Active Disturbance Rejection Control Strategy Research Articles

Active Disturbance Rejection Control in Magnetic Bearing Rotor Systems with Redundant Structures.

At present, magnetic bearings are a better energy-saving choice than mechanical bearings in industrial applications. However, there are strongly coupled characteristics in magnetic bearing–rotor systems with redundant structures, and uncertain disturbances in the electrical system as well as external disturbances, and these unfavorable factors degrade the performance of the system. To improve the anti-interference performance of magnetic bearing systems, this paper proposes the inverse of the current distribution matrix W−1 meaning that the active disturbance rejection control simulation model can be carried out without neglecting the current of each coil. Firstly, based on the working mechanism of magnetic bearings with redundant structures and the nonlinear electromagnetic force model, the current and displacement stiffness models of magnetic bearings are established, and a dynamic model of the rotor is constructed. Then, according to the dynamic model of the rotor and the mapping relationship between the current of each coil and the electromagnetic force of the magnetic bearing, we established the equivalent control loop of the magnetic bearing–rotor system with redundant structures. Finally, on the basis of the active disturbance rejection control (ADRC) strategy, we designed a linear active disturbance rejection controller (LADRC) for magnetic bearings with redundant structures under the condition of no coil failure, and a corresponding simulation was carried out. The results demonstrate that compared to PID+current distribution control strategy, the LADRC+current distribution control strategy proposed in this paper is able to effectively improve the anti-interference performance of the rotors supported by magnetic bearings with redundant structures.

High-speed train speed tracking control based on active disturbance rejection control strategy

The speed tracking control of high-speed trains has the characteristics of nonlinearity, time delay, and multi-factor interference. Aiming at this, a train speed tracking algorithm based on active disturbance rejection control strategy is proposed. First, establish a train control model based on the train dynamics model. Secondly, design a second-order active disturbance rejection controller to set and compensate for unknown disturbances, and then convert the known train parameters to the controlled object for system simulation, the target speed curve is tracked, which proves the feasibility of the auto disturbance rejection control algorithm. Finally, compare traditional PD control algorithms in terms of anti-jamming performance and tracking error. The results show that the high-speed train speed controller based on active disturbance rejection control has greatly improved the tracking speed accuracy and the robustness of the control system.

Enhanced Active Disturbance Rejection Current Controller for Permanent Magnet Synchronous Machines Operated at Low Sampling Time Ratio

Recently, active disturbance rejection control (ADRC) scheme has been widely used for current regulation in ac drive systems owing to its robustness to system uncertainties and its high disturbance-rejection capability. However, it has not been considered as an option for high-speed drives usually operated at limited switching and sampling frequencies. Therefore, this article thoroughly analyzes and discusses the effects of high operating speed, modulation, and computational delays on the conventional ADRC. Based on this analysis, an enhanced ADRC for the current control is proposed to operate the drive system at low sampling time ratio with high robustness to the internal and external disturbances. Effect of model uncertainties on the proposed scheme has also been analytically analyzed and reported. Comprehensive simulation and experimental results have been presented to demonstrate the improved performance of the proposed ADRC scheme and to support the analytical studies.

Coordinated control by ADRC strategy for a wind farm based on SCIG considering low voltage ride-through capability

Wind farms are integrated with the power grid system to provide active and reactive power. Because in a wind farm, wind turbines (WTs) are highly coupled to their operating conditions, a central wind farm supervisory unit must take into account these conditions when producing power control references for each WT. The aim of this paper is to manage and control the active and reactive power of wind farms based on squirrel cage induction generators and back-to-back converters. The proportional distribution algorithm is used for distributing wind farm power to individual WTs. In addition, we consider the development of a local power management and control units for WTs. This is in order to extract the maximum available power from the wind, and to provide the active and reactive power predetermined by the transmission system operator, or to satisfy the grid code requirements considering Low Voltage Ride-through capability. The power dispatch strategy is to be used on all WTs using the distribution algorithm while ensuring the control loops using the proposed Active Disturbance Rejection Control strategy. The results demonstrate that the proposed strategies are efficient and can guarantee the safe integration of wind farms into the grid while respecting grid code requirements and power system stability.

