Synchronous Control System Based On The All-digital Fieldbus Network Strip Slitting

Fieldbus technology is the product of the development of computer, telecom and control technology. Fieldbus connects intelligent devices and remote monitor computer by using standard digital communication link, realizing data transmission and information sharing, which has formed a new control system. PROFIBUS-DP is a factory-level network. It has high transmission rate, good compatibility, and convenient execution, which has extensive application in the world.Digital network synchronous control system based on fieldbus, has the advantages of high transmission rate, high reliability. It is easy to run and maintain. In this paper, we designed a synchronous control system, which has combined human-machine interface (HMI), DC drive, and PLC communication module through PROFIBUS-DP interface. The progress of sending and receiving control values, setting system parameters are all realized through PROFIBUS-DP. The speed detection part is made up of revolving encoder with high resolution. The actual speed of each unit is measured by revolving encoder, then it is sent to the high pulse counting unit. The measured speed is computed and compared with the setting parameters using the designed synchronous control method by PLC. As a result, we get the speed setting values for the DC machine of each unit, which are written into DC drive through PROFIBUS-DP fieldbus.Also, we can read the related parameters of DC driver, such as the values of voltage, current and speed onto HMI through PROFIBUS-DP interface. The values on HMI can be monitored by manipulator, the manipulator can judge and regulate them according to the actual circumstances.In order to maintain high quality of the products and stability of the production in strip steel slitter line system, the tension between main stand and rolling stand must be kept stable required by rolling technique. In this paper, we analyzed the constant tension control principal and control method. Because the rolling system is complicated, nonlinear, and its load is variable, if the tension controller is designed basing on the tradition control theory, we would not achieve good control effect.Fuzzy control is one of intelligence control methods without relying on accurate mathematical model of the control object. It can overcome nonlinear disturbance, and has better robusticity. So fuzzy control is used effectively on electric driving area. Because of the reasons mentioned above, and considering the practicality of the project, we design the synchronous driving system based on the fuzzy control method.As to control arithmetic, we use "online rules self-regulation", that is when the error is big we use Bang-Bang control to raise response rate, and when the error is small, we use fuzzy control to get high performance of the system, "parameter self-regulation fuzzy control" is also introduced. We can adjust parameters effectually according to the performance of the control system, which can achieve satisfied control result.In the end, we finished the simulation using Matlab for the control system, and developed the S-function program with the simulation software.