Suction Force Control of Non-Contact Swirling Suction Cup Based Robot Adhesion Foot

The underwater adhesion technology is crucial for enabling underwater robots to perform inspection and maintenance of large underwater facilities such as dams and hydropower stations. To address the challenge of underwater adhesion in high velocity flow environment with potential turbulent disturbances, this paper proposes an active-passive disturbance rejection control method for a non-contact swirling suction cup-based robot adhesion foot module, allowing an adaptive suction force control. A fuzzy PID control algorithm is implemented to derive the desired suction force by maintaining gap equilibrium, while a feedforward PI controller regulates the actual suction cup output accordingly. Simulation and experimental results demonstrate that the proposed control strategy effectively mitigates both step and sinusoidal disturbances, ensuring stable adhesion and preventing detachment. Future study could be conducted to reveal possible unmodeled dynamics and refine system model through further real-world experiments in complex underwater environments.