Fault-tolerant heading control for a bionic gliding robotic dolphin with flipper faults

This paper presents a fault-tolerant heading-control method for a bionic gliding robotic dolphin operating in the presence of flipper faults. To achieve both high manoeuvrability and long endurance, a bionic gliding robotic dolphin that integrates the propulsion modes of dolphins and underwater gliders is introduced. The operational conditions of the flippers are considered meticulously, and common fault types that can arise during the gliding process, such as stuck, failure, and efficiency-loss faults, are analysed. These faults can affect the heading capabilities of the gliding robotic dolphin. To ensure normal navigation in the presence of flipper faults, a fault-tolerant heading control method is devised for the gliding robotic dolphin. This method applies backstepping sliding control to establish control laws based on a dynamic model. Subsequently, a flipper angle solver is designed to convert the controller outputs into deflection angles for the flippers. Simulation results obtained under three typical flipper faults demonstrate the effectiveness of the proposed fault-tolerant control method. This fault-tolerant control method ensures the safety of gliding robotic dolphins under complex deep-sea conditions.