Robust control synthesis for dynamic vessel positioning

Abstract

This article considers key theoretical and practical issues that arise in the robust control synthesis for dynamic positioning. A dynamically positioned vessel maintains its position (fixed location or predetermined track) by means of active thrusters and propellers. The concise kinematics and vessel dynamics are presented using three degrees of freedom model for describing the horizontal motions. Then, the mixed H N and m-synthesis framework has been employed to deal with perturbed model under external disturbances as well as measurement noises. To avoid excessive control energy for dynamic positioning system, the high frequency waves have been filtered using simple weighting functions. Using optimal Hankel-norm model approximation, the resulting full-order controller has been significantly reduced to make it easy to implement the practical works. Next, the simulation results in both frequency and time domains are presented to demonstrate the effectiveness of the robust control algorithms using the appropriate weighting functions. Finally, it is found that the proposed dynamic positioning system provides good maneuverability and robustness over a wide range of operating conditions, even under parametric variations and sea disturbances with sensor noises.

Composite anti-disturbance control for ship dynamic positioning systems with thruster faults

“…Selecting h 0 = ½20m, 20m, 10rad T and v 0 = ½0m=s, 0m=s, 0rad=s T , then X(0) = ½1, 1, p=4, 0, 0, 0 T . Select ing the designed parameters as a = 10, b = 20, g 1 = 2310 4 , g 2 = 1310 À9 , and s = 1310 3 . Based on Theorem 1, one has…”

“…The dynamic positioning (DP) can keep the ship in a predetermined trajectory in the presence of external environmental disturbance. 1–3. For unknown constant disturbance, a nonlinear set-point-regulation controller was proposed using a port-Hamiltonian framework.…”

Robust Control of Small Turbojet Engines

“…A nonlinear, predictive robust controller was better in control of an autonomous plane, even with data delays, plane degradation, and instability, compared to linear controllers. The problem of vessel positioning control was also solved using H ∞ and µ synthesis, with good simulation results in frequency and time domain [17]. An efficient combination of fuzzy control and robust control strategies were applied to design the controllers for solar collector fields [18].…”