Expert Experience and Data-Driven Based Hybrid Fault Diagnosis for High-SpeedWire Rod Finishing Mills

The reliable operation of high-speed wire rod finishing mills is crucial in the steel production enterprise.As complex system-level equipment,it is difficult for high-speed wire rod finishing mills to realize fault location and real-time monitoring.To solve the above problems,an expert experience and data-driven-based hybrid fault diagnosis method for high-speed wire rod finishing mills is proposed in this paper.First,based on its mechanical structure,time and frequency domain analysis are improved in fault feature extraction.The approach of combining virtual value,peak value with kurtosis value index,is adopted in time domain analysis.Speed adjustment and side frequency analysis are proposed in frequency domain analysis to obtain accurate component characteristic frequency and its corresponding sideband.Then,according to time and frequency domain characteristics,fault location based on expert experience is proposed to get an accurate fault result.Finally,the proposed method is implemented in the equipment intelligent diagnosis system.By taking an equipment fault on site,for example,the effectiveness of the proposed method is illustrated in the system.

Vibrations characterization in milling of low stiffness parts with a rubber-based vacuum fixture

Fixtures are a critical element in machining operations as they are the interface between the part and the machine.These components are responsible for the precise part location on the machine table and for the proper dynamic stability maintenance during the manufacturing operations.Although these two features are deeply related,they are usually studied separately.On the one hand,diverse adaptable solutions have been developed for the clamping of different variable geometries.Parallelly,the stability of the part has been long studied to reduce the forced vibration and the chatter effects,especially on thin parts machining operations typically performed in the aeronautic field,such as the skin panels milling.The present work proposes a commitment between both features by the presentation of an innovative vacuum fixture based on the use of a vulcanized rubber layer.This solution presents high flexibility as it can be adapted to different geometries while providing a proper damping capacity due to the viscoelastic and elastoplastic behaviour of these compounds.Moreover,the sealing properties of these elastomers provide the perfect combination to transform a rubber layer into a flexible vacuum table.Therefore,in order to validate the suitability of this fixture,a test bench is manufactured and tested under uniaxial compression loads and under real finish milling conditions over AA2024 part samples.Finally,a roughness model is proposed and analysed in order to characterize the part vibration sources.

Adaptive Coordinated Control for Hot Strip Finishing Mills

To further improve the control accuracy for strip dimension of hot strip mills,an adaptive control scheme is investigated for a hot strip finishing mill based on the decentralization and coordination among the controllers of gauge,tension and looper.Consequently,the adaptive controller designed can regulate simultaneously the strip exit thickness,the strip tension and the looper angle to ensure better performance of the strip quality of finishing mills.Moreover,the control scheme is proposed in consideration of the essential nonlinearity and the unavoidable friction phenomena in the mechanical system,so the controller can be efficient in a wider range of working situations.The simulation results of a model obtained from a real hot strip finishing mill show the effectiveness of the proposed control scheme in comparison with the conventional control method.

Guaranteed cost sliding mode control for discrete-time looper systems in hot strip finishing mills

A guaranteed cost sliding mode control(SMC)algorithm is investigated to further improve the control accuracy of looper-tension systems in hot strip finishing mills.First,a global sliding mode surface function is designed by linear matrix inequalities and guaranteed cost technique,which can force the system states into switching region initially,and can guarantee the system robustness with a good performance during the whole control process.Then,a novel reaching law is designed,which can satisfy the sliding mode reaching conditions.Simulation results demonstrate that the proposed control scheme has good stability and robustness comparing with traditional SMC.The designed controller can regulate the strip tension and looper angle to ensure better performance,which is very suitable for complex looper systems.