Interoperable control [production control]

Focussing on shop floor control for discrete parts cellular manufacturing systems, the author proposes a functional architecture for managing the flow of work through the system in quasi real time. The shop floor control (SFC) system must be flexible, portable and also must support interoperability     

Stock control

If inventory cannot be eliminated, it must be kept to a minimum and kept under control. The author presents one approach to looking after stock in an assembly area     

数控车削多头螺纹（或蜗杆）的精度控制方法

应用数控车床加工多头螺纹（或蜗杆）是目前生产中常用的方法,对于精度要求较高的多头螺纹（或蜗杆）加工,要经过粗车和精车两个工艺过程,并且要在粗车和精车两个工艺过程之间加上测量环节,根据测量值进行数控车床的磨耗调整后再进行精加工,就能达到很高的加工精度。     

Chaos maximizing optimal control

A chaos maximizing optimal control problem is formulated and applied to Duffing's equation to maximize the largest Lyapunov exponent. The resulting bang-bang optimal controller yields a positive value of the largest Lyapunov exponent, indicating chaotic behavior. In fact, the largest Lyapunov exponent is approximately twice as large as that achieved with simple sinusoidal forcing at the same amplitude bounds. However, the resulting phase portrait of the optimal trajectory is a limit cycle and is not chaotic at all. This paradoxical result contradicts the basic theory that a bounded trajectory with at least one positive Lyapunov exponent must be chaotic. Details concerning the development of a chaos measurement that is viable for current optimal control theory, a method of continuous normalization, the paradoxical chaotic limit cycle, resolution of the paradox, and closed-loop optimal jump condition in an augmented space are presented. In particular, for systems of differential equations with only piecewise differentiable right-hand sides due to a switching control, a jump discontinuity condition must be imposed on the state perturbations in order to compute correct Lyapunov exponents.     

注油系统用调节阀

注油管路系统，特别是多分支的泵送管路系统，一方面管路结构形式多样，另一方面工作状态多变，因此，在系统工作中均需对工况进行调节与控制。本文针对其工况变化的情况，研究系统的调节控制方法，介绍几种成功用于该类系统控制的压力调节阀。     

双捻机数字式控制系统

某型号双捻机由5台变频电机驱动,根据工艺要求,设备的运转速度需可调,且各电机之间要保持同步.基于变频调速技术和现场总线技术,研究开发了该双捻机数字式控制系统,文中介绍了系统的硬件构成和软件实现.经现场运用表明,系统运行情况良好,满足所要求的功能和精度要求.且使用维护方便.     

Monitoring and control of tools in multifunctional machine tools

Machining centers and multifunctional machine tools are used in computerized integrated production. They are equipped with a large number of cutting tools for production of a specific batch of parts. In such automatic systems, monitoring and control systems replace the human operator. Monitoring of the state of machining systems is essential today in monitoring and control of the machining operations [1, 2]. It is important to create monitoring systems to support reliable tool operation in multifunctional machine tools. The goals of such systems are to minimize the damage from serious disruption of tool operation and to ensure timely tool replacement. To that end the multifunctional machine tools and/or the numerical control system must be equipped with sensors and various monitoring devices. A strategy must be developed for the prevention of disruption of the machining process and tool failure.     

基于单片机的学习型专家系统水位控制器

锅炉汽包水位是一种非线性、时变大、强耦合的多变量系统。目前,锅炉的给水调节普遍采用PID控制器来进行控制,控制系统需要根据锅炉运行状况的变化而相应地调整PID参数,其整定值往往凭经验给定,不容易达到系统最好的控制效果。将智能控制理论应用于锅炉水位控制,不需求解系统复杂的数学模型,可以取得较好的控制效果。     

基于现场总线技术的大电流整流控制系统

针对某电化厂大电流整流装置设计了一套现场总线控制系统（fieldbus control system,FCS）。给出了系统结构图,并详细说明FCS的设计方案。提出现场总线技术在大电流整流控制系统应用中需注意的几个问题。采用了这套FCS后,保证了装置的安全平稳运行,显著提高了该厂的生产效率和管理水平。     

