Like the human limbs which inspired them most robots are discrete mechanisms with rigid links connected by single degree of freedom joints. In contrast, 'continuum' and 'serpentine' robot mechanisms move by bending through a series of continuous arcs producing motion which resembles that of biological tentacles or snakes. This paper provides a single reference to the expanding technology of continuum robot mechanisms. It defines the fundamental difference between discrete, serpentine and continuum robot devices, presents the 'state of the art' of continuum robots, outlines their areas of application, and introduces some control issues. Finally, some conclusions regarding the continued development of these devices are made.

AMADEUS is a dexterous subsea robot hand incorporating force and slip contact sensing, using fluid-filled tentacles for fingers. Hydraulic pressure variations in each of three flexible tubes (bellows) in each finger create a bending moment, and consequent motion or increase in contact force during grasping. Such fingers have inherent passive compliance, no moving parts, and are naturally depth pressure-compensated, making them ideal for reliable use in the deep ocean. In addition to the mechanical design, development of the hand has also been considered for closed loop finger position and force control, coordinated finger motion for grasping, force and slip sensor development/signal processing, and reactive world modelling/planning for supervisory "blind grasping". Initially, the application focus is for marine science tasks, but broader roles in offshore oil and gas, salvage, and military use are foreseen. Phase I of the project has been completed, with the construction of a first prototype. This paper summarizes the developments in Phase I. Further details for each area of investigation are referenced.