Eigenvalue and eigenvector approximate analysis for repeated eigenvalue problems
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Hou, Gene J. W.↗
Engineering topics
Kenny, Sean P.
Publications and source records attributed to Kenny, Sean P..
Nonlinear modeling of a long flexible manipulator and control by inertial devices
The authors consider the modeling and control of a planar, long flexible manipulator that is representative of current space-based robotic arms. The arm is equipped with three actuators: 1) a shoulder motor; 2) a torque wheel at the tip; and 3) a proof-mass actuator at the tip. The goal is to investigate the potential use of inertial devices as control inputs for maneuvering tasks and vibration suppression. The parameters used for the inertial devices at the tip are comparable to those specified for the Mini-Mast facility at the Langley Research Center. A nonlinear distributed parameter model is obtained by the extended Hamilton principle. The associated eigenvalue/eigenfunction problem is solved and a finite-dimensional state space model is assembled. A preliminary design of a linear quadratic regulator is used, and computer simulation results illustrate the benefits of using the proposed actuators.
Barbieri, Enrique↗
Active damping application to the shuttle RMS
Control Structure Interaction (CSI) is a relatively new technology developed over the last 10 to 15 years for application to large flexible space vehicles. The central issue is recognition that high performance control systems necessary for good spacecraft performance may adversely interact with the dynamics of the spacecraft structures, a problem increasingly aggravated by the large size and reduced stiffness of modern spacecraft structural designs. The CSI analysis and design methods were developed to avoid interactions while maintaining spacecraft performance without exceeding structural capabilities, but they remain largely unvalidated by hardware experiments or demonstrations, particularly in-space flight demonstrations. One recent proposal for a low cost flight validation of CSI technology is to demonstrate active damping augmentation of the Space Shuttle Remote Manipulator System (RMS). An analytical effort to define the potential for such an active damping augmentation demonstration to improve the structural dynamic response of the RMS following payload maneuvers is described. It is hoped that this study will lead to an actual inflight CSI test with the RMS using existing shuttle hardware to the maximum extent possible. By using the existing hardware, the flight demonstration results may eventually be of direct benefit to actual Space Shuttle RMS operations, especially during the construction of the Space Station Freedom.
Gilbert, Michael G.↗
Eigenvalue and eigenvector sensitivity and approximate analysis for repeated eigenvalue problems
A set of computationally efficient equations for eigenvalue and eigenvector sensitivity analysis are derived, and a method for eigenvalue and eigenvector approximate analysis in the presence of repeated eigenvalues is presented. The method developed for approximate analysis involves a reparamaterization of the multivariable structural eigenvalue problem in terms of a single positive-valued parameter. The resulting equations yield first-order approximations of changes in both the eigenvalues and eigenvectors associated with the repeated eigenvalue problem. Examples are given to demonstrate the application of such equations for sensitivity and approximate analysis.
Hou, Gene J. W.↗
Eigensensitivity in integrated design
An application of eigensensitivity analysis to the control-structure integrated design process is presented with an emphasis placed on computational efficiency improvement of the overall design optimization process. The computational efficiency of eigenvalue/vector sensitivity analysis is demonstrated using the Earth Pointing Satellite in the context of a control-structure integrated design program. Results for a 2 percent design variable perturbation with and without the effects of the actuator mass show a 42 and 52 percent reduction in CPU time, respectively.
Kenny, Sean P.↗
Eigensensitivity analysis for space structures with applications in design optimization
An approximate structural eigenvalue/vector analysis technique which uses eigensensitivities in a truncated Taylor series expression is presented. It is shown that this technique can provide the computational efficiency urgently needed for large scale control-structure optimization problems. In addition, a unified formulation and solution approach for calculating eigenvalue and eigenvector derivatives of the real symmetric structural eigenvalue problem is presented.
Kenny, Sean P.↗
Eigensensitivity analysis for space structures
The main thrust of this paper is to study eigensensitivity analysis techniques and their applications to design optimization of space structures. It is found that in general, space structures show four types of eigenvalue problems most of which are related to repeated eigenvalues. This paper first gives a detailed derivation of eigensensitivity equations. Later, numerical examples are provided to verify the derived sensitivity equations as well as to demonstrate the applicability of those sensitivity equations in an iterative design environment.
Hou, Jean W.↗