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Can continuous-time disturbance be represented by sampled input disturbance? |
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Gyunghoon Park, Hyungbo Shim(Seoul National University, Korea), Kyoungchul Kong(Sogang University, Korea) |
| In this paper, we study whether any continuous-time disturbance to a continuous-time plant can be equivalently
represented by a sampled input disturbance to a sampled-data model. With the help of the sampled-data system theory,
we show that such equivalent sampled disturbance exists for almost sampling period and even for mismatched continoustime
disturbances. Moreover, it is also discussed that whether the equivalent sampled disturbance is bounded significantly
depends on the zeros of the sampled-data system. Simulation results verify the validity of the stability analysis. |
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On Extended State Predictor Observer based Active Disturbance Rejection Control for Uncertain Systems with Sensor Delay |
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Wenchao Xue, Ping Liu, Sen Chen, Huang Yi(Chinese Academy of Sciences, China) |
| This paper considers the control problem for a class of sensor delay systems with nonlinear unknown dynamics and external disturbances. The extended state predictor observer (ESPO) based active disturbance rejection control (ADRC) is first proposed to timely estimate and compensate for the ``total disturbance'' under sensor delay. The time-domain stability of the closed-loop system is rigorously studied by discussing the bound of tracking error between state and its desired trajectory. More importantly, it is proven that the proposed method can greatly improve the existing PO based control |
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Tuning ADRC for Multi-Variable System Based on Existing PID Parameters |
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Chunzhe Zhao(Chongqing Three Gorges University, China), Donghai Li(Tsinghua Univ, China), Chun-E Huang(Beijing Union University, China) |
| Due to the long-time engineering practice, the existing PID controllers and their parameters contain the valuable information about the models of the industrial processes. Such information is absorbed to simplify the design and tuning process of the active disturbance rejection controller (ADRC) in this study. If one channel of the multivariable system is stabilized by PID, then ADRC can be built to replace the PID scheme, and the ADRC parameters can be calculated from the PID parameters. This technique can be operated channel by channel until all channels are stabilized by ADRC, which is veri |
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Disturbance Rejection of Steam Superheated Temperature in a Utility Boiler: A Cascaded Disturbance Observer based Control Solution |
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Li Sun, Yali Xue, Donghai Li(Tsinghua University, China), Kwang Y. Lee(Baylor University, United States) |
| This paper derived a model for the superheated steam temperature based on the open-loop step response. A cascaded control structure based on disturbance observer (DOB) is proposed to accommodate the control difficulties. The simulation results show the great performance improvement compared with the conventional cascaded control structure. This paper is a preliminary research to the cascaded DOB control structure. Much improvement, theoretic analysis and experimental demonstration will be carried out in the future. |
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Active Disturbance Rejection Control for Nanopositioning Systems with Piezoelectric Actuators |
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Wei Wei, Ran Zhang(Beijing Technology and Business University, China), Jing Wang(University of Science and Technology Beijing, China), Guangbo Hao(University College Cork, Ireland) |
| Nanopositioning proposes a high demand for its control system. However, hysteresis, a common nonlinear phenomenon existing in piezoelectric actuator, decreases precision of nanopositioning. In this paper, active disturbance rejection control (ADRC) is designed to estimate and cancel the influence of hysteresis, and integral time absolute error (ITAE) optimal index is chosen to determine the parameters of ADRC. Simulations are performed on the basis of mathematic model of nanopositioning system, and numerical results show that ADRC is effective in the control of nanopositioning. |
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Active Disturbance Rejection Control for Fluidized Bed Combustor |
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Zhenlong Wu, Donghai Li(Tsinghua University, China), Lingmei Wang(Shanxi University, China), Jing Wang(University of Science and Technology Beijing, China) |
| Active disturbance rejection control (ADRC) is applied in fluidized bed combustor (FBC) facing some control difficulty. By analyzing the difficulties, ADRC controllers are designed for the power loop and the bed temperature loop of FBC system. The simulation demonstrates both loops with ADRC have a better tracking speed and a stronger robustness, the power loop can inhibit the input and output disturbance quickly and the temperature loop has a slight advantage in disturbance rejection. Besides, manipulated variables is analyzed by the phase diagrams. |
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