Use sjtc and generate /clock topic (#58)

* Use scaled JTC by default

* Add gz_bridge for /clock topic

* Add dependency on ros_gz_bridge

* Fix dependency and tests

Since we now use the scaled JTC we have to depend on ur_controllers
and make sure the tests use the scaled JTC.

ur_simulation_gz/config/ur_controllers.yaml

@@ -88,6 +88,7 @@ scaled_joint_trajectory_controller:
     state_interfaces:
       - position
       - velocity
+    speed_scaling_interface_name: ""
     state_publish_rate: 100.0
     action_monitor_rate: 20.0
     allow_partial_joints_goal: false

ur_simulation_gz/launch/ur_sim_control.launch.py

@@ -169,6 +169,16 @@ def launch_setup(context, *args, **kwargs):
         }.items(),
     )
 
+    # Make the /clock topic available in ROS
+    gz_sim_bridge = Node(
+        package="ros_gz_bridge",
+        executable="parameter_bridge",
+        arguments=[
+            "/clock@rosgraph_msgs/msg/Clock[gz.msgs.Clock",
+        ],
+        output="screen",
+    )
+
     nodes_to_start = [
         robot_state_publisher_node,
         joint_state_broadcaster_spawner,
@@ -177,6 +187,7 @@ def launch_setup(context, *args, **kwargs):
         initial_joint_controller_spawner_started,
         gz_spawn_entity,
         gz_launch_description,
+        gz_sim_bridge,
     ]
 
     return nodes_to_start
@@ -243,7 +254,7 @@ def generate_launch_description():
     declared_arguments.append(
         DeclareLaunchArgument(
             "initial_joint_controller",
-            default_value="joint_trajectory_controller",
+            default_value="scaled_joint_trajectory_controller",
             description="Robot controller to start.",
         )
     )

ur_simulation_gz/package.xml

@@ -17,12 +17,14 @@
 
   <buildtool_depend>ament_cmake</buildtool_depend>
 
-  <exec_depend>ros_gz_sim</exec_depend>
   <exec_depend>gz_ros2_control</exec_depend>
   <exec_depend>joint_state_publisher</exec_depend>
   <exec_depend>launch</exec_depend>
   <exec_depend>launch_ros</exec_depend>
+  <exec_depend>ros_gz_bridge</exec_depend>
+  <exec_depend>ros_gz_sim</exec_depend>
   <exec_depend>rviz2</exec_depend>
+  <exec_depend>ur_controllers</exec_depend>
   <exec_depend>ur_description</exec_depend>
   <exec_depend>ur_moveit_config</exec_depend>
   <exec_depend>urdf</exec_depend>

ur_simulation_gz/test/test_gz.py

@@ -112,7 +112,7 @@ def tearDownClass(cls):
     def init_robot(self):
         self._follow_joint_trajectory = ActionInterface(
             self.node,
-            "/joint_trajectory_controller/follow_joint_trajectory",
+            "/scaled_joint_trajectory_controller/follow_joint_trajectory",
             FollowJointTrajectory,
         )
         # TODO: Replace this timeout with a proper check whether the robot is initialized