Research on underwater robot localization method based on the fusion of monocular camera and IMU

Underwater robots need to perform accurate positioning to complete their operations. However, the current commonly used underwater positioning methods are expensive, difficult to operate, and complex to recover. In response to the above problems, this paper combined the advantages of the Inertial Measurement Unit (IMU) with strong concealment and stability, low camera cost and high accuracy in a small range, and applied a positioning technology based on the fusion of monocular camera and inertial measurement unit to underwater robots. In this method, the IMU will obtain high-frequency internal motion information of the robot, while the camera can obtain rich visual information. Using the VINS-Mono framework, the image information collected by the monocular camera could be fused with the IMU data to construct a monocular vision/IMU’s tightly coupled nonlinear optimization model. Finally, the model was evaluated through experiments in the underwater environment, and it was proved that the model could meet the high-precision positioning requirements of underwater robots in a small range of shallow waters.