Interactive microcomputer-aided design of circular suspension cable roofs

This paper presents interactive computer-aided design of circular suspension cable roofs. A microcomputer program developed in Advanced BASIC and according to the principles of structured programming is presented. The program can display/plot the plan of cable roof, the elevation of the structure including the loading on the cables and the cross-section of the reinforced concrete compression ring. The interactive program helps the user to explore many design alternatives rapidly and arrive at a practically optimum design.     

基于VB与Access数据库的电缆快速设计系统

为了提高电缆设计效率、减少重复劳动,提出了电缆快速设计方法,创建了一套基于VB与Access数据库的电缆快速设计系统。对电缆设计现状做了简要的说明,指出了电缆快速设计需要解决的两个问题,在此基础上规划了总体设计方案。研究了VB、Access数据库和AutoCAD之间相互链接的方式,以及电缆数据库的创建方法。通过一条简单电缆的演示验证了电缆快速设计系统的可行性。     

Cable installation simulation by using a multibody dynamic model

A major concern when installing the cables into the underground conduit is minimizing the tensile forces exerted on the cables as they are pulled. This knowledge makes it possible to avoid over conservative design practices and to achieve substantial saving during construction. A general computing algorithm of predicting the tensile force of the cable pulled through the underground conduit with an arbitrary configuration is presented in this paper, which is based on multibody system dynamic formulation. The presented multibody dynamic model for this problem consists of the cable, the underground conduit, and the interaction between the cable and the conduit. In this paper, the cable is modeled by the finite cable element based on an absolute nodal coordinate formulation. The interaction between the cable and the underground conduit is described by the Hertz contact theory. Numerical examples are presented to illustrate the effectiveness and efficiency of the proposed method for estimating the cable tension.     

Structural optimization by chance constrained programming techniques

The minimum cost design of structures with probabilistic objective and constraints is considered. The techniques of chance constrained programming are applied to solve the resulting stochastic optimization problem. The optimum design of a cable stayed box girder is considered as an example problem. The optimum results obtained from the probabilistic formulation are compared with those given by the deterministic formulation. Finally a parametric study is made to find the effects of the coefficients of variation of various strength parameters and the probability level at which the constraints are satisfied on the optimum design.     

Optimum topology and shape design of prestressed concrete bridge girders using a genetic algorithm

The purpose of this study is to optimize the topology and shape of prestressed concrete bridge girders. An optimum design approach that uses a genetic algorithm (GA) for this purpose is presented. The cost of girders is the optimum design criterion. The design variables are the cross-sectional dimensions of the prefabricated prestressed beams, the cross-sectional area of the prestressing steel and the number of beams in the bridge cross-section. Stress, displacement and geometrical constraints are considered in the optimum design. AASHTO Standard Specifications for Highway Bridges are taken into account when calculating the loads and designing the prestressed beams. A computer program is coded in Visual Basic for this optimization. Many design examples from various applications have been optimized using this program. Several of these examples are presented to demonstrate the efficiency of the algorithm coded in the study.     

一个实用的调优技术

文中介绍了一种实用的调优技术，提出了调优过程中一种新颖的试验模型，以三因子新设计试验与正交旋转回归设计试验为例作了分析比较，并介绍了寻找参数最佳工作区域的数学分析方法．     

Cladding-network interaction in pretensioned cable roofs, studied by dynamic relaxation

Current methods of analysis and design of pretensioned cable roofs disregard the cladding contribution to the overall stiffness of the structure, and therefore full-scale constructions suffer from excessive pretensioning of the cables. This paper investigates cladding stiffening effects in pretensioned cable roof models, using a dynamic relaxation algorithm. A mathematical model of cladding-network interaction in combined response to static external loads is presented, developed on the assumption of a discrete membrane surface of the cladding attached to the cable network. Detailed results are presented for a partially and fully clad hyperbolic paraboloid model. Comparisons are made between the results from the analysis of the composite structure clad with panels of varying stiffness and the corresponding “bare” network analysis. Results show that the cladding makes a substantial contribution to the stiffness of the composite structure, and suggest that future design of foundations for the cable anchorage should take this into account.     

