Intelligent active flutter control of aeroelastic system with microtab surface based on data-driven robust disturbance rejection controller

The integration of photovoltaic (PV) systems with the grid connected four-leg voltage source inverters (4LVSI) offers more efficient power conversion and distribution. However, the complexity of these higher-order systems presents significant control challenges due to the sensitive nature of both DC bus voltage and 4LVSI output currents, which introduce complex dynamic interactions within the 4LVSI control system and limit its overall control performance, particularly under system uncertainties and disturbances such as variations in irradiance, PV cell temperature, and grid voltage. To address these challenges, an enhanced active disturbance rejection control (EADRC) scheme based on a super-twisting sliding mode observer (STSMO) is designed for the outer DC bus voltage control loop. The STSMO is incorporated in the ADRC method for its fast uncertainties and external disturbances estimations, high resilience against uncertainties, and good immunity to measurement noise. The proposed STSMO-based ADRC approach effectively estimates and compensates for system uncertainties and external disturbances, thereby enhancing DC bus voltage dynamics and stability, improving resilience against uncertainties, increasing immunity to measurement noise, ensuring better steady-state accuracy of the DC bus voltage, and increasing system reliability while reducing cost and size. The effectiveness and superiority of the proposed control method for the PV grid-connected 4LVSI system are validated through both simulation and real-time studies using the OPAL-RT simulator. The results demonstrate robust performance under parameter uncertainties and disturbances, including variations in irradiance, PV cell temperature, DC bus capacitor value, and grid voltage sags.

In order to overcome the problems of linear control method, which are unfavorable performance and highly depending on the accuracy of vehicle model, active disturbance rejection control(ADRC) strategy is used to complete active front wheel steering(AFS) control in this paper. According to the general principle of ADRC, a second order ADRC strategy is designed. Under the operation conditions of high speed single lane change and braking on µ-split road, the control performance is studied by means of simulation. The results show that the ADRC strategy can realize AFS control effectively and decrease the dependence on the accuracy of vehicle model. At the same time, the performance is better than that of PID control.

The PID control strategy is usually used to control the motor in the electric servo loading system CESLS), however there are some nonlinear factors such as mechanism clearance and surplus torque in the loading process, the conventional PID control method can't guarantee the control performance and the loading accuracy of the ESLS. A position feed-forward compensation controller is introduced in the ESLS, and an outer loop active disturbance rejection control (ADRC) strategy is designed to eliminate position disturbance and surplus torque disturbance in this paper. The method of “observation + compensation” used in the outer loop ADRC controller is not only to suppress the surplus torque, but also to improve the steady-state performance of the ESLS. The simulation result shows that the electric servo loading system based on ADRC strategy can effectively improve the tracking accuracy of the ESLS and enhance the stability of the ESLS.

Active disturbance rejection control for spacecraft relative motion in libration point orbits subject to actuator saturation and time-delays

Finite-time output consensus control of nonlinear uncertain multi-agent systems via extended state observer

Integrated flight-propulsion control (IFPC) in cruise mode is under study for ramjet powered supersonic vehicle. The longitudinal flight control and propulsion control model are built with system disturbance and measurement noise. We propose a decoupling active disturbance rejection control (ADRC) scheme for IFPC design. For velocity control loop, a second-order linear extended state observer (ESO) is used. The altitude control loop includes inner pitch angle control and outer altitude control. Two third-order linear ESOs are applied in the altitude control loop. These ESOs estimate the disturbances on altitude and pitch angle, and their parameters are determined by their bandwidth. Two tracking-differentiators (TD) ensure the transient process of velocity and altitude. The linear combinations of state error feedback are applied. The control design eliminates coupling effects between altitude and velocity and attenuates measurement noise.

This paper presents a predictor-based active disturbance rejection control (PADRC) scheme for input delay systems. In the proposed control scheme, the extended state observer (ESO) is modified by delaying the control signal to compensate the time delay from the observation loop. Moreover, a predictor is designed in time domain to obtain estimated states for current time and cancel the effects of input delay on the closed-loop system, where the approximation of disturbances is considered for corrective prediction purposes. Furthermore, a PD controller is designed to compensate disturbances and control the system. Then, the stability of the closed-loop system is analyzed by the Lyapunov function method. Finally, the effectiveness of the PADRC is demonstrated by simulations.

Flue gas desulfurization in thermal power plants is critical to the environmental and human health. Aiming for field application, this article presents a new predictor-and-observer-based active disturbance rejection control (ADRC) scheme for Wet Flue Gas Desulfurization (WFGD) process which is subject to long time delay and unknown disturbances. First, the working principles and control problems of WFGD system are illustrated, and the WFGD process model is identified based on the field experimental data. Then, a predictor-based ADRC approach is carefully devised to address its control issues. Specifically, a filtered smith predictor (FSP) is designed to obtain stable delay-free prediction output, and a reduced-order model-assisted extended state observer (MESO) is devised to estimate the “total disturbance” with less phase lag. Based on the equivalent control structure, its stability, including the perfect delay matching and delay mismatch cases, is theoretically investigated using the zero exclusion criterion. A simple “separation tuning procedure” is also provided, where the ADRC parameters are tuned directly based on the delay-free process, while the FSP filter is specified to achieve desired robustness. Finally, the validity of the proposed method is demonstrated by comparison simulations and field tests in a 1000MW thermal power unit. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This article focuses on sulfur dioxide (SO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_2$</tex-math> </inline-formula> ) control and proposes a new predictor-based ADRC approach for the WFGD process subject to long time delay and unknown disturbances. Taking the WFGD system as an example, it systematically describes the whole process of modeling, control system design and simulation & experimental verification, which can provide an intuitive reference for practitioners. The zero exclusion criterion is used to analyze the closed-loop stability and determine the stable delay range for a given predictor-based ADRC control system. A detailed tuning procedure is also provided, which can simplify the time-consuming tuning process and help engineers grasp the performance and robustness of the control system. It is evident that the proposed method can be extended to a general class of industrial time-delay systems, which facilitates the practitioner’s practice in general single-input-single-output time-delay system control. The field test results demonstrate the superiority of the proposed method and show promise for practical application in other systems.

