Slocum Glider energy measurement and simulation infrastructure

Abstract

Abstract-Autonomous underwater vehicles (AUVs) are indispensable tools for marine scientists to study the world's oceans. Depending on their missions, AUVs are equipped with advanced sensors (sonar, cameras, acoustic communication, bio-sensors), have on-board computers for data analysis (image analysis, data compression), and are capable of on-board decision making (resource planning, swarming). Since AUVs operate solely on battery power, power and energy management is a crucial issue. Missioncritical tradeoff decisions have to be made between energy consumption and sensing, data processing, and communication activities. Mission planning has to consider these tradeoffs when provisioning resources for expected future events, or when dealing with changing environmental conditions such weather, water currents, and seafloor profiles. Effective power and energy management requires knowledge about the actual energy consumption of each active component within the AUV. Effective planning requires simulators that can predict energy consumptions based on expected future events and environmental conditions.In this paper, we discuss the design and implementation of a power measurement infrastructure for the Teledyne Webb research Slocum glider. This infrastructure can be used for online power/energy management or to better understand the time-dependent energy consumption profile of the active glider components during a particular mission. We also discuss the design of a new simulation environment for the Slocum glider which uses the power/energy data obtained by our measurement infrastructure, in addition to seafloor and coastal radar information. We illustrate the effectiveness of the new tools in the context of planning a glider flight across the continental shelf off the coast of New Jersey.

Underwater Gliders: A Review

“…The Webb Research Corp's (WRC) developed Slocum Thermal for long duration missions in waters with a well-developed thermocline [9,14]. Because temperature and heat vary at the different depths, heat is absorbed and released, causing the volume of working fluid to change [15].…”

Using Slocum gliders for coordinated spatial sampling

“…In our previous work, [9], a power measurement infrastructure is described that records the power required of a subset of the glider's components. This infrastructure consists of a measurement board populated with Hall effect sensors to gather readings of the current draw of the devices.…”

“…A more precise cost was investigated in the August 2010 sea trials because previous deployments, [9], did not achieve the full depth range capable of the 100 meter coastal version of the AUV. A new energy model for the buoyancy engine, derived from measurements recorded by the infrastructure during the deployment, is depicted in Fig.…”

“…The effectiveness of the formation strategies described are evaluated using a Slocum glider simulator first presented in [9]. The simulation framework is capable of using multiple speed models.…”

“…The AUV coordination strategy is implemented and evaluated on the infrastructure described in our previous work [8], [9], [10]. This section will briefly describe the WHOI Micro-Modem, which is the essential technology required to perform the formation among the vehicles.…”