【作者】 孙健；

【导师】 汪晋宽；

【作者基本信息】 东北大学 ， 控制理论与控制工程， 2009， 硕士

【摘要】 随着过程控制技术的不断发展,人们对控制系统数据传输速度和精度的要求越来越高。为了满足这一要求,20世纪90年代初,现场总线技术受到广泛关注。它是融合了计算机、通信和控制等多学科的一门综合技术,已成为过程控制中的关键技术。现如今,现场总线技术已经广泛应用于过程自动化、医药、加工制造、交通运输、国防、航天、农业和楼宇等多个领域。本文以新疆某公司水采船控制系统作为研究对象,按照工艺对控制系统的要求,应用SLC500系列PLC、GPS、无线通信电台等先进设备,设计了一套基于DeviceNet现场总线的控制系统。在控制系统平台方面,采用SLC500系列PLC、智能MCC等设备,利用RSLogix500、RSView32等软件对系统进行设计,实现了水采船和锚船的自动控制。在网络结构方面,水采船控制系统利用DeviceNet和EtherNet/IP相结合的网络平台,具有无缝链接和信息共享的特点,保证了数据传输的可靠性,提高了网络通信效率。针对水采船位置不固定的特点,提出了无线通信的要求,采用无线串行电台、无线以太网电台、PDL/EDL数传电台相结合的远程通信方式,实现了控制信号的远程高精度传输。根据对水采船导航和定位精度的要求,设计了双天线的GPS定位导航控制系统,实现了水采船的位置控制和角度(姿态)控制。考虑到对过程变量(压力、密度、流量、液位、温度等)的准确性要求,在下位机软件设计中采用了PID控制算法,从而提高了控制系统的整体性能,使得系统能够快速的达到稳定状态。传统PID控制参数主要依据一些经验公式或者试验法进行整定,往往难以满足系统的控制要求,本文对下位机软件设计中的传统PID算法进行改进,提出了基于BP神经网络的PID控制算法。该算法具有响应速度快、超调量小、抗干扰能力强等优点,在按照一定的学习率确定权值系数后,不断调整PID控制器的三个参数,使得系统能够快速稳定的达到平衡状态。水采船控制系统运行证明,系统具有可靠性高、稳定性好、控制精确、升级能力强、人机界面友好、可扩展性强等特点,满足了生产现场的要求,是现场总线控制系统成功应用于过程控制领域的典型案例,在化工生产的自动控制领域具有普遍性和推广价值。更多还原

【Abstract】 With the development of process control technology, the requirement for the speed and precision of the control system data transmission becomes higher and higher. In order to meet this requirement, in early1990s, the fieldbus has received wide attention. It is an integrated technology based on computer, communication and control technology, and has become the necessary way of the industry control field. Now, fieldbus has been widely used in many domains such as automatization, pharmaceuticals industry, manufacturing, transportation, national defense, spaceflight, agriculture and construction.Based on the requirement of the control system, the paper has taken mining vessel control system craftwork of a certain company in Xinjiang as study subject, adopted the SLC500PLC, GPS, wireless transmitter-receivers and other equipments, thus the thesis has presented a suit of control system based on DeviceNet Fieldbus. In the aspect of the control system platform, the mining vessel has adopted the hardware SLC500, MCC and the software RSLogix500, RSView32to design the control system, then to realize the automatic control of the mining vessel and anchor vessel. In the aspect of the network structure, the combination of EtherNet/IP and DeviceNet Fieldbus is applied in the mining vessel control system, which has the characteristic of continuous broadcasting and information sharing, ensures the dependability of data transmission, and improves the capability of system network. Considering that the position of mining vessel is not fixed, the paper has put forward the requirement of wireless communication, designed the wireless communication system using wireless transmitter-receivers combined with PDL, EDL, ensured control signals’ long-distance and nicety transportation. According to the high requirement of the localization and navigation of the mining ship, the navigation control system has proposed two antennae GPS, which not only realizes the high precision localization control but also the high precision stance control. Given the high demands on precision of process variables, such as heat, density, flux, level and temperature, this paper has designed the software system based on PID algorithm, thus improved the capability of the control system, made the system steady soon.As the traditional PID controller parameter method was mainly based on some experimental formula or experimentation, it couldn’t meet the controlling requirement. The paper has ameliorated the PID algorithm and put forward the BP Neural Network Algorithm. This algorithm has the characteristics of good astringency, small overshoot and strong ability against disturbance. According to the hository date we can modify the weight parameters and adjust the parameters of the PID controller serially. This process will push the system go to optimum position step by step.By the running of the mining vessel control system, it is proved that the system has the characteristics of high reliability, good stability, accurate controlling, strong upgrade, friendly man-machine interface, strong extendibility and so on. It can meet the requirement of the production and is a typical example that the fieldbus control system applied in the process control domain. It also has universality in the chemical production automatic control domain.更多还原