A New Calculating Method for the Flowfield of Turbomachinery

In this paper, a new method is developed to solve the N-S equations with vorticity-velocity variables, which is suitable for describing the flow-field of turbomachinery in non-inertia coordinates. It is derived that the expansions of the vorficity-velocity equations (VVE)have the same form in arbitrary non-orthogonal curvilinear coordinates, because the non-inertia effect is only related to the initial and the boundary conditions. This method greatly simplifies the solution for the flowfield of turbomachinery with complicated geometrical domain and reduces the calculation cost.     

Simulation Modeling of the Motion Control of a Two Degree of Freedom, Tendon Based, Parallel Manipulator in Operational Space Using MATLAB

In this paper a dynamical model of a two degree of freedom, tendon based, parallel manipulator （TBPM） system is proposed. The motion control methods of the TBPM system were designed. Using MATLAB, the motion control simulation of this model TBPM system was implemented in preparation for actual experiments. The results of the simulation demonstrated that the response time of the system was in a reasonable range, the motion behavior of the platform was stable and the tension forces acting on the tendons were in a safe range and acceptable. Furthermore, the parameters of the controllers were optimized using MATLAB and better results for the time response were obtained.     

Application of the Network Flow Method for Eigenvalue Control in Power System Dispatch

A kind of dispatch method for power system eigenvalue control is proposed-in this paper. With the help of this method, not only the low-frequency oscillation of a power system can be prevented and controlled, but also the probabilistic power oscillatoin on the interconnection lines of an interconnected power system can be reduced. The proposed method has the advantages of high calculation speed and good convergency. Therefore, the method has much prospect of on-line application.     

General Expression of LRC Method in Estimation of Bridge’s Equivalent Static Wind Load

桥梁等效静力风荷载广义荷载-响应相关法

董锐^1,2,葛耀君²,赵林²,韦建刚^1,3

（1.福州大学 土木工程学院,福州350108;

2.同济大学 土木工程防灾国家重点实验室,上海 200092;

3.福建工程学院 土木工程学院, 福州 350118）

摘 要：

根据荷载和响应之间的关系,结构的等效静力风荷载可采用荷载-响应相关法,即LRC（Load-response correlation）法计算。LRC法是计算结构背景响应等效静力风荷载的精确方法。LRC法经典表达式根据结构某一关键位置处的某一关心响应推导得到,并且具有唯一性。本文根据结构全部位置处的某一关心响应推导得到LRC法广义表达式,并将结构的等效静力风荷载以矩阵的形式表达为荷载-响应相关系数、响应-响应相关系数、脉动风荷载RMS值和峰值因子的乘积。与LRC法广义表达式相比较,经典表达式是广义表达式的一种特例。LRC法广义表达式引入了响应-响应相关系数,为结构工程师计算等效静力风荷载提供了更多的选择,同时对LRC法的本质有了更深入的认识。最后,分别以斜拉桥、三跨连续梁桥和悬索桥为例验证了LRC法广义表达式的正确性。

关键词：桥梁;等效静力风荷载;荷载-响应相关法;背景响应;广义表达式;荷载-响应相关系数;响应-响应相关系数

     

Discussion of the Evaluation Method and Value of Green Building’s POE in the Era of Large Data

China vigorously is carrying out the construction of green building and ecological city during ＂ The 12th five-Year plan＂. Now, although the identification system of design and operation have been implemented in the evaluation of green building, lacking of appropriate evaluation after use. The actual operation results of many buildings, which have got a green building logo, are not satisfied from the user,s perspective. In this paper, an evaluation method that combines the actual building energy consumption and users＇ satisfaction has been discussed, based on the post oceupaney evaluation （POE） theory and the Big data technology. Through the comparison and analysis of building objective operational metrics and users subjective feelings indicators, the green buildings＇ POE has been achieved. Finally, the study analyzes the assessed value of green building＇ s POE from the three-time dimensions, short-term, medium-term and long-term. And the outlook of the direetion is looking forward to the follow-up study.     

Comparison of phase unwrapping algorithms for living cell’s interference pattern

A multiphase microscopic interference system is designed to measure the height of cell which is important to the research of collective cell migration in physiology and medicine. This sys- tem can quantitatively measure cell height across a living monolayer without knowing the refractive index of cells. For the interference pattern, because the phases are all wrapped between - π to π, it is necessary to get the real phase through phase unwrapping,a method to restore the wrapped phase data of the object by using numerical calculations. Three representative algorithms are selected to unwrap the interference pattern of ceils： branch-cut method, quality-guided method and network method. Although each of them can restore the phase, their performances are obviously different. We compare these methods and find that branch-cut method needs the smallest execution time and can obtain good unwrapped patterns when noises are not serious.     