A modified active disturbance rejection control strategy based on cascade structure with enhanced robustness

Active disturbance rejection control (ADRC) is considered to be a common control method in the presence of external disturbances and uncertainties. This work proposes a modified ADRC control strategy to further enhance robustness to uncertainties. First, the cascade structure of modified ADRC composed by two control loops is introduced. Two extended state observers that can be tuned independently are arranged in a cascade structure. The outer loop observer provides system state estimation to build the feedback controller, and the inner loop observer deals with the generalized disturbance. Then, the enhanced robustness is verified by the improved sensitivity in the intermediate frequency range. Finally, for the axial magnetic bearing system with unstable system dynamics, the variation trend in maximum sensitivity with different control parameters is explained in the simulation. The experiments are conducted under varying disturbances and parameter uncertainty to verify the enhanced control performance.

An Active Disturbance Rejection Control Strategy for a Three-Phase Isolated Matrix Rectifier

Single-stage three-phase isolated matrix rectifiers (TIMRs) have high efficiency and compact configurations and are very suitable for electric vehicle (EV) chargers. However, external and internal disturbances challenge the robustness and tracking performance of EV chargers, and conventional proportional integral (PI) controllers cannot solve the unmodeled dynamics and the uncertainty of model parameters in the system, so other feedback controllers, which have disturbance rejection performance, need to be designed. Therefore, this article proposes a dual-loop control strategy based on active disturbance rejection control (ADRC) to guarantee high-speed dynamic response and strong robustness against disturbances. First, the dynamic model of the TIMR is established and divided into two parts to facilitate the controller design. Second, the extended state observer (ESO) is designed to estimate and compensate for the disturbances of the system, and the inner current loop and the outer current loop are designed based on the second-order ADRC. In addition, a simplified parameter-tuning method of the proposed control scheme is presented in detail. Finally, a frequency-domain analysis is given to explain the robust performance of the proposed control scheme. The effectiveness and feasibility of the proposed controller are verified by simulation and experimental results.

An Enhanced Linear ADRC Strategy for a Bearingless Induction Motor

To provide faster speed response, better current characteristics, more stable suspension, and stronger disturbance immunity for a bearingless induction motor (BIM) system, an enhanced linear active disturbance rejection control (ELADRC) strategy is proposed. First, based on the air-gap flux-oriented control, the speed LADRC and the suspension LADRC are, respectively, designed for the torque winding and suspension winding. The uncertainties and disturbance of the system are treated as a total disturbance in LADRC and linear extended state observer (LESO) is used to observe and compensate for it in real time. Second, by analyzing the defects of LADRC, the speed ELADRC and the suspension ELADRC with cascaded LESO are designed based on LADRC to improve the stability and disturbance immunity. Third, the stability and the tracking performance of the second-order ELADRC are analyzed. Finally, simulation and experimental comparisons of the PID control strategy, the LADRC strategy, and the ELADRC strategy are carried out. The analysis and results show that the proposed strategy not merely has good speed response and current characteristics and lowers the influence of load disturbance, but also realizes the fast and stable suspension of the rotor and improves the anti-disturbance performance of the suspension system.

Systematic design of nonlinear ADRC for laser seeker system with FPGA-based rapid prototyping validation

