Full-order sliding mode control of underwater flexible manipulators with echo state network disturbance compensation
Hui Xian Huang, Guoyuan Tang, Hongxuan Chen, Jianjun Wang, Lijun Han, De Yong Xie · Transactions of the Canadian Society for Mechanical Engineering · 2025
In this article, a full-order sliding mode controller with echo state network (ESN-FOSMC) disturbance compensation is proposed for the trajectory tracking and vibration suppression of underwater flexible manipulators (UFM). To improve the robustness under lumped disturbances and reduce the computational complexity of traditional recurrent neural networks method, ESN, a continuous recurrent neural network, is used to approximate and compensate model uncertainties and hydrodynamic disturbances. A FOSMC is designed to ensure accurate tracking of joints and end-effectors, and proportional-derivative (PD) control method is utilized to further suppress flexible vibration. The adaptive law of ESN is formulated by using Lyapunov method, integrating the ESN method with sliding mode control method. Then, Lyapunov method is used to prove the stability of the control system. Finally, the virtual prototype system of the UFM is established to validate the effectiveness of the proposed control method. Simulation results present that, compared with the nonsingular fast terminal sliding mode controller and a FOSMC with radical basis functions (RBF-FOSMC) neural network disturbance compensation, the ESN-FOSMC achieves superior tracking accuracy with reduced vibration.