作动系统健康状况对飞行安全影响的评估方法

机电作动系统的故障往往导致灾难性的后果。采用自上而下的设计思路,建立了机电作动系统对飞行安全影响的分析方法。综合机电作动系统故障模式及飞控系统故障模型,对机电作动系统进行故障模式及影响分析,用Monte-Carlo法对故障进行随机性仿真,求得机电作动系统的故障概率,应用极值理论计算飞行安全概率。仿真实验说明：该方法可以用做进行安全监控的依据。     

基于键合图的汽车悬架系统建模与仿真

键合图是一种图形工具,它可以清晰形象地描述系统内部的能量结构.文中给出了功率键合图理论对汽车1/4、1/2悬架系统建模的详细方法,建立了1/4、1/2悬架的键合图模型.对1/2悬架键合图模型进行仿真时,文中没有采用传统的推导状态方程方法,而是将键合图模型按照键合图与方块图的转化关系直接转为方块图模型,再利用MATLAB软件的Simulink工具箱对1/2悬架的方块图进行建模仿真.给出了仿真模型,得到了较好的仿真结果.验证了键合图结合方块图理论对系统建模和分析的优越性.     

基于20-sim软件的非线性电路仿真

利用20-sim软件的功能,可以对非线性电路进行直接面向方程的仿真分析,也可以在现有非线性电路的基础上,转换成相应的键合图模型,利用键合图理论进行仿真分析.为了对这两种仿真分析方法进行对比分析,选取杜芬方程作为研究对象,提出了运算放大器的键合图模型,分别用图形化的方法与键合图方法进行了仿真,并对两种方法进行了结论性的比较.     

基于功率键合图和Matlab／Simulink的液压激振系统的建模及仿真

液压振动系统是采用激波器控制的机电液一体化系统,具有高动态特性。运用键合图方法建立液压振动系统的键图模型,提出将控制参数加入键图模型,用于控制液压振动系统功率流向的交替变化;根据键合图理论和控制关系建立系统的数学模型;并利用Matlab／Simulink仿真软件建立其仿真模型,可以直观地表达系统的功率流向和控制关系;根据液压振动系统模型易产生病态的特点,利用Matlab提供多种求解方法的优势,设置合理的仿真参数以得到更精确的仿真结果;利用键合图方法的扩展功能和Simulink建模的模块化可以深入研究系统中受关注的任何子系统,为液压振动系统的设计和应用提供理论依据。     

基于键合图模型的新型解析冗余关系故障诊断方法研究

研究了通过诊断键合图模型建立系统解忻冗余关系(ARRs)的故障诊断方法.通过在系统键合图中加入虚拟传感器的方法建立系统的诊断键合图,根据诊断键合图模型的因果关系路径构建系统的解析冗余关系和系统故障特征矩阵,并利用系统实际观测特征与故障特征的比较进行系统的故障检测和隔离,通过在双容水箱系统的仿真验证,证明了该方法便捷性和...     

新型解析冗余关系法在传感器故障诊断中的应用

介绍了多容水箱系统所有可能出现的故障类型,并分析了多容水箱系统的结构与特点。利用基于键合图模型的新型解析冗余关系（ARR）方法对多容系统中传感器故障进行了研究。根据键合图理论给出了多容水箱系统键合图模型,通过在系统键合图中加入观测信号和虚拟传感器的方法建立系统的诊断键合,根据诊断键合图模型得到系统的ARR。通过分析诊断键合图的因果关系构建系统的故障特征矩阵。利用20-sim键合图仿真软件对各类故障进行仿真分析,验证了基于键合图模型的新型ARR方法在传感器故障检测与隔离方面的可行性。     

面向功率键合图的通用仿真软件的研究大连铁道学院

本文介绍了一种面向功率键合图的通用的系统动态特性仿真软件-PBGSIM.该软件在MATLAB平台上二次开发而成,充分发挥了功率键合图法在分析系统动态特性方面的优势,可以处理包含各种环节的复杂系统.软件从系统的键合图模型出发,自动辨错提示、自动建立数学模型(字符型和数值型)、进行仿真计算并按要求输出仿真结果.用户可以方便地修改元件参数或模型直至得到满意的结果.还可以给定优化变量,对系统的动态特性进行参数优化.该软件的研制为采用键合图建模仿真提供了全新的手段,为复杂系统的动态设计、优化提供了一个有效的工具.     

