Reduced-order observer-based robust synchronisation control of cold rolling mills with measurement delay

Abstract

To improve the quality of strip thickness, synchronisation control is investigated for cold rolling mills driven by dual-cylinder electro-hydraulic servo systems. Realising synchronised control in hydraulic automatic gauge control (HAGC) systems of cold rolling mills has challenges with not only the inherent nonlinearities of hydraulic servo systems and uncertainties of load variation but also measurement delay of strip thickness. Since all states are not measurable in practice, output feedback robust synchronisation control problem should be addressed for uncertain nonlinear systems with output delay. Thus, a reduced-order observer-based robust synchronous controller is presented by employing Lyapunov functional stability theory. The controller designed by incorporating the integral of the position synchronisation error of two pistons into state variables successfully guarantees asymptotic convergence to zero of both tracking errors and synchronisation error simultaneously regardless of the nonlinearities and uncertainties as well as the measurement delay. Simulation results in a model obtained from a real cold strip rolling mill demonstrate the effectiveness of the approach.

Double closed-loop adaptive rectification control of a shield tunneling machine with hydraulic actuator dynamics subject to saturation constraint

“…Meanwhile, with the aid of this double closed-loop control structure, the saturation constraint is considered as well. Note that a similar control structure is also reported by Sun and Chiu (2002) and Jiao and Mei (2010), but the load forces and dynamic behaviors of rectification of the shield tunneling machine are very different from the proposed cases.…”

Robust consensus control for multiple robotic manipulators

“…As a consequence, it has become a classical topic in system and control domain to deal with the synchronization of MRMS, which has drawn many attentions from control theory and engineering [3][4][5][6][7]. And many solutions have been come up with, such as cooperative or coordinated MRMS and so on, which are proven to be effective.…”

H$$_{\infty }$$ controller for the vibration suppression of rolling mill systems with time-varying input delay

“…A fault-tolerant output feedback controller for the hydraulic automation gauge control system of cold rolling mills was developed in [31] using Lyapunov stability theory and a linear matrix inequality approach. In [32], the L-K functional stability theory was employed to give suitable requirements for the system's asymptotic stability, and a robust output controller was constructed in the rolling mill. An eventtriggered H-infinity controller was designed for an active seat suspension and the simulation and experimental data were provided to illustrate the efficacy of the recommended control strategy in [33].…”

“…Linear matrix inequalities (LMIs) were developed in [34] by applying the delay dependent L-K functional and were utilized to synthesize the controller to accomplish chatter suppression in milling. In fact, references [32,35] pointed out that there is an inevitable time delay issue in the rolling processes. However, the time delay problem caused by the strip thickness measurement delay in the rolling mill system is not considered in the aforementioned literature on vibration control algorithms.…”