Order Active Disturbance Rejection Control Research Articles

Research on Active Repetitive Control for Tracking Lissajous Scan Trajectories with Voice Coil Motors Actuated Fast Steering Mirror

The performance of laser beams in tracking Lissajous scan trajectories is severely limited by beam jitter. To enhance the performance of fast steering mirror (FSM) control in tracking Lissajous scan trajectories, this paper proposed a fractional order active disturbance rejection controller (FOADRC) and verified its effectiveness in improving system scanning tracking accuracy. A dynamic mathematical model of a fast steering mirror was studied, and the design of parameters for the control mode of the closed-loop system was determined. A reduced-order linear active disturbance rejection controller suitable for FSM systems was designed, and the corresponding fractional-order proportional differentiation (FOPD) controller was determined according to the mathematical model. The use of the designed controller enabled high-performance tracking of high-frequency Lissajous scanning curves (X-axis 500 Hz, Y-axis 350 Hz) and met the need for high-frequency repetitive scanning. The controller has the characteristics of simple implementation and low computational complexity and is suitable for closed-loop control applications in engineering.

Motor control technology based on fractional active disturbance rejection

For non-linear, strongly coupled, multivariable and naturally unstable motor control systems to realize the rapid return of the motor to the original equilibrium point without overshoot, the traditional PID controller algorithm is prone to defects such as large overshoot and long response time. The study proposes fractional order active disturbance rejection control for the motor self-balancing control method. A novel controller composed of a fractional order controller and an active disturbance rejection controller is designed and its control characteristics are analyzed and simulated. The experimental results show that compared with the traditional PID control, the controller has better dynamic performance, steady-state performance and anti-interference ability so that the motor can reach the equilibrium position quickly, stably and accurately. The illustrations of the experimental verification have been modified and explained.

A composite fractional order active disturbance rejection control method for a class of uncertain systems with multiple disturbances

SummaryThe existing active disturbance rejection control (ADRC) method may not provide sufficient disturbance rejection to multiple mismatched disturbances for the fractional order systems. In this paper, a composite disturbance rejection approach is developed for a class of fractional order uncertain systems, by synthesizing the fractional order ADRC (FOADRC) approach and a disturbance observer (DO)‐based compensation scheme. Taking advantage of more disturbance information and a filter structure, an improved DO is developed to achieve precise estimation of disturbances in the presence of sensor noises. In addition, a state transformation is developed to convert the system into a simple integral chain model with only matched disturbances. Then a composite control law is designed to compensate the disturbances and provide satisfying dynamic performance. The efficiency of the proposed method is demonstrated by a numerical simulation and an actual servo control simulation, as well as the comparison with two kinds of the existing ADRC methods and the commonly used integral sliding mode control (I‐SMC) method.

Control strategy for the anode gas supply system in a proton exchange membrane fuel cell system

Stable pressure control can improve the lifespan, efficiency, and stability of proton exchange membrane fuel cell system (PEMFCs). We successfully implemented a feedforward-based proportion-integral controller (FPIC) to control the anode pressure of a 100 kW fuel cell system. The bench experimental results demonstrate that the fuel cell stack achieves a maximum efficiency of 62.3 %, while the fuel cell power generation system achieve a maximum efficiency of 53.5 %. Under the steady-state and dynamic conditions, the strategy achieves a pressure tracking control accuracy of 98.93 % and 94.47 %, respectively. To address the large overshoot phenomenon and slow response speed of the FPIC when controlling the anode pressure, we further design a second order active disturbance rejection controller (SOADRC). The simulation results show that the SOADRC exhibits higher control stability and lower overshoot than FPIC. Moreover, it demonstrates a 51.3 % increase in response speed and an 80.7 % improvement in control stability under steady-state conditions compared to FPIC. The evaluation metrics for the error integral criterion (eISE = 0.023, eITSE = 2.58, eIAE = 0.35, and eIEAE = 36.76) are lower than FPIC, which demonstrates that the SOADRC provides more precise control of anode pressure, and enhances the stability of PEMFCs.