Integrated Mechanism Design and Control for Completely Restrained Hybrid-Driven Based Cable Parallel Manipulators

This paper deals with a methodology of simultaneous optimal design of mechanism and control for completely restrained hybrid-driven based cable parallel manipulators (HDCPM) in order to improve the dynamic performance of the HDCPM system. The HDCPM have the advantages of both the cable parallel manipulator and the hybrid-driven planar five-bar mechanism (HDPM). Kinematics and dynamics of the HDCPM are studied based on closed loop vector, geometric characteristic of mechanism and Lagrange method separately. Following that the integrated optimization model is established based on mechanics analysis and optimum control performance, and a genetic algorithm is used to carry out the optimization solution. As an example, separated optimization design and integrated optimization design for the completely restrained HDCPM with 3 Degrees of Freedom are comparatively investigated on the basis of the above design objectives. Simulation results illustrate that the dynamic performance of the HDCPM system can be significantly improved after integrated optimization design.     

A cable feeder tool for robotized cable winding

Cable winding is an alternative technology to create stator windings in large electrical machines. Today such cable winding is performed manually, which is very repetitive, time-consuming and therefore also expensive. This paper presents the design, function and control system of a developed cable feeder tool for robotized stator cable winding. The presented tool was able to catch a cable inside a cable guiding system and to grab the cable between two wheels. One of these wheels was used to feed cable through the feeder. A control system was integrated in the tool to detect feeding slippage and to supervise the feeding force on the cable. Functions to calculate the cable feed length, to release the cable from the tool and for positional calibration of the stator to be wound were also integrated in the tool. In validating the function of the cable feeder tool, the stator of the linear generator used in the Wave Energy Converter generator developed at Uppsala University was used as an example. Through these experiments, it was shown that the developed robot tool design could be used to achieve automated robotized cable winding. These results also complied with the cycle time assumptions for automated cable winding from earlier research. Hence, it was theoretically indicated that the total winding cycle time for one Uppsala University Wave Energy Converter stator could be reduced from about 80 h for manual winding with four personnel to less than 20 h in a fully developed cable winding robot cell. The same robot tool and winding automation could also be used, with minor adjustments, for other stator designs.     

A combined shape control procedure of cable mesh reflector antennas with optimality criterion and integrated structural electromagnetic concept

A combined shape control procedure with optimality criterion and integrated structural electromagnetic concept for cable mesh reflector antennas is presented in this study. Using the optimality criterion, the shape control algorithm drives the distorted surface towards the ideal shape. The optimality criterion is implemented by pseudo inverse of sensitivity matrix of surface nodal displacements with respect to cable member dimensions to accelerate the iterative convergence. The following integrated structural electromagnetic design is performed to make good electromagnetic performance by a sequential quadratic programming optimization model. A distorted offset cable mesh reflector antenna is employed to show its effectiveness.     

一种基于蓝牙技术的航天器无线数据网络方案

针对有线网络数据传输给航天器设计带来的不便,提出了一种基于蓝牙技术的航天器上无线数据网络方案,给出了具有容错能力的主备网络的设计架构,对BlueCore芯片完成了高低温循环和抗电子辐照环境试验,并就如何在太空环境中应用蓝牙技术给出了一些具体的分析.结论表明:BlueCore芯片可以工作在-70～100℃的温度环境,并可以耐受26krad(Si)的电子辐照,能够应用于太空环境,提出的数据与分析可以作为航天器总体设计和工程应用的参考.     

基于DM642的桥梁缆索表面缺陷图像采集及传输系统设计

针对目前国内桥梁缆索表面缺陷检测的不足,提出一种基于DM642的缆索表面缺陷图像采集及传输系统。介绍了该系统的硬件平台以及软件设计。系统的硬件平台主要由3路视频解码芯片SAA7113、可编程逻辑器件(CPLD)、物理层收发器LXT971A以及信号处理器DM642等组成;软件设计主要介绍了系统功能实现流程、图像压缩算法设计等。     

Mechanics of flexible interconnect in lateral tape open drives

A mechanics modeling is presented in this paper with focus given to understanding effect of flexible printed circuit cable’s dynamic effect on tape head actuator’s lateral motion in advanced, high capacity tape drives. The flexible printed circuit cable which connects the actuator to printed circuit board is first examined through establishment of analytical model to predict its profile with considerations of boundary conditions and mechanical design parameters. Secondly, equivalent stiffness produced by the flexible printed circuit cable when the linear tape head actuator is positioned along its lateral positions is examined. Finally, effect of tape head actuator’s voice coil motor is studied and modeled as a magnetic suspension, contributing to stability and controllability of the actuator lateral motion dynamics. Validated by calibrated laboratory experiments, the work presented in this paper can add to the literature regarding dynamics and control of LTM in modern LTO drives.     