矿用电动轮车交流传动系统的建模与仿真

矿用电动轮自卸车的交流传动系统是一个复杂的多能域系统,主要由功率变换器和电机组成。采用可调变换器附加导通电阻Ron的方式建立功率变化器开关器件的键合图模型,并以其为基本部件建立功率变换器的键合图模型。根据其建立的模型在所有开关模式下具有同样的因果关系,不需要因为系统模式的变化而重新指派计算因果关系。根据d-q坐标系下电机的等效电路图建立电机的键合图模型,并由键合图模型推导出电机的状态方程。采用MTLAB/Simulink和20-sim软件对功率变换器和电机的键合图模型分别进行仿真,实验结果验证了模型的正确性,说明键合图理论能够用于复杂多能域系统的统一建模。     

汽液两相流键合图建模与仿真

为了研究汽液两相流管道系统动态特性,从质量守恒、能量守恒和动量守恒方程出发,采用交错网格有限体积法,推导出汽液两相流通用微分方程的离散形式,结合键合图理论建立了分段集总参数键合图模型.为了求解工质热力性质,利用多领域统一建模语言Modelica建立了键合图模型的仿真程序,并以直流锅炉受热管为例,在Dymola平台上进行仿真.仿真结果反映了热负荷阶跃变化时管内压力、温度、含汽率动态变化与分布情况,为管道系统设计与分析提供了依据.     

船用蒸汽轮机键合图建模与仿真研究

从基本物理规律出发,应用键合图理论研究了船用蒸汽轮机的仿真建模问题,以规范化的方式统一分析了汽轮机装置中同时存在的热功转换、热传递和质量迁移3种能量作用,建立了一类具有通用性的船用汽轮机装置全工况键合图模型。结合具体算例对模型进行验证,通过仿真结果与实测值比较证明模型能够真实地反映船用汽轮机装置的静态与动态工作特性,具有较好的精确性和实时性。对键合图理论在热工对象仿真建模领域内的应用作了一些探讨,所得结论具有一定的理论和工程实用价值。     

Modelling and robust FDI of steam generator using uncertain bond graph model

In this paper, a bond graph model based approach for robust FDI (Fault Detection and Isolation) in the presence of parameter uncertainties is presented. Due to the energetic and structural properties of the bond graph, the whole of nonlinear model, structural analysis, residual with adaptive thresholds generations, and sensitivity analysis of the residuals can be synthesized using this same tool. This method is applied online on an industrial steam generator. Experimental results are given to support the theoretical development.     

A model for simulating a lead-acid battery using bond graphs

This paper presents a model of a lead-acid battery developed with bond graphs. The bond graph structure is used to reproduce the behavior of reversible electrochemical cells in charging conditions or in discharging conditions. The work presented here has been applied to the particular case of lead-acid battery, so widely used in the automotive industry as standard 12 V batteries and as traction batteries in electrical or hybrid vehicles.The model considers each half-cell independently. For each half-cell the main electrode reaction and the electrolysis reaction of water are considered, that will be the hydrogen evolution reaction in the negative electrode and the oxygen evolution reaction in the positive.Electrochemical principles are considered in order to consider the main phenomena that appear in the battery, like the equilibrium potential, and the overpotential, modeled by means of the activation or charge transfer and the diffusion mechanisms.Each one of this phenomena are modeled with their corresponding bond graph elements and structures, showing the correspondence between bond graph elements and its physical interpretation in this field.First, an isothermal model has been developed in order to show the behavior of the main phenomena. A more complex model has also been developed including thermal behavior. This model is very useful in the case of traction batteries in electrical and hybrid vehicles where high current intensities appear.Some simulation results are also presented in order to show the accuracy of the proposed models and the differences of behavior if thermal effects are considered.     

