Further Results on Active Magnetic Bearing Control with Input Saturation

We study the low-bias stabilization of active magnetic bearings (AMBs) subject to voltage saturation based on a recently proposed model for the AMB switching mode of operation. Using a forwarding-like approach, we construct a stabilizing controller of arbitrarily small amplitude and a control-Lyapunov function for the AMB dynamics. We illustrate our construction using a numerical example.Comment: 9 pages, 2 figures. IEEE Transactions on Control Systems Technology, accepted for publication in January 200

Integrated chaos generators

This paper surveys the different design issues, from mathematical model to silicon, involved on the design of integrated circuits for the generation of chaotic behavior.Comisión Interministerial de Ciencia y Tecnología 1FD97-1611(TIC)European Commission ESPRIT 3110

Digital Conversion of Nonlinear Compensators with Antireset-Windup Compensation: Studies, Analysis and Design

All physically realizable systems are subject to saturations of one form or another. Control systems having saturations are susceptible to the nonlinear problem of reset-windup if the controllers within those systems contain one or more integrators. Reset-windup is a condition whereby the integrator continues to integrate the feedback error and add to the control signal, even in the presence of a decreasing error signal. This phenomenon can lead to excessive overshoot in the system in response to large setpoint changes. This paper discusses the problem of reset-windup in detail and presents several methods for correcting this problem in continuous-time systems as discussed in existing controls literature. Two approaches to the elimination of reset-windup are discussed in detail: the conventional anti-reset windup (CAW) scheme and the override signal (OS) scheme. The application of these methods to continuous-time systems is reviewed for simple example systems. The paper then proposes implementations of these methods for discrete-time systems, discusses problems associated with these implementations, including the phenomenon of chatter , and presents design criteria to make these implementations useful. Finally, the practical application of antireset-windup compensation is discussed through the design of a digital controller for an existing system

F100 multivariable control synthesis program: Evaluation of a multivariable control using a real-time engine simulation

The design, evaluation, and testing of a practical, multivariable, linear quadratic regulator control for the F100 turbofan engine were accomplished. NASA evaluation of the multivariable control logic and implementation are covered. The evaluation utilized a real time, hybrid computer simulation of the engine. Results of the evaluation are presented, and recommendations concerning future engine testing of the control are made. Results indicated that the engine testing of the control should be conducted as planned

Reports on Hybrid-computer Hardware

Hybrid computer and differential analyzer design and development for university instruction progra

Biquadratic Filter Applications Using a Fully-Differential Active-Only Integrator

A new class of active filters, real active-only filters is described and possible implementation issues of these filters are discussed. To remedy these issues, a fully-differential active-only integrator block built around current controlled current conveyors is presented. The integration frequency of the proposed circuit is adjustable over a wide frequency range. As an application, a real active-only filter based on the classical two-integrator loop topology is presented and designed. The feasibility of this filter in a 0.35µm CMOS process is verified through SPECTRE simulation program in the CADENCE design tool

Methods for Determining Blood Flow Through Intact Vessels of Experimental Animals Under Conditions of Gravitational Stress and in Extra-terrestrial Space Capsules Final Report, 1 Nov. 1960 - 31 Dec. 1964

Electromagnetic blood flow meter to determine blood flow through intact vessels of test animals in gravitational stress and in extraterrestrial space capsule