The extreme conditions of the deep sea require the use of large and expensive diving robots designed to withstand the high pressure in these depths. In order to reduce the costs for sediment sampling in the deep sea and thus facilitate the explorations of rare deep-sea ecosystems, the goal of this research is to design an alternative manipulator for deep-sea suction sampling. Instead of relying on heavy hydraulic rigid manipulators that deep-sea diving robots are commonly equipped with, we introduce a new concept for a lightweight actuation system that can be used in combination with a traditional diving robot and a suction sampling system. The proposed concept consists of a series of rigid links connected by angled swivel joints. Each segment is actuated by tendons, which allows for continuous bending. The system can be adapted to various sizes of host systems, and the links and joints are printed in place, simplifying the manufacturing process.

Deep-sea research represents invaluable opportunities to unravel hidden ecosystems, uncover unknown biodiversity, and provide critical insights into the Earth’s history and the impacts of climate change. Due to the extreme conditions, exploring the deep-sea traditionally requires costly equipment, such as specific diving robots, engineered to withstand the high pressure. Our research aims to reduce the costs of deep-sea sediment sampling by introducing a novel actuation system for suction samplers, that capitalises the advantages of soft material actuators. At first glance, soft material actuators may not appear suitable for the harsh conditions that prevail in the deep-sea, but when combined with a rigid, bistable mechanism there is great potential for improving the accessibility of sampling and research in this challenging environment. The binary actuation system that results from this combination, is modular, scalable, lightweight, and low cost in comparison to existing solutions.

Soft Robotics has established itself as an integral field in the broader discipline of general robotics through multiple advantages like inherent safety, adaptable morphology, and energy- and weight efficiency. Especially in environments hostile to humans and classical robots like the deep sea, soft robotic structures made out of silicone and actuated by seawater have numerous advantages. An application with a huge scientific and commercial potential for soft robotic solutions is suction sampling for marine geology in depths of up to 6000 m. In this paper, we propose a single channel soft robotic actuator that is able to bend into six directions while absorbing process forces. By embedding a low melting point alloy (LMPA) acting as switchable strain-limiting structures, the actuator is capable of hexa-planar bending of up to 40° and elongation of 30 % with only one valve used for actuation. In addition, the LMPA chambers enable a stiffening factor of 4.1 and locking the actuator in its bending state for energy efficient usage in robotic deep-sea suction sampling.