Supervision of an industrial steam generator. Part II: Online implementation

A bond graph model based Fault Detection and Isolation approach applied to design of a supervision system for a complex steam generator is presented. The non-linearities and energetic couplings involved in the dynamics require a suitable and adaptive supervision environment. The analytical redundancy relations are derived from bond graph model of the process by utilising of the structural and causal properties of the model. The decision procedure to detect and isolate the faults uses the residuals, evaluated online. Due to measurement noises and uncertainties in the process, many complementary decision procedures based on different methods of signal treatment are used to form an integrated supervision environment. The integrated platform allows to monitor the plant in normal operation as well as in the presence of faults. Finally, redundancy information is used for both automatic and manual reconfigurations to safely increase process availability by using adaptive real-time modifications to process control laws as well as equations of the process and the residuals to reflect the dynamics of the new configuration.     

键合图在火电厂热工对象建模中的应用

针对火电机组这种复杂的多能量转换系统,功率键合图以能量守恒定律为依据,用4种统一的物理变量表达不同的工程系统,在机、电、液、热等多种能量范畴的耦合系统建模中具有独到优势。在研究热工对象汽包的工作过程基础上,利用功率键合图理论,将其分解划分为相关键图子系统,通过连接各子系统键图模型综合得到汽包对象的键合图模型,并推导了该模型对应的数学描述,通过仿真验证了键合图模型的精确性,为热工对象的建模提供了一种崭新方法。     

Supervision of an industrial steam generator. Part I: Bond graph modelling

Model based supervision of most process engineering plants is difficult due to the complexities arising out of the energetic couplings in the model. Bond graph modelling is a suitable tool to represent the model structures of such processes along with their control system instrumentation. In this paper, bond graph model of a steam generator installation consisting of complex industrial components such as a boiler, a condenser, etc. is developed and validated through experimental observations. It is further shown that the causal properties of bond graphs not only allow validating the model, but they also provide the computational algorithms to eliminate the unknown variables from coupled thermo-fluid models and thus generate analytical redundancy relations (ARR) in terms of measurements and parameters. Structural analysis of the model is used to obtain the fault signatures and also to identify the hardware redundancies in the sensor placement. Thereafter, quantitative evaluations of ARR are used to yield residuals, which are subsequently implemented in an online integrated supervision system described in the sequel to this paper. The fault tolerant control and reconfiguration strategies implemented in that supervision platform are based on the available hardware redundancies in the process, which have been deduced directly from bond graph model using the methodology presented in this paper.     

A bond graph approach to the modeling and simulation of switch regulated DC-to-DC power supplies

A bond graph approach is proposed for the modeling and simulation of switched DC-to-DC power converters of the boost type, regulated by means of a pulse-width-modulation (PWM) strategy. An average bond graph model of the PWM regulated DC-to-DC power converter is derived using ideal lossless transformer elements. The proposed bond graph model constitutes an “input” to a computer aided package, called DESIS, which automatically generates the system model as a set of differential equations with explicit control parameters. The computer package is also capable of simulating both the average and the actual discontinuous PWM regulated responses of the DC-to-DC power converter for a given feedback duty ratio policy.     

Pseudo bond graph model of coupled heat and mass transfers in a plastic tunnel greenhouse

In greenhouses, models built are classified into two kinds; heterogeneous approaches based on computational fluid dynamics (CFD) codes and homogeneous one based on heat and mass balance equations. Bond graph modelling was not seriously introduced in greenhouse modelling in spite of the concordance of the energetic based approach of bond graphs with the nature of the greenhouse plant.In this research work, a pseudo bond graph model of a greenhouse was elaborated to simulate temperature and relative humidity inside. The model proposed is an energetic lumped approach which describes coupled heat and mass transfers in a plastic tunnel greenhouse. This model includes convection, evaporation/condensation phenomena, air change flow and soil heat and mass transfer. Multiport (3 ports) bond graph elements are introduced to describe the state of the two elements (dry air and water vapor) fluid. New bond graph schemes are used to characterize the coupling effect between heat and mass transfer, and for modelling free evaporation/condensation mechanism. Big leaf assumption was used to model the canopy. New boundary layer elements are added in the model, these elements allow a separation of the different phenomena inside greenhouse and thus a simplification of the modelling task. The practical results obtained from an experimental tunnel greenhouse are used here as validation elements for the greenhouse bond graph model. A good correlation is observed between measured and predicted samples.