Kraken: A wirelessly controlled octopus-like hybrid robot utilizing stepper motors and fishing line artificial muscle for grasping underwater

Abstract

Underwater exploration or inspection requires suitable robotic systems capable of maneuvering, manipulating objects, and operating untethered in complex environmental conditions. Traditional robots have been used to perform many tasks underwater. However, they have limited degrees of freedom, manipulation capabilities, portability, and have disruptive interactions with aquatic life. Research in soft robotics seeks to incorporate ideas of the natural flexibility and agility of aquatic species into man-made technologies to improve the current capabilities of robots using biomimetics. In this paper, we present a novel design, fabrication, and testing results of an underwater robot known as Kraken that has tentacles to mimic the arm movement of an octopus. To control the arm motion, Kraken utilizes a hybrid actuation technology consisting of stepper motors and twisted and a coiled fishing line polymer muscle (TCP FL ). TCPs are becoming one of the promising actuation technologies due to their high actuation stroke, high force, light weight, and low cost. We have studied different arm stiffness configurations of the tentacles tailored to operate in different modalities (curling, twisting, and bending), to control the shape of the tentacles and grasp irregular objects delicately. Kraken uses an onboard battery, a wireless programmable joystick, a buoyancy system for depth control, all housed in a three-layer 3D printed dome-like structure. Here, we present Kraken fully functioning underwater in an Olympic-size swimming pool using its servo actuated tentacles and other test results on the TCP FL actuated tentacles in a laboratory setting. This is the first time that an embedded TCP FL actuator within elastomer has been proposed for the tentacles of an octopus-like robot along with the performance of the structures. Further, as a case study, we showed the functionality of the robot in grasping objects underwater for field robotics applications.

Soft Wearable Rehabilitation Robots with Artificial Muscles based on Smart Materials: A Review

“…The actuator works by converting a temperature change into strain or stress. In general, TCP actuators are driven by Joule heating (Figure 7a), adding a layer of a conductive material (e.g., silver) over the precursor fiber [74,75] or by embedding a resistance wire within the actuator [76,77] (Figure 7b). Consequently, the actuator can be modeled as an electrothermal-mechanical system.…”

Focus Control System of a Celestron 2000 Telescope Based on Arduino for Remote Observations in Astronomy Laboratory Department of Physics Universitas Negeri Malang

“…The stepper motor can precisely rotate [15][16]. Therefore, stepper motors are often used in devices requiring high precision, such as in robotic applications [17] and surgical robots [18]. Another advantage of the stepper motor is that it can be an option when a device requires a movement that can be controlled [18] using an Arduino.…”

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“…Furthermore, their muscle-like properties and various methods of cooling them for faster movement prove their relevance in robotic applications [18]. Fishing line muscles (TCPFL) are similar to silver-coated TCP (TCPAg) muscles in terms of fabrication and manufacturing, but they are developed from a monofilament nylon 6 fishing line rather than a thread, allowing them to produce higher actuation in particular cases, which have been demonstrated in underwater soft robotics [19].…”