Robotic fish: Opening a new era of underwater detection

Escalating competition within aquatic environments, particularly in oceans, underscores the imperative for innovative solutions in underwater operations. These solutions necessitate the development of intelligent underwater equipment, with robotic fish emerging as a promising contender. Leveraging advancements in robotics and artificial intelligence, robotic fish offer a suite of advantages that position them as transformative assets in underwater exploration and operations. Robotic fish are autonomous robots designed based on biomimetics principles that mimic the appearance of fish and can autonomously swim and perform specific tasks in water. The robot exhibits notable advantages, including high propulsion efficiency, robust maneuverability, effective concealment, low noise emission, and minimal environmental impact. These attributes position robotic fish as viable substitutes for manual long-term operations in heavily polluted, high-risk, and low-visibility waters, thereby addressing the vulnerabilities inherent in traditional propeller drives. Consequently, research into robotic fish has gained significant attention among scholars globally, as shown in Figure 1.

The streamlined body structure of robotic fish facilitates propulsion through tail oscillation or body undulation, endowing them with high maneuverability and the capability for agile navigation even in narrow passages. The current mainstream dynamic mode of robotic fish is to use the propulsion provided by the caudal fin drive and the assistance of the pectoral fins to achieve straight, turning, and diving movements. Through diversified transmission structures, intelligent materials, and modular design, the motion characteristics of biological fish can be better simulated. By utilizing robust and highly adaptable control algorithms, the performance indicators of robotic fish can meet different task requirements. Furthermore, leveraging biomimetic characteristics reminiscent of fish, robotic fish demonstrate considerable potential applications in resource exploration, water-quality monitoring, fault detection, and military reconnaissance missions.