T-S fuzzy control strategy for the 3-RSR wave compensation platform

Abstract:

To improve the anti-interference ability and control accuracy of wave compensation control for parallel robots, and to address the problem of insufficient robustness of existing methods in complex marine environments, this study proposes a novel TNL function observer and a T-S fuzzy control strategy for a 3-RSR parallel robot. Firstly, a kinematic model incorporating limb constraints is constructed based on the kinematic characteristics of the mechanism, and the Jacobi matrices between the joint and operational spaces are deduced; a nonlinear dynamics model is established through the principle of virtual work and the Newton-Euler method to elucidate the coupling mechanism of inertial, Coriolis, and gravitational forces. Secondly, to address the highly nonlinear characteristics of the system, the T-S fuzzy model is adopted to accurately approximate the dynamical equations, thereby realizing local linearization modeling based on membership functions. The TNL function observer is innovatively designed, and the robust stability condition characterized by LMIs is constructed by combining the Lyapunov stability theory to solve the problem of unmeasurable system states. Finally, through a co-design of the observer and fuzzy controller, an anti-disturbance closed-loop system is constructed, and convex optimization is used to solve controller parameters that satisfy the H∞ performance index, thereby guaranteeing dynamic stability under disturbances. Simulations show that the TNL function observer has better performance than the conventional types. The proposed architecture can effectively address the challenges of nonlinear state estimation and robust control, providing an innovative solution for wave compensation in marine engineering equipment, which is of great practical value for enhancing the performance of operations such as ship-to-ship transfer and maritime rescue.