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In this article, an active disturbance rejection controller (ADRC) based on deep reinforcement learning (DRL) algorithm is proposed to be used in the flux weakening control (FWC) system of motors for more electric aircraft. Artificial intelligence algorithm is introduced into ADRC motor control system for the first time, and DRL is designed as the automatic tuning for the parameters optimization of ADRC. The interface module scheme is proposed to realize the conversion between the relevant quantities of the control system and the DRL Agent according to the characteristics of ADRC. The parameters are optimized in the form of parameter modification, and a new DRL-ADRC control framework is proposed which can avoid being trapped into local optimum. The ADRC model designed for the speed loop of FWC system are first introduced. An interface module is subsequently built to enable DRL to interact with the FWC system automatically. DRL agent is trained to optimize the internal parameters of ADRC, which have the characteristics of large quantities, weak sensitivity and strong coupling. Deep deterministic policy gradient is used as the strategy of DRL, which can quickly determine the descent gradient and converge the multiobjective optimization problem. Simulation and comparison with classical heuristic algorithms and disturbance rejection methods are carried out to show the superiority of DRL. The feasibility and effectiveness of the proposed control method are verified by experiments on an aerospace motor for MEA. [ABSTRACT FROM AUTHOR]

As the higher order or generalized extended state observer (ESO), generalized proportional-integral (GPI) observer (GPIO) haves been proposed to enhance the active disturbance rejection (ADR) control (ADRC) system's disturbance rejection ability. However, different ADR controllers can be deduced based on the same order GPIO, resulting in different dynamic performances. In this article, ten different ADR controllers based on the fourth order GPIO are present. In order to reveal the relationship between these ADR controllers and the conventional ADR controllers based on the third order ESO, six different third-order-ESO-based ADR controllers are present and compared with the fourth-order-ESO-based ADR controllers. To ease the comparison between different ADRC systems, a common expression is built for different ADR controllers. A novel frequency-domain analysis method is also introduced to reveal how the observer and feedback control law affects the closed-loop control system's dynamic performance. The effectiveness of the proposed method is verified on the test bench based on dSPACE DS1103. [ABSTRACT FROM AUTHOR]

This article presents an optimal direct torque control (DTC) strategy with variable flux for a switched reluctance motor using the improved linear active disturbance rejection control (LADRC) plus the hybrid optimization algorithm (HOA). First, the constant flux amplitude is substituted by the variable flux DTC (VF-DTC) to reduce the torque ripple. Then, the LADRC with the improved extended state observer applied in speed controller is utilized instead of the conventional PI control to improve the speed of the observer, antidisturbance ability, and robustness. Moreover, the HOA is employed to search for the optimal control parameters and acquire satisfactory dynamic performances. Finally, the optimal VF-DTC system is implemented on a 12/8 SRM. Simulation and experimental results are carried out to compare the performances of the conventional DTC, the VF-DTC with LADRC, the VF-DTC with PI using HOA, and the proposed optimal VF-DTC using HOA. The results show that the proposed control method has a faster speed response, superior antidisturbance ability, and lower torque ripples. [ABSTRACT FROM AUTHOR]

Active disturbance rejection control using extended state observer (ESO) is less dependent on the knowledge of the system. It has proved to be an excellent scheme for speed control of electrical drives. However, for time-varying disturbance, the observation precision of conventional ESO is undesired, which limits the speed tracking accuracy. Accordingly, this article proposes an enhanced speed controller for electrical drives based on adaptive switching high-order ESO (ASHESO). First, the critical parameters affecting the steady-state performance of ASHESO are determined according to frequency analytical results. Then, optimized observer gain is obtained by modifying a part of pole locations, which weakens the influence of noise on estimated state. Finally, an adaptive switching gain mechanism is proposed according to the closed-loop tracking error and the swiftness of dynamic response is maintained. The proposed speed controller has achieved high estimation accuracy for disturbance and strong immunity to measurement noise. The feasibility and effectiveness of the strategy is verified on a laboratory permanent magnet synchronous motor (PMSM) drive system. [ABSTRACT FROM AUTHOR]

In this article, a predictive active disturbance rejection control (ADRC) scheme is proposed for high-precision position tracking control of servo systems with communication delays via sliding mode approach. In the proposed framework, a filtered state predictor is employed to handle time delays in the networked control system. Based on the predictive states, a linear extended state observer is used to compensate unknown perturbations for ADRC, and a boundary layer solution of the sliding mode control is applied via the internal model control rules for robust control. Since the filtered predictive scheme can compensate the time delays and alleviate the effect of the ignored high-frequency dynamics, higher control gains and observer bandwidth of the ADRC can be achieved, leading to a better position tracking accuracy of the control system in the presence of uncertainties and disturbances. The stability of the overall control system is also analyzed via the Lyapunov method. Comparative experiments were carried out to validate the superior performance of the proposed controller. [ABSTRACT FROM AUTHOR]

Multiactive bridge (MAB) converter is a promising solution for integrating multiple renewable sources, storage, and loads for various applications. However, the MAB converter is challenging to control due to the inherent coupling between the port power flows. To that end, this article presents a decoupling control strategy based on linear active disturbance rejection control. The proposed controller observes the coupling disturbance using a linear extended state observer and subsequently rejects the observed disturbance resulting in dynamic decoupling. Experiments conducted on a 2-kW 100-kHz Si-C-based four-port MAB converter laboratory prototype illustrate the decoupling performance of the proposed control strategy. Compared to the traditional decoupling control strategy, the proposed approach is decentralized and model independent, only requiring information regarding its order. [ABSTRACT FROM AUTHOR]

