Active Disturbance Rejection Control System Research Articles

Auto-disturbance rejection fault-tolerant control of quadrotor based on adaptive observer

To solve the problem of fault diagnosis and adjustment of the quadrotor actuator, a model of the quadrotor vehicle system is established by using the Newton-Euler method considering the unmodeled uncertainty of the system. A fault diagnosis observer with an adaptive threshold is designed to isolate the fault and estimate the fault amplitude. By using the compensation function to improve the extended state observer, an improved active disturbance rejection control system with high order feedback is constructed to improve the robustness and security of the system. Numerical simulation results show that the proposed method is feasible.

Attitude Control of Quadrotor UAV Using Improved Active Disturbance Rejection Control

The quadrotor UAV has complex aerodynamics, unstable altitude, and easy to be disturbed by internal and external uncertainties during flight, so good attitude control becomes a challenge, this paper improves the active disturbance rejection controller to improve the system's anti-jamming ability and response speed in response to the above problems. Firstly, a quadrotor UAV dynamics model is established; then the Ifal function is constructed, which solves the problems that the inflection point of the fal function is not smooth, which is easy to cause the system jitter and the system gain is large when the error is large, and finally the performance is verified by using MATLAB/Simulink simulation software. The simulation results show that the constructed Ifal function is smoother and has better convergence, and compared with the traditional active disturbance rejection control, the improved active disturbance rejection control system has faster response speed, stronger anti-jamming ability and robustness in the attitude control of quadrotor UAV.

Modified Nonlinear Active Disturbance Rejection Control for PMSM Speed Regulation With Frequency Domain Analysis

Strong robustness and smooth speed are two crucial goals of the high-performance permanent magnet synchronous motor (PMSM) drive systems. Conventional active disturbance rejection control (ADRC) strategy generally increases the bandwidth of the extended state observer (ESO) to improve the unsatisfactory disturbance rejection ability, which will inevitably amplify the measurement noise. To address this tough issue, a nonlinear extended state observer (NESO) using finite-time technique is constructed in this paper to enhance the anti-disturbance property. On this basis, the NESO with small bandwidth is sufficient to guarantee strong robustness without sacrificing noise suppression performance. Utilizing the frequency sweep method, the advantages of the proposed NESO based modified ADRC (MADRC) system can be analyzed in terms of frequency domain characteristics, which is more practical than traditional theoretical analysis from a mathematical point of view. Meanwhile, a quasi-resonant (QR) controller is combined with MADRC system to attenuate the main harmonic component of torque ripple for smooth speed. Experimental results are carried out to verify the effectiveness of the proposed control scheme and frequency sweep analysis method.

Linear Matrix Inequality Based Stability Analysis of Linear/Nonlinear Switching Active Disturbance Rejection Control System

Linear Matrix Inequality Based Stability Analysis of Linear/Nonlinear Switching Active Disturbance Rejection Control System

Verification of the Improvement Effect of Artificial Intelligence Computer Control Technology on Electrical Automation Control

In order to improve the effect of electrical automation control, this paper combines the intelligent computer technology to construct the electrical automation control system, explores the principle of the active disturbance rejection controller, and applies it to the induction motor vector control system. The active disturbance rejection controller estimates the state variables of the system and their changing trends in real time through the extended state observer, compensates them by nonlinear feedback method, and provides appropriate control signals. In addition, this paper builds the induction motor active disturbance rejection control system based on ant colony algorithm and conducts a lot of simulation analysis. The research shows that the electrical automatic control system based on the intelligent computer algorithm proposed in this paper has a good electrical automatic control effect.

Active disturbance rejection control for non-minimum phase systems under plant reconstruction

Active disturbance rejection control (ADRC) for non-minimum phase (NMP) systems is a challenging problem due to the conflict between stability and feedback tuning. The key point on this issue is to avoid heavy feedback tuning for robustness enhancement. We perform plant reconstruction to obtain an explicit expression of internal disturbance, such that it can be reduced by cascade compensation. Then, a new ADRC scheme is developed based on plant reconstruction and the internal stability criterion for ADRC system is derived. The stability conditions provide guidelines on the design of the cascade compensator and disturbance observer. It also indicates that the cascade compensation contributes to the robust stability of NMP systems. Simulation results of two typical NMP systems are provided to show the efficacy of the proposed ADRC scheme. Physical realizability is also demonstrated through experiments on a motion NMP system.

Design and test of an improved active disturbance rejection control system for water sampling unmanned surface vehicle

Unmanned surface vehicles (USVs) have wide application prospects in military and civil fields. Motivated by the large demand for environmental protection equipment, a water-sampling USV (WS-USV) system is designed in this study. The software and hardware of the entire system are designed and developed independently. Two water sampling modes, a manual remote control mode and remote interface automatic control mode are designed for handling emergencies. The WS-USV is propelled by twin-propellers. These propellers have many input constraints owing to their inherent structure, making the design of the controller very difficult. In this study, an improved active disturbance rejection control (ADRC) method is proposed and a saturation function is introduced to design a path-following control system for the WS-USV. This enhances the anti-disturbance ability for addressing environmental disturbances by wind, waves and currents in the water sampling process. The stability of the system is improved. The feasibility, stability and performance superiority of the control system are proven by water sampling contrast experiments.

