Time-domain fixed-structure closed-loop model identification of an unstable multivariable maglev nanopositioning system

2011 ◽  
Vol 9 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Huzefa Shakir ◽  
Won-jong Kim
Keyword(s):  
Time Domain ◽  
Closed Loop ◽  
Model Identification ◽  
Loop Model ◽  
Fixed Structure

scholarly journals Full-Closed-Loop Time-Domain Integrated Modeling Method of Optical Satellite Flywheel Micro-Vibration

2021 ◽  
Vol 11 (3) ◽  
pp. 1328
Author(s):  
Yang Yu ◽  
Xiaoxue Gong ◽  
Lei Zhang ◽  
Hongguang Jia ◽  
Ming Xuan
Keyword(s):  
Time Domain ◽  
Closed Loop ◽  
Modeling Method ◽  
Integrated Modeling ◽  
Frequency Error ◽  
Vibration Source ◽  
Loop Model ◽  
Model Framework ◽  
Ground Experiment ◽  
Micro Vibration

Due to the micro-vibration of flywheels, the imaging quality of a high-resolution optical remote sensing satellite will be deteriorated, and the micro-vibration effect on the payload is complicated, so it is essential to establish a reasonable and accurate theoretical simulation model for it. This paper presents a method of full-closed-loop time-domain integrated modeling to estimate the impacts of micro-vibration generated by flywheels on optical satellites. The method consists of three parts. First, according to the satellites’ micro-vibration influence mechanism in orbit, this paper establishes a full-closed-loop model framework. The overall model input is the instructions received and the output is the image shift. Second, in order to meet the requirements of time-domain simulation, this paper proposes a time-domain vibration source subsystem model in the form of cosine harmonic superposition, and it integrates vibration source, structural, control, and optical subsystem models to create a full-closed-loop time-domain analysis model that can obtain the responses of micro-vibration in time and frequency domains. Lastly, the author designs a ground experiment and compares simulation results with experiment results. Compared with the ground experiment, frequency error is less than 0.4% at typical responses. Although the amplitude error is large at some typical responses, the mean root square error is less than 35%. Based on the data, the proposed integrated modeling method can be considered as an accurate methodology to predict the impacts of micro-vibration.

Closed-loop model identification and PID/PI tuning for robust anti-slug control

2013 ◽  
Vol 46 (32) ◽  
pp. 233-240 ◽  
Author(s):  
Esmaeil Jahanshahi ◽  
Sigurd Skogestad
Keyword(s):  
Closed Loop ◽  
Model Identification ◽  
Loop Model

Discrete-Time Closed-Loop Model Identification of Fixed-Structure Unstable Multivariable Systems

2007 ◽  
Author(s):  
Huzefa Shakir ◽  
Won-Jong Kim
Keyword(s):  
System Identification ◽  
Discrete Time ◽  
Closed Loop ◽  
Model Identification ◽  
Order Reduction ◽  
Loop System ◽  
Loop Model ◽  
Frequency Range ◽  
Closed Loop System ◽  
Closed Loop Identification

This paper presents improved empirical representations of a general class of open-loop unstable systems using closed-loop system identification. A multi-axis magnetic-levitation (maglev) nanopositioning system with an extended translational travel range is used as a test bed to verify the closed-loop system-identification method proposed in this paper. A closed-loop identification technique employing the Box-Jenkins (BJ) method and a known controller structure is developed for model identification and validation. Direct and coupling transfer functions (TFs) are then derived from the experimental input-output time sequences and the knowledge of controller dynamics. A persistently excited signal with a frequency range of [0, 2500] Hz is used as a reference input. An order-reduction algorithm is applied to obtain TFs with predefined orders, which give a close match in the frequency range of interest without missing any significant plant dynamics. The entire analysis is performed in the discrete-time domain in order to avoid any errors due to continuous-to-discrete-time conversion and vice versa. Continuous-time TFs are used only for order-reduction and performance analysis of the identified plant TFs. Experimental results in the time as well as frequency domains verified the accuracy of the plant TFs and demonstrated the effectiveness of the closed-loop identification and order-reduction methods.

scholarly journals On error analysis of a closed-loop subspace model identification method

2021 ◽  
Vol 54 (9) ◽  
pp. 701-706
Author(s):  
Hiroshi Oku ◽  
Kenji Ikeda
Keyword(s):  
Error Analysis ◽  
Closed Loop ◽  
Model Identification ◽  
Identification Method

scholarly journals A computationally efficient physiologically comprehensive 3D–0D closed-loop model of the heart and circulation

2021 ◽  
Vol 386 ◽  
pp. 114092
Author(s):  
Christoph M. Augustin ◽  
Matthias A.F. Gsell ◽  
Elias Karabelas ◽  
Erik Willemen ◽  
Frits W. Prinzen ◽  
...  
Keyword(s):  
Closed Loop ◽  
Loop Model ◽  
Computationally Efficient

The application of compound proportional resonant control strategy in multiple PV inverters system

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840098
Author(s):  
Yuan Li ◽  
Huifang Shen ◽  
Chao Xiong ◽  
Yaofei Han ◽  
Guofeng He
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Control Strategies ◽  
Integrated Control ◽  
Reference Signal ◽  
Loop Model ◽  
Harmonic Compensation ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Set Up

In order to eliminate the effect on the grid current caused by the background harmonic voltage and the reference signal on the grid connected multi-inverter, this paper adopts the double closed-loop feed-forward control strategy. This strategy is based on the inductor voltage and the grid-connected current, and the integrated control strategy of quasi-proportional resonance loop parallel to a specific harmonic compensation loop. Based on the closed-loop model of multiple inverters, the change curves of the transfer function of the two control strategies are compared with the feed-forward control and the composite proportional resonance. The two corresponding control methods are used to analyze the current quality of the multi-inverter impact. Finally, the MATLAB/Simulink simulation model is set up to verify the proposed control strategies. The simulation results show that the proposed method can achieve better tracking of the sinusoidal command signal at the fundamental frequency, and enhance the anti-interference ability of the system at the 3rd, 5th, and 7th harmonic frequency.

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