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Mahtab Delpas,1,Mohammad Farrokhi2.[en_title][J].Control Theory and Technology,2024,22(2):254~268.[Copy]
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Enhanced adaptive nonlinear extended state observer for pure feedback systems withmatched andmismatched disturbances
MahtabDelpasand1,MohammadFarrokhi2
0
(1 School of Electrical Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran;2 Center of Excellence for Modelling and Control of Complex Systems, Iran University of Science and Technology, Tehran 16846-13114, Iran)
摘要:
In this paper, an enhanced adaptive nonlinear extended state observer (EANESO) for single-input single-output pure feedback systems in the presence of external time-varying disturbances is proposed. In this paper, a nonlinear system with matched and mismatched disturbances is considered. The conventional extended state observer (ESO) can only be applied to systems that are in the form of integral chains. Moreover, this method has limitations in the face of mismatched disturbances. In the presence of time-varying disturbances, the traditional ESOs cannot estimate the disturbances accurately. To overcome this limitation, an EANESO is proposed in this paper. The main idea is to design the nonlinear ESO (NESO) to estimate the states of the system and multiple disturbances simultaneously. The observer gains are considered time-varying and adjusted with adaptation laws to improve the estimation accuracy and overcome the peaking phenomenon. Next, the proposed controller is designed based on output feedback to eliminate the effects of multiple disturbances and stabilize the closed-loop system. Subsequently, the stability analysis of the closed-loop system and convergence of the observer error are discussed. Finally, the proposed method is applied to the inverted pendulum system. The simulated results show good performance of the proposed method as compared with a recently published scheme in the related literature.
关键词:  Nonlinear extended state observer · Enhanced adaptive extended state observer · Adaptation law· Multiple-channel disturbances · Inverted pendulum system · Time-varying gain
DOI:https://doi.org/10.1007/s11768-024-00197-8
基金项目:
Enhanced adaptive nonlinear extended state observer for pure feedback systems withmatched andmismatched disturbances
Mahtab Delpasand1,Mohammad Farrokhi2
(1 School of Electrical Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran;2 Center of Excellence for Modelling and Control of Complex Systems, Iran University of Science and Technology, Tehran 16846-13114, Iran)
Abstract:
In this paper, an enhanced adaptive nonlinear extended state observer (EANESO) for single-input single-output pure feedback systems in the presence of external time-varying disturbances is proposed. In this paper, a nonlinear system with matched and mismatched disturbances is considered. The conventional extended state observer (ESO) can only be applied to systems that are in the form of integral chains. Moreover, this method has limitations in the face of mismatched disturbances. In the presence of time-varying disturbances, the traditional ESOs cannot estimate the disturbances accurately. To overcome this limitation, an EANESO is proposed in this paper. The main idea is to design the nonlinear ESO (NESO) to estimate the states of the system and multiple disturbances simultaneously. The observer gains are considered time-varying and adjusted with adaptation laws to improve the estimation accuracy and overcome the peaking phenomenon. Next, the proposed controller is designed based on output feedback to eliminate the effects of multiple disturbances and stabilize the closed-loop system. Subsequently, the stability analysis of the closed-loop system and convergence of the observer error are discussed. Finally, the proposed method is applied to the inverted pendulum system. The simulated results show good performance of the proposed method as compared with a recently published scheme in the related literature.
Key words:  Nonlinear extended state observer · Enhanced adaptive extended state observer · Adaptation law· Multiple-channel disturbances · Inverted pendulum system · Time-varying gain