机械式离心调速器系统混沌的线性反馈反控制

建立了机械式离心调速器系统的动力学方程，求出了系统的平衡点。利用系统的相图分析了给定参数下自治系统及非自治系统的运动状态，用Poincare映射图分析了非自治系统混沌的形成过程。利用线性反馈反控制方法实现了自治系统及非自治系统混沌的反控制，将自治系统及非自治系统的周期运动利用适当的控制强度反控制到混沌运动轨道。     

一类单边刚性碰撞系统的分岔与混沌控制

研究了一类单自由度刚性碰撞系统的分岔和混沌运动。建立系统周期运动的Poincaré映射,通过数值仿真揭示了系统通过倍化分岔通向混沌的道路和系统的周期运动、混沌运动。最后运用外加恒定载荷控制方法对系统的混沌运动进行了有效的控制,使系统达到不同的周期轨道。     

含双侧约束碰撞振动系统的OGY混沌控制

以单自由度含双侧约束碰撞振动系统为研究对象,数值仿真了系统1-1-1周期运动经周期倍化分岔和Grazing分岔向混沌转迁的路径;给出了OGY控制方法的原理和步骤。利用混沌运动对参数微小扰动的敏感性和混沌轨道的遍历性质,选择嵌入混沌吸引子中的一个不稳定不动点作为控制目标,当系统状态访问目标不动点的微小邻域时,给系统参数施加微小扰动,把混沌控制到期望的目标轨道。仿真结果表明,在极短的时间内系统的混沌得到了抑制。     

机械式离心调速器系统混沌的非线性反馈反控制

根据拉格朗日方程建立了机械式离心调速器系统的动力学方程,求出了系统的平衡点,利用系统的相图分析了给定参数下自治系统及非自治系统的运动状态,用Poincaré映射图分析了非自治系统混沌的形成过程。利用非线性反馈反控制方法实现了自治系统及非自治系统混沌的反控制,将自治系统及非自治系统的周期运动利用适当的控制强度反控制到混沌运动轨道。     

碰撞振动系统中两种混沌门槛值的判据

以一类简单的碰撞振动系统为例，验证了两种混沌门槛值判据的等价性。即非扰动情形具有广义同宿轨道，扰动为鞍型周期运动的碰撞振动系统中，如果相对于该鞍型周期解的相对流形上仍存在同宿轨道，则它与Ｐｏｉｎｃａｒｅ截面上稳定流形和不稳定流形横截相交是等价的。因而它可作为Ｓｍａｌｅ马蹄意义下混沌门槛值的判据，但相对流形上的判据在碰撞振动系统中显得直观简洁。     

Bonhoeffer-van der Pol方程中双吸引子的混沌控制

基于延时反馈混沌控制方法和相空间压缩法,提出一种改进的延时反馈混沌控制方法。该方法不仅可用于单个吸引子混沌系统的控制,而且由于克服了Pyragas控制方法的不能简便地将混沌系统稳定到嵌入在不同混沌吸引子内周期轨道的不足,也可以用于多个混沌吸引子混沌系统的控制。以Bonhoeffer-van der Pol系统为例,数值验证此改进方法用于两个混沌吸引子系统控制的有效性,结果表明,在延时反馈控制中增加适当的相空间限制器,可以快捷地将系统稳定在期望的周期轨道上。     

离心调速器系统的混沌及速度反馈控制

建立离心调速器反馈控制系统的动力学方程,利用系统的相图和Poincaré映射图分析系统的混沌形成过程.通过对离心调速器反馈控制系统增加一个速度反馈控制器,利用它控制系统从混沌运动转化为周期运动.数值仿真表明,该控制方法在离心调速器反馈控制系统的混沌控制中的有效性与可行性,可利用适当的控制强度镇定系统中不稳定的周期轨道.     

基于神经网络模型预测控制的混沌运动的研究

为了实现混沌运动的控制,应用神经网络模型预测控制的策略.首先通过系统辨识建立要控制的混沌系统的神经网络模型,并设计出神经网络模型预测控制器,然后通过该控制器对混沌运动进行预测控制,使混沌吸引子中的不稳定周期轨道被镇定到不动点.最后借助MATLAB平台进行数字仿真,结果表明该控制方法对混沌控制是有效的.     

含时变啮合刚度的间隙非线性齿轮系统的混沌控制

基于含时变啮合刚度和间隙非线性单级齿轮系统的动力学模型,分析了系统响应的动态特性。针对系统在部分参数区域发生的混沌运动,运用OGY控制原理,以混沌吸引子内部不稳定周期轨道为目标,通过对系统的外激励参数实施连续的小扰动,使系统的轨道始终落在未加扰动的鞍点轨道的稳定流形上,从而实现了系统运动的稳定化。     

基于神经网络模型预测控制的混沌运动的研究

为了实现混沌运动的控制,应用神经网络模型预测控制的策略。首先通过系统辨识建立要控制的混沌系统的神经网络模型,并设计出神经网络模型预测控制器,然后通过该控制器对混沌运动进行预测控制,使混沌吸引子中的不稳定周期轨道被镇定到不动点。最后借助MATLAB平台进行数字仿真,结果表明该控制方法对混沌控制是有效的。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.