892 resultados para Numerical Control System
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介绍了如何把模糊控制算法与现场总线中的CAN总线结合起来应用于控制系统 ,并设计了一种智能型模糊控制算法 ,给出了系统的整体结构和现场模糊控制单元的硬件实现电路及其软件设计思路 ;系统的仿真结果表明 ,该系统实时性好 ,控制精度较高 ,鲁棒性强 ,在现场控制中有效可行
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从工业生产实际要求出发 ,提出了大供电稳流系统专家控制方案 ,它使控制器的理论设计变得简单、方便。工业生产实用结果表明 ,系统可靠性高 ,实时性好。
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现场总线的发展与应用引起了传统控制系统结构的改变,CAN总线因其自身的特点被广泛应用于自动控制领域。本文介绍了一种基于CAN总线的粮情测控系统,给出了系统的总体结构,并对系统的硬件配置和软件功能作了详细的说明。实际应用表明本系统具有结构简单、可靠性高、灵活方便等优点,并且具有较好的性能价格比,有着广泛的应用前景。
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目前变速箱涂胶主要采用人工作业,本项目是为实现了该类设备的自动化而研制的智能控制系统。本文根据株州齿轮厂提出的设计要求,在查阅大量有关文献基础上,分析了涂胶的全部工艺,设计并开发了经济实用数控涂胶机,符合国情,推动了我国变速箱自动化装配线的发展。本文完成了以下研究工作和创新性成果: 系统采用一种基于PC机和运动控制卡的开放式、模块化的智能控制系统方案,用运动控制卡和交流伺服组成闭环控制系统,实现了在线编程和运动控制的并行处理。 采用模块化的结构对涂胶机实行分层控制,涂胶机采用手动和自动两种工作方式,应用先进的示教方法实现涂胶机的开放性,并且对整个涂胶机实现实时监控以及智能保护。 论文提出了一种智能保护系统方案。通过胶嘴定位系统进行位置检测,利用红外传感器进行生产区域安全防护,对伺服报警信号进行监控和设计三重限位保护等方法,切实增强了系统的安全性和稳定性。 开发了数控系统的仿真器,使用户在涂胶前就可以看到胶线的轨迹,防止发生浪费。同时开发了数控系统的执行控制器。实现了数控程序的编辑和管理,以及通过RS232串行接口接收用户离线编写的数控程序。在智能涂胶机上进行实际涂胶,涂胶效果良好。 课题开发的涂胶系统的速度为4.8米/分钟,涂胶精度为0.01毫米,已经远远超过了现场要求的涂胶精度,而且在制造和维护成本上占有很大优势,获得了用户好评。
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托辊在国民经济的各行各业扮演着十分重要的角色,尤其在矿业生产的输送过程中,托辊更是发挥着巨大的作用。本项目旨在为托辊的自动化装配线提供整套控制执行系统。本文根据沈阳机床集团所提出的装配线控制要求,在查阅大量相关文献基础上,分析了托辊装配的整个工艺过程,结合先进制造的理念和技术,研究设计出包括制造过程底层信息系统在内的装配线控制系统。本文主要完成了以下研究工作及相关的创新性成果: 系统的供配电设计。根据设备的配电要求及相关规范,对整套控制系统的供配电进行合理的设计。 整条装配线的协调控制及信息系统设计与实现。结合目前广泛采用的工业现场总线技术,设计了整套分层控制及信息系统。整套系统分为三层,在顶层设计有监控系统,该系统通过以太网与下层的单台机床控制器进行信息互换。通过OPC技术将底层控制器采集到的现场信息在上位机上以友好的图文界面显示出来,供操作人员监控。同时还将每台机床的相关信息及以往报警历史按时间进行归档,形成现场装配过程信息备份,供上层的分析与决策系统使用。 现场每台机床采用独立的现场控制器进行控制。因为整条装配线被设计定位为柔性装配线,所以在机床控制上采用了伺服控制技术,以实现针对不同装配产品型号对托辊的支撑及夹具进行准确定位。控制器采用集逻辑、工艺、伺服控制于一体的西门子SIMOTION控制器。该控制器完成整个机床的动作及工艺控制,同时在现场每台机床控制器都配备一个触摸屏作为现场级人机界面,供机床现场调试和人机交互之用。 论文从整体上阐述了装配线控制系统的整体架构,并结合在线检测机床对机床的控制进行了讨论,从多方面体现出该控制及信息系统的完整性和先进性。 该项目开发的托辊装配线控制及信息系统旨在实现托辊安全、快速地自动化装配。并以单台机床单元控制器为主体通过现场总线技术为上层信息管理系统提供信息接口,为整条线的管理功能智能化扩展提供一个良好的平台。
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随着电子技术和计算机技术的不断发展,工业生产过程的控制系统正在向着智能化、数字化和网络化的方向发展。传统的集散控制方式和计算机分层控制方式已经开始让位于智能终端与网络结合的总线网络控制方式。当今,在工厂中过程控制环境下的分布式自动化系统变得越来越复杂,尤其系统内部的各设备之间需要快速交换大量的信息,以便实现对被控系统更为精确的控制和提供一些辅助的评价函数。这就意味着要不断增加带宽和提高通信速率以满足网络通信的需要。在现有的多种可利用网络设备中,CAN总线以其清晰的定义、极高的可靠性及其独特的设计,被认为是最能有效地解决这一问题的途径之一。而且市场上基于通信技术的产品中,就实时性考虑,由于CAN总线采用的非表意性的通信方式,因此其结构更为简单,实时性更好。基于此背景,我们以CAN总线作为通信媒介,将分布于各控制现场的传感器、执行器和控制器有序地连接起来,构成了一个基于CAN总线的分布式局域网络控制系统。本文首先介绍了基于CAN总线的分布式数据采集与控制系统的总体结构。然后从硬件方面描述了基于CAN总线的通信协议转换单元、数据采集单元和输出控制单元的功能、硬件配置及各单元功能的具体实现过程,给出了各单元的性能指标。软件方面,以C语言作为平台,开发了基于CAN总线的上位计算机管理与监控软件,实现了对整个网络设备的系统管理和系统控制功能。对于该总线系统,作者运用了PID控制和模糊控制算法实现了对水箱液位的控制,达到了理想的效果。基于CAN总线的控制系统很好地解决了集散控制系统难以解决的难题,模糊控制的应用能很好地把总线控制系统应用到具有非线性、大时滞和难于获得精确模型的控制系统中。