PurposeA laser seeker is an important element in missile guidance and control systems, responsible for target detection and tracking. Its control is, however, a challenging problem due to complex dynamics and various acting disturbances. Hence, the purpose of this study is to propose a systematic design, tuning, analysis and performance verification of a nonlinear active disturbance rejection control (ADRC) algorithm for the specific case of the laser seeker system.Design/methodology/approachThe proposed systematic approach of nonlinear ADRC application to the laser seeker system consists of the following steps. The complex laser seeker control problem is first expressed as a regulation problem. Then, a nonlinear extended state observer (ESO) with varying gains is used to improve the performance of a conventionally used linear ESO (LESO), which enables better control quality in both transient and steady-state periods. In the next step, a systematic observer tuning, based on a detailed analysis of the system disturbances, is proposed. The stability of the overall control system is then verified using a describing function method. Next, the implementation of the NESO-based ADRC solution is realized in a fixed-point format using MATLAB/Simulink and Xilinx System Generator. Finally, the considered laser seeker control system is implemented in discrete form and comprehensively tested through hardware-in-the-loop (HIL) co-simulation.FindingsThrough the conducted comparative study of LESO-based and NESO-based ADRC algorithms for the laser seeker system, the advantages of the proposed nonlinear scheme are shown. It is concluded that the NESO-based ADRC scheme for the laser seeker system (with appropriate parameters tuning methodology) provides better control performance in both transient and steady-state periods. The conducted multicriteria study validates the efficacy of the proposed systematic approach of applying nonlinear ADRC to laser seeker systems.Practical implicationsIn practice, the obtained results imply that the laser seeker system, governed by the studied nonlinear version of the ADRC algorithm, could potentially detect and track targets faster and more accurately than the system based on the common linear ADRC algorithm. In addition, the article presents the step-by-step procedure for the design, field programmable gate array (FPGA) implementation and HIL-based co-simulation of the proposed nonlinear controller, which can be used by control practitioners as one of the last validation stages before experimental tests on a real guidance system.Originality/valueThe main contribution of this work is the systematic procedure of applying the ADRC scheme with NESO for the specific case of the laser seeker system. It includes its design, tuning, analysis and performance verification (with simulation and FPGA hardware). The novelty of the work is also the combination and practical realization of known theoretical elements (NESO structure, NESO parameter tuning, ADRC closed-loop stability analysis) in the specific case of the laser seeker system. The results of the conducted applied research increase the current state of the art related to robust control of laser seeker systems working in disturbed and uncertain conditions.

Robust EMRAN-aided coupled controller for autonomous vehicles

This paper presents a coupled, neural network-aided longitudinal cruise and lateral path-tracking controller for an autonomous vehicle with model uncertainties and experiencing unknown external disturbances. Using a feedback error learning mechanism, an inverse vehicle dynamics learning scheme utilizing an adaptive Radial Basis Function (RBF) neural network, referred to as the Extended Minimal Resource Allocating Network (EMRAN) is employed. EMRAN uses an extended Kalman filter for online learning and weight updates, and also incorporates a growing/pruning strategy for maintaining a compact network for easier real-time implementation. The online learning algorithm handles the parametric uncertainties and eliminates the effect of unknown disturbances on the road. Combined with a self-regulating learning scheme for improving generalization performance, the proposed EMRAN-aided control architecture aids a basic PID cruise and Stanley path-tracking controllers in a coupled form. Its performance and robustness to various disturbances and uncertainties are compared with the conventional PID and Stanley controllers, along with a comparison with a fuzzy-based PID controller and an active disturbance rejection control (ADRC) scheme. Simulation results are presented for both slow and high speed scenarios. The root mean square (RMS) and maximum tracking errors clearly indicate the effectiveness of the proposed control scheme in achieving better tracking performance in autonomous vehicles under unknown environments.

Regulator sa aktivnim potiskivanjem poremećaja na besposadnim guseničnim vozilima

Significant improvement of the unmanned vehicles possibility has achieved by increasing its autonomy, i.e. by excluding the human operator from the guidance loop. In this paper is considered the autonomous control of the unmanned tracked vehicle (UTV) in the presence of the unknown caterpillar tracks slippage. The longitudinal and lateral control model for the UTV path following problem are developed. To handle unknown uncertainties and slippage disturbances, the design of active disturbance rejection control (ADRC) for both, longitudinal and lateral control channels, are proposed. ADRC strategy is enabled that all the control channel uncertainties and disturbances are treated as one lumped (total) disturbance, which is defined as an extended system state and estimated by appropriate extended state observer (ESO). Further, applying the appropriate closed-loop control laws, based on the total disturbance estimation, the complex longitudinal and lateral control problems are reduced to disturbance-free model control. The numerical simulations for the different path following scenarios and caterpillar tracks slippage dynamics are given to verify effectiveness of the proposed UTV control.

Immersion and invariance based active disturbance rejection control for LCL grid-connected inverter

To improve the anti-disturbance ability of LCL grid-connected inverter system, a novel immersion and invariance based on active disturbance rejection control(I&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&I) control law is adopted to design the state error feedback（SEF）control law, thus I&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.

