G1 Arm RTC: A Real-Time Control Stack for a Humanoid Upper Body

A 1 kHz C++ control stack for the 10-DOF upper body of a Unitree G1 (three waist joints and the seven-joint right arm) running against MuJoCo. Five torque controllers, a momentum observer that estimates external joint torque without torque sensors, collision detection and contact-link isolation, online payload identification, a supervisor state machine with four collision reflexes, and a planning pipeline (IK, RRT-Connect, splines and torque-limited TOPP-RA), also exposed behind a ROS 2 Jazzy node.