How to send joint_position command from Isaac SDK to Omniverse Isaac Sim

I have successfully send base_command to Isaac Sim for Jetbot_REB.usd that use REB_DifferentialBase with this c++ code.
isaac::messages::DifferentialBaseControl cmd;
cmd.linear_speed() = 1;
cmd.angular_speed() = 0;
ToProto(cmd, tx_out().initProto(), tx_out().buffers());
where tx_out is StateProto. Then, I want to play with Simple_articulation_REB.usd which used REB_JointControl. How can I do that?

Hi @desperadobuster, please have a look at the sample here (Manipulation Sample Applications — ISAAC 2021.1 documentation). This should give you an idea on how to use REB_JointControl.