A vehicle that has artificial intelligence but can also be controlled by a human user if needed, usually to solve problems that the AI cannot. These types of vehicle are typically unmanned and controlled in a fly-by-wire fashion either by radio or sometimes using fibre optic cables attached as an umbilical. Not restricted to any one type of vehicle, but typically used for aircraft and submersibles. Also referred to as a SAV and its underwater equivalent is a SAUV.

This comment helps explain why these types of vehicles have been created:

Manned submersibles or remotely operated vehicles are costly because the operations must be commanded from a ship, with all the accompanying costs and risks of taking a ship to sea. The performance of these vehicles also depends largely on the skill of human operators and such factors as time delays within the man-machine control loop in the hazardous marine environment.

A solution to these shortcomings could be found in semi-autonomous underwater vehicles, which would be pre-programmed to conduct their undersea missions and would also roam free of human operation unless deemed necessary.

--- Adapted from: Xtreme engineering. Semi-Autonomous Underwater Vehicles. http://xtreme.eng.hawaii.edu/research-projects/sauv/. College of Engineering University of Hawai’I at Monoa. Accessed: 00:42 GMT 27 March 2004.

The vehicles typically sport technologies such as ladar, sonar and cameras.

Typical uses from these vehicles are: