Page 517 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

514 CHAPTER 19 Manipulators
(b)
FIGURE 19.12
(a)
(a) SeaBotix vehicle with grabber and (b) various end effectors.
19.1.2.9 Sensors and controller
(Courtesy SeaBotix.)
The interface between the robot and the human is the controller (sometimes termed the “OCU” for operator control unit as used in industrial robotics). The controller can range in complexity from a simple three-position “fail-to-center” open/off/close switch to a complicated position-controlled dexterous arm controller with force feedback.
By far the biggest issue with controlling a manipulator arm is the lack of sensory feedback from the environment to the operator. An additional difficulty of operating a manipulator arm subsea is the lack of stereoscopic vision when viewing operations through a typical single-channel camera. Most manipulator operators term the simple remote operation of a manipulator system (as well as the entire vehicle for that matter) as “looking at the world through a single drinking straw.” The advent of force feedback has allowed more sensory perception to circle back to the operator while stereo and 3D camera systems, along with positional indicators (and inertial sensors), assist enor- mously in delicate remote tasks. Technology is constantly evolving, thus allowing for more realistic telepresence. While man-in-the-environment is still far superior in sensory perception to that of tele- presence (with current technology), the advent of tooling interface standards allows for complicated tasks to be performed through simple and common interfaces.