Temperature Adaptive Control System Of Large Bogie-hearth Resistance Furnace

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...