Design Boundary Layer Thickness and Switching Gain in SMC Algorithm for AUV Motion Control

Abstract

SummaryDesigning the boundary layer thickness and switching gain in the nonlinear part of sliding mode controller (SMC) is one of the main subjects in SMC design that needs human experience, knowledge on the amplitude of disturbances, and information about the bounds of system uncertainties. In this paper, to reduce the trial-and-error effort by the designer(s) two different fitness functions in the horizontal and vertical planes are presented and a heuristic method is used for their optimization. The optimal switching gain in the proposed approach properly compensates the unmodeled dynamics, model uncertainty, and external disturbances. Chattering phenomenon in control signals and noise measurement effect are reduced by the optimal selection of boundary layer thickness. This proposed method is applied to an autonomous underwater vehicle (AUV) and evaluated through the real-time and cost-effective manner. The execution code is implemented on a single-board computer (SBC) through the xPC Target and is evaluated by the processor-in-the-loop (PIL) test. The results of the PIL test in the two different test cases indicate that the chattering phenomenon and amplitude of control signal applied to the actuators are reduced in comparison with the three conventional approaches in the AUV motion control.

Tribo-dynamic analysis and motion control of a rotating manipulator based on the load and temperature dependent friction model

“…A thin layer is usually chosen to achieve this goal, while the tracking performance and robustness against noise and disturbance could be compromised to some extent. 42…”

“…A thin layer is usually chosen to achieve this goal, while the tracking performance and robustness against noise and disturbance could be compromised to some extent. 42 Remark 8. The parameters l 1 ; l 2 and l 3 in equation (20) determine the learning rate of the estimated system disturbance upper bound coefficientsâ 0 ;â 1 and a 2 .…”

Robust Adaptive Tracking Control of Underwater Vehicles: Design, Stability Analysis, and Experiments

“…A type-2 robust adaptive fuzzy SMC has been reported in [24], which has a short rise time; but, its performance degrades when the vehicle changes its orientation. In [25], the robustness of a classical SMC toward parameter uncertainties for trajectory tracking of an autonomous underwater vehicle has been investigated. However, the proposed approach suffers from slow finite-time convergence on yaw tracking as the ratio of the uncertainty increases.…”

SMCSPO-Based Robust Control of AUV in Underwater Environments including Disturbances

“…When an AUV moves underwater, external forces such as added mass and drag force affect the operation of the AUV. In order to overcome the effects of various disturbances in the underwater environment, many studies have been carried out on the dynamics analysis and control theories of underwater vehicles [1][2][3][4][5][6].…”

“…The real twisting algorithm showed the best performance in terms of the lateral dynamics of position and velocity control of the AUV of the proposed controllers. Taheri designed a thickness of a boundary layer and switching gain in the sliding mode control (SMC) algorithm to reduce the chattering phenomenon amplitude of the control input [4]. However, the chattering phenomenon is still observed in sliding mode control under strong disturbances.…”