临界喷管充气混合装置

一种能快速混合均匀的充气装置──双临界喷管充气装置，及其设计、调节、标定方法，经色谱检验结果表明：性能良好，结构简单，适用于各种预混燃烧试验。     

氢涡轮泵转子非线性振动

弹性支承设计应该满足临界转速与工作转速间离和转子定心两方面要求。试验和分析结果表明，眼位器的非线性效应使临界转速增大，可能使临界转速与工作转速靠近，此外还可能诱发转子次谐波振动，因此限位器不适于氢涡轮泵转子定心设计。     

基于非线性干扰观测器的空天飞行器轨迹线性化控制

研究一种新的空天飞行器基于非线性干扰观测器的轨迹线性化飞行控制方案。轨迹线性化控制是一种新颖有效的非线性跟踪和解耦控制方法,但空天飞行器飞行过程中存在的建模误差和外界干扰等不确定因素将导致其性能下降甚至失效。为了满足空天飞行器高精度高稳定控制的要求,本文利用非线性干扰观测器对系统中存在的不确定进行估计,其输出用以设计新的补偿控制律,从而使当前轨迹线性化方法的控制性能得到改善。最后利用该方案设计出空天飞行器飞行控制系统,通过高超声速飞行条件下的仿真,验证了该方法的有效性。     

带扰动观测器的永磁同步电机非线性预测跟踪控制

针对永磁同步电机系统转速跟踪控制问题,基于非线性预测控制方法设计控制系统,使该系统满足高性能控制要求。并将负载转矩作为未知扰动来考虑,利用扰动观测器得到其估计值,从而提高系统鲁棒性。仿真实验结果表明,本文方法能够快速准确地实现转速跟踪,并提高系统对负载转矩扰动的鲁棒性。     

An LMI-based decoupling control for electromagnetic formation flight

Electromagnetic formation flight(EMFF) leverages electromagnetic force to control the relative position of satellites. EMFF offers a promising alternative to traditional propellant-based spacecraft flight formation. This novel strategy is very attractive since it does not consume fuel. Due to the highly coupled nonlinearity of electromagnetic force, it is difficult to individually design a controller for one satellite without considering others, which poses challenges to communications.This paper is devoted to decoupling control of EMFF, including regulations, constraints and controller design. A learning-based adaptive sliding mode decoupling controller is analyzed to illustrate the problem of existing results, and input rate saturation is introduced to guarantee the validity of frequency division technique. Through transformation, the imposed input rate saturation is converted to state and input constraints. A linear matrix inequalities(LMI)-based robust optimal control method can then be used and improved to solve the transformed problem. Simulation results are presented to demonstrate the effectiveness of the proposed decoupling control.     

Effect of flexibility on unsteady aerodynamics forces of a purely plunging airfoil

Introducing flexibility into the design of a vertically flapping wing is an effective way to enhance its aerodynamic performance. As less previous studies on the aerodynamics of vertically flapping flexible wings focused on the lift generated in a wide range of angle of attack·a 2D numerical simulation of a purely plunging flexible airfoil is employed using a loose fluid–structure interaction method. The aerodynamics of a fully flexible airfoil are firstly studied with the flexibility and angle of attack. To verify whether an airfoil could get aerodynamic benefit from the change in structure, partially flexible airfoil with rigid leading edge and flexible trailing edge were further considered. Results show that flexibility could always reduce airfoil drag while lift and lift efficiency both peak at moderate flexibility. When freestream velocity is constant, lift is maximized at a high angle of attack about 40° while this optimal angle of attack reduces to 15° in drag-balanced status. The airfoil drag reduction, lift augmentation as well as efficiency enhancement mainly attribute to the passive pitching other than the camber deformation. Partially deformed airfoil with the longest length of moderate flexible trailing edge can achieve the highest lift. This study may provide some guidance in the wing design of Micro Air Vehicle (MAV).     

一种基于串级线性自抗扰控制的四旋翼无人机控制方法

提出了一种基于串级线性自抗扰控制器的四旋翼无人机控制方法。根据建立的紊流模型形成了干扰风,在干扰风的环境下建立了四旋翼的运动学模型,并设计了一个串级的线性自抗扰控制器,其中外环采用位置控制,内环采用姿态控制。对比了该控制器与非线性自抗扰控制器和经典PID控制器在无风干扰和有风干扰下无人机的定点悬停的性能。仿真试验结果表明,无论是在无风干扰下还是在有风干扰下,该控制器的性能均好于非线性自抗扰控制器和PID控制器,具有较好的鲁棒性,能够运用到各种类型的旋翼无人机的工程控制中。     

某型弹用涡扇发动机振动故障建模与分析

针对某型弹用涡扇发动机振动超标问题,建立了1维有限元梁模型进行仿真与模拟,并结合实际试车数据进行了故障分析和仿真。结果表明:压气机前、后支承刚度对系统第2阶临界转速有很大影响,不合适的支承刚度使系统在工作转速范围内出现第2阶临界转速,从而导致整机振动超标。因此,降低该故障的途径是有效控制支承装配精度。     

PTFE/CFRP/铝合金叠层材料钻削试验研究

对PTFE/CFRP/铝合金叠层材料进行了钻削试验研究。结果表明:最高钻削温度随主轴转速的增大而增大,但随进给量的增大反而下降;相同钻削参数下,从铝合金侧钻入能获得更低的钻削温度;采用较大的进给量有利于铝合金形成碎屑状切屑,避免带状切屑排出时划伤已加工CFRP表面;采用较低主轴转速和较大的进给量可获得更好的铝合金孔出口质量。     

重力扰动对高精度惯性导航初始对准 的影响与补偿

初始对准时, 通常是基于地球参考椭球, 用正常重力公式计算重力矢量, 而实际情况下地球内部质量分布不均匀,实际重力包含正常重力和重力扰动。重力扰动 包括参考椭球面切线方向的分量（垂线偏差）和法线方向分量（重力异常）。研究重力 扰动下的初始对准,导出了重力扰动下水平姿态误差角与垂线偏差大小等值。重力扰动 下初始对准的方法是利用EGM2008 地球重力场模型计算出对准点的重力扰动并从加速度 计中剔除掉。仿真分析表明,补偿重力扰动后可提高初始对准精度。