An extension of 2D Janbu’s generalized proce-dure of slices for 3D slope stability analysis I――Basic theory

1 Introduction Most slope stability analyses were performed under 2D limit equilibrium framework in geotechnical engineering. As indicated by Stark and Eid[1], in the existing 2D methods, the calculation of the factor of safety for a slope was carried out under assuming a plane-strain condition, i.e. the failure surface of the slope was assumed infinitely wide. Although 2D slope stability analysis for a slope was relatively conservative, the devel- oped theories and numerical methods were st…     

Parametric design strategy of a novel cylindrical negative Poisson’s ratio jounce bumper for ideal uniaxial compression load-displacement curve

A cylindrical negative Poisson’s ratio (CNPR) structure based on two-dimensional double-arrow negative Poisson’s ratio (NPR) structure was introduced in this paper. The CNPR structure has excellent stiffness, damping and energy absorption performances, and can be applied as spring, damper and energy absorbing components. In this study, the CNPR structure was used as a jounce bumper in vehicle suspension, and the load-displacement curve of NPR jounce bumper was discussed. Moreover, the influences of structural parameters and materials on the load-displacement curve of NPR jounce bumper were specifically researched. It came to the conclusion that only the numbers of cells and layers impact the hardening displacement of NPR jounce bumper. And all parameters significantly affect the structure stiffness at different displacement periods. On the other hand, the load-displacement curve of NPR jounce bumper should be in an ideal region which is difficult to be achieved applying mathematical optimization method. Therefore, a parametric design strategy of NPR jounce bumper was proposed according to the parametric analysis results. The design strategy had two main steps: design of hardening displacement and design of stiffness. The analysis results proved that the proposed method is reliable and is also meaningful for relevant structure design problem.     

Simulation of automobile fuel consumption and emissions for various driver’s manual shifting habits简

The effects of different habits of the drivers on gear shifting strategies for manual powertrain were investigated. For the realization of simulation, the shifting habits of the drivers were conducted in the Advisor software to investigate and compare the emission rates. Simulation was developed based on the optimal gear shifting strategy and criteria and was validated both in fuel economy and emissions by analyzing the results in the various driving cycle and driving styles. To explore an optimal gear shifting strategy with best fuel economy and lowest emission for a manual transmission, a strategy was designed with a highest possible gear criterion as long as the torque requirement can be satisfied. Based on two different criteria, namely the engine working conditions and the driver＇s intention, the governing parameters in decision making for gear shifting of manual transmission in conventional engine were discussed. It is also shown that the optimum gear shifting strategy is based on that both the engine state and the driver＇s intention eliminates unnecessary shiftings that are present when the intention is overlooked. The optimum shifting habit and the best driving cycle in terms of minimum emissions and fuel consumption were proposed.     

基于动作基元的拟人机械臂仿人运动规划

拟人机械臂的仿人运动作为仿人机器人的运动基础,一直都是研究的热点及难点.针对拟人机械臂仿人运动的模型多样化及运动相似性特点,提出了一种基于动作基元的拟人臂仿人运动规划算法,使拟人臂在满足仿人运动特点的基础上进一步提高运动的精度.首先,对手臂结构进行解耦,建立手臂模型,满足运动多样化要求.提出动作基元的提取法则,确定不同...     

预设性能控制算法对机械臂运动控制的改进

PD控制是在工业生产过程控制中,应用比较广泛,结构最简单的控制策略之一。传统的PD控制侧重于控制系统的稳态性能,而对系统的动态性能（包括超调量和收敛速度等）控制不够,如果想要提高响应速度就会使超调量变大,加剧响应振荡;如果想要超调量小,可能又会使响应速度变慢。响应速度与超调量似乎是一对比较矛盾的性能参数,单纯使用传统的PD控制,很难做到提高响应速度的同时降低超调量。所谓预设性能控制,指的是控制误差的收敛速度及超调量满足预先设定的条件,同时把控制误差收敛到一个预先指定的比较小的区域内。本文将PD控制与预设性能控制相结合,利用简单的PD控制结构和以对数形式误差变换为基础的预设性能函数来设计机械臂运动控制器, 该控制器在设计的过程中可以预先设定稳态误差,而不像传统的PD控制器要通过多次的参数整定及调试后才能逐步减少控制误差。因此本文提出的控制算法设计过程比较简洁方便,具有比较精确的控制精度和比较快的响应速度,同时还能把超调量控制在合理的范围内。通过空间三关节机械臂的建模仿真分析,改进后的预设性能PD控制与传统PD控制相比较,响应速度提高了40%左右,超调量减少了10%左右。通过4自由度Dobot机械臂的样机实验分析,改进后的预设性能PD控制与传统PD控制相比较,响应速度提高了20%左右,超调量减少了5%左右,因此该算法对控制系统动态响应性能的改善是比较明显的。     

