Order of JointInterface and ActuatorInterface

[qiayuanl]

Describe the bug
The order of JointInterface and ActuatorInterface are given by joint_names, and actuator_names, and the order is used in all multip-acutaor-multip-joint transmission mapping.

However, the get_name() use std::set to remove duplicate name, resulting in ascending lexicographical order. As a result, there is no way (expected changing the name of actuators) to set the correct order according to <role> tag in URDF, since the order of interface passing to Transmission::configure() doesn't affect anything.

Environment:

• OS: Ubuntu22.04
• Version: Humble
• Anything that may be unusual about your environment

Additional context
BTW, I can't find any example of usage of <role> tag in URDF.

[christophfroehlich]

Additional context BTW, I can't find any example of usage of <role> tag in URDF.

Contributions are welcome, maybe in addition to https://github.com/ros-controls/ros2_control_demos/tree/master/example_8