91 research outputs found
Towards control of autonomous surface vehicles in rough seas
This paper addresses the problem of controlling an Autonomous Surface Vehicle (ASV) in rough sea-states, with a view towards minimising wave-induced forces, whilst maintaining headway. This is a challenging control application since, and as is derived in the paper, the interaction between the vessel and the wave disturbance is nonlinear and coupled. This subsequently motivates the novel application of the Real Time Iteration Scheme (RTI) for Nonlinear Model Predictive Control (NMPC) of the ASV. Analysis of the resulting control signal provides an important insight into the role of the wave encounter frequency. Specifically, by actuating at twice the average wave encounter frequency, the nonlinear controller is able to reduce the wave forces, compared to an open-loop controller that achieves the same average velocity
The Superspace of Geometrodynamics
Wheeler's Superspace is the arena in which Geometrodynamics takes place. I
review some aspects of its geometrical and topological structure that Wheeler
urged us to take seriously in the context of canonical quantum gravity.Comment: 29 pages, 8 figures. To appear in the Wheeler memorial volume of
General Relativity and Gravitatio
Divergent patterns of abundance and age-class structure of headwater stream tadpoles in burned and unburned watersheds
Using genetic methods to describe and infer recent colonizations by desert bighorn sheep
State-selective one-electron capture by slow state-prepared N2+(P-2) ground-state ions in collisions with hydrogen atoms
Using genetic methods to describe and infer recent colonizations by desert bighorn sheep
Using genetic methods to describe and infer recent colonizations by desert bighorn sheep
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