A nonlinear controllability analysis for fixed-wing aircraft has been performed in an earlier effort by the authors, which revealed a novel roll mechanism due to a nonlinear interaction between elevator and aileron control inputs. In this effort, we perform a detailed investigation of this novel roll mechanism, called LIBRA (Lie Bracket Roll Augmentation). First, we show the nonlinear flight physics associated with the LIBRA mechanism. Second, using the Fliess functional expansion, we perform a theoretical study of the effectiveness (degree of controllability) of the LIBRA mechanism in comparison to the conventional mechanism (using ailerons only). Third, to simulate the airplane response to a LIBRA input, we cast the problem of executing the LIBRA mechanism as a nonholonomic motion planning problem. In such a problem, a Lie bracket input is applied to generate motion along an unactuated direction. A Lie bracket input represents a nonlinear interaction between two (or more) control inputs to steer the system along a direction that is not directly actuated by any of these inputs (or their linear combinations). In this language, the LIBRA mechanism is simply a Lie bracket interaction between the elevator and aileron control inputs. We modify existing nonholonomic motion planning algorithms for systems with drift to be more feasible for flight control applications with bounded controls. We show that the LIBRA novel roll mechanism is superior compared to the conventional one during stall, where the aileron sensitivity degrades. In particular, the novel roll mechanism can provide an order of magnitude enhancement in the rolling capability over the conventional roll mechanism near stall.

中文翻译：

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飞机非线性横滚机构的高阿尔法运行横摇架设计

作者在早期的工作中已经对固定翼飞机进行了非线性可控性分析，该分析揭示了由于升降舵和副翼控制输入之间的非线性相互作用而产生的新型滚转机制。在这项工作中，我们对这种称为 LIBRA（Lie Bracket Roll Augmentation）的新型侧倾机制进行了详细研究。首先，我们展示了与 LIBRA 机制相关的非线性飞行物理。其次，使用 Fliess 功能扩展，我们对 LIBRA 机制与传统机制（仅使用副翼）相比的有效性（可控程度）进行了理论研究。第三，为了模拟飞机对 LIBRA 输入的响应，我们将执行 LIBRA 机制的问题视为非完整运动规划问题。在这样的问题中，应用李括号输入以生成沿未驱动方向的运动。一个李括号输入表示两个（或多个）控制输入之间的非线性相互作用，以沿不受这些输入（或其线性组合）直接驱动的方向引导系统。在这种语言中，LIBRA 机制只是升降舵和副翼控制输入之间的李括号交互。我们针对具有漂移的系统修改现有的非完整运动规划算法，使其更适用于具有有界控制的飞行控制应用程序。我们表明，在失速期间，LIBRA 新型横滚机制优于传统的横滚机制，在这种情况下，副翼灵敏度会降低。特别是，