Nonlinear Flight Physics of the Lie-Bracket Roll Mechanism

摘要

In this paper, we summarize the relation between nonlinear controllability and motion generation in unactuated directions through nonlinear interactions between two or more control inputs. Applying this technique to the airplane flight dynamics near stall, a new rolling mechanism is discovered through nonlinear interactions between the elevator and aileron control inputs. This mechanism, referred to as the Lie Bracket Roll Augmentation (LIBRA) mechanism, possesses a significantly higher roll control authority near stall in comparison to the conventional roll mechanism using ailerons only. More than an order-of-magnitude enhancement in the roll response is achieved over the first second using the LIBRA mechanism. The main contribution of this paper is to study the nonlinear flight physics that lead to this superior performance of the LIBRA mechanism.