Bio-inspired, soft and smart robotics

The robotic fish emulates the movement of a live fish and utilizes the emerging field of soft robotics. Credit: Ann Hermes/The Christian Science Monitor via Getty Images

Soft robotics are burrowing their way into industries from medicine to deepsea mining. Claudio Flores and Danilo Flores, founders of innovation consultancy Kybernesia, depict a futuristic scenario that applies this groundbreaking technology to dredging

Imagine that a retrofitted suction hopper dredger is about to commence operations. The vessel is tasked with deepening the basin of a new liquefied natural gas terminal along the Northern Sea Route in the pristine Arctic waters close to Franz Josef Land. The suction pipes underneath move with a surgical precision along the seabed, gulping up the silt with great efficiency. Manta ray-shaped autonomous underwater vehicles (AUVs) observe this spectacle that is reminiscent of the dance of two gigantic sea snakes.

The blinking lights of the school of drones betray lively communication among each other; if the sand clouds swirled up are too misty for the optical channel, the swarm switches to short-range acoustic. It is their job to monitor the environmental effect of the dredging operation in real time and send compliance reports to the non-governmental organisation charged with assessing the ecological consequence of the project. The undertaking had only been greenlighted under the condition that in situ turbidity tracking is performed at all times to ensure that the arctic fauna remains undisturbed. Were it not for the advanced soft robotics’ dredging capabilities, a project in a delicate environment like this would have been impossible.

This scenario is a piece of design fiction, a new foresight tool that proactively pictures a desired future timeline rather than try to derive trends from the present. In this case, it considers how dredging could be undertaken if soft robotics were used in its operations. Soft robotics is an emerging paradigm in the bio-inspired robotics field. Rather than being composed of rigid, metallic skeletons, the robots of the future could well be more akin to squishy, malleable, and morphologically adaptive biological organisms found across terrestrial and marine ecosystems – think snakes, octopuses, or jellyfish. This highly interdisciplinary field draws together materials scientists, mechanical and biomedical engineers, and intelligent systems researchers.

Often, the inspiration for the design and implementation via advanced bio-materials of many soft robotic systems comes from nature. Soft robots are made from soft, elastic materials and offer unique opportunities in various applications and extreme environments that are unsuitable and impractical with conventional rigid robots. Such examples include pipeline inspection; emergency search-and-rescue response after earthquakes, where survivors have to be located among inaccessible piles of rubble; or maritime-related operations such as deepsea exploration.

Aquatic influencers

In fact, soft robotics development projects have been tied to oceanographic research from the very inception of this field. Since then, the amazing feats of aquatic organisms have provided a treasure trove of inspiration for the roboteers. This field has also influenced ideas of how highly miniaturised soft robotics could be applied in a biomedical context: drug delivery, non-invasive surgical procedures, assistive devices, prostheses, or artificial organs.

Flagship initiatives in soft robotics are under way at engineering schools and startups. Often, the research is funded by military agencies such as the US Defense Advanced Research Projects Agency, hinting at the dual-use potential of the new breed of compliant robots.

The Wyss Institute at Harvard University, for example, is working on fluid-driven origami-inspired artificial muscles that add strength to soft robots, enabling them to lift objects that are up to 1,000 times their own weight. The muscles are made of a foldable scaffold and a liquid or air medium sheathed in a flexible skin. Contractive and expansive muscle motions are powered by pressure differences. The artificial muscles can grip, lift, and twist objects. While these prototypes are designed for terrestrial use, other projects are working on letting robots loose in aquatic environments.

Eelume, a spin-off from the Norwegian University of Science and Technology, is crafting a snake robot for subsea inspection, maintenance, and repair. Besides acting as a long-range survey AUV, the eel-like contraption can assume a U-shape and act as a dexterous robotic arm with two manipulators mounted on each end of its body. Highly modular and designed for various situations, its slender shape allows the vehicle to reach into the hidden recesses of underwater structures and areas that would otherwise remain inaccessible to human intervention.

Breeze Automation from San Francisco showcased a radical new approach to robotic design. Its contract work for NASA and the US Navy has given birth to a fully pneumatic robotic arm that used airflows to actuate movements. According to founder Gui Cavalcanti, the advantage of a robot with a fully soft core – compared with a robot possessing merely a soft-end effector – was the added flexibility when navigating around and interacting with real-world environments that are more unpredictable and unstructured than laboratory settings.

What does the soft robotics revolution hold in store for the dredging industry? In the future, we might see bio-inspired soft robotics AUV fleets that deliver real-time environmental monitoring of indicators, such as water quality or sediment proxies to ensure that disturbance to the ecosystem during capital dredging operations remains within a permissible range.

Also, these autonomous underwater patrols could check-up on waterways and channels to assess siltation over time and optimise maintenance dredging schedules. In a more ambitious scenario, we may envision highly dirigible soft robotics-enhanced suction hoses made from advanced polymer materials suspended from next-generation dredgers. Such pipes might contract, expand, and swivel, thus unbinding the vessels above from conventional manoeuvring restrictions.

The industry should be ready for flexible, highly durable polymer-based suction tubes with a ‘smart’ array of actuators for increased degrees of freedom when dredging, and dredge heads for burrowing and digging, inspired by earthworms and mole crickets.

Suction techniques may also take inspiration from aquatic lifeforms, such as the octopus’s beak or remora fish’s suction disc. In principal, such systems can be conceived, designed, and prototyped within current technology-readiness levels, since many of the described components have already been reviewed in biomimetics journals over the years. Advanced autonomous platforms have been realised within the nascent deepsea mining enterprise and dredging should definitely keep an eye out on developments in the industrial deployment of soft robotics.