Soft Underwater Robot Actuated by Shape-Memory Alloys “JellyRobcib” for Path Tracking through Fuzzy Visual Control

Abstract

Recent developments in bioinspired technologies combined with the advance of intelligent and soft materials have allowed soft robots to replicate the behavior of different animal species. These devices can perform complicated tasks such as reaching or adapting in constrained and unstructured environments. This article proposes a methodology to develop a soft robot called “JellyRobcib” inspired in morphology and behavior by jellyfish, using shape-memory alloy springs as actuators (as bio-muscles). Such actuators can move the jellyfish both vertically and laterally by applying closed-loop fuzzy and visual controls. Additionally, Computer-Assisted Designs and Computational Fluid Dynamics simulations have been carried out to validate the soft robot model. The results show that the robot movements are very close to the morphological behavior of a real jellyfish regarding the curves of displacements, speeds and accelerations, after performing several experiments for autonomous movement: vertical ascent, lateral movements and trajectory tracking, obtaining an accuracy of ±1479 cm and repeatability of 0.944 for lateral movements for fuzzy visual control. Furthermore, thermal measurements were taken throughout a given path, allowing the generation of temperature gradients within the underwater environment for monitoring purposes.

An Intermetallic NiTi-Based Shape Memory Coil Spring for Actuator Technologies

“…Electrically driven tiny/micro-sized smart robotic actuators made with NiTi-based SMAs can perform natural sensitive biomimicking gesticulations like walking, jumping, climbing, whirling, and swimming. The advantages of using NiTi as one of the base materials is its corrosion resistibility and lightweight characteristics, especially when used in marine environments [67][68][69]. It is not surprising that SMAs ubiquitously reached technological maturity with promising industrial engineering applications in the mechatronics field amongst various smart materials.…”

Development of an Actuator for Translatory Movement by Means of a Detented Switching Shaft Based on a Shape Memory Alloy Wire for Repeatable Mechanical Positioning

“…The SMA wire generates the required rotation of the shaft. If the applied voltage heats the wire (19), it activates and contracts. The shift fork (14) moves over the carriage (15) in the X direction.…”

“…The resulting reduction 2 of 16 in weight and installation space also makes the SMA actuator systems interesting for the aviation [15] and automotive industries [16,17]. Recently, soft robotic applications have become more and more focused upon [18][19][20][21][22]. For those applications, the shape memory actuator must be able to generate different strokes besides the two positions "fully activated" and "fully reset" [23][24][25].…”

An Android and Arduino Based Low-Cost Educational Robot with Applied Intelligent Control and Machine Learning

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