Two freedom linear parameter varying μ synthesis control for flight environment testbed

To solve the problem of robust servo performance of Flight Environment Testbed(FET)of Altitude Ground Test Facilities(AGTF) over the whole operational envelope, a two-degree-offreedom μ synthesis method based on Linear Parameter Varying(LPV) schematic is proposed, and meanwhile a new structure frame of μ synthesis control on two degrees of freedom with double integral and weighting functions is presented, which constitutes a core support part of the paper. Aimed at the problem of reference command's rapid change, one freedom feed forward is adopted, while another freedom output feedback is used to meet good servo tracking as well as disturbance and noise rejection; furthermore, to overcome the overshoot problem and acquire dynamic tuning,the integral is introduced in inner loop, and another integral controller is used in outer loop in order to guarantee steady errors; additionally, two performance weighting functions are designed to achieve robust specialty and control energy limit considering the uncertainties in system. As the schedule parameters change over large flight envelope, the stability of closed-loop LPV system is proved using Lyapunov inequalities. The simulation results show that the relative tracking errors of temperature and pressure are less than 0.5% with LPV μ synthesis controller. Meanwhile, compared with non-LPV μ synthesis controller in large uncertainty range, the proposed approach in this research can ensure robust servo performance of FET over the whole operational envelope.     

PLC双行车全自动控制程序的设计

本文介绍了使用ＰＬＣ对两台车进行全自动控制的程序设计过程，重点 利用表格法驱动行车的方案和具体实现方法。     

A Probabilistic Strongest Neighbor Filter Algorithm for m Validated Measurements

A new form of the probabilistically strongest neighbor filter (PSNF) algorithm taking into account the number of validated measurements is proposed. The probabilistic nature of the strongest neighbor (SN) measurement in a cluttered environment is shown to be varied with respect to the number of validated measurements. Incorporating the number of validated measurements into design of the PSNF produces a consistent and cost effective data association method. Simulation studies show that the new filter is less sensitive to the unknown spatial clutter density and is more reliable for practical target tracking in nonhomogeneous clutter than the existing PSNF. It has similar performances to the probabilistic data association filter amplitude information (PDAF-AI) with much less computational complexities.     

NOVEL RADAR SIGNAL SORTING METHOD BASED ON GEOMETRIC COVERING

With the increase of complexity of electromagnetic environment and continuous appearance of advanced system radars, signals received by radar reconnaissance receivers become even more intensive and complex. There- fore, traditional radar sorting methods based on neural network algorithms and support vector machine （SVM） cannot process them effectively. Aiming at solving this problem, a novel radar signal sorting method based on the cloud model theory and the geometric covering algorithm is proposed. By applying the geometric covering algo- rithm to divide input signals into different covering domains based on their distribution characteristics, the method can overcome a typical problem that it is easy for traditional sorting algorithms to fall into the local extrema due to the use of complex nonlinear equation to describe input signals. The method uses the cloud model to describe the membership degree between signals to be sorted and their covering domains, thus it avoids the disadvantage that traditional sorting methods based on hard clustering cannot deinterleave the signal samples with overlapped param- eters. Experimental results show that the presented method can effectively sort advanced system radar signals with overlapped parameters in complex electromagnetic environment.     

Bernoulli particle flter with observer altitude for maritime radiation source tracking in the presence of measurement uncertainty

For maritime radiation source target tracking in particular electronic counter measures（ECM）environment,there exists two main problems which can deteriorate the tracking performance of traditional approaches.The frst problem is the poor observability of the radiation source.The second one is the measurement uncertainty which includes the uncertainty of the target appearing/disappearing and the detection uncertainty（false and missed detections）.A novel approach is proposed in this paper for tracking maritime radiation source in the presence of measurement uncertainty.To solve the poor observability of maritime radiation source target,using the radiation source motion restriction,the observer altitude information is incorporated into the bearings-only tracking（BOT）method to obtain the unique target localization.Then the two uncertainties in the ECM environment are modeled by the random fnite set（RFS）theory and the Bernoulli fltering method with the observer altitude is adopted to solve the tracking problem of maritime radiation source in such context.Simulation experiments verify the validity of the proposed approach for tracking maritime radiation source,and also demonstrate the superiority of the method compared with the traditional integrated probabilistic data association（IPDA）method.The tracking performance under different conditions,particularly those involving different duration of radiation source opening and switching-off,indicates that the method to solve our problem is robust and effective.     

Aspects of Global Magnetospheric Processes

Magnetospheric global modeling is a method to link observations from distant regions via physical laws and has long played a unique and crucial role in space physics. It, different from computer simulations, represents the highest level of abstraction of the physical understanding of the processes that cause observed phenomena. It results in various specific models. While it appears in the form of cartoons, it is based on and has to be qualitatively consistent with physical laws. With the advancement of computer simulations, clues to the connection between physical laws and observation can be perceived much more easily than as ever before. However, computer simulation results are highly dependent on the used boundary conditions and numerical methods which may or may not represent the reality, even if the initial conditions are properly set. Therefore, simulations can easily mislead the investigations. Furthermore, a simulation result needs to be examined using diagnostic tools, such as field line tracing and streamline tracing programs. There are uncertainties in these diagnostic methods. The errors can be very large in certain areas under certain conditions. For example, a small error may link two different field lines or stream lines. The interpretations of the simulation results can be misled by these errors. The knowledge of global modeling can be useful in identifying the inconsistencies in the simulations and the flaws in the theoretical interpretation from the simulations. This review-tutorial article outlines the principles of the global modeling and discusses the successes and flaws of several global models.     

数控加工中切削用量的确定

数控加工在当今的冷加工中应用越来越多,其切削用量与普通机床有很大不同。本文对数控加工中切削用量的确定做了简要的分析,提供了一些选取原则和方法,并对应该注意的问题进行了分析,以供数控操作人员参考。     

微小卫星星座用于侦察的设想

导弹攻防是空间对抗的重要领域.采用以信息技术为基础的电子攻击手段对目标防御系统实施对抗是导弹突防的有效措施之一.信息认知是夺取制天权的制高点.信息攻击的制高点是对目标信息传感器的信息掌握和信息认知.提出采用微小卫星星座侦察站专职从事对特定区域雷达传感器的信息获取、监视和认知的设想,并对卫星轨道及时间段无缝侦察星座作了初步构想.     

无穷观问题的研究(Ⅱ)——从Hausdorff的直觉和Poincaré的名言到Brouwer剧场现象

本组系列论文 ( )～ ( )从数学和认识论的角度系统地研究了无穷观问题的历史发展和现状 ,确立了无穷观背景世界的三分法原则 ,指出了两种无穷观相互排斥的局限性 ,形成了统一两种无穷于同一框架中的基本观点 ,并建立了一个统一实无限与潜无限于同一框架中的公理集合论系统 APAS。     

基于XML语言和代理模型的翼型通用气动数据库技术

建立翼型气动数据库对翼型的选择和设计具有重要的意义。本文基于一种建立翼型通用气动数据库的思想,介绍该数据库的基本框架和基本功能;该数据库采用一种基于可扩展标记语言的通用数据格式进行存储,包含翼型几何特性数据、不同流动状态下力系数、物面压力分布等各种气动数据,并且还可提供灵活多样的数据处理功能;采用代理模型和变可信度模型技术,实现气动数据快速检索和插值功能。通过DU93-W-210翼型算例初步表明如何实现气动数据生成和快速插值,从而初步展示了所提出翼型气动数据库技术的可行性。