Control of Linear Servo Carts with Integral-Based Disturbance Rejection

This paper describes a system designed for linear servo cart systems that employs an integral-based Linear Active Disturbance Rejection Control (ILADRC) scheme to detect and respond to disturbances. The upgrade in this control technique provides extensive immunity to uncertainties, attenuation, internal disturbances, and external sources of noise. The fundamental technology base of LADRC is Extended State Observer (ESO). LADRC, when combined with Integral action, becomes a hybrid control technique, namely ILADRC. Setpoint tracking is based on Bode’s Ideal Transfer Function (BITF) in this proposed ILADRC technique. This proves to be a very robust and appropriate pole placement scheme. The proposed LSC system has experimented with the hybrid ILADRC technique plotted the results. From the results, it is evident that the proposed ILADRC scheme enhances the robustness of the LSC system with remarkable disturbance rejection. Furthermore, the results of a linear quadratic regulator (LQR) and ILADRC schemes are comparatively analyzed. This analysis deduced the improved performance of ILADRC over the LQR control scheme.

Motion Control of Autonomous Underwater Vehicle Based on Fractional Calculus Active Disturbance Rejection

An active disturbance rejection control based on fractional calculus is proposed to improve the motion performance and robustness of autonomous underwater vehicle (AUV). The active disturbance rejection control (ADRC) method can estimate and compensate the total disturbance of AUV automatically. The fractional-order PID (proportional integral derivative) has fast dynamic response, which can eliminate the estimation error of extended state observer. The fractional calculus active disturbance rejection strategy combines the advantages of the above two algorithms, and it is designed for AUV heading and pitch subsystems. In addition, the stability of fractional calculus ADRC heading subsystem is proven by Lyapunov stability theorem. The numerical simulations and experimental results document that the superior performance has been achieved. The fractional calculus ADRC strategy has more excellent abilities for disturbance rejection, performs better than ADRC and PID, and has important theoretical and practical value.

Adaptive Active Disturbance Rejection Control of Solar Tracking Systems with Partially Known Model

In this article, the trajectory tracking control of a solar tracking system is tackled by means of an adaptive active disturbance rejection control scheme. The state and disturbance estimation system is based on the combination of a time varying identification system and an adaptive observer. The stability and robustness of the controller is mathematically tested by means of the second method of Lyapunov, and its effectiveness is experimentally tested in a robotic test bed, achieving both lower energy consumption and better tracking results with respect to a PID-based controller.

Model predictive control of direct-driven surface-mounted permanent magnet synchronous generator based on active disturbance rejection controller

PurposeThis paper aims to mainly discuss how to suppress the disturbances accurately and effectively in the wind energy conversion system (WECS) of the direct drive surface mount permanent magnet synchronous generator (SPMSG).Design/methodology/approachThe disturbances in wind energy conversion system have seriously negative influence on the maximum power tracking performance. Therefore, a model predictive control (MPC) method of model compensation active disturbance rejection control (ADRC) strategy in parallel connection is designed, which optimizes the speed tracking performance compared with the existing control strategy of MPC and ADRC in series connection. Based on the traditional ADRC, a multi parameter model compensation ADRC strategy is added to better estimate the disturbances. At the same time, a torque feedback strategy is added to compensate the disturbances caused by load torque and further optimize the speed loop tracking performance.FindingsThe simulation results show that the designed control method has advantages than the traditional control method in compensating the disturbances and tracking the maximum power more effectively.Originality/valueThe simulation results show that the designed control method is superior to the traditional proportional control method, which can better compensate the internal and external disturbances and track the maximum power more effectively.

Decoupling Control Strategy of Alkali Recovery Furnace

In order to analyze the correlation between the variables in the combustion process of the alkali recovery furnace, this paper uses the control variable method to design the combustion process experiment of the alkali recovery furnace in the actual field. Through the analysis of the experimental results, it is shown that the first two of the three key parameters of furnace temperature, flue gas oxygen content, and furnace negative pressure have a strong coupling relationship, while the interaction between furnace temperature, flue gas oxygen content and furnace negative pressure is relatively weak. For this reason, this paper introduces the linear active disturbance rejection control strategy into the control of the alkali recovery furnace, regards the mutual influence between variables as disturbances, designs disturbance observers for estimation, and designs error feedback control laws to compensate. The results of simulation and actual operation show that, compared with the traditional PID controller, the control strategy can effectively eliminate the mutual interference between variables, and obtain a better control effect, to ensure that the alkali recovery furnace can run more safely, stably, and efficiently.

