Engineering news
A remotely piloted robot propelled by wave and solar power has been used by scientists for the first time to measure water characteristics and collect samples in near real-time.
The UK's Centre for Environment, Fisheries and Aquaculture Science, and American company Liquid Robotics, successfully deployed, tested and recovered a remotely piloted Wave Glider called “Lyra” in the southern North Sea about 60km off Lincolnshire’s coast. The device spent 48 days at sea before being recovered 20 miles off Lowestoft.
While deployed, the Wave Glider was remotely piloted 24/7 by the Liquid Robotics' operations team from their California headquarters almost 9000km away and covered more than 2,700km at sea.
The Wave Glider converts wave motion into propulsion using its two-part architecture. On the surface the 3.05m floating platform has a modular design for self-contained data collection and on-board computing power based upon Linux and Java. It also contains configurable sensor modules and multiple communications options, such as GSM Communications and Wi-Fi, and solar modules that can collect up to 156W and battery packs with storage between 9kWh and 4.5kWh
Under the platform is a 2.13m sub attached by a standard 8m long umbilical cord which captures wave motion. As waves move the float up and down wings on the sub rise and fall propelling the vehicle forward. Solar electric thrusters are also available for extra speed when needed.
Wing Gliders can carry payloads of up to 500kg, travel to speed up to 3kn and swim for up to a year.
An integrated Cefas water sampler on Lyra allowed scientists to collect 11 samples, on demand, over the duration of the mission by sending commands over the Iridium satellite network. This meant that samples could be collected in areas of particular interest.
Using experimental daily satellite images of a harmful algal bloom, Cefas scientists navigated Lyra to a small suspected bloom of harmful Karenia algae north of the Dogger Bank. Once in the area of the bloom, scientists monitored the near-real time data from the on-board chlorophyll sensor to confirm its presence. They then commanded the water sampler on Lyra to take two samples that have since been confirmed to contain the phytoplankton Karenia.
Dr. David Pearce, Cefas Marine Observations systems manager in command of the mission, said the technology allowed his team to collect specific samples more efficiently. He added: “We demonstrated that there is great potential in smart solutions for monitoring ocean conditions and I am excited about the future for autonomous vehicles, such as the Wave Glider, as innovative ways to meet our scientific and monitoring goals.”
“The Wave Glider is a highly adaptable, unmanned surface vehicle and mission tests like this allow us to work with scientists to provide data for near real-time decision making.”
Cefas scientists are now planning to use the Cefas Water Sampler on additional upcoming Lyra missions. The sampler will be used to pump out “tracer” material. When combined with the on-board sensors, this extends the research applications of this technology to, for example, mapping localised areas of sea surface. Lyra expands Cefas’ research and monitoring capabilities in areas such as water quality monitoring, fisheries assessments, aquaculture health and ambient noise measurement.