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US 5,374,011 AGranted
Multivariable adaptive surface control
AssigneeMassachusetts Institute of Technology
InventorsKenneth B. Lazarus, Edward F. Crawley
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AssigneeMassachusetts Institute of Technology
InventorsKenneth B. Lazarus, Edward F. Crawley
Estimating the term…
An adaptive sheet structure with distributed strain actuators is controlled by a dynamic compensator that implements multiple input, multiple output control laws derived by model-based, e.g., Linear Quadratic Gaussian (LQG) control methodologies. An adaptive lifting surface is controlled for maneuver enhancement, flutter and vibration suppression and gust and load alleviation with piezoceramic elements located within, or enclosed by sheets of composite material at a particular height above the structure's neutral axis. Sensors detect the amplitudes of lower order structural modes, and distributed actuators drive or damp these and other modes. The controller is constructed from an experimental and theoretical model using conventional control software, with a number of event recognition patterns and control algorithms programmed for regulating the surface to avoid instabilities. The number of control states of the compensator is then reduced by removing states having negligible effects on the plant, and a smaller set of control laws are optimized and then adjusted based on analytical models bench and wind-tunnel testing.
A system controlling disturbances and instabilities in a sheet structure having a surface contacting a surrounding fluid and dynamically interacting therewith, such system comprising
A controllable sheet structure comprising a skin of a first material having a surface in contact with a surrounding fluid and in dynamic interaction therewith, and at least one actuator of a second material attached to said structure for coupling strain energy over a region into said structure, wherein mechanical impedance of each said actuator is matched to stiffness of said structure over the region to optimize coupling of strain energy thereto, and a dynamic compensator operative on sensed physical parameters of said structure for determining state variables and producing control outputs, said control outputs controlling outputs of a multi-channel amplifier in accordance with the determined state variables to drive selected ones of the actuators with an amplitude to control a dynamic physical condition of said sheet structure.
Dependencies are inferred from the claim text.