While we pay so much attention to exploring the mysteries of outer space, there are plenty of unexplored places on our own planet under the water. The ocean covers 71% of the Earth’s surface, yet more than 95% of the underwater world remains unexplored. But now, thanks to the evolution of underwater robots, we will be able to discover the great unknown water world. Most of these robots are inspired by the biology and design engineering of nature. The applications for underwater robots are vast, however the most immediate and demanding needs are in the areas of oil and gas, mineral exploration, underwater data collection, search and rescue, monitoring sea life and underwater environmental changes, and military and defense.
Companies like Liquid Robotics, Bluefin Robotics, Atlas Maridan, Deep Ocean Engineering, and Teledyne are already pursuing these opportunities. With their Autonomous Underwater Vehicles (AUVs), Bluefin Robotics and Atlas Maridan are focused on various commercial, defense and scientific applications. Liquid Robotics is more specialized on oceanic observation, making data collection and monitoring easier, safer, and more cost-effective by using wave energy and stored solar energy in their wave gliders. Meanwhile, Deep Ocean Engineering and Teledyne are more focused on the development of Remotely Operated Vehicles (ROVs) for various underwater applications from ship hull inspection to underwater lost treasure hunting. Open source and community-based projects like OpenROV is another way to create more accessible, affordable systems for underwater exploration.
Most underwater robots have now achieved a certain degree of flexibility in their motion with superior navigation, imaging, and sensing that enable them to perform much better than was previously possible, but still not good enough in terms of reliability, mingling with sea life and tackling unknown problems. There are huge challenges in front of research labs and companies that are building underwater robots. Those challenges are as follows.
- Underwater Communications
Underwater communication systems involve the transmission of information in the form of sound, electromagnetic (EM), or free-space optical (FSO) waves. Sound waves in shallow water can be adversely affected by temperature gradients and surface ambient noise. Electromagnetic waves do not work well in an underwater environment due to the conducting nature of the medium, especially in the case of seawater. Free-space optical waves used as wireless communication carriers are generally limited to very short distances. Moreover, high power levels are needed for underwater communication due to more complex signal processing.
- Positioning Measurements
Marine navigation has always faced the challenge of obtaining precise positioning, and this is especially true in underwater environments. In air (aerial, terrestrial or surface), the geo-referenced positioning is facilitated by the use of GPS information. Underwater, GPS fails to provide location and time information. There are a few solutions available to mitigate this problem such as commercially available GPS Intelligent Buoys, but much work remains to be done toward the development of more robust and cost-effective underwater positioning system capable of yielding adequate performance.
- Mid-Depth Zone Navigation
There have been some improvements in the surface and near-bottom navigation by the underwater robots currently available, but still, mid-depth zone (the water depth zone that is far from the sea surface and far from the seafloor) navigation has not improved significantly. This severely limits the navigational and exploration capabilities of the robot. At this time, there are not sufficient commercially available sensors that can work at this mid-depth for precise and accurate measurements.
- Unpredictable Disturbances
Environmental disturbances due to weather changes, waves, wind, and ocean currents have a significant impact on underwater robot motion and stability. Such environmental disturbances play an important role in defining the degree of autonomous behavior and mission planning in underwater robots. The odds of encountering a totally new problem in the underwater environment are extremely high. Efficient maneuvering and obstacle avoidance by the robot are big challenges for the robot under unpredictable scenarios.
The global underwater robot market is expected to grow at a compound annual growth rate (CAGR) of around 7% over the next 5 years and, according to various reports, one of the main drivers for the underwater robotics market is the exploration of undersea minerals. The global mining industry has the deep pockets and motivations to pursue deep undersea mining operations. The development of cost-effective underwater robots running on natural renewable energy has already started to gain pace. However, it will be a herculean task for underwater robots to meet expectations and discover the new worlds within our world until the major challenges are solved.