# Octopus Predation-Inspired Underwater Robot Capable of Adsorption through Opening and Closing Claws
###### Abstract  
Underwater unmanned robots are an essential tool for human underwater exploration and detection and are widely employed in a variety of underwater operational settings. One of the hottest issues in this field is applying bionic notions to the creation of underwater unmanned robots by simulating fish swimming or cephalopod crawling. Using the tentacle suction cup adsorption technique during octopus' predation as a model, underwater magnetic adsorption robots with the opening and closing claws were studied in this paper. First, the robot's general structural design is presented. The claw mechanism is demonstrated by mimicking the octopus's tentacle action during feeding, which primarily consists of an opening and closing claw that replicates the octopus's tentacle and a magnetic adsorption unit that replicates the octopus's suction cup adsorption. Then, the Kriging response surface optimization method is used to optimize the design of the claw mechanism to obtain excellent mechanical properties, and simulation software is used to verify. Finally, a robot prototype was built and its pool tests were conducted, with some experimental results presented. The experimental results show that after the robot reaches the predetermined position through pneumatic ejection and secondary propulsion launch, it can quickly open its claws within 0.11 s and apply 462.42 N adsorption force to complete the adsorption of the target. bionic octopus; predator adsorption mechanism; underwater robots; kriging response surface optimization method; pool experiment +
Footnote †: journal:crawling of octopuses, were employed by [PERSON] et al. in their kinetic modeling of underwater soft robotics [12]. An eight-armed soft robot was created by [PERSON] et al., and its performance was assessed by experiments. The bionic octopus idea was applied by an eight-armed soft robot, which combines eight radially extending limbs with a central body housing primary processing units. The primary functions of the forearms are grabbing and extending, whereas the other muscles are involved in movement. The outcomes of the experiment demonstrate that the robot modeled like an octopus can walk in water by employing the same technique as the animal model and that, because of its conical form and soft arm material, it can grip things of all sizes and shapes [13]. Inspired by the gripping behavior of octopuses, [PERSON] and [PERSON], et al. presented a solution for grasping and movement in soft robots. The octopus arm muscles were mimicked by fabricating a silicone arm with wires inserted in it. The new arm can move in a propulsion-based manner and grip items, like the crawling motions of an octopus [14]. At present, the majority of octopus-inspired underwater robot designs mimic the movement of their tentacles to enable them to adapt to the complex underwater environment. Only a small percentage of these designs refer to the tentacles' flexibility to design robotic hands that perform well in gripping, and very few mimic the octopus suction cup adsorption of biomimetic design. This paper presents the design of an octopus predation-inspired underwater robot capable of adsorption through opening and closing claws. The design was inspired by the opening tentacles of octopuses, which employ suction cups to adsorb food as they feed on prey. The robot's claw mechanism is made up of two parts: the design of the opening and closing claws, which mimics the octopus's tentacles, and the design of the magnetic adsorption unit, which is modeled after the suction cups found on the octopus's tentacles. The basic construction of the robot, which has an overall length of around 370 mm, is made up of three components: the propulsion module, the power module, and the claw mechanism. The interior of the capsule can also hold mission payload systems, such as reconnaissance modules. An underwater unmanned vehicle (UUV) moves the robot to a prearranged location, and the UUV's launcher propels it toward the target.