Development of an actively compliant underwater manipulator
Development of an actively compliant underwater manipulator
Date
1988-05
Authors
DiPietro, David M.
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DOI
10.1575/1912/4957
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Keywords
Vehicles, remotely piloted
Oceanographic instruments
Oceanographic instruments
Abstract
This thesis describes the design, construction, and evaluation of
an actively compliant underwater manipulator for installation on the
underwater remotely operated vehicle (ROV) JASON. The goal of this work
has been to produce a high fidelity force-controllable manipulator
exhibiting no backlash, low stiction/friction, high backdriveability, wide
dynamic range, and possessing a large work envelope. By reducing the
inherent dynamic nonlineari ties, a wide range of joint compliances can
realistically be achieved. This feature is important when implementing
various force control schemes, particularly impedance control. In
addition, a mechanically "clean" transmission reduces the need for sensors
and allows the user to rely on integral motor sensors to provide torque,
position, and velocity information.
A three axis manipulator rated to full ocean depth was built.
Each of the revolute joints is driven by a DC brushless sensorimotor
working through a multi-stage cable/pulley transmission. The manipulator
mechanism and wiring is fully enclosed by cast aluminum housings filled
with mineral oil. Mineral oil functions to pressure compensate and
lubricate the system. Exterior surfaces of the manipulator are smooth and
continuous, and were designed to act as work surfaces. Joints one and two
have a 240° range of motion, while joint three can rotate 380°. The
manipulator transmissions are modeled and predictions of manipulator
stiffness, dynamic range, payload capacity, and hysteresis are compared
with the results of tests conducted on the actual system. Operation of the
cable/pulley transmissions are evaluated and suggestions for improvements
are given.
Description
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 1988
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Citation
DiPietro, D. M. (1988). Development of an actively compliant underwater manipulator [Doctoral thesis, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution]. Woods Hole Open Access Server. https://doi.org/10.1575/1912/4957