Reactor Temperature Control Based on Improved Fractional Order Self-Anti-Disturbance

In the chemical industry, a reactor is an absolutely necessary container. The fact that its dynamic qualities are nonlinear and unknown, however, is what causes the temperature to deviate from the value that was specified. As a result, the typical PID control cannot fulfill the prerequisites of the production process. A new nonlinear function is presented to replace the function that was previously used, and a temperature controller that is based on better fractional order active disturbance rejection is devised. On the basis of a new fractional order temperature detector (FOTD), a new fractional order equilibrium state observer (FOESO), and nonlinear function, an improved fractional order active disturbance rejection controller has been developed. A model of the reactor was created, and the dynamic properties of temperature control were investigated. By simulation and experimentation, it was demonstrated that the strategy has a number of benefits and is effective. In this approach, the information provided by the model is exploited to its maximum potential, and the temperature of the inlet cooling water is employed as the temperature control disturbance for feedforward compensation. Over the entirety of the process, this guarantees that the desired temperature will be preserved. When compared to FADRC, PID, and ADRC, the rising time is increased by 5 s, and the overshoot is raised by 25%. It has been established that the fraction-order active disturbance rejection controller has a quicker response speed, a higher capacity for anti-interference, and a quicker speed of stabilization.

Fractional Order Active Disturbance Rejection Control for Canned Motor Conical Active Magnetic Bearing-Supported Pumps

Active magnetic bearings (AMBs) are electromagnetic mechanism systems in which non-contact bearings support a rotating shaft using attractive forces generated by electromagnets through closed-loop control. For complete support of a five degree of freedom (DOF) rotor system, most AMB structures include two radial actuators and one for the axial direction. Conical active magnetic bearings (CAMBs) is one of the development directions of conventional magnetic bearings in which the requirement of the axial bearing can be eliminated. In this paper, we propose a structure with a CAMB integrated into a canned motor pump to eliminate the need for mechanical bearings and shaft seals. However, this system necessitates a more complicated control strategy due to a significant coupling effect between rotor motion and hydrodynamic disturbances. This paper presents a fractional order active disturbance rejection control (FOADRC) including a fractional order extend state observer (FOESO) and a proportional derivative controller (PD) to track and reject lumped disturbances actively. The proposed controller achieves better performance than the integer-type ADRC and traditional PID controller. The control performance of the proposed FOADRC is illustrated in terms of very good disturbance rejection capability that is demonstrated through MATLAB/Simulink simulation results.

Combustion stability control of a single-piston free piston engine generator

Free piston engine generator is an effective alternative to conventional range ex-tender, which is able to facilitate the transportation sector decarbonization attributed to its high thermal efficiency and ultimate fuel flexibility. However, due to the lack of crankshaft mechanism, stable and robust operation of free piston engine generator is difficult to achieve since various disturbances may exist during its operation. In this paper, a combustion stability control based on active disturbance rejection control algorithm was proposed for a single piston free piston engine generator. To develop this control, a thermodynamic model of the free piston engine generator system was calibrated and validated through experimental data. Afterward, a 2nd order active disturbance rejection control based speed control was developed by leveraging the developed free piston engine generator model. The proposed active disturbance rejection control was employed into multiple abnormal combustion scenarios through a simulation, including various fuel heat released, ignition positions and burn durations, aimed to verify the control ability of rejecting disturbances and enhancing the robustness of the free piston engine generator operation.

Fractional order active disturbance rejection control design for non-integer order plus time delay models

This paper proposes a time-delayed fractional order active disturbance rejection control (TD-FADRC) strategy to address a class of time-delayed fractional order systems represented by non-integer order plus time delay (NIOPTD) models. To accurately estimate the fractional order states, the fractional order extended state observer (FESO) is utilized with introducing an artificial delay block to synchronize inputs. The studied model and its corresponding observer are treated as a holistic plant, based on which several types of fractional order proportional-integral-derivative (FPID) with constrained order are employed as feedback controllers. By unfolding the resulting open-loop plant in the frequency domain, the controller gains can be derived explicitly from the typical robustness metrics, that is, the phase margin and gain crossover frequency. The performance, robustness, and delay issue are consequently all concerned. To guarantee the closed-loop stability, the controller gains under a given observer bandwidth are limited within a bounded region mapped by the D-decomposition method. Through representative simulations, the merits of the proposed strategy for such models are revealed.

