||Biagiotti L., Lotti F., Melchiorri C., Palli G., Tiezzi P., Vassura G.
||Innovative Design of Robot Hands for Space Activities
||Submitted to 8th ESA Workshop on Advanced Space Technologies for Robotics and Automation, 'ASTRA 2004' ESTEC - Noordwijk, The Netherlands, 2-4 November 2004.
||Robotics Hand Design, Space robots, Humanoid Robot, Dexterous Manipulation
|Aim of this work is the development of an articulated robot hand resulting from an optimal trade-off between
dexterity and complexity. The key point of the overall project (called UB Hand III – University of Bologna
hand, third version) is an innovative mechanical design based on compliant mechanisms.
Each finger is made of rigid elements (the phalanges) connected through elastic hinges, obtained from steel
spiral coils that are used also as sheath for tendon routing, that allow relative motion due to self bending.
Their structure presents four joints: the proximal allows adduction-abduction (yaw) motion, while the
intermediate and the distal ones permit finger bending. Each joint is actuated by forces exerted on the
phalanges by remotely actuated tendons, that slide inside routing paths along the finger structure and pass
through the hinges along their bending axis. After early attempts to develop "monolithic" fingers with
hinges and tendons integrated in a single item, the current version adopts different materials for the hinges,
the phalanges structure, and the tendons.
By exploiting the finger structure the sensory apparatus (including position and force sensors) has been
integrated in the hand. In particular, the forces exchanged with the environment are measured by
monitoring (by means of strain gauges) the deformation imposed by the tendons on the purposely shape
connector, which link the tendon with the actuated phalange. The same principle (the measure of a
deformation) is used to know the configuration of the fingers. By measuring the momentum imposed by a
bended coil, which behaves like a spring, on a sensorized element it is possible to know the bending angle
and, therefore, the relative positions between the phalanges.
|| b125.Document.pdf (272555 bytes)