基于数控加工原型的快速模具制造工艺

提出一种将常规数控加工技术与精密材料成形技术结合应用于快速模具制造的新工艺。工艺路线为在CAD环境中对零件的CAD数据进行前期误差补偿,用普通加工中心快速加工出精密成形用的专用蜡基或泡沫塑料基模具原型,并优化其加工工艺和后处理工艺,最后通过精密铸造工艺制造出模具,使之在少量加工或者不加工条件下能用于实际生产。     

微机械隧道陀螺仪的时变线性二次高斯预测控制

为了降低微机械隧道陀螺仪系统的非线性,增大器件的带宽并提高系统的信噪比,隧尖与相应隧道电极之间的隧道间距应控制在1 nm附近,且其必须在闭环模式下工作.本文鉴于线性二次高斯(LQG)控制理论的抗干扰特性和鲁棒性以及哥氏加速度的时变特征,采用时变卡尔曼滤波器和LQG最优控制器串联而成的LQG预测控制策略设计了隧道陀螺仪闭...     

Preconditioning for moisture control in ethylene oxide sterilization

The moisture condition of a product must be controlled to obtain sterility and maintain product viability during ethylene oxide sterilization. A sterilization process in which prehumidification of product is used to provide moisture condition control was shown to be effective in 2 years of production sterilization experience. On-stream process analysis with a gas chromatograph showed that addition of steam to the chamber was unnecessary when properly preconditioned medical devices packaged in corrugated paper-board were sterilized. Reproducible gas-chamber moisture control and microbial sterility assurance were obtained.     

Damping and local control of mirror suspensions for laser interferometric gravitational wave detectors

The mirrors of laser interferometric gravitational wave detectors hang from multi-stage suspensions. These support the optics against gravity while isolating them from external vibration. Thermal noise must be kept small so mechanical loss must be minimized and the resulting structure has high-Q resonances rigid-body modes, typically in the frequency range between about 0.3 Hz and 20 Hz. Operation of the interferometer requires these resonances to be damped. Active damping provides the design flexibility required to achieve rapid settling with low noise. In practice there is a compromise between sensor performance, and hence cost and complexity, and sophistication of the control algorithm. We introduce a novel approach which combines the new technique of modal damping with methods developed from those applied in GEO 600. This approach is predicted to meet the goals for damping and for noise performance set by the Advanced LIGO project.     

The four-tank control problem: Comparison of two disturbance rejection control solutions

The paper aims to compare and prove a pair of disturbance/uncertainty rejection control laws for the well-known four-tank control problem. The control requirements are expressed in terms of a set point sequence as usual in the literature. The uncertainty class is defined as the union of four sub-classes: unknown disturbance, parametric uncertainty, measurement errors and neglected dynamics. Modelling and design give insight on the dynamic properties of the problem. Two theorems, which fix the range of application, are presented. These theorems are confirmed by the simulated results, and indicate the correct way to further broaden the control design applicability. The disturbance rejection design is deployed using the Embedded Model Control methodology. Accordingly, only the unknown disturbance and parametric uncertainty can be rejected, whereas the effects of neglected dynamics must be filtered. As a result, simple performance and stability inequality can be formulated in the frequency domain: they guide the closed-loop pole placement. These inequalities reveal whether pole placement is feasible and how feasibility can be recovered. The latter is an issue, which at the authors’ knowledge, is rarely encountered in the literature. Simulated runs prove the effectiveness of the design procedure.     