Formation tracking is a critical issue in the consensus control of multiagent systems (MASs). This article presents a time-varying formation tracking strategy with predefined performance for a class of uncertain nonaffine nonlinear MASs connected through a directed topology. The nonaffine nonlinear MASs are transformed into affine nonlinear ones with uncertainties via the idea of active disturbance rejection control (ADRC). The uncertainties in the MASs are approximated and compensated by extended state observers (ESOs) in real time. Tracking differentiators (TDs) are introduced to reduce the complexity in the computation of the derivatives of virtual control variables. Employing funnel variables, our strategy guarantees the formation of tracking errors to stay within the desired ranges, thus improving the control performance of the closed-loop system. It is proved that all signals of the system are bounded and the formation errors can be made arbitrarily small within a residue around the origin by appropriate choices of control parameters. Case studies are carried out to demonstrate the effectiveness of the proposed control strategy. Note to Practitioners—The motivation of this article is to present a time-varying formation tracking strategy with predefined performance for a class of uncertain nonaffine nonlinear MASs within a directed topology. To simplify the process of solving the formation tracking problem, the presented strategy incorporates ADRC with the backstepping technique. Employing ADRC, our strategy approximates the uncertainties of the MAS followers via ESOs. The uncertainties are then compensated through real-time estimations of extended states. Moreover, with ADRC, TDs are used to estimate the derivatives of complex nonlinear functions, eliminating the requirement of the operations of higher order derivatives of virtual control variables. It provides a feasible strategy for industrial applications. [ABSTRACT FROM AUTHOR]

A novel active disturbance rejection based repetitive learning control scheme, including three channels, namely, feedforward, feedback, and disturbance rejection channels, is investigated. The goal of this work is to achieve a high-quality output voltage and robustness to disturbances and uncertainties in the inverter system. The mathematics model of the inverter is replaced by a chain of two integrators to avoid model identification and time-varying parameter estimation when designing the controller. The ignored system dynamics, the uncertainties, and the nonrepetitive factors caused by nonrepetitive disturbances are all defined as part of the total disturbance to be estimated and compensated for, which decreases the controller sensitivity for the system parameters and operating environment. The stability conditions of the control system scheme along the periods are analyzed, and the mitigation of different frequency-band disturbances using the combination control scheme is demonstrated on the frequency spectrum. Finally, the algorithm is validated on a hardware platform, and the tolerability of varying parameters is tested. [ABSTRACT FROM AUTHOR]

A linear/nonlinear active disturbance rejection control (ADRC) switching control (SADRC) strategy for permanent magnet synchronous motors (PMSMs) is proposed in this article to integrate the merits of the linear ADRC (LADRC) and nonlinear ADRC (NLADRC), and handle the trouble in parameter tuning and stability analysis of the NLADRC. The advantages and disadvantages of the LADRC and NLADRC are analyzed theoretically and a hysteretic switching strategy is presented to estimate and compensate the total disturbance smoothly and precisely. Based on the proposed control strategy, the SADRC controller of the PMSM is designed to achieve the accurate and robust speed control of the PMSM. Moreover, a parameter tuning strategy of the SADRC is proposed as well to simplify the parameter tuning of the NLADRC linked inextricably with that of the LADRC due to limitation of the switching conditions. Finally, the feasibility and superiority of the proposed control strategy are demonstrated on a 180 W PMSM platform. [ABSTRACT FROM AUTHOR]

An observer-based containment control issue is addressed for a class of uncertain nonlinear multiagent systems with a directed topology via the active disturbance rejection control and backstepping techniques. A kind of nonlinear extended state observers (ESOs) based on fractional power functions is developed, and the estimations of extended states are utilized to compensate uncertain dynamics in real time. Compared with linear ESOs, the advantages of the ESOs in this paper lie in peaking reduction and better tolerance of measurement noise for the closed-loop system. Moreover, tracking differentiators are employed to avoid the explosion of complexity caused by repeated differentiations of nonlinear functions. It is proven that the containment errors of the followers converge to small neighborhoods of the origin and they are adjustable by suitable choice of parameters. Finally, two simulation examples, both practical and numerical ones, are shown to demonstrate the effectiveness of the proposed control approach. [ABSTRACT FROM AUTHOR]

A control method that combines a vector resonant controller and an active disturbance rejection control controller is proposed in this article for suppressing the current harmonics of permanent magnet synchronous linear motors. First, the resonant controller is improved by changing its transfer function so that it can suppress current harmonics better. Then, an active disturbance rejection control (ADRC) is designed to suppress the parameter disturbance of motors, which will adversely affect the improved resonant controller. The parameter disturbance is estimated by an extended state observer, and linear feedback control is used for disturbance compensation. The ADRC and the improved resonant controller work together to not only suppress harmonics but also improve resistance against system disturbance. Finally, a linear motor control platform is built, and experimental results are presented to verify the significance and correctness of the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper, an active disturbance rejection control (ADRC) method is investigated for the ranger neutral buoyancy vehicle (RNBV) via a delta operator approach. In order to eliminate unmodeled nonlinearities and exogenous disturbances for a neutral environment, a novel delta-domain ADRC method is put forward to achieve the tracking control performance of the RNBV. In the proposed ADRC method, an extended-state-observer (ESO) is designed in the delta domain to estimate the so-called total disturbance that reflects the aggregated impacts of the nonlinearities and disturbances. Then, by using the estimates provided by the ESO, a composite controller is developed such that the closed-loop system can be input-to-state stable. It is shown in practical experiments that the proposed delta-domain ADRC outperforms its discrete-domain counterpart in consideration of the finite-word-length effects. [ABSTRACT FROM AUTHOR]