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Closed-loop Reference Model Adaptive Control Design And Application

Posted on:2020-02-18Degree:MasterType:Thesis
Country:ChinaCandidate:Y F LiuFull Text:PDF
GTID:2428330599955700Subject:Mechanical and electrical engineering
Abstract/Summary:PDF Full Text Request
With the development of science and technology,the manufacturing industry is demanding increasingly better control performance.Because of its advantages that adaptive control can overcome unknown disturbance and unknown dynamics,adaptive control has great significance for improving the performance of control system.Closed-loop model reference adaptive control(CRM)which is proposed as an effective modified method of model reference adaptive control(MRAC)can achieve better convergence performance of tracking error than traditional model reference adaptive control.This paper aims to study the closed-loop reference model adaptive control and looks for methods to address the peaking phenomenon and further improve the control performance of closed-loop reference model adaptive control.The research results of this paper are applied to the 3-DOF helicopter to validate their effectivenesses.In order to have a better understanding of what the closed-loop reference model adaptive control is,we first introduce the model reference adaptive control and analyze its control performance.How to choose a proper adaptive gain has been a problem for model reference control system,though high adaptive gain in the adaptive law can help to address the effect of uncertainties in the transient response may also excite high frequency unmolded dynamics that could deteriorate the tracking performance.Recently,researchers have proposed closed-loop reference model adaptive control as a solution to address the problem causing by adaptive gain.Then this paper introduces the closed-loop reference model adaptive control and analyze its control performance and analyze the cause of peaking phenomenon.Then a new prospective was provided to analyze the bound of peaking value by using L2 norm and Cauchy-Schwartz inequality,which shows the factors that may influence the peaking phenomenon.Based on the analyses above,we propose two methods to address the peaking phenomenon existing in closed-loop reference model adaptive control.The first method is to introduce a compensation item to the controller to alleviate the peaking phenomenon of closed-loop model reference adaptive control system.The second method is to modify the adaptive law to alleviate the peaking phenomenon.Simulation results are provided to validate the effectiveness of those two proposed methods to address the peaking phenomenon.At the end of this paper,through experiment results of 3-DOF aircraft which is designed by our laboratory,the effectivenesses of those two proposed modified methods are validated,which shows that the proposed methods can alleviate the peaking phenomenon of CRM-based control system and improve the control performance of closed-loop reference model adaptive control.
Keywords/Search Tags:adaptive control, closed-loop reference model adaptive control, peaking phenomenon, high frequency unmolded dynamics
PDF Full Text Request
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