Linear Active Disturbance Rejection Controllers for PMSM Speed Regulation System Considering the Speed Filter

In the permanent magnet synchronous motor speed regulation system, the dynamic performance of the conventional active disturbance rejection control (ADRC) system will be deteriorated by using a low bandwidth speed filter. To solve this problem, two ADRC controllers considering the speed measurement noise are proposed in this article. One proposed ADRC system is based on the extended state observer (ESO), the other proposed ADRC system is based on phase-locking loop observer (PLLO). In the proposed two ADRC systems, an integrator is employed as the speed filter so that the measured position can be directly used for observing the speed and disturbance without speed calculation. Meanwhile, by using an integrator as the speed filter, the dynamic performance of the proposed ESO-based ADRC system is not affected since it is independent of the speed filter, and the proposed PLLO-based ADRC system has a better rejection ability for the low-frequency disturbance. Experimental results validate the proposed methods.

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.

Measurement Compensation for Time-Delay Seeker and Three-Dimensional Adaptive Guidance Law Design.

The time delay of seekers has grown to be a serious issue for tactical missile guidance with the development of flight vehicle technologies. To address the problem, a measurement compensation system for the seeker, with lags and delays based on predictive active disturbance rejection control, is proposed. In addition, to eliminate the effects of target maneuvers to the tactical missile guidance, an adaptive finite-time convergent sliding mode guidance law, based on super-twisting algorithm, is proposed in three-dimensional missile-target engagement kinematics. Specifically, the compensation system consists of a predictive tracking structure and an active disturbance rejection control system, which could follow a virtual measurement without lags and delays. The compensation system has advantages in disturbance rejection and model inaccuracy addressing, compared with existing compensation methods for seeker measurement. As for the sliding mode guidance law design, the proposed approach is based on an improved super-twisting algorithm with fast convergent adaptive gains, which has advantages in addressing unknown but bounded target maneuvers and avoiding chattering of the classical sliding mode control. As a result, the measurement compensation system and the adaptive sliding mode guidance law is verified robust and effective under the proposed constraints by the simulation examples.

Design of auto disturbance rejection control system for pneumatic manipulator based on PLC Technology

Aiming at the coupling effect between joints of two degree of freedom pneumatic mechanism in reciprocating motion, and the reciprocating motion problem caused by the imprecision and jitter of dynamic model in high-speed motion, an auto disturbance rejection control system of Pneumatic Manipulator Based on PLC technology is designed, and the parameter model of flexible joint manipulator system is established, and the cubic spline interpolation is optimized by PLC technology, The effective control mode of operation space is realized. The correctness and stability of the active disturbance rejection control system of Pneumatic Manipulator Based on PLC technology are verified by simulation experiment.

Active Disturbance Rejection Controller for Speed Control of Electrical Drives Using Phase-Locking Loop Observer

An active disturbance rejection control (ADRC) controller using phase-locking loop observer (PLLO) is proposed in this paper to improve the disturbance rejection property of speed control system. First, to simplify the comparison with other controllers, a universal speed controller design method based on disturbance estimation is employed, and a unified expression for different controllers is presented. Then, several common speed controllers are compared with each other, and two PLLO-based ADRC controllers are presented. After that, considering the variations of load inertia, robustness of the proposed ADRC system to inertia variation is analyzed. Finally, to improve the tracking performance for sinusoidal speed reference, an adaptive speed control system using identified inertia is presented. Simulation and experimental results verify the effectiveness of the proposed method.

Bandwidth Based Stability Analysis of Active Disturbance Rejection Control for Nonlinear Uncertain Systems

This paper focuses on the stability analysis of the active disturbance rejection control (ADRC) for a class of uncertain systems. To overcome the difficulty of defining a reasonable Lyapunov function and setting limitations of system parameters, the converse Lyapunov theorem and the disturbance theory are employed. This paper proves that the estimation error of the extended state observer (ESO) and the tracking error of the closed-loop system using ADRC are uniformly ultimately bounded and monotonously diminishing with the increase of their respective bandwidth, so that the stability of the ADRC system could be performed. In order to further illustrate the relationship between the stability range and bandwidths, it analyzes quantitatively the performance of ESO and ADRC based on the root locus and the step response. Finally, an example based on a typical control system is carried out, and simulation results verify the theoretical analysis proved in this paper.

An approach to improve active disturbance rejection control

ABSTRACTIn order to reduce the error and phase delay of the classical extended state observer (ESO) in estimating the system state and disturbance, in this paper, we combine ESO and tracking differentiator (TD) to construct a tracking differential extended state observer (TDESO). The observation error and observation speed of TDESO are also discussed. Then a nonlinear active disturbance rejection control system improved by TDESO for a linear plant is transformed into a Lurie system. Moreover, the circular criterion is used to analyse the absolute stability of the transformed Lurie system. Finally, TDESO is optimised and an improved linear state error feedback (PLSEF) is proposed to improve the rapidity of the system by using simulation and time domain analysis. And a second-order system is used to illustrate the performance of the proposed scheme. The simulation results show that our algorithm is effective.

