Design and Development of a Fish-Like, Soft Biomimetic Robot

Abstract Among the robotic systems, biomimetic robots performing fish-like locomotion have been the focus of much attention recently as there are many applications for swimming robots, including monitoring of underwater environments, detection of pollution, and disaster relief. This study presents the design and development of a biomimetic fish-like robot based on real carp locomotion. The robot has five main body parts including the head, soft neck, hinged body, compliant tail, and caudal fin. The head houses three ultrasonic sensors to guide the robot while connected to the body through two degrees of freedom (DOF) soft link resembling the neck vertebrate. The 2 DOF soft link enables the head to bend up, down, left, and right which is essential for controlling the soft robot’s direction. The body is connected to the soft tail using a quick return crank mechanism to actuate the tail. The tail integrates a soft tail and a rigid caudal fin. While all parts of the soft fish-like robot are 3D printed using polylactic acid (PLA), thermoplastic polyurethane (TPU), the mold is made from silicone rubber to waterproof. The ultrasonic sensors are utilized to detect obstacles so that the robot may maneuver around. The swimming pattern only for two-dimensional motion is tested in the air and underwater. According to the experimental results, the proposed robot better imitates the fish through its soft 2 DOF link and tail.