Improving Remote System Response in Increasingly Hostile Oceans
Wind and Waves and Hydrogen, Oh My!
Improving remote system response in increasingly hostile oceans
This article is a continuation of a series about OOI Surface Moorings. In this article, OOI Integration Engineer Alexander Franks discusses the mooring software and details some of the challenges the buoy system controller code has been written to overcome.
Components of the OOI buoys working in concert make up a system that is designed for deployment in some of the most challenging areas of our world’s oceans. These systems collect valuable scientific data and send it back to Wood Hole Oceanographic Institution (WHOI) servers in near real time. Mechanical riser pieces (wire rope, and/or stretch hoses) moor the buoy to the bottom of the ocean. Foam flotation keeps the buoy above water in even the worst 100-year storm, while its masthead supports instrumentation and satellite radios that make possible the continuous relaying of data. The software controlling the system is just as important as the physical aspects that keep the system operating.
The system software has a variety of responsibilities, including setting instrument configurations and logging data, executing power schedules for instruments and parts of the mooring electronics, controlling the telemetry system, interfacing with lower-level systems including the power system controller, and distributing GPS and timing. The telemetry system is a two-way communication path, so the software controls data delivery from the buoy, but also provides operators with the ability to perform remote command and control.
Software flow diagram created by OOI Integration Engineer Alex Franks
The unforgiving environment and long duration deployments of OOI moorings lead to occasional system issues that require intervention. Huge storms, for example, can build waves so high that they threaten wind turbines on the moorings. At the Irminger Sea Array, ice can accumulate so much as to drastically increase the weight of the masthead, and with subsequent buoy motion, risk dunking the masthead and instruments. Other mooring functions require constant attention. The charging system must be monitored to ensure system voltages stay at safe levels and hydrogen generation within the buoy itself is kept within safe limits. Two-way satellite communication allows operators to handle decision making from shore using the most up-to-date information from the buoy.
“Since starting in 2015 and following multiple mooring builds and deployments, I’ve realized that issues can rapidly arise at any time of the day or night. I started thinking about what the buoys can do for themselves, using the data being collected onboard,” Franks said.
One of the game-changing upgrades implemented by Franks was to read environmental data and make automated buoy safety decisions in real-time that were previously performed by the team manually. For example, previously, the team would need to monitor weather forecasts and decide preemptively whether changes to buoy operations were advisable. With recent software changes, the system can now change its configuration based on a variety of sensor inputs. These variables include system voltage, ambient temperature, hydrogen levels inside the buoy well, wind speed, and buoy motion (for sea state approximation). In addition to the software updates, the engineering team redesigned the power system controller. They added charge control circuits and the ability to stop the wind turbines from spinning. The software and electrical upgrades now provide redundant automated safeguards against overcharging situations, hydrogen generation, and turbine damage, maximizing buoy operability in harsh environments.
Onshore engineers are able to keep track of Irminger Sea buoys and instrumentation on this new new dashboard.
With a largely independent system, operators also needed a way to easily monitor status of the buoys and instrumentation. The software team created a new shoreside dashboard that allows operators to set up custom alerts and alarms based on variables being collected and telemetered by the buoy. While the buoy systems can now operate autonomously, alerts and alarms maintain a human-in-the-loop component to ensure quality control.
As operations and management of the moorings have progressed, the operations team has found opportunities to fine tune how operators and the system handle edge cases of how the system responds to hardware failures and extreme weather. In the past, sometimes conditions changed faster than the data being transmitted back to shore. This new sophisticated software automates some of the buoy’s responses to changing conditions in real time, which helps to ensure their continued operation even under challenging conditions. The decreased response time to environmental and system events using an automated system, coupled with the ability to monitor and interact remotely, has increased the reliability and survivability of OOI moorings.
