A Fuzzy Control Based Robotic Fish with Multiple Actuators

[[abstract]]This paper shows an application of fuzzy logic in designing and fabricating an intelligent robotic fish with multiple actuators which can swim freely and autonomously avoid obstacles in water. The multiple actuators on the robotic fish consist of two pectoral fins, one on each side of the fish, two tail sections, a center of gravity adjuster for the head of the fish, and a pump used to draw in or expel water. Based on the multiple actuators having adequate controls, the fish can swim forward, turn to the right, turn to the left, rise, and sink with high agility. The two main functions of the robotic fish are obstacle avoidance and target tracking. The distance between the fish and the obstacle is detected and measured by four infrared sensors on the fish's body. The fish can then avoid the obstacle autonomously when it approaches the obstacle. Obstacle avoidance is achieved using fuzzy control technique. As shown in the simulation and practical experiment, the path of obstacle avoidance using fuzzy control is much smoother than that using intuitive control. The other function is target tracking, in which the robotic tracker fish can track the robotic target fish autonomously and due to the obstacle avoidance function the two will not collide. All of the above motion controls are implemented by FPGA with the aids of several sensors.[[note]]SC