Active fault-tolerant control of liquid-transport overhead cranes using a multi-objective constrained LMI-integrated sliding surface controller

Abstract

This paper presents a comprehensive framework for robust control and active fault-tolerant operation of overhead crane systems transporting liquid payloads under nonlinear dynamics, external disturbances, and actuator faults. A novel dynamic modeling approach is developed that explicitly incorporates the coupled hook-container dynamics and nonlinear liquid sloshing effects, providing a realistic representation of the flexible coupling and energy exchange mechanisms inherent in practical crane operations. To address the challenges of vibration suppression and precise positioning under harsh operating conditions, a Multi-Objective Constrained Linear Matrix Inequality-Integrated Sliding Surface Controller (MO-Constrained LMI-ISSC) is proposed. The controller systematically integrates H_∞ disturbance attenuation, decay rate constraints for transient regulation, and explicit input-output constraints within a unified sliding mode control framework, ensuring robust performance while satisfying physical and safety requirements. Furthermore, an active fault-tolerant control scheme is established by integrating a Full-Order Fault Estimation Observer (FFEO) designed using frequency-domain-dependent H_∞ performance criteria based on the generalized Kalman-Yakubovich-Popov (KYP) lemma. This observer-based approach enables simultaneous actuator fault reconstruction and disturbance attenuation with reduced conservatism compared to conventional full-band designs. The estimated fault information is utilized for online compensation, enhancing system reliability and operational safety under faulty conditions. Simulation results demonstrate the effectiveness of the proposed integrated framework in achieving improved precise positioning, vibration suppression, and fault tolerance in safety-critical liquid transportation applications.