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Thaler, G. J.

Publications and source records attributed to Thaler, G. J..

13 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Steady-state decoupling and design of linear multivariable systems

A constructive criterion for decoupling the steady states of a linear time-invariant multivariable system is presented. This criterion consists of a set of inequalities which, when satisfied, will cause the steady states of a system to be decoupled. Stability analysis and a new design technique for such systems are given. A new and simple connection between single-loop and multivariable cases is found. These results are then applied to the compensation design for NASA STOL C-8A aircraft. Both steady-state decoupling and stability are justified through computer simulations.

Thaler, G. J.↗
NASA NTRS1974

Steady state decoupling and design of linear multivariable systems

A constructive criterion for decoupling the steady states of linear multivariable systems is developed. The criterion consists of n(n-1) inequalities with the type numbers of the compensator transfer functions as the unknowns. These unknowns can be chosen to satisfy the inequalities and hence achieve a steady state decoupling scheme. It turns out that pure integrators in the loops play an important role. An extended root locus design method is then developed to take care of the stability and transient response. The overall procedure is applied to the compensation design for STOL C-8A aircraft in the approach mode.

Huang, J. Y.↗
NASA NTRS1972

Boundedness regions of discrete-time dynamic systems

Techniques for obtaining quantitative information about boundedness properties are developed and applied to the sampled-data control of satellite attitude with quantization. Relevant stability concepts are introduced as a series of definitions, and interrelationships between various definitions are discussed. The boundedness regions are estimated by means of quadratic Liapunov functions, and a sufficient condition for the existence of a boundedness region is given for a certain class of systems. A quadratic Liapunov function is applied to the Lur'e-Postinkov class of systems, where the linear part of the system is not asymptotically stable and the quantizer represents the nonlinear characteristic. A numerical calculation of the region of boundedness estimates is performed for satellite attitude control and is compared with simulation results. It is tentatively concluded that the Liapunov results may be good and that simulation results may be difficult to interpret and time-consuming to generate. The Lur'e-based technique yields estimates of regions of absolute boundedness, but at the cost of greater analytical complexity.

Siljak, D.↗