Robust Adaptive Dynamic Surface Control Based on Structural Reliability for a Turret-moored Floating Production Storage and Offloading Vessel
- 41 Downloads
For floating production storage and offloading (FPSO) vessels, a dynamic positioning controller is necessary because using only a mooring system is not possible to keep the ship within a predefined region. Position control of the FPSO vessel is extremely challenging due to model uncertainties and unknown control coefficients. This paper develops a new robust adaptive positioning controller consisting of several components: adaptive law, dynamic surface control (DSC) technology, sigmoid tracking differentiator (STD), Nussbaum gain function, and structural reliability index. Model uncertainties can be estimated by the adaptive law derived from the Lyapunov theory. The DSC technology is used to eliminate repeated differentiation by introducing first-order filtering of the virtual control. The chattering-free STD with the characteristics of global fast convergence can estimate the derivatives of model uncertainties that are difficult to calculate directly. Therefore, the DSC and STD techniques make the proposed controller simpler to compute and easier to implement in engineering practice. Most of the traditional controllers require the information about the control coefficients to guarantee the stability of the closed-loop system while the Nussbaum gain function can remove the requirement for a priori knowledge of the sign of control coefficients. The capacity of the mooring system can be fully utilized to position the FPSO vessel by adjusting the structural reliability index on the premise of ensuring the safety of mooring lines, and hence less control effort is needed for the positioning controller. Simulations using two sets of system parameters demonstrate the proposed controller’s effectiveness. In addition, a qualitative comparison with the adaptive backstepping controller shows that our proposed controller is computationally more efficient and does not require a priori knowledge of the sign of control coefficients. A quantitative comparison with robust adaptive controller without the structural reliability shows that less control effort is needed using our proposed controller.
KeywordsAdaptive dynamic surface control Nussbaum gain positioning for ships structural reliability index
Unable to display preview. Download preview PDF.
- Y. Wang, Y. Sui, J. Wu, and J. Jiao, “Research on nonlinear model predictive control technology for ship dynamic positioning system,” Proc. of the IEEE International Conf. on Automation and Logistics, pp. 348–351, 2012.Google Scholar
- Y. Wang, C. Zou, F. Ding, X. Dou, Y. Ma, and Y. Liu, “Structural reliability based dynamic positioning of turretmoored fpsos in extreme seas,” Mathematical Problems in Engineering, vol. 2014, 2014.Google Scholar
- B. Niu, H. Li, T. Qin, and H. R. Karimi, “Adaptive NN dynamic surface controller design for nonlinear purefeedback switched systems with time-delays and quantized input,” IEEE Transactions on Systems, Man, and Cybernetics: Systems, doi: 10.1109/TSMC.2017.2696710.Google Scholar
- C. Wu, J. Liu, Y. Xiong, and L. Wu, “Observerbased adaptive fault-tolerant tracking control of nonlinear nonstrict-feedback systems,” IEEE Transactions on Neural Networks and Learning Systems, doi: 10.1109/TNNLS.2017.2712619.Google Scholar
- Q. Zhou, H. Li, L. Wang, and R. Lu, “Prescribed performance observer-based adaptive fuzzy control for nonstrictfeedback stochastic nonlinear systems,” IEEE Transactions on Systems, Man, and Cybernetics: Systems, doi: 10.1109/TSMC.2017.2738155.Google Scholar
- L. Wang, M. Basin, H. Li and R. Lu, “Observer-based composite adaptive fuzzy control for nonstrict-feedback systems with actuator failures,” IEEE Transactions on Fuzzy Systems, doi: 10.1109/TFUZZ.2017.2774185.Google Scholar
- H. O. Madsen, S. Krenk, and N. C. Lind, Methods of Structural Safety, Courier Corporation, North Chelmsford, Massachusetts, USA, 2006.Google Scholar
- S. Ryu and M. H. Kim, “Coupled dynamic analysis of thruster-assisted turret-moored FPSO,” Proc. of OCEANS 2003, vol. 3, pp. 1613–1620, 2003.Google Scholar