What functions are typically required for underwater robot manipulator systems?

Okay, no problem.

You can imagine an underwater robot manipulator as our own arm, but it's stronger and can swap out various "hands" to perform different tasks. Essentially, it needs to have several core capabilities:

First, the most basic and important, is the ability to "grip" things. Just like our hands, it needs to be able to open and close, grab underwater objects, lift them, and then release them. This "hand" is quite special; depending on the task, it can be replaced with simple two-finger grippers, more complex five-finger dexterous hands, or even specialized hooks or nets for retrieving ropes.

Second, it must have "flexible movement". Being able to grip isn't enough; it needs to be able to reach the target location. So, the manipulator needs joints, just like our shoulders, elbows, and wrists. The more joints it has, the more flexible it becomes, allowing it to reach into various nooks and crannies to perform work. In technical terms, this is called "degrees of freedom" (DOF); the higher the DOF, the more agile its posture, and the more complex operations it can accomplish.

Third, it needs "senses" and "eyes". During underwater operations, the operator is far away on a ship or shore, unable to see or touch directly. Therefore, the manipulator usually needs to be equipped with cameras, which serve as its "eyes," allowing the operator to see the real-time situation. At the same time, it also needs force feedback capabilities, its "sense of touch." This allows the operator to feel how much force is being applied when gripping something, whether it's grabbing a rock or crushing an egg, preventing excessive force from damaging objects.

Fourth, and also a crucial point, is the ability to "change tools for various chores". Besides gripping, many times more specialized work is required. In such cases, the manipulator's end-effector "hand" can be replaced with various specialized tools, such as:

• Cutters: Used to cut underwater ropes, cables, or pipelines.
• Cleaning brushes: To clean marine fouling from ship hulls, pipelines, or offshore platform legs.
• Samplers: For example, using a small shovel to collect seabed sediment, or a drill to take rock samples.
• Wrenches/Screwdrivers: Used to tighten or loosen bolts when installing or disassembling equipment underwater.

So, in summary, a qualified manipulator system is an "underwater Swiss Army knife" that integrates gripping, movement, sensing, and multi-functional tools, enabling robots to perform various complex tasks in the deep sea, just like a human diver, where we cannot go.