Some theorems on stability of discrete circulatory systems.
Stability theorems for discrete linear circulatory systems with N degrees of freedom for static and dynamic loss of stability in presence of velocity dependent forces
Herrmann, G.↗
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Stability, controllability and observability of linear matrix-second-order systems
The stability, controllability and observability of lightly damped linear mechanical systems are considered and gyroscopic effects (e.g., control moment gyros) are also included. The structure of the equations is further specified to include both 'rigid' and 'elastic' modes, possibly coupled by gyroscopic terms. Stability and asymptotic stability results are summarized in two theorems. The special structure of the system equations permits a statement of the necessary and sufficient conditions for controllability and observability in terms of simple rank tests. Of great practical significance, the minimum number of actuators and sensors are among the necessary conditions derived. Natural definitions for modal controllability and observability are also evolved which give a direct indication of beneficial locations for actuators and sensors.
Hughes, P. C.↗
Safety Verification of a Fault Tolerant Reconfigurable Autonomous Goal-Based Robotic Control System
Fault tolerance and safety verification of control systems are essential for the success of autonomous robotic systems. A control architecture called Mission Data System (MDS), developed at the Jet Propulsion Laboratory, takes a goal-based control approach. In this paper, a method for converting goal network control programs into linear hybrid systems is developed. The linear hybrid system can then be verified for safety in the presence of failures using existing symbolic model checkers. An example task is simulated in MDS and successfully verified using HyTech, a symbolic model checking software for linear hybrid systems.
goal network↗
A design procedure for discrete adaptive control systems.
Design synthesis of adaptive control system for linear discrete plants with time varying parameters, noisy measurements and statistical and deterministic disturbances
ADAPTIVE CONTROL SYSTEM↗
Investigation of optimization of attitude control systems Second annual report, 15 Sep. 1965 - 30 Jun. 1966
Linear autonomous system theory and optimal control analysis for launch vehicle stability and antenna pointing direction
LINEAR SYSTEM↗
On the decoupling of multivariable systems.
Necessary and sufficient conditions for decoupling time-invariant linear multivariable system by state variable feedback, discussing transfer matrix consequences
MATRIX ALGEBRA↗
Experimental and Theoretical Results in Output Trajectory Redesign for Flexible Structures
In this paper we study the optimal redesign of output trajectories for linear invertible systems. This is particularly important for tracking control of flexible structures because the input-state trajectores, that achieve tracking of the required output may cause excessive vibrations in the structure. We pose and solve this problem, in the context of linear systems, as the minimization of a quadratic cost function. The theory is developed and applied to the output tracking of a flexible structure and experimental results are presented.
Dewey, J. S.↗
The development of computational techniques for the identification of linear and nonlinear mechanical systems subject to random excitation, part 1 Final report
Computational procedures for determining differential equation governing motion of linear and nonlinear structural systems subject to random excitation
Gersch, W.↗
Minimum sensitivity design of linear multivariable feedback control systems by matrix spectral factorization
Scalar measure of system sensitivity to plant parameter variations applied to design of linear lumped stationary multivariable feedback control systems
Bongiorno, J. J., Jr.↗
Multiphysics Modeling of an Annular Linear Induction Pump With Applications to Space Nuclear Power Systems
An annular linear induction pump (ALIP) that could be used for circulating liquid-metal coolant in a fission surface power reactor system is modeled in the present work using the computational COMSOL Multiphysics package. The pump is modeled using a two-dimensional, axisymmetric geometry and solved under conditions similar to those used during experimental pump testing. Real, nonlinear, temperature-dependent material properties can be incorporated into the model for both the electrically-conducting working fluid in the pump (NaK-78) and structural components of the pump. The intricate three-phase coil configuration of the pump is implemented in the model to produce an axially-traveling magnetic wave that is qualitatively similar to the measured magnetic wave. The model qualitatively captures the expected feature of a peak in efficiency as a function of flow rate.
Kilbane, J.↗
On the input-output properties of linear time-invariant systems.
