Application And Research Of Eccentric Flying Shear Control System In Cross Shearing Unit

Cross shearing unit (CTL) is the final process line in which a coil is cut to specified length. Fixed-ruler flying shears (FRFS), which make continuous production in high speed possible, are widely applied in CTLs. A CTL in Baosteel applies an eccentric flying shear (EFS). Its dimension tolerance is less than0.5mm. Because the EFS’s motion control software is delivered in executable binary code, it is not decipherable. In addition, few technical documents on the EFS’motion control are provided to users. Thus, significant difficulty exists in EFS maintenance and fault resolution. A thorough study on the structure of the EFS system, its motion procedure, and the key technology in its control system is of enormous practical value. Findings in this research shall help improve machinery maintenance and efficiency in fault resolution. In addition, valuable reference can be provided for equipment import and development in the future.Base on examining a large amount of domestic and foreign literature on flying shears, this thesis is started with an introduction of EFS’s mechanical structure and its control system. The function and control principle of every axis is analyzed in consideration of the relevant requirements on cutting processing. The motion control model of the top blade is then established. A trajectory-planning algorithm is derived from with the known cutting to length. When there is a fixed deviation between the designed length and the delivered length of the products, certain parameters can be adjusted to yield the desired results. Finally, the whole motion control law of the EFS is obtained.To address the shortcomings in the self-diagnosis function of the EFS control system, a set of high-speed real-time data acquisition and playback software for the shear is developed. High-speed real-time data are collected by the software from the shear controller under the OPC communication protocol. The data are then stored in the PostgreSQL database. Data playback system reads the real-time data from the database and draws historical performance curves, which are transmitted to professionals for research and analysis. After the implementation of the software, production-related faults are more effectively resolved, the equipment safety is enhanced, and the work efficiency is improved.