便携式电缆测试仪的设计

为了实现部队某型导弹电缆的自动测试维护，针对部队维护使用特点，研制了一种小型、便携、实用的电缆测试仪；该产品采用嵌入式计算机技术，硬件电路模块化设计技术，便于测量通道扩展，实现了导弹电缆的导通测试和绝缘测试；文中阐述了该系统的工作原理、设计方案和硬件、软件实现方法；试用结果表明，该测试仪能够对各种型号设备和电缆的导通电阻、绝缘电阻等电气性能参数进行自动测量，能及时快速地检测设备电缆存在的故障隐患，缩短检测时间，提高检测效率。     

Integral feasible prestress of cable domes

Cable domes, first proposed by Geiger, belong to the indeterminate and prestressed assembly. Thus, the geometric stability analysis and the optimal prestress design are very important to understand the behaviour of cable domes. A new specific equilibrium state of integral feasible prestress is presented in this paper. Applying this specific state, the algorithm of geometric stability analysis of cable domes is modified and the optimal prestress of the domes is also designed. The numerical results show the proposed state of integral feasible prestress is unique to a specific dome and it is therefore useful for further research of cable domes.     

数字有线电视前端的设计

我国电视网络在追求构建一张覆盖地区、互连互通、资源共享、开放型的有线电视综合业务网的奋斗目标下,必须对电视网络进行改造。本文以天津天津有线电视台为例,进行数字有线电视前端的设计。     

采煤机音视频及数据综合传输系统的设计

针对现有采煤机视频、音频及工况监控数据实时传输系统采用无线局域网、光缆或单独拖曳通信电缆时存在不稳定、故障率高、维护困难等缺点,提出了一种基于采煤机主电缆内嵌单根射频同轴电缆的多路视频、音频及数据综合传输系统的设计方案。该系统采用数据调制传输频率高于视频监控信号调制频段的设计方法,避免了数据通信对监控图像质量的影响,且因数据传输具有较高的功率余量,保障了控制数据通信的低误码率。     

Hard disk drive seek-arrival vibration reduction with parametric damped flexible printed circuits

Seek-arrival track-mis-registration (TMR) is one of the most critical dynamic design factors for modern hard disk drives to achieve high data transfer-rate performance goal. With its flexible structural nature, the flex cable itself inevitably renders low-frequency natural modes which have been a challenge with respect to balancing design efforts among servo control, mechanical design, and manufacturing process in disk drive industry. In this paper, particular focus will be given to vibration damping approach to reduce flex cable related seek-arrival dynamics in a state of the art magnetic disk storage drive. Experimental parameter studies of a typical constrained-layer damped flex cable vibrations are presented with cable exposed to various damper length and fold in different geometries. Effectiveness of the damper is also demonstrated by frequency responses with random excitation from actuator arm. Several design options toward reducing the flex circuit related arrival TMR will also be discussed in this paper.     

Design of a large-scale cable-driven robot with translational motion

The design of a new cable-driven robot for large-scale manipulation is presented with focus on the tension condition in the cables. In this robot, the arrangement of the cables is such that the moving platform has three translational motions. The robot has potentials for large-scale robotic manipulations, machining of large parts and material handling. The design analysis presented here is towards the synthesis of the robot as well as the sizing of the actuators and cables. The synthesis of this robot is dependent on the results of the tensionable workspace analysis previously published by the Alikhani et al. [6]. The analysis of the cable forces is presented in detail, which is then used to size the actuators. For this purpose, a geometrical approach is used to represent the capability of the end-effector for applying forces and moments as convex polyhedra. The design problem is then reduced to the sizing of these polyhedra according to the design requirements and manufacturing limitations. A prototype is also designed and fabricated, which is presented at the end to further elaborate on the proposed approach.