Fault-accommodation with intelligent sensors

Optimal sensor fault-accommodation is considered for faults modelled by an increase in measurement noise. This noise is taken to be bounded and its probabilistic properties unknown. It is assumed that intelligent (e.g. self-validating) instrumentation is in use and estimates of the noise bounds are available. The fault-tolerant controller is designed to optimize a noise rejection and a nominal reference tracking index and leads to a mixed norm minimization problem (l₁/l₂). We exploit known results and a particular feedback configuration to show that it is possible to optimize simultaneously without a trade-off the two performance indices. The results are applied to systems where the presence of auxiliary measurements allows for an optimal fault-accommodation strategy. Using properties of the optimal solution, we define a factorization for the optimal controller alternative to the Youla parametrization, leading to an algorithm which is optimal, transparent and efficient.     

Tracking trajectories of the cart-pendulum system

The problem of tracking a periodic trajectory of the well-known cart-pendulum system is solved. After a change of coordinates and a change of feedback, the equations of this system are nonlinear but feedforward. This property is extensively used to carry out for this system the design of uniformly asymptotically stabilizing time-varying state feedbacks by using the forwarding approach.     

N-溴丁二酰亚胺／吡啶氧化合成己二酰基双偶氮化合物

以己二酰二氯和不同取代基的苯肼合成了N,N'-二芳基己二酰二肼类中间体,然后在N-溴丁二酰亚胺(NBS)／吡啶氧化体系下室温合成了8种己二酰基双偶氮化合物。第一步反应条件为:n(己二酰二氯):n(取代苯肼)=1:2,反应温度0-5℃,反应时间4 h,收率80%-93％;第二步反应条件为:n(N,N’-二芳基己二酰二肼):n(NBs／吡啶)=1:2,氧化反应时间0．5-1．0 h,收率80%-94%。并用元素分析、IR、1H NMR对合成的中间产物及目标化合物进行了表征。     

A time aggregation approach to Markov decision processes

We propose a time aggregation approach for the solution of infinite horizon average cost Markov decision processes via policy iteration. In this approach, policy update is only carried out when the process visits a subset of the state space. As in state aggregation, this approach leads to a reduced state space, which may lead to a substantial reduction in computational and storage requirements, especially for problems with certain structural properties. However, in contrast to state aggregation, which generally results in an approximate model due to the loss of Markov property, time aggregation suffers no loss of accuracy, because the Markov property is preserved. Single sample path-based estimation algorithms are developed that allow the time aggregation approach to be implemented on-line for practical systems. Some numerical and simulation examples are presented to illustrate the ideas and potential computational savings.     

火控虚拟仪器实验室建设

本文针对传统火控实验室受传统测试仪器的功能限制,提出了建立火控虚拟仪器实验室的构想.坦克火控虚拟仪器以LabVIEW软件为核心,其强大的数据分析能力为火控系统的研制提供了有力的支持.该软件的模块化和层次化结构,使非程序员的火控工程师游刃有余地完成测试成为可能.     

Algorithm for finding all k nearest neighbors

A very simple algorithm for computing all k nearest neighbors in 2-D is presented. The method does not rely on complicated forms of tessellation, it only requires simple data binning for fast range searching. Its applications range from scattered data interpolation to reverse engineering.     

原始组织及加热方式对Al-5.8wt%Cu合金熔化行为的影响

利用DSC分析手段，研究了具有3种不同凝固组织的Al-5.8wt%合金在7种不同加热方式下的熔化开始温度和熔化热，发现凝固组织中存在的非平衡共晶在加热过程中大部分扩散溶解，溶入基体，剩余部分参与共晶熔化，其熔化开始温度与组织状态无关，随加热速度的增大略有升高，溶解部分的体积分散与组织状态和加热方式有关，随加热时间和非平衡相表面积的增大而增大。