A parallel bellows continuum actuator has been developed for use as a finger in a subsea dextrous hand mounted on a commercial underwater hydraulic manipulator. To improve grasping and manipulation performance, a 3D force control system has been designed for each finger, using in-house proprietary force sensor designs. The paper describes the control system design, focusing on the derivation of the continuum actuator Jacobian matrix and kinematic equations ("continuumatics") necessary to implement the multi-dimensional control.

Presents the design of the fingertip sensing subsystem constructed for use in a dextrous underwater gripper. Two distinct types of sensor were developed specifically for this application, a force sensor and a slip sensor. The force sensor is used to determine the force exerted by the gripper on the target object, and hence allow the force loop closure required for carrying out dextrous manipulation and the handling of delicate marine samples. The function of the slip sensor is to detect the occurrence of slippage between the fingertip and the target. The information can be used in a variety of ways, for example providing a warning system to the force control loop or enhancing the gripper's exploratory capabilities in areas of poor visibility. Two quite different methods of extracting the force data from the sensor readings are presented and evaluated. The performance of the slip sensor is assessed, as is its potential usefulness in acting in tandem with the force sensor.

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.