Stability-Aware Banked Turn Maneuver Control and Command Augmentation for 2-DOF Pendulum-Driven Spherical Robots

Abstract

Executing banked turns at elevated speeds poses significant dynamic challenges for 2-DOF pendulum-driven spherical robots. A steady-state torque balance reveals that centripetal loading at high speeds limits feasible roll angles and demands increasingly aggressive pendulum actuation. We derive a closed-form expression for the required pendulum angle and integrate this into a bank-aware Command Augmentation System (CAS) and control law that automatically alters infeasible commands. Experimental tests on Texas A&M RAD Lab's RoboBall II platform demonstrate that the CAS-equipped bank controller enables stable bank maneuvers at speeds up to 6 rad/s (1.83 m/s), where previous controllers fail, by dynamically limiting roll commands based on velocity and internal pressure.