Force Control of Swirling Sucker for Underwater Concrete Drilling Robot

Underwater concrete drilling is essential for underwater structure leakage management. However, in practice, underwater concrete drillings are usually performed by professional divers, whose efficiency is low when operating on depth limit. In this paper, a suction force control system to control a swirling sucker is proposed, which is used to provide stable suction force during the drilling operation for underwater drilling robots. First, a mathematical model of the sucker system is established through system identification. Second, drilling force control system framework is proposed, including an estimator for the drilling force estimation, and a sliding-mode controller to control the suction force and reject drilling force disturbances. A testbed is constructed, and the experimental results show that the proposed control system can respond well to disturbances and maintain the drilling stability.