基于仿真模板的控制系统可靠性分析

提出面向对象的计算机辅助故障模式影响分析(CFMEA)方法,建立了控制系统仿真模板,将其数据、操作和性能封装成一个对象,对象间通过属性进行因果推理,实现FMEA向故障树(FTA)的自动转换.引入控制系统性能可靠性概念,建立控制系统性能和功能综合可靠性模型,开发相应的解算方法.实例分析证明了基于仿真模板的控制系统可靠性分析的有效性, 综合了功能和性能可靠性分析的优点.      

基于案例推理的直接维修成本预计方法

在飞机研制初期就开始对直接维修成本(DMC)进行分析和控制对于降低飞机全寿命周期成本、增强飞机市场竞争力具有重要的意义。然而,现有的DMC预计方法存在精度低、大量依靠专家经验的缺陷,针对这些缺陷提出一种基于案例推理的预计方法。经过验证,此方法不仅需要的经验知识大大减少,而且简单、快捷,精度比其他方法提高了十几个百分点。     

基于动态模糊观测器的故障诊断方法研究

研究了T S模糊系统中存在未知输入、多重故障时的诊断问题,提出了基于动态模糊观测器的诊断方法。仿真结果表明,该方法推理简单,解耦多重故障准确有效。     

固体火箭发动机多层粘接结构超声图像诊断

针对固体火箭发动机的钢壳、绝热层、衬层、推进剂多层粘接结构的粘接质量检测问题,利用聚焦探头采用斜声束液浸反射回波法,选用往返透射率高的板波模式,特别是采用了双模式检测技术以提高检测信号能量,获得有效检测信号,并开发出了检测系统。通过一次C扫描获得了双层包覆三个界面粘接质量诊断图像,其脱粘检测分辨率≤Φ5 mm。采用聚集探头双模式检测技术实现了固体火箭发动机多层粘接结构超声图像诊断。     

多阶复合振动的模糊推理移相控制研究

针对空间柔性结构阻尼小、非线性以及不确定性等特点,采用模糊推理智能控制方法,对柔性结构多阶频率的振动进行控制。结果表明,模糊推理智能控制对于非线性、不确定性结构的振动控制较为有效,控制精度较高,并有较强的鲁棒性和稳定性。     

一个具有双层推理模型的医学专家系统

介绍一个成功的、具有双层推理模型的医学专家系统及其双层模型的构造、因果关系模型深层知识的获取、推理策略以及解释功能的设计技术。双层推理模型是经验推理和致因分析深层推理相结合的联合推理模型，它克服了第一代专家系统经验推理的局限性和脆弱性以及求解策略的单一性，增强了系统求解能力，提高了系统解释功能的深度，它是第二代专家系统设计技术的一次成功的研究和探索。最后给出了具有双层推理模型的医学专家系统运行时的一个诊断实例。     

基于知识工程的固体火箭发动机装药设计技术研究

为了实现对以往设计经验及知识的继承和重用,在固体火箭发动机装药设计中引入了基于知识工程的设计思想。首先建立了装药设计的SBF表示模型,从产品设计的角度说明了装药设计实质;然后完成了药形选择的神经规则表示;同时,实现了基于案例推理的药形几何参量确定,具体内容包括建立尺寸无关药形几何参量的案例表示模型,给出基于案例推理的药形几何参数确定算法。最后,结合实际应用对上述工作进行了具体实践;并针对实际型号进行了装药设计。通过对设计结果的正确性验证,证明该技术可行、有效。     

Performance evaluation of complex systems using evidential reasoning approach with uncertain parameters

The composition of the modern aerospace system becomes more and more complex. The performance degradation of any device in the system may cause it difficult for the whole system to keep normal working states. Therefore, it is essential to evaluate the performance of complex aerospace systems. In this paper, the performance evaluation of complex aerospace systems is regarded as a Multi-Attribute Decision Analysis (MADA) problem. Based on the structure and working principle of the system, a new Evidential Reasoning (ER) based approach with uncertain parameters is proposed to construct a nonlinear optimization model to evaluate the system performance. In the model, the interval form is used to express the uncertainty, such as error in testing data and inaccuracy in expert knowledge. In order to analyze the subsystems that have a great impact on the performance of the system, the sensitivity analysis of the evaluation result is carried out, and the corresponding maintenance strategy is proposed. For a type of Inertial Measurement Unit (IMU) used in a rocket, the proposed method is employed to evaluate its performance. Then, the parameter sensitivity of the evaluation result is analyzed, and the main factors affecting the performance of IMU are obtained. Finally, the comparative study shows the effectiveness of the proposed method.     

Mental spatial transformations of objects and perspective

This study sought evidence for the independenceof two classes of mental spatialtransformation: object-based spatialtransformations and egocentric perspectivetransformations. Two tasks were designed toselectively elicit these two transformationsusing the same materials, participants, andtask parameters: one required same-differentjudgments about pairs of pictures, while theother required left-right judgments aboutsingle pictures. For pictures of human bodies,the two tasks showed strikingly differentpatterns of response time as a function ofstimulus orientation. Moreover, acrossindividuals, the two tasks had differentrelationships to psychometric tests of spatialability. The chronometric and individualdifference data converge withneuropsychological and neuroimaging data insuggesting that different mental spatialtransformations are performed by dissociableneural systems.