A simplified model based disturbance rejection control for highly accurate positioning of an underwater robot

In this paper, a simple active-model-based control scheme is developed for the quadrotor slung load (QSL) system. The scheme works to improve the rejection of the influences caused by the abruptly changed load as a complementary enhancement while maintaining the structure and parameters of the original controller. A linearized model is first constructed with respect to the hovering state of a quadrotor. Modeling error is then introduced to describe the uncertainties caused by the load change and the simplified model. The modeling error is actively estimated by a Kalman filter (KF), while the estimation is further integrated into a normal controller, to enhance its performance of disturbance rejection. Experiments are conducted on a quadrotor controlled by the Pixhawk, which is one of the most popular controllers commercially available on the market. The improvements of the proposed scheme are shown by the comparisons between the controls with and without the active-model-based enhancement. The experiments also indicate that, with its simple structure and less computational algorithm, this active-model-based enhancement would be a feasible approach to enhance the commercial UAV controller to handle more uncertainties.

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Active disturbance rejection control for a piezoelectric nano-positioning system: A U-model approach

Measurement and Control ◽

10.1177/00202940211000075 ◽

2021 ◽

pp. 002029402110000

Author(s):

Wei Wei ◽

Bowen Duan ◽

Min Zuo ◽

Weicun Zhang

Keyword(s):

Disturbance Rejection ◽

Control Input ◽

Phase Lag ◽

Active Disturbance Rejection Control ◽

Model Based ◽

Active Disturbance Rejection ◽

Disturbance Rejection Control ◽

Model Control ◽

Key Issues ◽

Speed And Accuracy

Both speed and accuracy are key issues in nano-positioning. However, hysteresis existing in piezoelectric actuators severely reduces the positioning speed and accuracy. In order to address the hysteresis, a U-model based active disturbance rejection control is proposed. Based on the linear active disturbance rejection control, a controlled plant is dynamically transformed to be pure integrators. Then, according to the U-model control, a common inversion is obtained and the controlled plant is converted to be “1.” By integrating advantages of both linear active disturbance rejection control and U-model control, the U-model based active disturbance rejection control does promote the reference tracking speed and accuracy. Stability and steady-state error of the close-loop system have been analyzed. Phase lag between the system output and the control input has been effectively eliminated, and the phase-leading advantage of the U-model based active disturbance rejection control has been confirmed. Experimental results show that the U-model based active disturbance rejection control is capable of achieving faster and more accurate positioning. Remarkable improvements and practical realization make the U-model based active disturbance rejection control more promising in nano-positioning.

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A Model-Based Unmatched Disturbance Rejection Control Approach for Speed Regulation of a Converter-Driven DC Motor Using Output-Feedback

IEEE/CAA Journal of Automatica Sinica ◽

10.1109/jas.2021.1004213 ◽

2021 ◽

pp. 1-12

Author(s):

Lu Zhang ◽

Jun Yang ◽

Shihua Li

Keyword(s):

Output Feedback ◽

Disturbance Rejection ◽

Dc Motor ◽

Control Approach ◽

Model Based ◽

Speed Regulation ◽

Disturbance Rejection Control

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Detection of Cracks in Turborotors—A New Observer Based Method

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2899130 ◽

1993 ◽

Vol 115 (3) ◽

pp. 518-524 ◽

Cited By ~ 45

Author(s):

D. So¨ffker ◽

J. Bajkowski ◽

P. C. Mu¨ller

Keyword(s):

Nonlinear Systems ◽

Disturbance Rejection ◽

Crack Depth ◽

Model Based ◽

Disturbance Rejection Control ◽

Opening And Closing ◽

Clear Statement ◽

Clear Relation

The clear relation between shaft cracks in turborotors and vibration effects measured in bearings can be established by model-based methods very well. Here a new concept has been presented, based on the theory of disturbance rejection control, extended for nonlinear systems and applied on a turborotor. Simulations have been done, showing the theoretical success of this method, especially for reconstructing disturbance forces as inner forces caused by the crack. Calculating the relative crack compliance as the ratio of additional compliance caused by the crack and undamaged compliance a clear statement about the opening and closing, and therefore for the existence of the crack, and about the crack depth is possible. Theoretically it has been shown that it is possible to detect a crack with very small stiffness changes which corresponds to a crack depth of 5 percent of the radius of the rotor.

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