Abstract: One of the major respects of the autonomous capability of underwater robots in unknown environment is to be capable of global path planning and obstacles avoiding when encountering abrupt events. For the Spherical Underwater Robot (SUR) to fulfill autonomous task execution, this paper proposed a novel fuzzy control method that incorporates multi-sensor technology to guide underwater robots in unknown environment. To attain the objective, a SUR we designed is used to design the controller. According to its kinematic model, the safety distance was calculated and sensors (US1000-21A) were arranged. The novel fuzzy control method was then explored for robot’s path planning in an unknown environment through simulation. The simulation results demonstrate the capability of the proposed method to guide the robot, and to generate a safe and smooth trajectory in an unknown environment. The effectiveness of the proposed method was further verified through experiments with a SUR in a real platform. The real environment experiments by using the novel fuzzy control method were compared with the basic control method. The experimental results show that in unknown environments, the proposed method improves the execution efficiency and flexibility of the SUR.

Key words: path planning, fuzzy control, spherical underwater robot, unknown environment