Adaptive Backstepping Terminal Sliding Mode Control Method Based on Recurrent Neural Networks for Autonomous Underwater Vehicle

• Published in: Chinese journal of mechanical engineering Vol. 31; no. 1; pp. 1 - 16
• Main Authors: Yang, Chao, Yao, Feng, Zhang, Ming-Jun
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.12.2018; Springer Nature B.V; SpringerOpen
• Edition: English ed.
• Subjects: Adaptive control; Autonomous underwater vehicle (AUV); Autonomous underwater vehicles; Backstepping method; Control methods; Dynamic models; Electrical Machines and Networks; Electronics and Microelectronics; Engineering; Engineering Thermodynamics; Heat and Mass Transfer; Instrumentation; Machines; Manufacturing; Marine environment; Mechanical Engineering; Neural networks; Ocean currents; Ocean Engineering Equipment; Ocean models; Original Article; Polynomials; Power Electronics; Processes; Recurrent neural networks; Reduction; Sliding mode control; Switching; Terminal sliding mode; Theoretical and Applied Mechanics; Tracking control; Tracking errors; Trajectory control; Trajectory tracking; Uncertainty; Autonomous underwater vehicle (AUV); Terminal sliding mode; Trajectory tracking; Neural networks; Adaptive control; Backstepping method
• ISSN: 1000-9345; 2192-8258
• DOI: 10.1186/s10033-018-0307-5

The trajectory tracking control problem is addressed for autonomous underwater vehicle (AUV) in marine environment, with presence of the influence of the uncertain factors including ocean current disturbance, dynamic modeling uncertainty, and thrust model errors. To improve the trajectory tracking accuracy of AUV, an adaptive backstepping terminal sliding mode control based on recurrent neural networks (RNN) is proposed. Firstly, considering the inaccurate of thrust model of thruster, a Taylor’s polynomial is used to obtain the thrust model errors. And then, the dynamic modeling uncertainty and thrust model errors are combined into the system model uncertainty (SMU) of AUV; through the RNN, the SMU and ocean current disturbance are classified, approximated online. Finally, the weights of RNN and other control parameters are adjusted online based on the backstepping terminal sliding mode controller. In addition, a chattering-reduction method is proposed based on sigmoid function. In chattering-reduction method, the sigmoid function is used to realize the continuity of the sliding mode switching function, and the sliding mode switching gain is adjusted online based on the exponential form of the sliding mode function. Based on the Lyapunov theory and Barbalat’s lemma, it is theoretically proved that the AUV trajectory tracking error can quickly converge to zero in the finite time. This research proposes a trajectory tracking control method of AUV, which can effectively achieve high-precision trajectory tracking control of AUV under the influence of the uncertain factors. The feasibility and effectiveness of the proposed method is demonstrated with trajectory tracking simulations and pool-experiments of AUV.