Modelling of Lake Waves to Simulate Environmental Disturbance to a Scale Ship Model

Abstract

In the development of ship motion control systems, software simulations or scale model experiments in pools or open water are very often carried out in the verification and testing stages. This paper describes the process of building a software wave simulator based on data gathered on the Silm Lake near Iława, Poland, where scale ship models are used for research and training. The basis of the simulator structure is a set of shaping filters fed with Gaussian white noise. These filters are built in the form of transfer functions generating irregular wave signals for different input wind forces. To enable simulation of a wide range of wind speeds, nonlinear interpolation is used. The lake wave simulation method presented in this paper fills a gap in current research, and enables accurate modelling of characteristic environmental disturbances on a small lake for motion control experiments of scale model ships.

Spectral Analysis of Compass Errors Based on Fast Fourier Transform and Reduction Absolute Errors Using a Pass-Band Finite Impulse Response Filter

“…Another important tool for digital image processing is the signal convolution algorithm, which can be used to suppress absolute compass errors in the low-frequency range, which are determined by a frequency analysis of the signal using the FFT algorithm. When designing such a filter, we can use the finite impulse response (FIR) [17] and infinite impulse response (IIR) [18] filtering algorithms, as used at the Simulation Laboratory Platform of Gdynia Maritime University (GMU), the Department of Marine Telecommunications [19], and in the modelling of lake waves to simulate environmental disturbance to a scale ship model [18] in the Department of Ship Automation at GMU.…”

Determination of Anchor Drop Sequence during Vessel Anchoring Operations Based on Expert Knowledge Base and Hydrometeorological Conditions

“…Improperly designed anchorage areas 2 of 23 may result in the inability to deploy all anchors, leading to delays in crew operations. Currently, there is a lack of literature and publications focused on anchorage planning from the perspective of positioning systems, as opposed to publications related to ship route planning [12][13][14][15][16][17][18] or precise maneuvering [19][20][21]. Existing publications related to anchorages often pertain to ships awaiting anchorage outside ports, as in the publication [22], where the authors present an anchorage planning algorithm in the presence of other anchored vessels.…”