Showing papers by "Richard H. Middleton published in 1991"
TL;DR: One of the key conclusions here is a set of rules of thumb, giving limitations on the closed loop bandwidth which are imposed by unstable open loop poles, non-minimum phase zeros and/or time delays.
330 citations
28 Sep 1991
TL;DR: In this paper, a comprehensive approach to the control of synchronous reluctance machines (SYNCRELs) based on the machine's ideal model is presented. But the effects of saturation and iron losses are briefly considered.
Abstract: This work develops a comprehensive approach to the control of inverter-fed synchronous reluctance machines (SYNCREL), based on the machine's ideal model. From the theory a control simulation is designed. Simulation and experimental results are presented. The effects of saturation and iron losses are briefly considered. >
201 citations
09 Apr 1991
TL;DR: This work removes the complete removal of the PE requirement as opposed to relaxing it to semi-PE, which makes the control structure much simpler and easier to implement.
Abstract: The exponential transformation is applied to obtain transformed robot dynamics. This is used to derive several adaptive control algorithms that achieve exponential path tracking. In contrast to the existing composite adaptive control method, where both the tracking error and the prediction error are used and persistent excitation (PE) is required, the proposed strategy requires only the tracking error. This makes the control structure much simpler and easier to implement. The main contribution of this work is the complete removal of the PE requirement as opposed to relaxing it to semi-PE. The fundamental idea introduced for exponential stability analysis is conceptually simple and global results are obtained. >
12 citations
26 Jun 1991
TL;DR: Examining adaptive controllers for a first order, linear, continuous time plant, with different estimators, and control laws, explicit solutions completely describing the nonliner behavior of the resultant adaptive systems are obtained.
Abstract: Examining adaptive controllers for a first order, linear, continuous time plant, with different estimators, and control laws, we obtain explicit solutions completely describing the nonliner 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 are analyzed. Implications of these results for the general indirect adaptive control case are discussed.
8 citations
TL;DR: In this paper, the authors examined the asymptotic properties of a hybrid adaptive control scheme, where the on-line parameter estimation and underlying control design are carried out in a discrete time using digital electronics and do not require any analog multiplications or divisions.
Abstract: This paper examines the asymptotic properties of a hybrid adaptive control scheme. While there are many different meanings of the word ‘hybrid’ control in the literature, we are referring to a scheme where the on-line parameter estimation and underlying control design are carried out in a discrete time using digital electronics and do not require any analog multiplications or divisions. This is of critical importance in practice since analog multipliers/dividers are subject to serious drift and offset errors. For such hybrid schemes we establish stability and an output tracking property without recourse to persistence of exitation. The proof of stability requires a sufficiently fast sampling rate for the discrete time parameter estimation and the underlying control design.
4 citations
11 Dec 1991
TL;DR: Adaptive direct feedback linearization of nonlinear oscillatory systems with parametric uncertainties is considered in this article, where the direct linearization technique and parameter adaptation approaches are applied to overcome parametric uncertainty.
Abstract: Adaptive direct feedback linearization of nonlinear oscillatory systems with parametric uncertainties is considered. The direct feedback linearization technique and parameter adaptation approaches are applied to overcome parametric uncertainties. The main result is that adaptive direct feedback linearization techniques applied to nonlinear oscillatory systems with parametric uncertainties give boundedness of all signals, together with asymptotic tracking of the set points. The proposed adaptive direct feedback linearization technique has been applied to power systems to achieve transient stability enhancement and voltage regulation. >
3 citations