A Two-Layer Active Disturbance Rejection Controller Design for Load Frequency Control of Interconnected Power System

This letter proposes a two-layer active disturbance rejection control (ADRC) method with the compensation of estimated equivalent input disturbances (EID) for load frequency control (LFC) of multi-area interconnected power system. This method has a capability of rejecting the effects of random load variations and parameter uncertainties, and guaranteeing high dynamic performance. The state-space model of LFC system is established. Then a full-order generalized state observer (GSO) is employed in ADRC system to estimate EID. A stability condition is derived based on the small-gain theory. Simulation results demonstrate the robust performance of the proposed method, by comparing with traditional one.

Absolute stability analysis of non‐linear active disturbance rejection control for single‐input–single‐output systems via the circle criterion method

This study focuses on the stability analysis of non-linear active disturbance rejection control (ADRC) for single-input–single-output systems. Firstly, a non-linear ADRC system for a linear plant is transformed into a Lurie system. Secondly, two extended circle criteria are obtained, and two numerical examples are presented to illustrate the absolute stability analysis, including both stable and unstable linear plants. Thirdly, local asymptotic stability of a non-linear ADRC system for a non-linear plant is also performed through linearisation by Taylor expansion. Finally, a comparison with the existed processing methods is further made, including the describing function method and time domain stability analysis method. It can be concluded that the circle criterion method is more convenient and practical for its frequency domain and graphical interpretation. The circle criterion method can also be extended to the stability analysis of a control system which applies linear ADRC to a plant with one non-linear term.

Frequency domain stability analysis of nonlinear active disturbance rejection control system

This paper applies three methods (i.e., root locus analysis, describing function method and extended circle criterion) to approach the frequency domain stability analysis of the fast tool servo system using nonlinear active disturbance rejection control (ADRC) algorithm. Root locus qualitative analysis shows that limit cycle is generated because the gain of the nonlinear function used in ADRC varies with its input. The parameters in the nonlinear function are adjustable to suppress limit cycle. In the process of root locus analysis, the nonlinear function is transformed based on the concept of equivalent gain. Then, frequency domain description of the nonlinear function via describing function is presented and limit cycle quantitative analysis including estimating prediction error is presented, which virtually and theoretically demonstrates that the describing function method cannot guarantee enough precision in this case. Furthermore, absolute stability analysis based on extended circle criterion is investigated as a complement.

Active Disturbance Rejection Control System Design for a Morphing Wing Structure

AbstractControl system design for a morphing wing structure, which is proposed by NextGen Aeronautics, Inc., is investigated in this paper. The dynamic model of the morphing wing, developed based on the Euler‐Lagrange equation, is nonlinear, multivariable coupled, over‐actuated and uncertain. The allocation‐decoupling controller is designed based on control efficiency and decoupling matrices. For each decoupled subsystem, nonlinear and linear active disturbance rejection control (ADRC) systems are designed and compared. The time‐optimal property and the convergence of nonlinear ADRC are analyzed theoretically based on the isochronic region and Lyapunov theories. The simulation results of the developed control systems show satisfactory performances of decoupling and extreme tolerance of internal uncertainty and external disturbance. The comparison of nonlinear and linear ADRC systems demonstrate that the nonlinear system can provide a little better performance while the linear system can greatly simplify the design procedure. The results indicate that, the methods of control system design proposed in this paper are practical and effective for motion control of complex uncertain dynamical systems.

Limit cycle analysis of active disturbance rejection control system with two nonlinearities

Introduction of nonlinearities to active disturbance rejection control algorithm might have high control efficiency in some situations, but makes the systems with complex nonlinearity. Limit cycle is a typical phenomenon that can be observed in the nonlinear systems, usually causing failure or danger of the systems. This paper approaches the problem of the existence of limit cycles of a second-order fast tool servo system using active disturbance rejection control algorithm with two fal nonlinearities. A frequency domain approach is presented by using describing function technique and transfer function representation to characterize the nonlinear system. The derivations of the describing functions for fal nonlinearities and treatment of two nonlinearities connected in series are given to facilitate the limit cycles analysis. The effects of the parameters of both the nonlinearity and the controller on the limit cycles are presented, indicating that the limit cycles caused by the nonlinearities can be easily suppressed if the parameters are chosen carefully. Simulations in the time domain are performed to assess the prediction accuracy based on the describing function.

On-Line Parameter Identification and Active Disturbance Rejection Control of Permanent Magnet Synchronous Motor

A new method named Windowed Least Square (WLS) to test main parameters of Permanent Magnet Synchronous Motor (PMSM) is proposed in this paper. Compared with Extended Kalman Filter (EKF) & Elman neural network and Recursive Least Square (RLS), WLS guarantees identification accuracy and excellent timeliness, and the issue of data saturation of RLS can be avoided. The PMSM model is built combining on-line parameter identification with Active Disturbance Rejection Control (ADRC) to improve the control performance of PMSM. The simulation results demonstrate that the performance of ADRC system using online estimation strategy is better than that of the system using PID method.