Multi-Disturbance Observers-Based Nonlinear Control Scheme for Wire Rope Tension Control of Hoisting Systems with Backstepping

Abstract

The objective of this paper is to pursue a wire rope control methodology for reducing the tension difference between two wire ropes of a hoisting system. As we know, complicated disturbances exist in the complex electro-hydraulic hoisting system, notably, some of these disturbances are coupled, such as high-speed airflow disturbances, structure vibrations and vibrations in flexible wire ropes. Furthermore, there are model errors in force modeling due to the Coulomb friction between two wire ropes and two moveable head sheaves in the real physical hoisting systems. To eliminate disturbances, two types of disturbance observers (DOs) are employed: a traditional disturbance observer (TDO) and a coupled disturbance observer (CDO), both of which are utilized to estimate and compensate for the Coulomb friction and coupled disturbances online. As a result, a nonlinear backstepping control scheme is presented with estimation values from the TDO and the CDO. The experiment’s results demonstrate the effectiveness of the proposed control methodology.