A fixed-time convergence control of Roll-to-Roll systems with a fault-tolerant mechanism

The operation of Roll-to-roll systems in complex manufacturing industries continuously confronts challenges primarily due to external disturbances, actuator failures, and model uncertainties. These factors directly deteriorate the system’s productivity and quality, resulting in low-quality products and potentially unstable operation. In order to overcome the aforementioned disadvantage, this paper aims to construct a fixed-time control strategy to enhance the system’s tracking performance of material surface tension and transport speed. First, a fixed-time sliding mode observer is developed to estimate disturbances and actuator faults. Subsequently, using the disturbance estimation from the observer, the fixed-time sliding mode control is designed to generate the required control moments for this studied system. Moreover, the control framework is mathematically proven to be fixed-time stable through the Lyapunov criteria, with both the tracking and the observation errors converging to zero over a fixed period. Finally, extensive comparative simulations with other nonlinear controllers are conducted and discussed to demonstrate the validity and feasibility of the proposed method in terms of tracking accuracy and fast settling time with the existence of disturbances, uncertainties, and actuator faults.