scholarly journals Robust Linear Output Regulation Using Extended State Observer

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Mehran Hosseini-Pishrobat ◽  
Jafar Keighobadi ◽  
Atta Oveisi ◽  
Tamara Nestorović
Keyword(s):  
Disturbance Rejection ◽  
Closed Loop ◽  
State Observer ◽  
Output Regulation ◽  
Loop System ◽  
Extended State Observer ◽  
Dynamical Structure ◽  
Extended State ◽  
Closed Loop System ◽  
Robust Output Regulation

This paper presents a disturbance rejection-based solution to the problem of robust output regulation. The mismatch between the underlying plant and its nominal mathematical model is formulated by two disturbance classes. The first class is assumed to be generated by an autonomous linear system while for the second class no specific dynamical structure is considered. Accordingly, the robustness of the closed-loop system against the first disturbance class is achieved by following the internal model principle. On the other hand, in the framework of disturbance rejection control, an extended state observer (ESO) is designed to approximate and compensate for the second class, i.e., unstructured disturbances. As a result, the proposed output regulation method can deal with a vast range of uncertainties. Finally, the stability of the closed-loop system based on the proposed compound controller is carried out via Lyapunov and center manifold analyses, and some results on the robust output regulation are drawn. A representative simulation example is also presented to show the effectiveness of the control method.

Adaptive extended state observer-based flatness nonlinear output control for torque tracking of electrohydraulic loading system

2017 ◽  
Vol 40 (10) ◽  
pp. 2999-3009 ◽  
Author(s):  
Chenghu Jing ◽  
Hongguang Xu ◽  
Xiaoming Song ◽  
Biao Lu
Keyword(s):  
Closed Loop ◽  
State Observer ◽  
High Accuracy ◽  
Loop System ◽  
Extended State Observer ◽  
Extended State ◽  
Closed Loop System ◽  
Output Control ◽  
Loading System ◽  
The Stability

Electrohydraulic loading system is a torque servo system with high-accuracy and high-frequency response. In this paper, an adaptive extended state observer-based flatness nonlinear output control is proposed to improve the torque tracking performance of electrohydraulic loading system. This method combines a flatness concept, expected state, adaptive extended state observer and system output to develop a stable control system. Expected input feedforward based on the flatness property is designed to provide model compensation for bandwidth enhancement. An adaptive extended state observer is proposed to estimate the unmeasured states and the unmodeled dynamics. Based on estimated states and disturbances, state feedback control is developed to ensure the stability of closed-loop system, and to improve torque tracking accuracy and system robustness. The stability of the closed-loop system is proved by the Lyapunov stability theory. Extensive experiments were carried out to verify the performance of high-accuracy tracking of the proposed control strategy.

scholarly journals Active Disturbance Rejection Station-Keeping Control of Unstable Orbits around Collinear Libration Points

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Min Zhu ◽  
Hamid Reza Karimi ◽  
Hui Zhang ◽  
Qing Gao ◽  
Yong Wang
Keyword(s):  
Disturbance Rejection ◽  
External Disturbance ◽  
State Observer ◽  
Libration Points ◽  
Extended State Observer ◽  
Unstable Periodic Orbits ◽  
Extended State ◽  
Station Keeping ◽  
Tracking Differentiator ◽  
Active Disturbance Rejection

An active disturbance rejection station-keeping control scheme is derived and analyzed for station-keeping missions of spacecraft along a class of unstable periodic orbits near collinear libration points of the Sun-Earth system. It is an error driven, rather than model-based control law, essentially accounting for the independence of model accuracy and linearization. An extended state observer is designed to estimate the states in real time by setting an extended state, that is, the sum of unmodeled dynamic and external disturbance. This total disturbance is compensated by a nonlinear state error feedback controller based on the extended state observer. A nonlinear tracking differentiator is designed to obtain the velocity of the spacecraft since only position signals are available. In addition, the system contradiction between rapid response and overshoot can be effectively solved via arranging the transient process in tracking differentiator. Simulation results illustrate that the proposed method is adequate for station-keeping of unstable Halo orbits in the presence of system uncertainties, initial injection errors, solar radiation pressure, and perturbations of the eccentric nature of the Earth's orbit. It is also shown that the closed-loop control system performance is improved significantly using our method comparing with the general LQR method.

