基于H∞方法的控制系统作动器最优控制仿真研究

在设计控制系统模型时,首先引入了有限差分法(FDM)离散化后的波动方程,然后基于H∞最优控制原理,检查闭环控制系统的稳定性和可探测性,对控制系统传感器和作动器的位置进行优化配置.通过计算闭环反馈系统的范数,最终得到了控制系统的最优控制算法.仿真结果表明,利用波动方程来优化控制系统传感器和作动器位置的算法是可行的,可广泛应用于飞控系统的设计中.     

Experimental study on plasma jet deflection and energy extraction with MHD control

This paper presents an integrated research scheme for vector deflection and energy extraction in a gas plasma jet under Magneto-Hydrodynamic (MHD) control. A MHD-controlled thrust-vector test rig was used to conduct the experimental research. A gas plasma was obtained by injecting ionization seeds of Cs₂CO₃ into the combustion chamber via artificially forced ionization. The effects of the gas temperature and ionization seed mass fraction on the plasma jet deflection and energy extraction were experimentally verified under an applied magnetic field. The experimental results were analyzed theoretically. The results showed that the deflection amplitude of the gas plasma jet and the extracted voltage signal intensity increased with increasing gas temperature and the ionization seed mass fraction. The extracted dynamic voltage signals proved that the ionization seeds of Cs₂CO₃ induced gas ionization at 1173 K. The experiment verified that it is feasible to simultaneously achieve jet deflection and extract energy under the action of an external magnetic field.     

基于改进准则法的复合壳阻尼结构拓扑减振动力学优化

针对复合壳阻尼结构的拓扑减振优化问题，以约束阻尼层的有限单元为设计变量，采用体积比、模态频率和振型为优化约束条件，构建以多模态权重系数的结构模态损耗因子数值关系为优化目标函数的拓扑减振优化模型。为了拓展优化目标灵敏度具有不局限于某一变密度法插值模型的形式，推导了数值表达式的一般函数式。动力学优化中优化目标灵敏度正、负数集共存，使得非凸性的目标函数设计变量出现负值或优化函数寻优于局部极值点。为此，推导出复合壳阻尼结构的全域灵敏度改进优化准则法迭代格，以确保每次迭代域均为全域设计变量集。结合有限单元法编程实现了复合壳阻尼结构改进准则法，并对复合壳结构进行拓扑减振优化分析。结果表明：在敷设体积减为全覆盖的50%时，复合壳结构的模态损耗因子增减偏差为10%，具有提升减振的轻量化设计目的；各阶目标函数和拓扑构型所需的迭代次数少，中间密度区域较小，多阶优于单阶模态优化函数，易于获得全域寻优的有效减振。     

低速大转矩永磁游标电机在发酵罐中的应用

采用秸秆生产丁醇时,为了达到高效率发酵,需要使发酵液中菌体分布均匀,所加物料需要及时搅拌。工业化生产丁醇的发酵罐尺寸较大,搅拌过程对驱动电机的输出转矩要求较高,因此高效率、小体积、低速大转矩的秸秆发酵搅拌电机对工业化发酵生产丁醇意义重大。设计了一种定转子永磁游标电机用于发酵液搅拌,并对电机的槽极数、电磁性能进行了具体的研究。制造样机并采用滞环控制实现了对液态发酵对象的快速响应,且实现了低能耗、高效率的发酵过程。     

A surface parametric control and global optimization method for axial flow compressor blades

An aerodynamic optimization method for axial flow compressor blades available for engineering is developed in this paper. Bezier surface is adopted as parameterization method to control the suction surface of the blades, which brings the following advantages:(A) significantly reducing design variables;(B) easy to ensure the mechanical strength of rotating blades;(C) better physical understanding;(D) easy to achieve smooth surface. The Improved Artificial Bee Colony(IABC) algorithm, which significantly increases the convergence speed and global optimization ability, is adopted to find the optimal result. A new engineering optimization tool is constructed by combining the surface parametric control method, the IABC algorithm, with a verified Computational Fluid Dynamics(CFD) simulation method, and it has been successfully applied in the aerodynamic optimization for a single-row transonic rotor(Rotor 37) and a single-stage transonic axialflow compressor(Stage 35). With the constraint that the relative change in the flow rate is less than0.5% and the total pressure ratio does not decrease, within the acceptable time in engineering, the adiabatic efficiency of Rotor 37 at design point increases by 1.02%, while its surge margin 0.84%,and the adiabatic efficiency of Stage 35 0.54%, while its surge margin 1.11% after optimization, to verify the effectiveness and potential in engineering of this new tool for optimization of axial compressor blade.     

助推-滑行式燃料最优真空飞行轨迹的设计方法

建立了飞行器助推-滑行式燃料最优真空飞行轨迹的最优控制模型,给出了一种更为简单、直观的内点约束条件和横截条件的推导方法,讨论了高效且更为稳定的数值计算方法,提出了两种应用模式,通过与连续推力式和脉冲式飞行方案的比较,说明这种设计方法在节省燃料方面具有优势.     

阵风载荷减缓系统故障分析

阵风引起的额外载荷会引起飞机结构疲劳,降低结构使用寿命。采用非定常气动力有理函数拟合方法建立时域状态空间下的动力学系统,设计了阵风载荷减缓系统。研究了阵风载荷减缓系统3种典型故障模式(副翼偏转饱和、舵机卡死、副翼偏转延时)的力学建模方法,并对机翼在阵风减缓系统故障模式下的阵风响应进行分析。仿真结果表明,3种故障模式均不利于阵风载荷减缓系统对阵风载荷的减缓,对于一些特定情况,故障模式下的阵风载荷减缓系统不仅不能减缓阵风载荷,还会带来由副翼偏转不当引起的额外负载。     

BL分析下的管制员差错本体建模研究

为分析识别空中交通管制任务中管制差错问题,结合BL(body loop,BL)压力产生模型研究管制员压力来源.提出领域本体的建模流程,确立推理模型的内部逻辑关系,构建管制差错领域本体模型.采用FaCT++推理机针对实际案例进行语义推理,从而识别管制差错类型,提出了基于本体的管制差错专家系统的系统框架.结果验证了构建推理模型的有效性和合理性.     

Laminar flow control research at TsAGI: Past and present

This paper presents a brief review of activities in laminar flow control being performed at the Central Aerohydrodynamic Institute named after Prof. N.E. Zhukovsky (TsAGI). These efforts are focused on the improvement of the existing laminar flow control methods and on the development of new ones. The investigations have demonstrated the effectiveness of aircraft surface laminarization applications with the aim of friction drag reduction. The opportunity of considerable delaying of laminar-turbulent transition due to special wing profile geometry and using boundary layer suction and surface cooling has been verified at sub- and supersonic speeds through various wind tunnel testing at TsAGI and during flying laboratory experiments at the Flight Research Institute (LII). The investigations on using hybrid laminar flow control systems for friction drag reduction were also carried out. New techniques of laminar flow control were proposed, in particular, the method of local heating of the wing leading edge, boundary layer laminarization by means of receptivity control, and electrohydrodynamic methods of boundary layer stability control.     

HED-21S数控综合实验台画笔自动控制机构设计

以数控系统的PLC控制为基础,设计HED-21S机械笔控制系统结构,它可控制电磁铁的动作,执行画笔的上下运动。这支笔在X、Z型十字窗格可以绘制任意几何形状,该设计符合要求的快速定位数控直线移动,及圆弧插补功能,有助于提高数控编程效率和数控教学质量。