Design Of Control System And Research On Control Method Of Transmission System With Varying Load For Electroslag Furnace

Electroslag furnace which is based on the electroslag remelting technique is a kind of extensive applied smelting-equipment in the province of special metallurgy. Electroslag Remelting (ESR) ingot with high purity, dense structure and fine machinery performances has extensively applied to the variously special situation, and the control accuracy of the smelting current is one of the key factors that decide the product of ESR ingot during the process of ESR. Most control methods for current are achieved by adjusting the distance and speed of electrode movement, so the control of electrode movement is very important for ESR.However, the most characteristics of electroslag furnace are that getting new electroslag ingot by means of melting consumable electrode, which is equivalent to the load on a wide range of changes for electrode transmission system. The extensive changed load seriously affectes the accuracy of control and even leads the remelting to breake. So the transmission speed must be controlled within a reasonable range. This paper firstly analyzes the special characteristics which are caused by the varying load on the process of ESR. The energy-saving hydraulic transmission system with variable weight and the intelligent control transmission system of ball screw equipped with dual-motor and gearbox are proposed based on these characteristics. The ball screw transmission system has the characteristics of the multi-variable, non-linear and time variability. According to these characteristics, the article makes use of neural network which has capability of self-learning, self-organizing, self-adaption, function approximation and large-scale parallel processing, and the feature that dose not require the precise mathematical model of the controlled object. The neural network and traditional PID are combined to a new control strategy, which has not only the flexibility and adaptability of neural network but also the high-precision of PID control. When it is employed to electrode transmission system, there will be an effective way to control system. The simulation of the control arithmetic shows that it can get satisfing control result, and it will make the massiness elements for the future.The background of the thesis is the 8-Ton switching electroslag furnace computer automatic control system in steel mill. According to the rapid industrial growth and requests of increasingly precise control accuracy, the paper developes a two-grade computer control system based on superior computer and PLC controller. In order to safeguard the continuity of melting, the redundant hardware configuration on inferior computer is based on S7-400H of SIEMENS Corporation. It controls the entire smelting process by adopting STEP7 Programming software. By using WinCC configuration software in redundant operator station, to complete designing monitoring program, which realizes the field data real-time recorded, storage, and printing the monitoring, and provides real-time tracking curves of processing parameters.