scholarly journals On-Line Compensation for the Disturbance Rejection Rate of a Platform Seeker Based on a High-Gain Extended State Observer

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Li Wei ◽  
Liu Shixiang ◽  
Zhang Wenjie ◽  
Xia Qunli
Keyword(s):  
Disturbance Rejection ◽  
Rejection Rate ◽  
High Gain ◽  
State Observer ◽  
Extended State Observer ◽  
Signal Extraction ◽  
Stable Region ◽  
Compensation Scheme ◽  
Extended State ◽  
On Line

This paper focuses on the on-line compensation of the disturbance rejection rate (DRR) for a platform seeker. The mathematical model of the typical platform seeker based on the inertial space is established, and the line-of-sight (LOS) rate from different signal extraction points is strictly derived. Considering the spring torque disturbance and damping torque disturbance caused by the missile attitude motion, the seeker DRR transfer functions are deduced and the amplitude and phase characteristics at different frequencies are also analyzed. In order to close the engineering practice, the DRR parasitic loop (DRRPL) model of the seeker is rationally simplified and the stable region of the parasitic loop from different extraction points is also obtained. However, to increase the stability and guidance accuracy of the missile terminal flight, the compensation scheme based on the high-gain extended state observer (ESO) is used to estimate the disturbance torques and eliminate the seeker DRR effect. Numerical simulations are conducted to verify the effectiveness of the proposed scheme. The simulation results show that the seeker DRR effect mainly exists in the middle and low frequencies and the stable region of the parasitic loop at different signal extraction points is different. The proposed compensation scheme can effectively eliminate the parasitic loop effect of the seeker and increase the flight stability of the missile. It can reduce the terminal miss distance of the missile and improve the strike accuracy.

Extended State Observer Based Controller Design for the Green Bank Telescope Servo System

2015 ◽  
Author(s):  
Trupti Ranka ◽  
Mario Garcia-Sanz ◽  
John M. Ford
Keyword(s):  
Disturbance Rejection ◽  
Pid Controller ◽  
Controller Design ◽  
Tracking Error ◽  
State Observer ◽  
Extended State Observer ◽  
Tracking Performance ◽  
Extended State ◽  
External Disturbances ◽  
Green Bank Telescope

The Green Bank Telescope is a large flexible structure, requiring rms tracking error ≤ 3 arcseconds against internal and external disturbances. We design an extended state observer (ESO) based controller in various configurations to improve tracking performance and increase disturbance rejection. The controllers are simulated with an experimentally validated model of the GBT. Through the simulations, the response of ESO based controllers and legacy PID controller are compared using time and frequency domain responses. We show that the ESO based controller when implemented in both position and velocity loop can give significant improvement in tracking performance and better disturbance rejection without increase in controller output.

Applying LESO for Disturbance Rejection of Space Station

2014 ◽  
Vol 721 ◽  
pp. 257-260
Author(s):  
Ping Liu ◽  
Wei Jie Sun
Keyword(s):  
Attitude Control ◽  
Disturbance Rejection ◽  
Space Station ◽  
State Observer ◽  
Extended State Observer ◽  
Disturbance Compensation ◽  
Extended State ◽  
Lqr Controller ◽  
Linear Extended State Observer ◽  
Simulation Results

In this paper, a combing method based on the linear extended state observer (LESO) and the LQR controller is presented. The LESO is applied to estimate the total disturbance of the space station, and an effective disturbance compensation strategy is proposed for the attitude control and moment management. The simulation results illustrate this method is effective

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