Control and design of a 3 DOF fish robot ‘ICHTUS’

Abstract

Recently, there is a rising interest on studying fish-like underwater robots because of real fish's great maneuverability and high energy efficiency. However, the researches about the fish-like underwater robots have not been done so much and there are still diverse problems in respect of using of the fish robot in the real environment such as in the river. For example, the fish robot has a short operating time and cannot move narrow passage such as swimming between aquatic plants. Therefore, this paper mainly describes a control method according to propulsion algorithm for improving energy efficiency and obstacle avoidance. The fish robot 'Ichthus' has a 3-DOF serial link-mechanism and is developed in KITECH. Also, we propose a dynamic equation of the fish robot to use the underwater environment. In the control portion, response characteristics of the fish robot were analyzed according to the input parameters of tail fin's amplitude and oscillation frequency. In consequence of this result, Control parameters of robot fish were found. These parameters are useful to increase energy efficiency and it can be used when the fish robot moves in the real environment.

Robotic Fish Propelled by a Servo Motor and Ionic Polymer-Metal Composite Hybrid Tail

“…Since various real-life environmental tasks require different characteristics, many groups have developed different types of robotic fish [6][7][8][9][10][11][12][13]. To achieve high agility in water, some robotic fish, including soft-body and multiple-link tails [14][15][16][17], use multiple actuators or a compliant actuation mechanism to make the body-tail more flexible. For example, Nakabayashi et al investigated robotic fish propulsion using a fin connected with a variable-effective-length spring [18].…”

Three-Dimensional Modeling of a Robotic Fish Based on Real Carp Locomotion

“…As it is known, many kinds of fish perform high-efficiently locomotion and maneuvering in the water. Propulsion efficiencies of the rotary propeller AUVs are limited below 70%, while the swimming mechanism of a real fish is 20% more efficient than rotary propellers [6]. In addition, the turning radius of propellers is big and speed performances are low.…”

“…In addition, the turning radius of propellers is big and speed performances are low. Therefore, this kind of propulsion is more noisy and ineffective than bio-inspired systems [6,7]. These advantages have great benefit for marine applications and fish-like robots have evolved to provide versatile solutions for a wide variety of underwater applications, such as undersea investigation, pollution detection, deep sea monitoring and mapping, military operations and protections, etc.…”

Mechatronic Design and Manufacturing of the Intelligent Robotic Fish for Bio-Inspired Swimming Modes

“…In ichthyology, more than 85% of fish swim by bending their bodies and/or caudal fins (BCF) and about 15% of fish swim by median and/or pectoral fins (MPF). Also, Carangiform swimming mode is the most common BCF locomotion type of the fish which uses undulatory motions [18][19][20]. These biological properties indicate that BCF type Carangiform robot model is an appropriate approach for AUV design.…”