Robust adaptive optimal control modification with large adaptive gain

A new adaptive control modification is presented that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. The modification is based on an optimal control formulation that minimizes the L₂ norm of the tracking error. The optimality condition is used to derive the modification using the gradient method. The adaptive optimal control modification results in a stable adaptation and allows a large adaptive gain to be used for better tracking performance with improved stability robustness. Simulations demonstrate the effectiveness of the proposed modification.