Work class remote operated vehicles (ROVs) are generally equipped with underwater manipulators and are widely used in underwater intervention and maintenance tasks. As the load of underwater operation is relatively heavy, most commercial underwater manipulators are hydraulically actuated and are not equipped with any sensor for joint angles to keep their architectures compact. Therefore, the automatic control methods widely used in industrial robots cannot be simply applied to underwater manipulators. In this paper, an estimation method on joint angles of manipulator is presented, in which several markers are arranged on the arm links and positioned from the corresponding cameras; consequently, the joint angles of the manipulator are estimated. The simulation results show that under typical optical vision positioning error (RMS: 5 mm), the positioning error of the end effector can be estimated as about 10 mm (RMS), which means that the proposed estimation method is feasible for the state estimation for automatic control of underwater manipulators.

中文翻译：

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基于视觉定位的水下机械臂状态估计方法及其仿真研究

工作级别的遥控车辆（ROV）通常配备水下操纵器，并广泛用于水下干预和维护任务。由于水下操作的负担比较重，因此大多数商用水下操纵器都是液压驱动的，并且没有配备用于关节角度的任何传感器以保持其结构紧凑。因此，在工业机器人中广泛使用的自动控制方法不能简单地应用于水下机械手。提出了一种估计机械手关节角度的方法，该方法在手臂连杆上布置多个标记，并从相应的摄像头定位。因此，估计了机械手的关节角度。仿真结果表明，在典型的光学视觉定位误差（RMS：5 mm）下，