Showing papers by "Richard H. Middleton published in 1992"
01 Feb 1992
TL;DR: An attempt is made to organize and survey recent work, and to present it in a unified and accessible form, on the need for a new approach suitable for high-speed processing and the use of difference operators in numerical analysis.
Abstract: An attempt is made to organize and survey recent work, and to present it in a unified and accessible form. The need for a new approach suitable for high-speed processing is discussed in the context of several applications in control and communications, and a historical perspective of the use of difference operators in numerical analysis is presented. The general systems calculus, based on divided-different operators is introduced to unify the continuous-time and discrete-time systems theories. This calculus is then used as a framework to treat the three problems of system state estimation; system identification and time-series modeling; and control system design. Realization aspects of algorithms based on the difference operator representation, including such issues as coefficient rounding and implementation with standard hardware, are also discussed. >
276 citations
16 Dec 1992
TL;DR: In this paper, a robust DFL (direct feedback linearization) nonlinear excitation controller is proposed to enhance transient stability for power systems, which is independent of the operating point.
Abstract: A robust DFL (direct feedback linearization) nonlinear excitation controller is proposed to enhance transient stability for power systems. A robust control technique for linear systems is extended to design this controller. The design of the controller is independent of the operating point. Simulation results show that the controller has the following advantages: the fault location does not need to be known and the controller can overcome the variation of the reactance of the transmission line. Both transient stability enhancement and voltage regulation can be achieved. >
100 citations
TL;DR: Using the properties of the element by element (or Hadamard) product of matrices, this paper obtained the robot dynamics in parameter-isolated form, from which a new control scheme was developed.
Abstract: Using the properties of the element by element (or Hadamard) product of matrices, the authors obtain the robot dynamics in parameter-isolated form, from which a new control scheme is developed. The controller proposed yields zero asymptotic tracking errors when applied to robotic systems with time-varying parameters by using a switching type control law. The results obtained are global in the initial state of the robot, and can be applied to rapidly varying systems. >
28 citations
TL;DR: In this article, the adaptive controllers for a class of first-order linear continuous-time plants, with different estimators, and control laws, were examined, and the authors obtained explicit solutions completely describing the nonlinear behavior of the resultant adaptive systems.
Abstract: Examining adaptive controllers for a class of first-order linear continuous-time plants, with different estimators, and control laws, the authors obtain explicit solutions completely describing the nonlinear behavior of the resultant adaptive systems. Some of these adaptive systems exhibit either finite time escapes, or other forms of unbounded behavior, due to a loss of stabilizability of the estimated model. Some fixes for the loss of stabilizability problem are analyzed. Implications of these results for the general indirect adaptive/control case are discussed. >
18 citations
TL;DR: The so-called Exp-transformation is applied to obtain transformed robot dynamics models which are used to derive several adaptive control algorithms that achieve exponential path tracking.
13 citations
24 Jun 1992
TL;DR: In this paper, an internally stable, parallel redundant controller structure for MIMO linear controllers is given for transducer failure tolerance, with particular emphasis on controller structures which correctly allow for multiple parallel controllers to be implemented.
Abstract: As controllers, and particularly digital controllers, are increasingly being used in expensive and/or critical applicants, failure tolerance becomes an important issue. Several researchers have looked at problems concerning transducer failures and using redundancy to improve fault tolerance. In this paper, tolerance to failures of the control hardware are considered, with particular emphasis on controller structures Which correctly allow for multiple parallel controllers to be implemented. In particular, an internally stable, parallel redundant controller structure is given for MIMO linear controllers.