Fast catamaran oscillates in shortwave sea conditions due to its low length to beam ratio and relatively light weight. T-foils or interceptors are effective stabilizers for alleviating the pitch and heave motions of fast craft. This work designs a catamaran motion decoupling combined control system utilizing 2 T-foils and 2 interceptors, which can not only control the longitudinal motion, but a...

Abstract— This paper presents an adaptive control strategy with LQ control of a quarter-car, which is ameliorated to smoothly follow the dynamically changing reference arm angle, in order to omit the heave sensor in this study. Linearized plant parameters are initially derived from model equation and then estimated by online estimator. LQ control method provides optimal control effort with corr...

An analysis of the system identification methods have been carried out and a new alternative approach is proposed in order to estimate models for heave, pitch and roll dynamics of a high speed craft. As starting point, a first approach resolves the identification subject as an optimization problem to fit the best model, and uses genetic algorithms and nonlinear least squares with constraints me...

At several school buildings in New York City, initial efforts to replace the tile wearing surfaces on clay tile arch floor systems were fraught with difficulties. Many of the replacement floors began to crack and heave within a few months after installation. The authors conducted in-situ and laboratory studies of the flooring systems, and identified numerous causes that contributed to the failu...

8 The formation of rhythmic lenses of ice in freezing soils is an intriguing geo9 physical phenomenon that is not fully understood, despite much experimental and 10 theoretical work over the past century. We review proposed mathematical models 11 of ice lens growth and frost heave, from early capillary theories and models based 12 on the concept of a frozen fringe, to more recent advances that ...

33°N, long. 127°W, about 650 km west of Los Angeles. These holes will be drilled to about 300 meters, the depth depending on the maximum which can be attained with one bit because hole reentry will not be feasible. The drilling will test the hypothesis of ocean floor spreading (1) and the generation of long, linear, magnetic anomalies according to the Vine-Matthews hypothesis (2), relating them...

A model describing the flow and pressure fluctuations in the bore-hole due to drillstring movement has been presented. It consists of a pair of coupled nonlinear partial differential equations modelling the distributed pressure and flow in the well, and a superposition of multiple sine waves for the disturbance. Considering only top-side flow and pressure as measurements, it is shown that the m...

In this paper, we apply recent results on disturbance rejection in the interior domain of a class of 2 × 2 linear hyperbolic systems of partial differential equations to the problem of rejecting heave-induced pressure fluctuations at the casing shoe in managed pressure drilling. We show that a PDE model of the drilling dynamics belongs to this class of systems, and derive both state feedback an...

A neuro-fuzzy system has been developed to model the behaviour of a fast ferry. The sources of the available knowledge are the physical laws of the vertical dynamics of the craft, and some experimental and simulated data of the ship performance in regular waves. The non-linear model has been obtained by applying adaptive neurofuzzy inference. It is focus on the vertical motion of the craft, bot...

This paper presents a fully nonlinear numerical investigation on the resonant waves in the gap between two floating barges by using the Quasi Arbitrary Lagrangian-Eulerian finite element method (QALEFEM) based on the fully nonlinear potential theory. In the investigations, two identical floating barges undergo forced oscillation in heave. The wave elevations and the force acting on barges are r...