Automatic Current-Constrained Double Loop ADRC for Electro-Hydrostatic Actuator Based on Singular Perturbation Theory

For an electro-hydrostatic actuator (EHA), the position, speed, and current cascade three-loop control architecture are dominant in existing active disturbance rejection control (ADRC). However, this architecture suffers from many problems, such as severe noise sensitivity of the extended state observer (ESO), excessive complexity of control structure, and too many tuned parameters, which makes the controller not easy to implement in practice. Aiming at the above drawbacks, a novel cascade double-loop ADRC strategy that is automatic current-constrained is proposed, which makes the whole ADRC architecture simplified to the position and the integrated speed–current double-loop architecture. Firstly, for the position control loop, the singular perturbation theory is used to reasonably reduce the order of the model for the position subsystem of EHA. A reduced order ADRC controller (ROADRC) is synthesized, which not only effectively reduces the noise sensitivity of ESO, but also circumvents use of the actuation acceleration information in the controller design process. Secondly, the integrated speed–current ADRC controller is designed by taking the speed and current subsystems of EHA into synthesis, which avoids the problem of excessive current loop bandwidth in conventional three-loop control architecture, and the number of tuned parameters is significantly reduced. Additionally, an uncomplicated and effective automatic current-constrained ADRC controller (CACADRC) is designed to solve the problem in the integrated speed–current ADRC that the current cannot be automatically constrained. Finally, by comparing the three-loop PI controller with the traditional three-loop ADRC, a detailed simulation analysis is carried out to verify the effectiveness and merits of the proposed controller. The simulation results show that the proposed controller not only inherits the advantages of high precision and strong disturbance rejection performance of the conventional ADRC, but can also efficiently decrease the noise sensitivity of ESO and effectively achieve the current-constrained control.

Robust frequency–voltage stabilization scheme for multi-area power systems incorporated with EVs and renewable generations using AI based modified disturbance rejection controller

The advent of modern artificial intelligence methods for performance improvement of optimal control strategy has paved a way for providing a reliable operation of power systems. Based on the modern advancements in such techniques, the present paper provides a detailed comparison for finding the optimal control strategy using such techniques. This is exhibited by developing a novel control strategy in the form of a 2nd order active disturbance rejection controller for concurrent frequency-voltage control of a hybrid power system. The hybrid power system comprises of renewable generations in the form of solar-thermal, wind plants. Moreover, the modern day electric vehicles (EVs) are also incorporated as energy storage and operate in vehicle-to-grid mode. The developed control strategy is compared with established industrial controllers to prove its dominance based on concurrent frequency-voltage control of the hybrid power system. Firstly, the controller gains are optimized using magnetotactic bacteria optimization (MBO) technique. Then, the developed control strategy is tuned using artificial neural network (ANN) methodology. Based on the simulation outcomes, the results for frequency deviations, voltage deviations and tie-line power deviations are compared with MBO and ANN optimized 2nd order active disturbance rejection controller. The simulations are carried out on one-area, two-area and standard IEEE-39 bus power systems for in depth validation. Results show that the ANN optimized 2nd order active disturbance rejection controller has superior performance with respect to MBO optimized one. The effects of modern day EVs and renewable generations on the power system is studied broadly.

A [formula omitted] order Active Disturbance Rejection Controller for coordinated frequency-voltage control of deregulated hybrid power system with optimal electric-vehicle integration

The emergence of deregulation delivers a reliable operation of power system due to the fact that deregulated concept encourages competition among different power companies, thus avoiding monopoly. The present paper extends the idea of deregulation for a two-area hybrid power system establishing concurrent frequency-voltage control. The deregulated power system under consideration involves conventional-thermal, solar-thermal, wind-sources with appropriate non-linearities and present day electric-vehicles (EVs). This paper introduces a novel study showing the effects of large penetration of EVs with the utility grid. Furthermore, the optimal number of connected EVs for improved power system performance is examined.For establishing effective control, a 2nd order Active Disturbance Rejection-Controller (ADRC) with extended-state-observer is modelled as secondary controller. Magnetotacticbacteria optimization technique is used to determine the optimal parameter values. Simulation results depict a major reduction in the voltage and frequency deviations for proposed ADRC strategy with respect to industrially applied controllers. Also, a considerable reduction in steady state error values are obtained. Moreover, the ADRC gains prove to be robust enough under varying system conditions. The present study makes a way for further research on ADRC as a market ready controller.

