Robust tracking control for dynamic positioning ships subject to dynamic safety constraints

• Published in: Ocean engineering Vol. 266; p. 112710
• Main Authors: Liu, Yeye, Lin, Xiaogong, Liang, Kun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.12.2022
• Subjects: Bioinspired neurodynamics model (BNDM); Dynamic positioning ships; Sliding mode disturbance observer (SMDO); Trajectory tracking; Unified barrier function (UBF); Dynamic positioning ships; Trajectory tracking; Sliding mode disturbance observer (SMDO); Unified barrier function (UBF); Bioinspired neurodynamics model (BNDM)
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2022.112710

This paper addresses the dynamic safety constraint problem for the Dynamic Positioning (DP) ship subject to model uncertainties and unknown environmental disturbances. To guarantee the dynamic safety constraints, a new constraint technique based on the unified barrier function (UBF) is used to convert the original constrained DP system into an equivalent “non-constrained” one. By blending the new coordinate transformation into backstepping design, the position and velocity of the DP ship keep within the given constraints. In addition, a bioinspired neurodynamics model (BNDM) is developed to solve the traditional differential explosion problem of the virtual control law and limit the output in a certain range. Further, a sliding mode disturbance observer (SMDO) is introduced to estimate the model uncertainties and unknown environmental disturbances with minor chattering and rapid convergence. Finally, the effectiveness of the proposed controller and observer of the DP ship is illustrated by numerical simulations. •A new robust tracking control framework is proposed based on unified barrier function (UBF).•The bioinspired neurodynamics model is introduced to avoid the complex differential calculations and simplify controller design.•A practical sliding mode disturbance observer (SMDO) in combination with the idea of boundary layer is proposed to estimate the lumped disturbances.•Numerical simulation of the DP ship is performed and the results show that the proposed method could keep the position and velocity of the DP ship within the dynamic safety constraints.