Development of a Robotic Arm for Mini-Class ROV Dexterous Manipulation

Dexterous underwater manipulator arms in common use are bulky and expensive, requiring large vehicles to support them. Manipulators for Mini-Class ROVs (∼15 kg) are typically constrained to 1 or 2 degrees of freedom, limiting their use to simple tasks. Consequently, for underwater activities requiring complex manipulation, either large vehicles or human divers must be used, which can be resource-intensive or dangerous. This paper describes a prototype miniaturized manipulator arm that enables dexterous manipulation capability for small underwater vehicles. The current prototype underwater mini-arm is a 6 degree of freedom robotic arm constructed of three identical wireless dual actuator units. Each actuator is a self-contained system including motors, gearboxes, seals, a battery, and custom circuitry for motor control, wireless communication, and wireless charging. As there is no external wire harnessing, the actuators are continuously rotatable and can be connected by solely mechanical links. This underwater manipulator arm represents miniaturized sampling capabilities as a key technology development for both Ocean Worlds and the Mini-Class ROV market.