An adaptive on-line sensor for roll eccentricity measurement and control

Abstract

This paper is concerned with the problem of roll eccentricity compensation in steel strip rolling mills. A new roll eccentricity sensor is proposed for the task of retrieving the desired reference signal from the available roll force measurement. The sensor implements a modified comb filter structure which can be arranged in either tunable or adaptive form. The comb filter structure consists of a number of second-order infinite impulse response notch filter modules. Error surface analysis is carried out for the adaptive comb filter. Results from this analysis confirms that convergence is guaranteed provided that the initial frequency estimate is selected within the unimodal region. Such a condition is easily satisfied in practice since the fundamental frequency is related to the roll speed. Simulation results based on typical experimental data clearly indicate that the proposed sensor is appropriate and offers distinct advantages over other methods. The final roll eccentricity compensator is based on this new sensor and the functional units making up the complete compensation system are discussed in some detail within the paper.