Investigation of Multiple Controller System Efficiency as Applied to the CSDLI Model

摘要

Modern optimal control methods are used to develop a three controller system. The control problem is formulated in state vector form using full state feedback, The control is implemented on a modal representation of the structural equations of motion. State estimates are provided by a deterministic observer. A computer model is used to generate controller and estimator gains using steady state optimal regulator theory. Means for extracting structural response and control effort time histories are developed and related to the computer model. The three controller system is used to control the model subjected to physical initial conditions. The model is a lumped mass tetrahedral truss consisting of four unit massed that are pin-connected by massless rods. Two versions of the model are used: The nominal version as designed by the Draper Lab and a perturbed version designed to minimize the deflection due to a static load. Four structure/controller configurations are tested via computer simulations. Compatibility of modal groupings and the use or non-use of system triangularization are the factors varied to form the controller configurations. All configurations use three controllers each controlling four of the twelve modes. Modal input to the program is supplied by a NASTRAN analysis of each structure. Time histories of structural response and expended control effort are computed for each test configuration using a series of structural response weightings to vary the control and estimator gains. Performance curves are formed for each configuration to allow comparison of system efficiencies. The effect of the separate combination of modal compatibility and use or non-use of system triangularization on system efficiency is examined.