《模糊滑模控制》PPT课件.ppt
《《模糊滑模控制》PPT课件.ppt》由会员分享,可在线阅读,更多相关《《模糊滑模控制》PPT课件.ppt(25页珍藏版)》请在三一办公上搜索。
1、Fuzzy arithmetic based reliability allocation approach during early design and development 初期阶段的设计和发展中基于模糊算法的可靠度分配方法,V.Sriramdas,S.K.Chaturvedi,H.Gargama,1.Introduction2.Factors based conventional reliability allocation method3.Fuzzy numbers and arithmetic4.The methodology5.Illustrative example6.Con
2、clusions,1.Introduction Reliability allocation is an important and iterative task during the design and development activities of any engineering system.It is also difficult task because of the obscured and incomplete design details and a number of factors have to consider in design process.During t
3、he design phase of a system with a specified target reliability level,the reliability levels of the subsystems affect the overall system reliability.Therefore,a proper reliability allocation method needs to be adopted to allocate the target system reliability to its constituent subsystems proportion
4、ately.,4,2.Factors based conventional reliability allocation method,In this allocation method,the target reliability based on the reliabilityfactors is apportioned to subsystems for which no predicted reliability values are known.The relationship between apportioned reliability of ith subsystem Ri(子
5、系统可靠度)and target system reliability R*(总系统可靠度)is defined with a weightage factor wi.,Ri=(R*)wi,(1),where weightage factor wi(权重因子)can be expressed with proportionality factor Zi(比例因子)as:,wi=Zi/Zi,(2),5,2.1.Complexity(复杂度),The complexity factor varies from subsystem to subsystem within a system and i
6、s measured in terms of number of active components that a subsystem is composed of.The number of components in a subsystem has a direct bearing on the reliability of the subsystem.Thus,complexity has a strong impact on the reliability allocation.The failure rate of the subsystem with high complexity
7、 is generally going to be high.So,the failure rate is allocated proportional to the complexity of the subsystem.Hence,Zi Ki,where Ki is the complexity factor for the itssubsystem.,1.Multiple functional relationships with the other groups.2.Number of components comprising subsystem.,6,2.2.Cost(成本),Fo
8、r a large system,the cost increment for reliability improvement is relatively high.The demonstration of a high reliability value for a costly system may be extremely uneconomical.Hence,Zi Coi,where Coi is the cost factor for the its subsystem.,2.3.State-of-the-art(工艺状态),When the component has been a
9、vailable for a long time,it is quite difficult to further improve the reliability of a component evenif the reliability is considerably lower than desired.Hence,Zi 1/Si,where Si is the state-of-the-art factor for the itssubsystem.,7,2.4.Criticality(临界值),Criticality is another very important factor i
10、n reliability allocation.It is logical,higher reliability target should be allocated tothe functionally critical sub-systems and thus Zi is proportionalto criticality.Hence,Zi 1/Cri,where Cri is the criticality factor for the itssubsystem.,2.5.Time of operation(运行时间),There may be some subsystems whi
11、ch are required to be operatedfor a period less than the mission time.So,for the subsystems with operating time lessthan the mission time,it is only logical to allocate relativelylower reliability.Hence,Zi 1/Ti,where Ti is the time of operation factor for theith subsystem,2.6.Maintenance(维护),A compo
12、nent which is periodically maintained or one which isregularly monitored or checked and repaired as necessary willhave,on an average higher availability than one which is not maintained Hence,Zi Mi,where Mi is the maintenance factor for the itssubsystem.The process of allocation of relative scales i
13、s carried out as ateam exercise,comprising of experienced members from the eachof the subsystem identified.From the previous discussions in thissection,after consideration of various factors,formula for proportionalityfactor(Zi)as:,3.Fuzzy numbers and arithmetic,Definition:A fuzzy number is a fuzzy
14、subset that is both convex,andnormal.The most commonly used fuzzy numbers are triangular and trapezoidal fuzzy numbers,parameterized by(a,b,c),and(a,b,c,d),respectively,the membership functions of these numbers are defined below:,Then the standard operations on trapezoidal fuzzy numbersare expressed
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 模糊滑模控制 模糊 控制 PPT 课件
![提示](https://www.31ppt.com/images/bang_tan.gif)
链接地址:https://www.31ppt.com/p-5537136.html