An Adaptive Flow Compensation Algorithm for Hydraulic Loopers Based on Servo Valve Current Control of Hydraulic Cylinders

ABSTRACT In the hot rolling process, the hydraulic looper device is the key actuator that maintains the dynamic stability of strip tension between stands. Its flow compensation strategy plays a critical role in mitigating tension fluctuations and enhancing control accuracy. To overcome the limitations of conventional hydraulic looper flow compensation methods that rely on empirical parameters and are unsuited to dynamic rolling environments, this paper proposes an adaptive flow compensation algorithm based on servo valve current control for hydraulic cylinders. Initially, a comprehensive model of the hydraulic looper system is developed, encompassing both a servo valve‐hydraulic cylinder sub‐model and an overall looper system model. This integrated model is then used to perform theoretical calculations of the flow compensation value. Subsequently, to address the impact of varying system parameters due to operational conditions and environmental disturbances, a state‐space model is formulated, and a Kalman filtering technique is employed for real‐time system state estimation and flow compensation prediction. This approach facilitates the adaptive regulation of the servo valve current. Experimental results demonstrate that the proposed method effectively suppresses strip tension fluctuations and significantly enhances the system's dynamic response and disturbance rejection capabilities.