In this paper an energy optimal dynamic attitude for a solar-powered aircraft is determined and implemented using the finite-time sliding mode approach. A nonlinear constrained optimization technique has been considered to determine the optimal attitude of the aircraft for given a geographical location, solar position, heading direction and other flight conditions for clear sky conditions. The optimization is performed so as to travel in the fastest possible way from one location to another location without utilizing the battery power, provided the solar energy is sufficient for the flight. The gain in the velocity due to the attitude optimization is validated with the test flight results of solar UAV Maraal which demonstrate the efficacy of the approach proposed here. CFD simulation is carried out to estimate aerodynamic forces acting on the aircraft at different sideslip angles. The developed aircraft dynamics incorporates the nonlinearities associated with relatively large aileron and rudder deflections. To obtain the desired attitude, a sliding mode based control scheme is considered. A power rate reaching law is applied to avoid chattering in the controls. Finite-time stability of the closed loop system is discussed and it is shown that the attitude angles reach the desired values in finite time.

中文翻译：

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使用基于滑模的姿态控制的太阳能飞机的最佳能量利用

在本文中，使用有限时间滑模方法确定并实现了太阳能飞机的能量最优动态姿态。已经考虑使用非线性约束优化技术来确定飞机在给定地理位置、太阳位置、航向方向和晴空条件下的其他飞行条件下的最佳姿态。执行优化以便在不使用电池电源的情况下以尽可能快的方式从一个位置旅行到另一个位置，前提是太阳能足够飞行。由于姿态优化而获得的速度增益通过太阳能无人机 Maraal 的试飞结果进行验证，这证明了本文提出的方法的有效性。进行CFD模拟以估计作用在飞机上不同侧滑角的气动力。开发的飞机动力学结合了与相对较大的副翼和方向舵偏转相关的非线性。为了获得所需的姿态，考虑了基于滑模的控制方案。应用电率达到定律以避免控制中的颤动。讨论了闭环系统的有限时间稳定性，表明姿态角在有限时间内达到期望值。应用电率达到法则以避免控制中的颤动。讨论了闭环系统的有限时间稳定性，表明姿态角在有限时间内达到期望值。应用电率达到定律以避免控制中的颤动。讨论了闭环系统的有限时间稳定性，表明姿态角在有限时间内达到期望值。