Elastic actuator for precise force control

Patent · 22 July 1997

OSTI ID:871062

Pratt, Gill A ^[1]; Williamson, Matthew M ^[2]

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1. Lexington, MA
2. Boston, MA

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.

• Research Organization: Jet Propulsion Laboratory
• Assignee: Massachusetts Institute of Technology (Cambridge, MA)
• Patent Number(s): US 5650704
• Application Number: 08/496,419
• OSTI ID: 871062
• Country of Publication: United States
• Language: English

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