Improved Active Disturbance Rejection Control of Dual-Axis Servo Tracking Turntable with Friction Observer

Friction nonlinear disturbance is one of the main factors affecting the control performance of servo tracking system. In this paper, an improved Active Disturbance Rejection Control (ADRC) scheme of dual-axis servo turntable is researched to achieve accurate tracking. Firstly, the mathematical dynamics model of dual-axis servo tracking turntable system is established. The Elastoplastic model is used to describe nonlinear friction, in which the immeasurable part is extended to be a new state. Secondly, considering the smooth and monotonic increasing property of hyperbolic tangent function, an improved tracking differentiator is introduced, which can provide better noise attenuation performance. Thirdly, based on adjustable parameter systematic pole placement method, the fuzzy control algorithm is applied to realize the intelligent tuning of the improved Extended State Observer (ESO) gains, in which the input of the fuzzy controller is the estimation error, while the output is the observer bandwidth. Finally, the improved ADRC system is transformed into a Lurie system, then the extended circle criteria are adopted to analyze the absolute stability of the proposed system. Simulation and experimental verification of the improved ADRC method for the dual-axis turntable tracking servo system are conducted. Results illustrate the effectiveness and robustness of the proposed controller.

Adaptive-based linear active disturbance rejection attitude control for quadrotor with external disturbances

This paper proposes a linear active disturbance rejection control (LADRC) scheme for a quadrotor unmanned aerial vehicle (UAV) with external disturbances based on adaptive control to address the attitude control problem. Firstly, the dynamic model of the quadrotor is established, and LADRC is used to control the altitude, yaw angle, pitch angle and roll angle of the quadrotor UAV affected by external disturbances, which enhances the anti-disturbance ability of the system. In addition, adaptive control is introduced to solve the problem of difficult parameter tuning in LADRC. Then, the stability of the system is demonstrated by Lyapunov theory. Finally, the simulation results verify the effectiveness of the proposed control scheme under external disturbances.

Active disturbance rejection-based industrial cascade control plant with cloud monitoring

PurposeThe purpose of this paper is to provide benefits for companies or organizations, which deal with fewer input-outputs and wanted to control their industrial processes remotely with a robust control strategy.Design/methodology/approachIn this paper, an active disturbance rejection control (ADRC) strategy is used for the two tank level process plant and it is remotely monitored with the industrial internet of things technology. The disturbances in a primary and secondary loop of the cascade process, which are affecting the overall settling time (ts) of the process, are eliminated by using the proposed, ADRC-ADRC structure in the cascade loop. The stability of the proposed controller is presented with Hurwitz’s stability criteria for selecting gains of observers. The results of the proposed controller are compared with the existing active disturbance rejection control-proportional (ADRC-P) and proportional-integral derivative-proportional (PID-P)-based controller by experimental validation.FindingsIt is observed that the settling time (ts) in the case of the proposed controller is improved by 60% and 55% in comparison to PID-P and ADRC-P, respectively. The level process is interfaced with an industrial controller and real-time data acquired in matrix laboratory (MATLAB), which acted as a remote monitoring platform for the cascade process.Originality/valueThe proposed controller is designed to provide robustness against disturbance and parameter uncertainty. This paper provides an alternate way for researchers who are using MATLAB and ThingSpeak cloud server as a tool for the implementation.

Study on Active Disturbance Rejection Control of a Bearingless Induction Motor Based on an Improved Particle Swarm Optimization–Genetic Algorithm

To overcome the limitations that active disturbance rejection control (ADRC) system of a bearingless induction motor (BIM) has difficulty in tuning parameters depending on experience to select parameters, an ADRC strategy based on improved particle swarm optimization-genetic algorithm (IPSO-GA) is proposed. Based on the orientation of the air-gap magnetic field, the first-order and the second-order ADRC are, respectively, designed for the BIM rotation and suspension parts according to the different order of the BIM system. Then, the parameters of the basic particle swarm optimization algorithm are optimized by considering the characteristics of the basic particle swarm algorithm parameters, and the crossover and mutation operations are introduced to enhance global search capability. Meanwhile, through the performance test based on the test function, the performance of IPSO-GA is verified, and the parameters of ADRC are adjusted by IPSO-GA. In addition, this strategy is analyzed with simulation in MATLAB/Simulink and verified on an experimental prototype. Both simulation and experimental results show that the proposed strategy not only effectively improves the starting performance and antidisturbance ability of the BIM but also reduces the maximum radial offset of the rotor and improves the suspension precision of the motor.