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Under the auspices of the 'knowledge-Innovation Program' of CAS, Institute of Geology and Geophysics has established the Broadband Seismic Laboratory. A new kind of 24-bit high-resolution seismograph DAS24-3B has been designed and manufactured in an effort of developing China's own technology of seismic array. Since these instruments will primarily be used in field operation, there is a need to optimize the system software of data acquisition system (DAS) to enhance its stability, compatibility and maintenance. The design ideas of the system software of DAS24-3B are partly learned from the advanced DAS 72A-08. In this system there are two exclusive communication programs DNAPI-COM1 and DNAPI-LPT1, which are suitable for all standard industrial computers with ECP parallel port and serial port. By these exclusive parallel and serial communication interface the system software is split into three parts, acquisition program, user's control program and graphical display program, which can function well in separate units and can run correctly in whole. The three parts of DAS24-3B's system software possess different functions and advantages. The function of acquisition program is to control the process of seismic data acquisition. DAS24-3B system reduced its power and harddisk read-write disturbance by using the extended memory attached to its CPU, which functions as enlarging the data buffer of system and lessening the times of harddisk read-write operations. Since GPS receiver of DAS is strongly sensitive to the around environment and has the possibility of signal loss the acquisition program has been designed with the ability to automatically trail the GPS locked time. The function of user's controlling program is to configure the system's work environment, to inform the user's commands to DAS, to trail the status of DAS in real-time. The function of graphical display program is to illustrate data in figures, to convert data file into some common formatted file, to split data file in parts and combine data files into one. Both user's control program and graphical display program are API (Application Programming Interface) in window 95/98 system. Both possess the features of clearness and friendship by use of all kind of window controls, which are composed by menu, toolbar, statusbar, dialogue box, message box, edit box, scrollbar, time control, button and so on. Two programs of systemic exception handles are provided to treat the trouble in field. The DAS24-3B DAS has been designed to be easier to use-better ability, more stable and simpler. It has been tested in field and base station and has been proved more suitable for field operation of seismic array than other native instruments.
