Design and Image Tracking Control of Underwater Manipulator

In the face of high-risk and unpredictable ocean conditions, it is impractical to send divers for underwater exploration. This research aims to develop a small and highly nimble underwater manipulator system. Additionally, an Underwater Vision Sensing System was used to distinguish the trajectory of the target through cameras, and to perform target grabs and retrieval work using unmanned underwater manipulator. The underwater multi-axis manipulator in this study used spatial coordinate transformation to calculate the forward and inverse kinematics of the manipulator. In addition, the appropriate movement posture that matches the manipulator was selected through condition filters, enabling the manipulators to achieve desired target position. In terms of control, LabView, a graphical programming platform, was used to design the user interface, and the gyroscope measured the angle error of the manipulators and fed it back to the controllers. There are two types of servo motor controllers tested in this research: a feedforward proportional-integral-derivative (PID) controller and a Gain-Scheduled PID controller. The gyroscopic measurement results showed that using Gain-Scheduled PID Controller provides higher accuracy than the others controller. This study applies existing underwater manipulator control theories to develop and modify the motion-controlling system through simulation and actual operation. The contribution of this research will expand the application of underwater exploration in both academic and industrial fields.