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We present an Anti-windup scheme in which once saturation is encountered the nominal controller is replaced with a continuous scheduled family of controllers. In the proposed scheme, when the command to the actuator reaches the saturation limit, based on the system behavior (e.g., the closed-loop state vector or compensator states), the control law selects a member of the family of controllers that provides the best performance while avoiding saturation. As a result, the controller has a quasi linear parameter varying structure. Numerically, the family of the controllers is based on linear splines, and can be obtained by standard LMI software.

We extend a class of scheduled controllers, that were originally developed to address actuator saturation in the disturbance attenuation problem, to the problem of tracking of generally unknown signals. The main assumption is that some (possibly conservative) bounds be known for peak magnitude and rate of the tracking signal. Both state feedback for and static output feedback controllers are presented, though the choice of the approach to obtain the latter is left to the user. The solvability conditions and effectiveness are shown through an example.

State and output feedback controllers are designed for disturbance attenuation in linear systems with bounded actuators. The controller is scheduled according to the proximity to the origin of the state of the plant in the state-feedback case and the compensator state in the case of output feedback. This procedure yields a linear parameter-varying structure for the controller that allows higher-gain and hence higher-performance controllers as the states move closer to the origin. The main results give sufficient conditions for the satisfaction of a parameter-dependent performance measure, without violating the saturation bounds. Linear splines are used to obtain solutions that can be obtained by standard LMI software. Examples-including an open-loop unstable system-highlight the application of the results.

This paper studies the problem of controller synthesis for systems subject to amplitude and rate saturation constraints in the actuators. The main approach assumes that each actuator has a dynamic model of order at least one. The controllers presented here are only state feedback, though extension to the output feedback is also possible. The solvability conditions for the problem are expressed as finite-dimensional linear matrix inequalities. In addition to stabilization, disturbance attenuation in terms of the L 2 gain from the disturbance to output is considered.

In ihis paper, we apply recently developed linear matrix inequality techniques to the design of feedback controllers for seismic-excited buildings. Unlike most applications in this area, we do not assume perfect model knowledge, but incorporate the uncertain structural parameters into the model. Both state feedback and dynamic output feedback are considered. LMIs cannot be applied easily to the dynamic output feedback case and we offer an alternative approach we believe is easier to solve.

Conventional spacecraft design techniques in the areas of structures, materials, and control systems are incapable of meeting future NASA and DOD agile space mission requirements. Breakthroughs are required in all areas, and the new approaches need to be integrated and verified with hardware test. TRW has developed a modular testbed to demonstrate the key technologies that will enable the success of future agile spacecraft. Testbed design was motivated by a unique set of goals including providing for cooperative research with faculty and graduate students at local universities (University of California Irvine, University of California Santa Barbara and University of Southern California). Work accomplished jointly by TRW and local faculty was incorporated into the testbed development. Our experience in cooperative research confirmed these mutual benefits: 1) heightened awareness by universities of the aerospace industry spacecraft control/dynamics problems, 2) formulation of relevant research topics for TRW’s employees pursuing master’s and Ph.D. theses and 3) confirmation of the relevance of current university research topics to practical industry applications. This paper summarizes how industry can direct its research into key technologies in a way that can coherently involve university faculty and students.