一类不确定非线性系统的自适应滑模控制

滑模变结构控制系统能够通过控制其本身结构的变化,使得系统性能保持一直高于一般固定结构控制所能达到的性能,突破了经典线性控制系统的品质限制,适用于非线性的不确定系统。同时滑模控制能保证在模型的不确定和外部扰动的情况下系统的稳定性与鲁棒性,而且以损失能导致抖振的最优控制性能而得到稳定鲁棒性,同时它的不确定性上界必须是已知的,但有时候很难得到上界。这样提出一种自适应的方法以进一步避免这些问题,同时这种方法能保证闭环系统的稳定性。本论文给出仿真结果来验证该方法的有效性。     

Functions and interfaces in a flexible production planning and control system

Production control systems with a future cannot function on the basis of planning only the simple aspects of production in as much detail as data acquisition and computing systems allow, rather than according to the needs, and not planning complicated aspects at all (or only roughly). The opportunities offered by modern production, organizational and computer technology can only be realized for production technology if the entire production process (effectively limited only by the company's limits) is seen as a single, complex production system, in which all subprocesses must be effectively integrated, regardless of how extensive, automated, predetermined, etc., the individual subprocesses are. This perpetual matching process needs a constant readiness and willingness to communicate. Communication must be seen as an opportunity to react flexibly to any situation, be it to catch up when lagging behind, or to give the next production stage a work advantage. One thing is certain: these opportunities will be lost if the only time dialogue takes place is when there is a need to document mistakes and allocate responsibility, or to ‘chase’ up again. Modelling techniques and a production planning and control system developed to overcome some of the above problems are described.     

Shop-floor control

Any company that wishes to be a world class manufacturer must first gain full control of its shop floor processes. The author tells the story of one such company. Early in 1993, Nortel Defence Systems (now Cogent), part of the global telecoms corporation Northern Telecom (Nortel), opened a new facility on a greenfield site in Newport, South Wales. The Newport facility is purpose built, and includes, among other areas, a major area for the production of specialist and complex cables, both electrical and fibre optic. Manufacturing is normally for one off items and includes prototype cables, using product and process development. Cogent Defence Systems consists of several businesses, which have extensive experience in communications for secure and harsh environments. One of Cogent's business policies is to become a world class manufacturer. `Policy' is a business requirement; its solution is strategy. The solutions determined to support this strategy are summarised. The strategy developed so far includes the implementation of shop floor control, followed by finite capacity planning and scheduling. Materials requirements, calculated to the finite capacity plan, are identified next, with the company forming closer links with suppliers. Meanwhile, continuous improvement philosophies are being put into place     

基于图形指令的参数化遥控系统的研制

为了使自动化机械在更多的企业中得以推广使用,进而推动高新技术向生产力的转化,有必要研制对机械手及其它自动化机械的参数化控制系统。要使操作简单化,就必须使设备智能化。本文介绍了基于图形指令的参数化遥控系统的研制,以及该系统对机械手进行参数化柔性控制的实际应用。     

数控机床丝杠误差补偿面临的问题

采用编码盘-丝杠进给系统的数控机床会由于丝杠的受力变形和热变形而很难有较高传动定位精度。利用误差补偿技术可以提高丝杠传动的定位精度，但却面临的几个具体问题。本文通过对这几个问题的分析、讨论得出尽管对特定丝杠进行误差补偿具有一定效果，但误差补偿技术并不能普遍应用于提高丝杠传动定位精度的结论。     

Sensitivity analysis of anti-resonance frequency for vibration test control of a fixture

The test specimen in environmental vibration test is connected to the fixture through several attachment points. The forces generated by the shaker must be transmitted equally to all attachment points. The forces transmitted to attachment points, however, are different because of the flexural vibration of the fixture. The variations of the transmitted force cause the undertest, especially at anti-resonance frequencies, in vibration test control. Anti-resonance frequencies at the attachment points of the fixture must be same in order to avoid the under-test in vibration test control. The structural modification of the fixture is needed so that anti-resonance frequencies at attachment points have the same value. In this paper, the method to calculate the anti-resonance frequencies and those sensitivities is presented. This sensitivity analysis is applied to the structural modification of the fixture excited at multi-points by the shaker. The antiresonance frequencies at the attachment points of the fixture can have the same value after structural modification, and the under-test in the vibration test control can be removed. Several computer simulations show that the proposed method can remove the under-tests, which are not removed in conventional vibration test control.