConnectTM]
  /send_script [tm_msgs/srv/SendScript]
  /set_event [tm_msgs/srv/SetEvent]
  /set_io [tm_msgs/srv/SetIO]
  /set_positions [tm_msgs/srv/SetPositions]
  /tm_sct/describe_parameters [rcl_interfaces/srv/DescribeParameters]
  /tm_sct/get_parameter_types [rcl_interfaces/srv/GetParameterTypes]
  /tm_sct/get_parameters [rcl_interfaces/srv/GetParameters]
  /tm_sct/list_parameters [rcl_interfaces/srv/ListParameters]
  /tm_sct/set_parameters [rcl_interfaces/srv/SetParameters]
  /tm_sct/set_parameters_atomically [rcl_interfaces/srv/SetParametersAtomically]
  /tm_svr/describe_parameters [rcl_interfaces/srv/DescribeParameters]
  /tm_svr/get_parameter_types [rcl_interfaces/srv/GetParameterTypes]
  /tm_svr/get_parameters [rcl_interfaces/srv/GetParameters]
  /tm_svr/list_parameters [rcl_interfaces/srv/ListParameters]
  /tm_svr/set_parameters [rcl_interfaces/srv/SetParameters]
  /tm_svr/set_parameters_atomically [rcl_interfaces/srv/SetParametersAtomically]
  /write_item [tm_msgs/srv/WriteItem]

  My expectation will be that the tm_driver can be run once, before or after the client, while multiple joint positions could be set by running the set_positions demo multiple times. Am I missing something here?

Note: I'm running ROS2 Foxy with the latest tmr_ros2 drivers (at this time)

Thanks!

[jean-fernandez-imt]

Hello Mr. Claudiu,

This is a very helpful post! I am also running into the very same issue. I am going to try following your successful scenario procedure first thing on Monday.

I also wanted to add that this problem does not seem to appear on the tmr_driver, since I had no issues when running the tmr_moveit_cpp_demo, that uses that driver. Without launching any driver previously. I just ran the following code:

ros2 launch tmr_moveit_cpp_demo run_moveit_cpp.launch.py robot_ip:=<robot_ip_address> 

This will also take care of launching the tmr_driver, that seems to have extra functionalities compared to tm_driver. (#6)

Have a good day!

[TechmanRobotIncOwner]

This issue is default DDS of new version Foxy is a little bit different from previous version. So we recommend user other DDS, before we fixed this new issue.

Please refer to this below, use cyclone DDS.

export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp

If you have further question please let me know.