PurposeThis paper aims to study a disturbance rejection controller to improve the anti-interference capability and the position tracking performance of airborne radar stabilized platform that ensures the stability and clarity of synthetic aperture radar imaging.Design/methodology/approachThis study proposes a disturbance rejection control scheme for an airborne radar stabilized platform based on the active disturbance rejection control (ADRC) inverse estimation algorithm. Exploiting the extended state observer (ESO) characteristic, an inversely ESO is developed to inverse estimate the unmodeled state and extended state of the platform system known as total disturbances, which greatly improves the estimation performance of the disturbance. Then, based on the inverse ESO result, feedback the difference between the output of the tracking differentiator and the inverse ESO result to the nonlinear state error feedback controller (NLSEF) to eliminate the effects of total disturbance and ensure the stability of the airborne radar stabilized platform.FindingsSimulation experiments are adopted to compare the performance of the ADRC inverse estimation algorithm with that of the proportional integral derivative controller which is one of the mostly applied control schemes in platform systems. In addition, classical ADRC is compared as well. The results have shown that the ADRC inverse estimation algorithm has a better disturbance rejection performance when disturbance acts in airborne radar stabilized platform, especially disturbed by continuous airflow under some harsh air conditions.Originality/valueThe originality of this paper is exploiting the ESO characteristic to develop an inverse ESO, which greatly improves the estimation performance of the disturbance. And the ADRC inverse estimation algorithm is applied to ameliorate the anti-interference ability of the airborne radar stabilization platform, especially the ability to suppress continuous interference under complex air conditions.

Automatic carrier landing system based on active disturbance rejection control with a novel parameters optimizer

To improve the anti-disturbance ability of LCL grid-connected inverter system, a novel immersion and invariance based on active disturbance rejection control(I&amp;I-ADRC) scheme is proposed in this paper. First, the target system with stronger anti-disturbance ability is immersed into the ADRC standard model by using the target system mapping method of immersion and invariance control. Then, the disturbance estimated by extended state observer (ESO) is compensated, and the immersion and invariance(I&amp;I) control law is adopted to design the state error feedback（SEF）control law, thus I&amp;I-ADRC is built, which has improved anti-disturbance ability and dynamic response performance. The stability of grid-connected inverter system is proved by Lyapunov theory. Simulation results show that the proposed strategy can effectively suppress the disturbance and has better tracking performance.

This paper presents the design and implementation of a novel sliding mode control integrated with active disturbance rejection (SMCDR) for precise robust trajectory tracking of piezoelectric nanopositioning stages. The model uncertainties, nonlinearity, and external disturbances of the piezoelectric nanopositioning stage are regarded as a lumped disturbance, which is estimated by an extended state observer. The active disturbance rejection control (ADRC) strategy is used to realize a preliminary trajectory tracking, while the sliding mode control is adopted to handle the estimation error and residual uncertainties, and to improve the tracking performance. The exponential stability of the proposed SMCDR is proved using Lyapunov’s direct method. The proposed SMCDR controller combines the strength of both ADRC and sliding mode control, exhibits a simple structure, requires only the position measurements, and does not require any information of model parameters except for an approximate constant gain. Experimental results reveal the robustness of the SMCDR approach in suppressing the hysteresis of piezoelectric actuator, and illustrate the superior performance over conventional ADRC, integral sliding mode controller (ISMC) and PID controller for trajectory tracking control of piezoelectric nanopositioning stages.

It is unquestionably difficult to achieve precise path-following control for a parafoil system while taking sideslip angle effect into account. To address this challenge and enhance the robustness and flexibility of tracking control, this study presents an improved active disturbance rejection control (IADRC) strategy for parafoil path following based on the surge-guided line-of-sight (SGLOS) guidance law and the multi-strategy marine predator algorithm (MSMPA) optimization. Firstly, a guidance law is designed that simultaneously utilizes surge speed and heading angle for guidance. Then, IADRC is devised to enhance stability by mitigating observational errors from the extended state observer using fal function filters and phase predictions for pre-smoothing sideslip angles as well as abrupt yaw angle fluctuations. Additionally, a controller parameter tuning approach based on the improved MSMPA is proposed. Finally, the simulation results show that this strategy could effectively overcome the influence of wind field disturbances and achieve accurate path following control. Compared with the traditional PID control and linear active disturbance rejection control (LADRC), this method has a higher tracking accuracy and better robustness.

In order to meet the precision requirements and tracking performance of the continuous rotary motor electro-hydraulic servo system under unknown strong non-linear and uncertain strong disturbance factors, such as dynamic uncertainty and parameter perturbation, an improved active disturbance rejection control (ADRC) strategy was proposed. The state space model of the fifth order closed-loop system was established based on the principle of valve-controlled hydraulic motor. Then the three parts of ADRC were improved by parameter perturbation and external disturbance; the fast tracking differentiator was introduced into linear and non-linear combinations; the nonlinear state error feedback was proposed using synovial control; the extended state observer was determined by nonlinear compensation. In addition, the grey wolf algorithm was used to set the parameters of the three parts. The simulation and experimental results show that the improved ADRC can realize the system frequency 12 Hz when the tracking accuracy and response speed meet the requirements of double ten indexes, which lay foundation for the motor application.

Neural network-based active disturbance rejection control and its application in quadrotor unmanned aerial vehicle trajectory tracking.