Compensating of added mass terms in dynamically positioned surface vehicles: A continuous robust control approach

Abstract

In this work, we provide a tracking controller formulation for dynamically positioned surface vessels with an asymmetric added mass terms that affects the overall system dynamics at the acceleration level. Specifically a novel continuous robust controller is proposed for surface vessels that in addition to unstructured uncertainties in its dynamics, contains added mass effects in its inertia matrix. The proposed controller compensates the overall system uncertainties while ensuring asymptotic tracking by utilizing the knowledge of the leading principal minors of the input gain matrix. Stability of the closed-loop system and asymptotic convergence are proven via Lyapunov based approaches. Simulation studies are also presented to illustrate the viability of the proposed method.

Network-Based T–S Fuzzy Dynamic Positioning Controller Design for Unmanned Marine Vehicles

“…Note that sampler-to-controller and controller-to-actuator network-induced characteristics are taken into full consideration in closed-loop systems (16) and (19). If one considers only controller-to-actuator network-induced characteristics, the global dynamics of the observer in (18)…”

“…In this section, we analyse stability of network-based T-S fuzzy DPSs (16) and (19) for the UMV. In doing so, we construct the Lyapunov-Krasovskii functional as…”

“…If the networked T-S fuzzy DPS (19) under the premise matching is considered, the following stability criterion is followed immediately.…”

“…Theorem 2: For given scalars τ ca m ≥ 0, τ sc m ≥ 0, τ M > 0, h > 0, ̺ > 0, γ > 0, and matrices L j and K of appropriate dimensions, the network-based T-S fuzzy DPS (19) is asymptotically stable with an H ∞ norm bound γ, if there exist symmetric positive definite matrices P , Q 1 , Q 2 , R 1 , R 2 , R 3 , R 4 , S 1 , and S 2 such that the inequalities (27) and (28) hold for 1 ≤ i = j ≤ 4,…”

“…In [18], robust controller design for dynamic positioning of ships and offshore rigs using H ∞ and mixed-µ techniques was considered. A novel continuous robust controller for dynamically positioned surface vessels with added mass terms was constructed in [19]. A robust nonlinear control law for the dynamic positioning system of ships subject to unknown time-varying disturbance and input saturation was proposed in [20].…”