Guard condition to check node clock is not zero, to suppress "No clock received" error from ros2_control.

[ralphieraccoon]

Description
This adds a guard condition to Ros2Control::step() to check node clock is not zero, fixes the "No clock received" error. Basically stops a step update occurring unless the clock is not zero.

Affected Packages
List of affected packages:

• webots_ros2_control

[skpawar1305]

this might cause issues when simulation is running at realtime, can you check?

[skpawar1305]

I meant in webots with sim time as false

[ralphieraccoon]

I ran ros2 launch webots_ros2_epuck robot_launch.py "use_sim_time:=false" and sent a command to /cmd_vel. The video is below, it looks the same as if I run it with "use_sim_time:=true"

tmpwve0tke2_world_with_URDF_robot-10MB.mp4

Does that look right to you?