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In the present study, based on processing efficiency theory, we used the event-related potentials (ERP) and functional magnetic resonance image (fMRI) techniques to explore the underlying neutral mechanism of influences of negative emotion on three subsystems of working memory, phonological loop、 visuospatial sketh pad and the central executive. The modified DSMT (delayed matching-to-sample task) and n-back tasks were adopted and IAPS (International Affective Picture System) pictures were employed to induce the expected emotional state of subjects. The main results and conclusions obtained in the series of experiments are as the following: 1. In DSM tasks, we found P200 and P300 were reduced by negative emotion in both spatial and verbal tasks, however the increased negative slow wave were only observed in spatial tasks, not in verbal tasks. 2. In n-back tasks, the updating function of WM associated P300 was affected by negative emotion only in spatial tasks, not in verbal tasks. Current density analysis revealed strong current density in the fronto-parietal cortex only in the spatial tasks as well. 3. We adopted fMRI-block design and ROIs analysis, and found significant emotion and task effects in spatial WM-associated right superior parietal cortex; only emotion effect in verbal WM-associated Broca’s area; the interaction effect in attention-associated medial prefrontal area and bilateral inferior parietal cortex. These results implied the negative emotion mainly disturbed the spatial WM-related areas, and the attention control system play a key role in the interaction of spatial WM and negative emotion. 4. to further examine the effects of positive、negative and neutral emotion on tasks with different cognitive loads, the selective effect of emotion on the ERP components of spatial WM was only found in 2-back tasks, not in visual searching tasks. So, firstly the positive emotion as well as negative emotion selectively disturbed on spatial WM in light of the attention resource competition mechanism. Secondly, the selective influences based on the different WM systems, not the properties of spatial and verbal information. At last, the manner of the interaction of emotion and cognition is correlated with the cognitive load.
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Meng Q. and Lee M.H., Behaviour-Based Assistive Robotics for the Home, in Proc. SMC2001, IEEE 2001 Int. Conf. on Systems, Man and Cybernetics, Tucson, Arizona, Oct 2001, pp684-689.
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This paper shows how a minimal neural network model of the cerebellum may be embedded within a sensory-neuro-muscular control system that mimics known anatomy and physiology. With this embedding, cerebellar learning promotes load compensation while also allowing both coactivation and reciprocal inhibition of sets of antagonist muscles. In particular, we show how synaptic long term depression guided by feedback from muscle stretch receptors can lead to trans-cerebellar gain changes that are load-compensating. It is argued that the same processes help to adaptively discover multi-joint synergies. Simulations of rapid single joint rotations under load illustrates design feasibility and stability.
