The Wave Glider: A persistent platform for ocean science

2017

OCEANS 2017 - Aberdeen

Abstract-Renewable energy systems that extract power from sustainable sources such as wind, wave and solar can provide clean energy to a range of marine applications. Currently a major challenge is in providing an uninterrupted power supply, given the variation and uncertainty in these renewable energy sources. To deal with the unpredictable nature of renewable energy resources, this paper investigates the use of hybrid systems (systems that harvest multiple sources) to reduce the variation and uncertainty of the power generated. Considering the use of multiple renewable energy resources including solar, wind and wave, this paper first evaluates the available energy resources and the technical recoverable power using open-source, yearly, global, meteorological datasets. Based on the technical recoverable potential the complimentary features between solar and wind resources are investigated and compared to the propulsive power demand of various sized ocean going platforms and routes. The analysis shows that the resources can be complementary and that hybrid systems are more suitable for small vehicles, craft or maritime robotics system such as autonomous surface and underwater vehicles and oceanographic buoys.

Section: Introductionmentioning

confidence: 99%

Hybrid renewable energy system for ocean going platforms

Cao

2017

OCEANS 2017 - Aberdeen

“…Through utilizing the wave-induced response of submerged flapping foils at the bow and stern, AutoNaut propels itself based upon the techniques patented and developed by Linden and Jakobsen respectively [6,7]. The Wave Glider ASV, developed by Liquid Robotics, operates on a similar principle but predominantly harnesses the wave-induced heave motion of a surface float [8]. A series of prototype 'wave devouring' ASVs have also been developed by Terao at the Sakagami Laboratory, which are small catamarans with two submerged foils mounted at the bow [9].…”

Section: Introductionmentioning

confidence: 99%

“…A series of prototype 'wave devouring' ASVs have also been developed by Terao at the Sakagami Laboratory, which are small catamarans with two submerged foils mounted at the bow [9]. The forward speed of such vehicles is predominantly dictated by the encountered wave energy and current systems follow a circular pattern for station keeping scenarios [8].…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis of submerged flapping foils; implications for autonomous surface vehicles (ASVs)

Bowker

OCEANS 2016 MTS/IEEE Monterey

et al. 2016

Abstract-Autonomous surface vehicles (ASVs) have proven effective as ocean observing platforms for maritime operations. In most cases it is advantageous to operate ASVs for extensive missions in order to maximize their cost effectiveness. Such long endurance missions require ASVs to be capable of scavenging ambient energy from the surrounding ocean environment.Submerged flapping foils are currently utilized as an effective mechanism to convert ocean wave energy directly into propulsion. The authors propose a novel setup whereby these foils can heave relative to the surface vehicle and, through the application of a power take off (PTO) system, can recover a proportion of the incoming wave energy.Experiments were performed to investigate the coupled response between a surface vehicle and submerged flapping foils within the context of generating power and propulsion from incoming waves onboard ASVs. Results show that the response of a surface vehicle with submerged flapping foils is particularly sensitive to design parameters such as the longitudinal location of the foils and the seakeeping characteristics of the surface vehicle. Through optimising the PTO system, this setup could recover a useful proportion of wave energy for ASV platforms.

“…The Wave Glider, developed by Liquid Robotics, is passively propelled by a submerged set of foils, referred to as the 'glider', attached to a surface float via a tether [3]. As the float heaves in response to the ocean waves, the submerged glider heaved and plunged through the water.…”

Section: Introductionmentioning

confidence: 99%

“…The resulting effective flow over the foils generates thrust that drives the float forward over the waves. Figure 1: Convergence of ASV endurance and capability [3] [4][5] [6][7] [8] MOST (Autonomous Vessels) Ltd have also developed a long range endurance wave propelled ASV and have recently launched the commercial version called AutoNaut [7]. AutoNaut propels itself using the same technique patented and developed by Linden and Jakobsen respectively [9] [10].…”

Section: Introductionmentioning

confidence: 99%

Experimental study of a wave energy scavenging system onboard autonomous surface vessels (ASVs)

Bowker

et al. 2015

OCEANS 2015 - Genova

Abstract-Autonomous Surface Vehicles (ASV) have many potential applications in the maritime industry and ocean science. To subsist in the ocean space, an ASV must have the ability to scavenge energy from the surrounding environment. Waves are an abundant source of energy on the ocean surface and a suitable resource for an ASV to scavenge. Flapping foils have been shown to generate thrust in a wavy flow and power in a uniform flow. The aim of this experimental study is to investigate the relationship between flapping foil propulsion and power generation in the context of ASVs. Initial experiments incorporating fully passive flapping foils submerged at the bow and stern of a surface vessel in head waves were performed in a towing tank. The spring-loaded foils were located at the end of rigid pivot arms protruding at the bow and abaft of the vessel. The pivot arms were free to rotate about a location beneath the keel line and restrained by adjustable rotational dampers. In this free condition, wave energy is recovered in the form of work applied by the flapping foils through the rotary dampers which were used to simulate the damping effects of a power take-off device. Thrust was generated under conditions when the pivot arm was fixed. This system, referred to as the Flapping Energy Utilization and Recovery (FLEUR) system, could serve as a dualpurpose wave energy scavenging propulsor and power generator for long-endurance ASVs.