基于对偶数的相对耦合动力学与控制

针对空间交会对接等目标逼近任务中姿态和轨道运动相耦合的问题,推导给出了基于     

次流通道对双喉道气动矢量喷管的性能影响研究

为了进一步了解次流通道对双喉道气动矢量喷管(Dual Throat Nozzle,DTN)气动矢量性能的影响,基于二维DTN喷管构型进行了详细的数值模拟研究。结果表明:收扩的次流通道相对于平直的次流通道不会改善DTN喷管的推力矢量性能;随着次流流量增加,DTN的推力矢量角存在一个最大值,超过该值各推力矢量性能均会降低;次流通道宽度对DTN喷管推力矢量性能影响显著:(1)次流宽度不影响所能达到的最大推力矢量角;(2)小的次流宽度在进口总压较高的条件下具有更高的推力矢量角;(3)增大次流宽度能降低次流总压,但达到的矢量角会有所减小。     

地月空间星地双向单程测量高精度模型

针对使用星地双向单程测量技术实现给定场景下的地月空间高精度测量问题,建立了地月空间纳秒级星地时差解算模型与米级瞬时距离解算模型,定量分析了模型中各因素的量级,并对模型中收发时延、引力时延、定轨误差和大气延迟等多种因素引入的时差和距离估算误差进行了定量分析。仿真数据的处理结果校验了误差量级理论分析的准确性,时差估算的均方根误差优于7.6ns,瞬时距离估算均方根误差优于2.4 m。建立的模型可以对地月空间星地DOWR测量数据进行高精度处理,实现地月空间高精度时间比对,支持未来中国载人登月等任务及地月空间高精度导航技术。     

双模态超燃燃烧室性能准一维计算方法

为了快速准确地得到双模态超燃燃烧室性能,对已有准一维非稳态方法进行了研究,发现当燃烧室工作在亚燃模态时此方法不能正确预测预燃激波串的压力变化趋势。将预燃激波串模型耦合到准一维非稳态方法中,得到一种改进的准一维非稳态计算方法。通过四组不同算例验证表明,此方法能准确地预测双模态超燃燃烧室的压力变化趋势,同时也能准确地捕捉到压力峰值,具有较高的精度和较好的适用性。     

相控馈电双反射面天线辐射特性的研究

研究了用Fourier-Bessel法和射线光学法计算、分析相控阵馈电共焦双抛物面天线辐射场的有效方法,并初步探讨了通过选择天线系统参数来尽可能减少扫描损失的途径。     

Theoretical modeling of vectoring dual synthetic jet based on regression analysis

The excellent vectoring characteristic of Dual Synthetic Jet (DSJ) provides a new control strategy for the active flow control, such as thrust vectoring control, large area cooling, separated flow control and so on. For incompressible flow, the influence relation of source variables, such as structure parameters of actuators, driving parameters and material attributes of piezoelectric vibrating diaphragm, on the vectoring DSJ and a theoretical model are established based on theoretical and regression analysis, which are all verified by numerical simulations. The two synthetic jets can be deemed as a main flow with a higher jet velocity and a disturbing flow with a lower jet velocity. The results indicate that the influence factors contain the low-pressure area formed at the exit of the disturbing flow, which could promote the vectoring deflection, and the impact effect of the disturbing flow and the suppressive effect of the main flow with the effect of restraining the vectoring deflection. The vectoring angle is a complex parameter coupled by all source variables. The detailed theoretical model, whose error is controlled within 3.6 degrees, can be used to quantitatively assess the vectoring feature of DSJ and thus to provide a guidance for designing the control law applied in the active flow control.     

挠性双自旋卫星的姿态稳定判据

本文建立了挠性双自旋卫星的姿态稳定性判据。挠性双自旋卫星由半刚性平台、转子以及固连于平台的挠性附件组成,选择由姿态角和模态坐标表示的系统的相对能量函数为Liapunov函数,由此建立的姿态稳定判据由两个部分组成,即忽略附件弹性运动时,半刚性双自旋卫星的姿态稳定条件和附件振动频率所应满足的条件。文中还给出了具体的应用例子。     

Relative position and attitude estimation of spacecrafts based on dual quaternion for rendezvous and docking

The capacity to acquire the relative position and attitude information between the chaser and the target satellites in real time is one of the necessary prerequisites for the successful implementation of autonomous rendezvous and docking. This paper addresses a vision based relative position and attitude estimation algorithm for the final phase of spacecraft rendezvous and docking. By assuming that the images of feature points on the target satellite lie within the convex regions, the estimation of the relative position and attitude is converted into solving a convex optimization problem in which the dual quaternion method is employed to represent the rotational and translational transformation between the chaser body frame and the target body frame. Due to the point-to-region correspondence instead of the point-to-point correspondence is used, the proposed estimation algorithm shows good performance in robustness which is verified through computer simulations.     

Numerical investigation on flow field characteristics of dual synthetic cold/hot jets using POD and DMD methods

In order to improve the control ability of synthetic jets in compressible boundary layer, a novel control method based on dual synthetic cold/hot jets coupled control of velocity profile and temperature profile was proposed. As fundamental investigations on the effects of synthetic jet temperature on the jet behavior and flow field characteristics were essentially necessary, preliminary numerical simulations were conducted to study the influence of temperature (200 K and 400 K) on the flow field characteristics of synthetic jets using Large Eddy Simulations (LES) model. Time-averaged flow fields showed that different temperatures led to variable behavior of two strands of jets. For dual synthetic cold jets, a potential-core arose apparently with its height ranging from 0.01 to 0.03 m, while for dual synthetic hot jets, two strands of jets emerged downstream. The modal decomposition of instantaneous flow fields had been done using both Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD). Various modes showed different characteristics of the flow fields. As the POD method focuses on the energy of flow while the DMD method focuses on the frequency, the first two modes had many similarities, but the third and fourth modes demonstrated completely different vortex structures. The current researches play a role of preliminary investigations for further and comprehensive exploration of novel flow control measures in global velocity field.     

数控技术专业双证书认证试点方案制定——以西安航专数控技术专业双证书认证方案为例

以制定数控技术专业双证书认证试点方案为目的，结合市场需求，采用职业岗位能力分析的方法，将职业资格证书认证体系嵌入学历教育，构建了核心课程体系，设计了培养该专业学生核心职业能力的学习包，并设计了相对应的职业资格证书体系，从而制定了该专业双证书认证试点方案，通过实施，取得了好的效果。