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Physarum polycephalum is a well-studied microbial eukaryote with unique experimental attributes relative to other experimental model organisms. It has a sophisticated life cycle with several distinct stages including amoebal, flagellated, and plasmodial cells. It is unusual in switching between open and closed mitosis according to specific life-cycle stages. Here we present the analysis of the genome of this enigmatic and important model organism and compare it with closely related species. The genome is littered with simple and complex repeats and the coding regions are frequently interrupted by introns with a mean size of 100 bases. Complemented with extensive transcriptome data, we define approximately 31,000 gene loci, providing unexpected insights into early eukaryote evolution. We describe extensive use of histidine kinase-based two-component systems and tyrosine kinase signaling, the presence of bacterial and plant type photoreceptors (phytochromes, cryptochrome, and phototropin) and of plant-type pentatricopeptide repeat proteins, as well as metabolic pathways, and a cell cycle control system typically found in more complex eukaryotes. Our analysis characterizes P. polycephalum as a prototypical eukaryote with features attributed to the last common ancestor of Amorphea, that is, the Amoebozoa and Opisthokonts. Specifically, the presence of tyrosine kinases in Acanthamoeba and Physarum as representatives of two distantly related subdivisions of Amoebozoa argues against the later emergence of tyrosine kinase signaling in the opisthokont lineage and also against the acquisition by horizontal gene transfer.
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Synchronous islanded operation involves continuously holding an islanded power network in virtual synchronism with the main power system to aid paralleling and avoid potentially damaging out-of-synchronism reclosure. This requires phase control of the generators in the island and the transmission of a reference signal from a secure location on the main power system. Global positioning system (GPS) time-synchronized phasor measurements transmitted via an Internet protocol (IP) are used for the reference signal. However, while offering low cost and a readily available solution for distribution networks, IP communications have variable latency and are susceptible to packet loss, which can make time-critical control applications difficult. This paper investigates the ability of the phase-control system to tolerate communications latency. Phasor measurement conditioning algorithms that can tolerate latency are used in the phase-control loop of a 50-kVA diesel generator. © 2010 IEEE.
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Developmental processes are regulated by the bone morphogenetic protein (BMP) family of secreted molecules. BMPs bind to serine/threonine kinase receptors and signal through the canonical Smad pathway and other intracellular effectors. Integral to the control of BMPs is a diverse group of secreted BMP antagonists that bind to BMPs and prevent engagement with their cognate receptors. Tight temporospatial regulation of both BMP and BMP-antagonist expression provides an exquisite control system for developing tissues. Additional facets of BMP-antagonist biology, such as crosstalk with Wnt and Sonic hedgehog signaling during development, have been revealed in recent years. In addition, previously unappreciated roles for the BMP antagonists in kidney fibrosis and cancer have been elucidated. This review provides a description of BMP-antagonist biology, together with highlights of recent novel insights into the role of these antagonists in development, signal transduction and human disease.
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The work presented in this paper takes advantage of newly developed instrumentation suitable for in process monitoring of an industrial stretch blow molding machine. The instrumentation provides blowing pressure and stretch rod force histories along with the kinematics of polymer contact with the mould wall. A Design of Experiments pattern was used to qualitatively relate machine inputs with these process parameters and the thickness distribution of stretch blow molded PET (polyethylene terephtalate) bottles. Material slippage at the mold wall and thickness distribution is also discussed in relation to machine inputs. The key process indicators defined have great potential for use in a closed loop process control system and for validation of process simulations.
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Quantum-dot Cellular Automata (QCA) technology is a promising potential alternative to CMOS technology. To explore the characteristics of QCA and suitable design methodologies, digital circuit design approaches have been investigated. Due to the inherent wire delay in QCA, pipelined architectures appear to be a particularly suitable design technique. Also, because of the pipeline nature of QCA technology, it is not suitable for complicated control system design. Systolic arrays take advantage of pipelining, parallelism and simple local control. Therefore, an investigation into these architectures in QCA technology is provided in this paper. Two case studies, (a matrix multiplier and a Galois Field multiplier) are designed and analyzed based on both multilayer and coplanar crossings. The performance of these two types of interconnections are compared and it is found that even though coplanar crossings are currently more practical, they tend to occupy a larger design area and incur slightly more delay. A general semi-conductor QCA systolic array design methodology is also proposed. It is found that by applying a systolic array structure in QCA design, significant benefits can be achieved particularly with large systolic arrays, even more so than when applied in CMOS-based technology.