Tension control in hot strip process using adaptive receding horizon control

Abstract

This paper presents a new looper–tension control scheme to minimize the tension variation between two stands in the hot strip finishing mill. The proposed control scheme is designed on the basis of a 5th order state space model for a looper system and composed of two main parts. First, a receding horizon control (RHC) feedback controller with a minimal-order disturbance observer (DOB) is employed to satisfy the constraints on the control input/state and guarantee the stability. The observer is also designed for attenuating the speed disturbances of the main motor. Second, a subspace-based state space system identification (4SID) model identifier is introduced to adopt the variation of system parameters. It is shown through simulation that the proposed control scheme satisfies the constraints on the control input/state, diminishes the tension variation for the parameter variation and the speed disturbances, and reduces the computational burden for the model adaptation as well.