An application of the underactuated nonlinear ℋ∞ controller to two-wheeled self-balanced vehicles

This paper presents an application of the nonlinear ℋ_∞ controller to two-wheeled self-balanced vehicles. An underactuated mechanical control system representation under input coupling is used to design the control law. To achieve null steady-state error when persistent disturbances are acting on the system, the integral of the position error is considered in the state vector. Practical results obtained in experiments using a two-wheeled vehicle equipped with an embedded microcontroller system are presented. These results corroborate the good features of the proposed controller in presence of external disturbances, extreme initial conditions and unmodeled dynamics.