Sub-optimal fixed-finite-horizon spacecraft configuration control on SE(3)

For achieving the desired configuration of spacecraft at the desired fixed time, a sub-optimal fixed-finite-horizon configuration control method on the Lie group SE(3) is developed based on the Model Predictive Static Programming (MPSP). The MPSP technique has been widely used to solve finite-horizon optimal control problems and is known for its high computational efficiency thanks to the closed-form solution, but it cannot be directly applied to systems on SE(3). The methodological innovation in this paper enables that the MPSP technique is extended to the geometric control on SE(3), using the variational principle, the left-invariant properties of Lie groups, and the topology structure of Lie algebra space. Moreover, the energy consumption, which is crucial for spacecraft operations, is considered as the objective function to be optimized in the optimal control formulation. The effectiveness of the designed sub-optimal control method is demonstrated through an online simulation under disturbances and state measurement errors.     

飞行养成学员ESP教学研究

本文基于ESP的特点,讨论了飞行养成学员工作环境下使用英语进行有效交流的需要,对养成学员语言学习的需求进行了分析,并对EAP以及EOP课程设置和教学方法进行了探讨,指出ESP教师做好充分的准备是ESP教学成功的关键.     

非线性代数方程组的数值解法比较

本文通过比较几种求解非线性方程组的数值解法的特点，在如何兼顾计算量与收敛速度，选择不同数值解法求非线性方程组的近似解等方面给出了推荐意见。     

金融生态中特殊群体融资问题研究

在中国金融生态圈中客观存在着一部分特殊群体，他们的融资需求长期以来得不到满足；在重建金融生态系统的过程中，应考虑这部分人群的利益，建立包容性的、多层次金融生态体系。这不仅对于改善金融生态本身有利，而且对于减轻贫困，构建和谐社会都具有极其重要的意义。文章对金融生态中的特殊群体进行了界定，从理论和实践两方面论证了中国金融生态中特殊群体边缘化趋势，评述了现阶段政府的金融扶助政策，并从重建金融生态的角度，提出了解决特殊群体融资困难的政策建议。     

Pneumatic pressure control based on improved NMPC and its application to aeroengine surge simulation

In the semi-physical simulation of aeroengines, using the pneumatic pressure servo control technology to provide realistic pneumatic excitation to the sensors and electronic controller can improve the confidence of the simulation and reduce the test cost and risk. However, the existing methods could not satisfy the precise simulation of large-amplitude and high-frequency pulsating pressure during aeroengine surge. In this paper, a pneumatic pressure control system with asymmetric groups of the High-Speed on–off Valve (HSV) is designed, and an Improved Nonlinear Model Predictive Control (INMPC) method is proposed. First, the volumetric flow characteristics of HSV are tested and analyzed with Pulse Width Modulation (PWM) signal input. Then, a simplified HSV model with the volume flow characteristic correction is developed. Based on these, an integrated model for the whole system is further established and used as the prediction model in INMPC. To improve the computational speed of the rolling optimization process, the mapping scheme from control signal to PWM duty cycle of HSVs and the objective function with exterior penalty function are designed. Finally, the random step, sinusoidal and real engine surge data are set as the reference pressure in multiple comparative experiments to verify the effectiveness of the pressure tracking system.