Recently improved sufficient conditions for the Lp stability of multiple-input multiple-output linear time-invariant feedback systems are given. The continuous-time case is done in detail; the discrete-time case is outlined. Unstable open-loop systems with singular residue matrices are allowed.
Desoer, C. A.↗
A game theoretic controller for a linear time-invariant system with parameter uncertainty and its application to the Space Station
A game theoretic controller is developed for a linear time-invariant system with parameter uncertainties in system and input matrices. The input-output decomposition modeling for the plant uncertainty is adopted. The uncertain dynamic system is represented as an internal feedback loop in which the system is assumed forced by fictitious disturbance caused by the parameter uncertainty. By considering the input and the fictitious disturbance as two noncooperative players, a differential game problem is constructed. It is shown that the resulting time invariant controller stabilizes the uncertain system for a prescribed uncertainty bound. This game theoretic controller is applied to the momentum management and attitude control of the Space Station in the presence of uncertainties in the moments of inertia. Inclusion of the external disturbance torque to the design procedure results in a dynamical feedback controller which consists of conventional PID control and cyclic disturbance rejection filter. It is shown that the game theoretic design, comparing to the LQR design or pole placement design, improves the stability robustness with respect to inertia variations.
Rhee, Ihnseok↗
Linear continuous and sampled-data systems
Program performs general analysis of linear and continuous, discrete and sampled-data systems using state-variable techniques. Program is especially suited analysis of linearized control system problems. It also can be used to model system described by combination of differential equations and Laplace transform blocks, such as aircraft control system.
Edwards, J. W.↗
A suboptimal approach to the control of systems containing uncertain parameters.
Linear optimal control in systems with uncertain parameters, noting application to design of compensating network for flexible booster for uncertain value of first bending mode
OPTIMAL CONTROL↗
Linear dynamic analysis of the Space Station Freedom thermal/environmental control system
A methodology for dynamic analysis of the Space Station Freedom thermal/environmental control system is described which uses linear system analysis techniques to determine the ability of the system to accommodate thermal load transients. A nonlinear integrated model of the system as it exists at Stage 6, Man Tended Capability (MTC), is described which encompasses the cabin air cooling system, avionics air cooling system, internal and external thermal control systems. The nonlinear model is linearized at an assumed design operating point, and the linear model is evaluated by comparison with the nonlinear model. Transfer functions are derived to determine the response of the heat rejection system to time-varying thermal loads applied at various points in the heat acquisition system. The frequency response calculated from the transfer functions is used to determine allowable operating envelopes of thermal load magnitude and frequency for each point of application of thermal load. The dynamic operating envelopes provide a quantitative indication of the degree and duration of peak loads which the thermal/environmental system is able to transport and reject.
Tandler, John↗
Efficient optimal design of suspension systems for rotating shafts
A new technique is proposed for the optimum design of suspension systems for rotating shafts. In this approach the conventional method of trial and error search for optimum parameter values for a prescribed design configuration has been replaced by an efficient two-stage procedure. In the first stage a generic force is substituted for the suspension system to be designed and the absolute optimum (or limiting) performance characteristics of the shaft are computed. In the second stage, using a chosen suspension system configuration, parameter identification techniques are are applied to find the design parameters so that the suspension system will respond as close as possible to the absolute optimal performance. In this approach the repetitive shaft analyses required in the conventional search techniques are avoided. Hence, the new technique is relatively efficient computationally and is suitable for large systems. Both linear and nonlinear suspension systems can be designed. A simple Jeffcott rotor is used to demonstrate the new technique.
Pilkey, W. D.↗
The complex structured singular value
A tutorial introduction to the complex structured singular value (mu) is presented, with an emphasis on the mathematical aspects of mu. The mu-based methods discussed here have been useful for analyzing the performance and robustness properties of linear feedback systems. Several tests for robust stability and performance with computable bounds for transfer functions and their state space realizations are compared, and a simple synthesis problem is studied. Uncertain systems are represented using linear fractional transformations which naturally unify the frequency-domain and state space methods.
Packard, A.↗