Observer-based nonlinear cascade control approach of rewinding systems with uncertainties and disturbances compensation

In this paper, the goal is to design a controller based on the backstepping technique and a nonlinear disturbance observer to control the tension and angular velocity of multiple-span rewinding systems under disturbance and uncertainty. The backstepping control technique is considered a control method with great potential for underactuated nonlinear objects with multi-input multi-output. However, there is currently no secure stability in operation when the system is ominously affected by disturbances and uncertainties. Therefore, a non-linear disturbance observer is integrated with the method to address that problem. This observer is designed with auxiliary state variables to reduce the measurement disturbance. The convergence of the proposed observer is taken into consideration and the stability of the whole system is demonstrated by choosing a proper Lyapunov function. The effectiveness of the proposed control schematic is tested through comparative simulations with other typical nonlinear control algorithms on a two-span web transport system.