Precision Shape Control of Ultra-thin Shells with Strain Actuators

Document Type : Special Issue Paper

Authors

1 Department of Control Engineering and System Analysis, Université Libre de Bruxelles (ULB),‎ CP. 165-55, 50 Av. F.D. Roosevelt, B-1050 Brussels, Belgium‎

2 European Space Agency—ESA/ESTEC Keplerlaan 1, 2201 AZ Noordwijk ZH, The Netherlands‎

Abstract

This paper is part of an effort conducted at Université libre de Bruxelles (ULB) on behalf of European Space Agency (ESA) to control the shape of thin polymer shell structures with a unimorph layer of strain actuators (Polyvinylidenefluoride-co-trifluoroethylene, PVDF-TrFE), to achieve high quality light-weight foldable reflectors for space observation. The paper discusses the influence of the electrode size on the morphing capability of the system and addresses the difficulty associated with the ill-conditioning when controlling a very large set of electrodes. The final part of the paper describes a technology demonstrator currently under development and presents some simulation results fitting low order optical modes.

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[1] Marker, D.K., Jenkins, C.H., Surface Precision of Optical Membranes with Curvature, Optics Express, 1(11), 1997, 324-331.
[2] Flint, E., Bales, G., Glaese, R., Bradford, R., Experimentally Characterizing the Dynamics of 0.5 m Diameter Doubly Curved Shells Made from Thin Films, 44th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, AIAA Paper 2003-1831, Norfolk, Virginia, USA, p. 1831, 2003.
[3] Flint, E., Lindler, J., Hall, J., Rankine, C., Regelbrugge, M., Overview of Form Stiffened Thin Film Shell Characteristic Behavior, 47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Newport, Rhode Island, USA, p. 1900, 2006.
[4] Preumont, A., Vibration Control of Active Structures, An Introduction, 4rd Edition, Springer International Publishing, 2018.
[5] Chaudhry, Z., Lalande, F. and Rogers, C.A., Modeling of Induced Strain Actuation of Shell Structures, Journal of the Acoustical Society of America, 97(5), 1995, 2872-2877.
[6] Piefort, V., Loix, N., Preumont, A., Modeling of Piezolaminated Composite Shells for Vibration Control, ESA Conference on Spacecraft Structures, Materials and Mechanical Testing, Braunschweig, Germany, ESA SP-428, 1998.
[7] Preumont, A., Alaluf, D., Wang, K. and Rodrigues, G. Adaptive Thin Shell Reflectors for Future Space Telescopes, 14th European Conference on Spacecraft Structures, Materials and Environmental Testing (ECSSMET 2016), Toulouse, France, September 2016.
[8] Buss, S.R., Introduction to Inverse Kinematics with Jacobian Transpose, Pseudoinverse and Damped Least-Squares Methods, IEEE Journal of Robotics and Automation, 17(1-19), 2004, 16.
[9] Wang, K., Piezoelectric Adaptive Mirrors for Ground-based and Space Telescopes, Ph. D Thesis, Active Structures Laboratory, Université Libre de Bruxelles, Brussels, Belgium, 2019.