Inflatable actuators
- Paper number
IAC-06-C2.5.05
- Author
Mr. Gonzalo Taubmann, SENER Ingeneria y Sistemas, S.A., Spain
- Year
2006
- Abstract
Space industry founds the inflatable components to be an interesting alternative to the metallic components in some structural applications. The main feature is that low mass elements within a small stowing volume can become large structures. On the other hand, their field of application is constrained by poor final geometry shape accuracy, low stiffness and the special cares required in long life cases. These characteristics identify the inflatable concept to be adequate for large structures in which the inconveniences are justified by the significant mass saving. Since the technology to improve the structural behaviour of inflatable structures is being developed as well as deployment performances and folding procedures; this paper introduces and explores a new application for inflatable elements: The actuators. The working principle takes advantage of the variation of mechanical properties of balloons when the internal pressure changes. It means, that not only static performances of structural elements are studied, but also the dynamic behaviour and the transitional states during inflation. The most immediate application is to use a balloon for a linear end-to-end displacement, but in addition, another more sophisticated actuator is developed. It is based in the fact that the bending stiffness of a cylindrical balloon is very low if the balloon is not pressurized, but it takes the film stiffness when the balloon is tensioned with internal pressure. In other words, a cylindrical balloon tends to erect when the pressure increases. A combination of various balloons with different directions can move an element to several positions (as many as balloons are installed) by an adequate arrangement of pressurisations and depressurisations. The paper includes examples of the use of this technology in the Mars Sample Return mission. In this mission a mechanism is used by the Orbiter Vehicle to capture a container with samples. The mechanism requires a large capture volume, stiffness is not an advantage but good energy absorption is welcome; geometrical accuracy is not critical, because large margins shall be considered due to rendezvous misalignments and mechanism life is reduced to some days. Inflatable concept fits these characteristics. All sub-functions are performed with balloons: The deployment and generation of a large capture envelope; the actuation of the lid – with reopening capability - and the guidance and transfer of the Sample Container to the final location inside the Orbiter.
- Abstract document
- Manuscript document
IAC-06-C2.5.05.pdf (🔒 authorized access only).
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