机械手最优关节的显著性研究

运用正交试验设计原理验证了用冗余度法所确定的最优关节对机械手姿态影响的显著性，结果表明，冗余度法用于求解机械手最优关节是有效的     

Integrated Optimal Model of Structure and Control of the Single Arm Manipulator

Inthemodernmechatronicalsystem,moreand morestringentperformancerequirementsarepro posedinadvancedapplication.Theyresultinasitua tionwherecontrolsystemsinteractwiththeflexibili tyofthestructure.Thisisespeciallytrueforthehigh precisionmechatronicalsystem,suchastheindustrial robot,devicesformicroelectronicmanufacture,disc drive,etc.Inthesesituations,itisessentialtoinves tigatecarefullytheinteractionbetweenthecontrol systemandthemechanicalstructure.Since1990s,anumberofstudiesonintegrated structure…     

柔性机械臂的鲁棒轨迹跟踪控制

对多连杆柔性机械臂的轨迹跟踪控制提出了一种鲁棒控制方法。基于奇异摄动法将多连杆柔性机械臂系统分离为慢变和快变两个子系统，对两者分别采用滑模变结构控制和Ｈ∞控制，由此得出的组合控制使系统精确跟踪期望的轨迹，抑制弹性振动，并且使由非线性机械结构引起的结构不确定性和由弹性变形引起的非结构不确定性及外扰具有较强的鲁棒性。最后通过仿真实验说明其有效性。     

采用神经网络方法研究柔性机械臂逆运动学问题

本文以柔性机械臂为例,进行简单的逆运动学分析.并采用小脑模型神经网络方法对机械臂的逆运动学进行了数值仿真分析,可以看出,小脑模型神经网络可在较短的学习次数中有效地控制机械臂的振动.     

冗余复合构型微创手术机器人定位方法研究

根据冗余复合构型微创手术机器人兼具冗余关节和被动关节的特点,提出了一种针对此类复杂多自由度机器人的定位方法。首先分析了机器人构型特点,然后利用D-H法建立了机器人运动学方程,并结合临床实际,确定冗余关节角,将运动方程进行退化,得到合理的运动学逆解和定位角。利用微型磁定位传感器进行被动关节臂实时位形测定,开发出机械臂定位界面,提示操作者进行定位和臂形设置。实验结果表明,定位方法可行,可视化效果好,适于临床操作。     

机器人操作手的时间-能量综合最优解的存在性探讨

本文提出了机器人操作手的时间-能量综合最优的问题,并对综合最优解的存在性问题进行了探讨,建立了两个关节操作手的动态方程,对于高度非线性和强互耦性的机械手动力学模型,利用微分方程的延展定理和闭集定理,给出了对机械手时间-能量综合最优解存在性的详细证明.     

驱动器故障影响下柔性机械臂运动控制的进展与展望

随着机械臂技术的不断发展,传统刚性机械臂逐渐难以满足一些新式机械臂系统在轻质化、运动灵活性、大空间范围等方面的需求,如空间机械臂、手术机械臂、人机交互式机械臂等。越来越多的研究人员将目光投向柔性机械臂及其高精度运动控制方法的研究中。针对此类系统,目前已经有一些有效的运动控制方法被提出。然而,当机械臂的某一驱动器发生故障后,常规的控制方法难以保证原有的控制性能,甚至可能导致系统不稳定。研究驱动器故障影响下的柔性机械臂运动控制方法具有重要的理论意义和应用前景。本文首先概述柔性机械臂已有的运动控制方法。然后,从驱动器故障的类型出发,分析并综述驱动器性能故障、驱动器完全损坏故障以及驱动器突发故障对系统的影响及其克服方法的研究现状。最后,本文讨论了当前驱动器故障影响下柔性机械臂运动控制还需进一步解决的关键问题,总结了三点前景方向,对柔性机械臂运动控制的进一步研究具有一定的参考价值。     

基于PLC控制的冲床上下料气动机械手

针对冲床人工上下料效率低、精度差、存在安全隐患等问题,设计了基于PLC控制的冲床上下料气动机械手,给出了机械手的总体结构及工作原理,并对其气动、控制系统进行了研究;设计了机械手可换指端夹持器。该机械手结构紧凑、工作灵敏、可靠性高、柔性好、成本低且调试维护方便,符合企业的需求。