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无人机短距着陆控制技术研究
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作者 吕健玮 黄一敏 魏硕 《机械制造与自动化》 2024年第2期258-265,共8页
研究固定翼无人机短距着陆性能具有十分重要的现实意义。基于对象无人机三种襟翼构型中的着陆襟翼构型,分析以固定油门为基础的传统着陆控制方式存在的缺陷性问题,从动力学角度分析近地段在低速、大姿态状态下各项着陆指标间的相互制约... 研究固定翼无人机短距着陆性能具有十分重要的现实意义。基于对象无人机三种襟翼构型中的着陆襟翼构型,分析以固定油门为基础的传统着陆控制方式存在的缺陷性问题,从动力学角度分析近地段在低速、大姿态状态下各项着陆指标间的相互制约关系,并得出“空速为影响着陆性能的主导诱因”这一重要结论,从动力学角度提出油门速度闭环控制方案。在控制律设计过程中,创新性地采用线性化理论分析和半物理非线性仿真相结合的手段,充分结合工程实践经验,突出了油门速度控制的特殊性与有效性,使着陆性能得到前所未有的提升。 展开更多
关键词 固定翼无人机 短距着陆 着陆敏感性 推力非线性 速度控制
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Developing a 2D vertical flow and sediment transport model for open channels using the Youngs-VOF method
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作者 赵东淼 唐军 +3 位作者 吴修广 林昌宁 刘丽君 陈剑 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第2期444-451,共8页
A 2D vertical (2DV) numerical model, without o-coordinate transformation in the vertical direction, is developed for the simulation of flow and sediment transport in open channels. In the model, time-averaged Reynol... A 2D vertical (2DV) numerical model, without o-coordinate transformation in the vertical direction, is developed for the simulation of flow and sediment transport in open channels. In the model, time-averaged Reynolds equations are closed by the k-e nonlinear turbulence model. The modified Youngs- VOF method is introduced to capture free surface dynamics, and the free surface slope is simulated using the ELVIRA method. Based on the power-law scheme, the k-e model and the suspended-load transport model are solved numerically with an implicit scheme applied in the vertical plane and an explicit scheme applied in the horizontal plane. Bedload transport is modeled using the Euler-WENO scheme, and the grid-closing skill is adopted to deal with the moving channel bed boundary. Verification of the model using laboratory data shows that the model is able to adequately simulate flow and sediment transport in open channels, and is a good starting point for the study of sediment transport dynamics in strong nonlinear flow scenarios. 展开更多
关键词 sediment transport 2D vertical model Youngs-VOF Euler-WENO bed evolution
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