Membrane position control

Details Membrane position control Membrane position control

2000-10-23

2004-04-20

Budd, Mark (Department: 2834)

Electrical generator or motor structure

Non-dynamoelectric

Piezoelectric elements and devices

C310S331000

Reexamination Certificate

active

06724130

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is generally related to the control of membrane structures by electroactive bending actuators.
2. Description of the Related Art
Membrane inflatable and deployable space structures are widely employed by the government and commercially as reflectors, antennas, solar arrays, satellites, solar sails, etc. Although these membrane inflatable and deployable structures are widely used, many challenges exist which limit their performance for high precision applications. Factors affecting precision include surface smoothness, deviation from desired surface profile, surface deformations due to thermal fluctuations, and accurate membrane positioning. Actuation devices are used for many applications, including the shaping, tuning, positioning, controlling and deforming of membrane structures. To operate most effectively in the aforementioned applications, actuation devices require sufficient force and strain, and often need to produce complex motions.
Conventional piezoelectric ceramic, polymer, and composite actuators (including piezoelectric, electrostrictive, and electrostatic) lack the combination of sufficient strain and force to most effectively perform the aforementioned functions. Previous concepts for shaping and tuning membrane structures have primarily involved the use of piezoelectric ceramic materials. These ceramic piezoelectrics have the major problems of large mass, high density, low strain and high brittleness. Generally, piezoceramics also need additional mechanical devices to achieve a shaping, tuning, positioning, controlling or deforming function. In contrast to electroceramics, electroactive polymers are emerging as new actuation materials due to their enhanced strain capabilities.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an electroactive position control device.
Another object is to provide an electroactive position control device wherein the electroactive components have small mass, low density, high strain and low brittleness.
Another object is to provide an electroactively-controlled membrane.
Another object is to provide an electroactively-controlled membrane inflatable and deployable structure.
Another object is to provide an electroactive position control device using electrostrictive bending actuators.
Additional objects and advantages of the present invention are apparent from the drawings and specification that follow.
In accordance with the present invention, a membrane structure includes an electroactive device fixed to a supporting base. A connection means operatively connects the electroactive device to the membrane for controlling membrane position.


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