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Title: Elastic actuator for precise force control

Abstract

The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end ofmore » the central section to a proximal end of the central section.« less

Inventors:
 [1];  [2]
  1. Lexington, MA
  2. Boston, MA
Issue Date:
Research Org.:
Jet Propulsion Laboratory
OSTI Identifier:
871062
Patent Number(s):
5650704
Application Number:
08/496,419
Assignee:
Massachusetts Institute of Technology (Cambridge, MA)
Patent Classifications (CPCs):
H - ELECTRICITY H02 - GENERATION H02K - DYNAMO-ELECTRIC MACHINES
B - PERFORMING OPERATIONS B25 - HAND TOOLS B25J - MANIPULATORS
DOE Contract Number:  
959333
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
elastic; actuator; precise; force; control; provides; consisting; motor; drive; transmission; connected; output; element; series; positioned; support; weight; load; single; transducer; mount; generates; signal; based; deflection; indicates; applied; active; feedback; loop; controlling; deflect; amount; produces; desired; produced; substantially; independent; motion; torsional; spring; flexible; structure; flat; sections; integrally; extending; radially; central; section; extends; axially; distal; proximal; active feedback; control loop; force applied; extending radially; motor drive; central section; substantially independent; extends axially; motor control; elastic element; force transducer; torsional spring; force control; drive transmission; elastic actuator; transmission connected; extending radial; section extend; actuator consisting; /318/

Citation Formats

Pratt, Gill A, and Williamson, Matthew M. Elastic actuator for precise force control. United States: N. p., 1997. Web.
Pratt, Gill A, & Williamson, Matthew M. Elastic actuator for precise force control. United States.
Pratt, Gill A, and Williamson, Matthew M. Tue . "Elastic actuator for precise force control". United States. https://www.osti.gov/servlets/purl/871062.
@article{osti_871062,
title = {Elastic actuator for precise force control},
author = {Pratt, Gill A and Williamson, Matthew M},
abstractNote = {The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1997},
month = {7}
}

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Works referenced in this record:

A Robot Hand with Elastic Fingers and Its Application to Assembly Process
journal, January 1977


Force Control Of The Robot Finger Joint Equipped With Mechanical Compliance Adjuster
conference, January 1992


Experiments with a dual-armed, cooperative, flexible-drivetrain robot system
conference, January 1993

  • Pfeffer, L. E.; Cannon, R. H.
  • [1993] IEEE International Conference on Robotics and Automation, [1993] Proceedings IEEE International Conference on Robotics and Automation
  • https://doi.org/10.1109/ROBOT.1993.291839