Experimental results on the nonlinear H_∞ control via quasi-LPV representation and game theory for wheeled mobile robots

In this paper, nonlinear dynamic equations of a wheeled mobile robot (WMR) are described in the state-space form where the parameters are part of the state (angular velocities of the wheels). This representation, known as quasi-linear parameter varying (Quasi-LPV), is useful for control designs based on nonlinear H_infin approaches. Two nonlinear H_infin controllers that guarantee induced L₂-norm, between input (disturbances) and output signals, bounded by an attenuation level γ are used to control a WMR. These controllers are solved via linear matrix inequalities (LMIs) and algebraic Riccati equation. Experimental results are presented, with a comparative study among these robust control strategies and the standard computed torque, plus proportional-derivative, controller.