On Performance Losses in Some Adaptive Control Systems: I

1965 ◽  
Vol 87 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Masanao Aoki
Keyword(s):  
Adaptive Control ◽  
Control Systems ◽  
Unknown Parameter ◽  
A Priori ◽  
Control Policy ◽  
Optimal Estimation ◽  
Perfect Information ◽  
Point Of View ◽  
Unknown Parameters ◽  
Linear Differential

In controlling dynamic systems with unknown parameters and/or systems operating in unknown environment, the systems suffer due to the unknowness of pertinent parameter values, compared with situations with perfect information where all pertinent information is available to control systems optimally. The paper defines the concept of loss of performance to represent the loss in performance of some adaptive control situations compared with perfect information situations and defines the optimal control problems as the one where the loss of performance is minimized. This concept is illustrated for a control system governed by a scalar linear differential equation with unknown gain. The minimax control policy is defined as the control policy which minimized the maximum possible loss in performance where no a priori knowledge on the unknown parameter is available. It also discusses the optimal estimation problem of the unknown parameter from the point of view of loss of performance.

scholarly journals An Optimal Estimation Method for Nonlinear Models of Mechanical Systems

1994 ◽  
Vol 116 (4) ◽  
pp. 805-810 ◽  
Author(s):  
M. J. G. van de Molengraft ◽  
F. E. Veldpaus ◽  
J. J. Kok
Keyword(s):  
Nonlinear Models ◽  
A Priori ◽  
Mechanical Systems ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Model Structure ◽  
Unknown Parameters ◽  
Starting Point ◽  
Nonlinear Mechanical ◽  
Nonlinear Mechanical Systems

This paper presents an optimal estimation method for nonlinear mechanical systems. The a priori knowledge of the system in the form of a nonlinear model structure is taken as a starting point. The method determines estimates of the parameters and estimates of the positions, velocities, accelerations, and inputs of the system. The optimal estimation method is applied to an experimental mechanical system. The unknown parameters in this system relate to inertia, friction and elastic deformation. It is shown that the optimal estimation method on the basis of a relatively simple model structure can lead to a useful description of the system.

scholarly journals Adaptive Control Design with Assigned Tracking Accuracy for a Class of Nonlinearly Parameterized Input-Delayed Systems

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Dajie Yao ◽  
Jing Li ◽  
Jian Wu
Keyword(s):  
Adaptive Control ◽  
Closed Loop ◽  
A Priori ◽  
Tracking Error ◽  
Input Delay ◽  
Tracking Accuracy ◽  
Unknown Parameters ◽  
Controlled System ◽  
Delayed Systems ◽  
Nonlinearly Parameterized

This paper addresses the adaptive control problem of a class of nonlinear systems with unknown parameters and input delay, and the tracking accuracy of the controlled system is assigned a priori. The Pade approximation method is introduced to deal with the problem from the input delay. By creating a group of nonnegative functions, an appropriate controller is designed with the backstepping technology. It is shown that under the obtained controller, the boundedness of all the closed-loop signals is guaranteed, and the tracking error especially can converge to the accuracy assigned a priori. Finally, a simulation example is given to verify the effectiveness of the proposed scheme.

The Development of Adaptive Systems in Germany and France

1974 ◽  
Vol 96 (4) ◽  
pp. 405-413 ◽  
Author(s):  
I. D. Landau ◽  
H. Unbehauen
Keyword(s):  
Adaptive Control ◽  
Control Systems ◽  
Historical Development ◽  
Adaptive Systems ◽  
Point Of View ◽  
Experimental Point ◽  
Adaptive Control Systems

The paper presented shows the development of adaptive control systems in Germany and France. After a review of the historical development, typical theoretical principles and some representative examples of adaptive control systems in several fields of application are discussed. The paper shows that important results were obtained both from theoretical and experimental point of view by investigators in both countries.

scholarly journals BIFURCATIONS AND LIMIT DYNAMICS IN ADAPTIVE CONTROL SYSTEMS

2005 ◽  
Vol 15 (05) ◽  
pp. 1641-1664 ◽  
Author(s):  
G. R. ROKNI LAMOOKI ◽  
S. TOWNLEY ◽  
H. M. OSINGA
Keyword(s):  
Adaptive Control ◽  
Control Systems ◽  
Closed Loop ◽  
Initial Conditions ◽  
Adaptive Stabilization ◽  
Unknown Parameters ◽  
Adaptive Controllers ◽  
Limit System ◽  
Adaptive Control Systems ◽  
Second Order Systems

Adaptive controllers are used in systems where one or more parameters are unknown. Such controllers are designed to stabilize the system using an estimate for the unknown parameters that is adapted automatically as part of the stabilization. One drawback in adaptive control design is the possibility that the closed-loop limit system is not stable. The worst situation is the existence of a destabilized limit system attracting a large open subset of initial conditions. These situations lie behind bad behavior of the closed-loop adaptive control system. The main issue in this paper is to identify and characterize the occurrence of such bad behavior in the adaptive stabilization of first- and second-order systems with one unknown parameter. We develop normal forms for all possible cases and find the conditions that lead to bad behavior. In this context, we discuss a number of bifurcation-like phenomena.

A Fatal Error of Locke’s?

2017 ◽  
Author(s):  
Galen Strawson
Keyword(s):  
Personal Identity ◽  
John Locke ◽  
A Priori ◽  
Point Of View ◽  
Radical Theory ◽  
Single Person

This chapter argues that the unqualified attribution of the radical theory to John Locke is mistaken if we are to take into account the fact that the theory allows for freaks like [Sₓ]. It first considers [I]-transfer without [P]-transfer—that is, [I]-transfer preserving personal identity—before discussing Locke's response to the idea that personal identity might survive [I]-transfer from an a priori point of view. It suggests that [I]-transfer is possible in such a way that the existence of a single Person [P₁] from t₁ to t₂ can successively (and non-overlappingly) involve the existence of two immaterial substances. It also explains how Locke's claim that [I]-transfer is possible opens up the possibility that it could go wrong, in such a way as to lead to injustice. Finally, it examines Locke's notion of “sensible creature,” which refers to a subject of experience who is a person.

scholarly journals Adaptive Control of a Vehicular Platoon with Unknown Parameters and Input Variations

2020 ◽  
Vol 53 (2) ◽  
pp. 13876-13881
Author(s):  
Mohammad Pourmahmood Aghababa ◽  
Mehrdad Saif ◽  
Bahram Shafai
Keyword(s):  
Adaptive Control ◽  
Unknown Parameters
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