【作者】 祝琴；

【导师】 龙伟；

【作者基本信息】 南昌大学 ， 控制理论与控制工程， 2006， 硕士

【摘要】 电阻炉热处理过程通常呈现严重大纯滞后、非线性、时变性，而且大型台车式电阻炉由于加热空间大，温度场存在强耦合、现场强干扰，给温度控制带来极大的不确定性，严重影响产品质量。因此，成功解决电阻炉温度控制问题以满足热处理工艺要求具有重要的现实意义。 本文首先介绍了我国电阻炉温度控制的现状、发展趋势及存在的问题。着重分析了大型台车式电阻炉热处理过程中温度控制所面临的问题。 其次根据热处理工艺的要求，完成了基于现场总线技术，集检测、控制和管理等功能为一体的自动化系统的开发。整个系统采用二级计算机控制方式，基础自动化级采用西门子公司S7—200系列PLC，实现对对台车、电源车的运行以及砂封、炉门升降和密封的控制。监控级为台湾研华生产的工业控制机，完成对系统的组态、监控、报警、制表等功能。系统操作简便，画面动感直观，并具有高适应性、高可靠性和高稳定性等特点。 本系统利用计算机高速、便于进行复杂计算的优势，替代普通控制仪表，实现了对27个加热区的温度控制，保证了这些加热区能同步、协调工作，现场参数整定简单方便；控制器输出经过独特的限幅技术，实现了温度的局部微调，较好的解决了炉内温度不均匀的问题，达到了大型工件表面温差≤±10℃的工艺要求。 针对现场环境恶劣，温度信号传输距离较长、干扰强等特点，系统利用热电偶温度采集专用模块将温度信号直接转化为对应的温度数字信号，提高了测量精度。另外，通过对温度采集专用模块的输入端采取抗干扰措施，有效地消除了传输线上较强的干扰信号，提高了系统的抗干扰性。 通过对大型台车式电阻炉热处理过程的理论分析，针对电阻炉温度具有严重的非线性、强耦合这一难题，本文采用先进的增益自适应Smith预估补偿控制算法，解决了电阻炉温度控制时滞性强、参数不确定性大、易受随机因素影响等问题，提高了控制的稳定性和精度，取得了满意的效果。 本文主要研究成果是：通过对大型台车式电阻炉的研制，解决了大型热处理设备制造过程中的关键技术问题，有利于对温度均匀和精度要求较高的热处理工艺的发展，提高了压力容器等设备的质量。推动了热处理加工行业的生产自动化，为大型化热处理设备的制造及改造提供了成功的经验。更多还原

【Abstract】 The non-linear, time-varying and lagging usually appears seriously in the process of heat treatment, and the large bogie-hearth resistance furnace has many characters such as strong coupleness, disturbance in the field and so on because of its large heat space. So it brings a great difficulties for temperature control . Therefore, the successful solution to control the furnace temperature according to the requirement of Industry is of importance.Firstly, the paper comprehensively analyzes the present situation, development trends and problems about the application of temperature control of large bogie-hearth resistance furnace.Secondly, according to the request of heat treatment, a automation system has been developed to test control and manage based on field bus technology. The system is composed of two layers of computer control structure, basic automation is completed to control the action of bogie and Power carriage, lift and seal of sand sieve grading and furnace’s gate by SIMEN PLC. Supervisor is made up with industrial computer from YanHua corporation of Taiwan, and fulfills many functions such as configuration, supervision, alarm, table, etc. The temperature control system is operated simply with the characteristic of active pictures, high adjustability, high reliability, and high stability.To take advantage of computer’s high speed and capability of complex calculate, computer is substituted for common control instrument in the system, temperature in 27 heat zones are controlled, ensures synchronization, work in harmony among these zones, it is simple and convenient to tune parameters. By a adding unique limiter to every output, It achieves in adjusting local tiny temperature, provides a better solution to temperature gradients, arrives at technics request difference in temperature in surface of big workpiece <± 10°CAimed at bad environment, long distance of transferring temperature signal, strong disturbance and so on, temperature signal is directly translated into its digital signal by thermocouple temperature-collection module, and measuring accuracy is increased. In addition, by taking rejecting disturbance measure in input unit of the module, it is effective to remove strong disturbance from transmission line, the ability of rejecting disturbance is improved.Through exhaustive and systemic theory analyse for heat treatment process in the large bogie-hearth resistance, aim at the difficult problem that the temperature has serious nonlinearity and strong couple, a gain adaptive smith predictor is adopted in the paper, it successfully solves problems : lagging, parameter uncertainty, be susceptible to be influenced by casual factors, enhances the stability and precision of control system and achieves satisfactory effect.The production of the paper follows: the key technical problem is settled successfully in the process of manufacturing great heat treatment equipment by designing the large bogie-hearth resistance furnace, the development of heat treatment technics requiring high temperature asymmetry and precision is furthered, the quality of press vessel and so on is greatly improved,production automation is promoted in heat更多还原