Aiming at the difficulty in locating and identifying the faults of oil-immersed transformers, a new spherical submersible transformer inspection robot is designed. The robot has a spherical structure with a zero turn radius, which ensures its flexible motion. It is a difficult problem for the underactuated spherical robot to realize the hovering control for identifying transformer fault points. To address the problem, the dynamic model and kinematics equations of the robot are derived by the hydrodynamic theory at first. Then, an adaptive sliding mode backstepping control (ASMBC) is used to design the cascade control system. The cascade control system consists of the depth control and the yaw control. The performance of the controller is verified by both simulation and real experiments. The simulation experimental results demonstrate that ASMBC controller is superior to the single neuron PID. The tank trial results show that the movement of the robot is flexible, and the hover control can satisfy the requirement of fault observation tasks.
- Oil-immersed transformer
- dynamic model
- sliding mode backstepping control