Active disturbance rejection control design for high-order integral systems

Active disturbance rejection control (ADRC) is designed for regular processes frequently, due to its strong ability to reject disturbances and handle system uncertainties. However, ADRC design for high-order integral systems existing in many natural systems is always ignored. The controller design for high-order integral systems is different from the regular systems due to no pole in the left and right half s-planes. The ADRC design for high-order integral systems is studied to explain this question theoretically in this paper. Based on the equivalent form of ADRC, a theorem about the necessary condition of ADRC is proven which can guarantee the closed-loop system’s stability. Additionally, the advantages of ADRC over proportional–integral–derivative (PID) controller in sensor noise rejection and control signal variation are analyzed theoretically. In order to achieve expected control performance for high-order integral systems, a practical design procedure of ADRC is summarized by the single variable method. Several comparative simulations and an experiment based on a ball and beam system are carried out. Running data verify that ADRC can obtain better control performance with strong robustness than PID controller. Eventually, a 100th order ADRC is designed for a 100th order integral system, and simulation results show that ADRC can be designed for high-order integral systems conveniently. Based on theoretical analyses and experimental verifications, ADRC shows some advantages for high-order integral systems.

Fractional order active disturbance rejection control with the idea of cascaded fractional order integrator equivalence

This paper presents a fractional order (FO)-active disturbance rejection control (ADRC) with a FO extended state observer (FOESO) design. Applying this FOESO, a typical second order motion plant can be converted into a cascadedfractionalorderintegrator(1∕s2r;0<r<1) with considering all other dynamics and internal/external disturbances as totaldisturbances. Therefore, a single proportional controller which is not sensitive to system noise can realize a stable control system. According to the frequency characteristics of equivalent FO system model, the FO-ADRC control system is robust to systematic uncertain dynamics and disturbances. Furthermore, without differential action which is needed for the typical double integrator plant control, the proposed control system achieves good robustness to high-frequency noise. Simulation and experiments on PMSM speed servo system are performed, showing that the proposed FO-ADRC behaves better than integer order ADRC (IO-ADRC) and FOPI controller. This FO-ADRC methodology can be simply extended to general control plants.

Stability Analysis of a Nonlinear MIMO System using Fractional Order Active Disturbance Rejection Controller

The study illustrates a study of fractional order proportional-integral-derivative (FOPID) controller using active disturbance rejection controller. The strategy is applied to a helicopter model of multiple input multiple output system after designing with tuned controller parameters. The motive of the system is to accomplish the control criteria and to investigate the stability of the structure using the principle of non-integer PID controller with a nonlinear feedback and active disturbance rejection. The immense criteria for stability analysis of the coupled system along with the disturbance rejection characteristics are given here in this study. Two new fractional variables as λ and μ are introduced to get better performance. In addition, disturbance control is also implemented from the designed controller.

Fractional order active disturbance rejection control for trajectory tracking for 4-DOF serial link manipulator

This paper presents fractional order active disturbance rejection control (FOADRC) for a 4-DOF serial link manipulator to track the desired path and to ensure the stability of the tracking error. The active disturbance rejection control (ADRC) is known as a good technique to estimate the total disturbances and compensate them through suitable feedback control. This work takes advantage of the ADRC and the fractional-order controller to control the robot manipulator. The proposed control strategy has three main phases. First, converting the cartesian space trajectory to joint space. Second, the FOARDC is developed to ensure good tracking in the joint space. The FOADRC uses the extended state observer (ESO) to estimate the disturbances and the fractional-order PD as a feedback controller. Finally, the forward kinematic is used to convert the real joint space trajectory to cartesian space coordination. Experimental results show that the FOADRC has better performance than the traditional ADRC.

Fractional order active disturbance rejection control for trajectory tracking for 4-DOF serial link manipulator

This paper presents fractional order active disturbance rejection control (FOADRC) for a 4-DOF serial link manipulator to track the desired path and to ensure the stability of the tracking error. The active disturbance rejection control (ADRC) is known as a good technique to estimate the total disturbances and compensate them through suitable feedback control. This work takes advantage of the ADRC and the fractional-order controller to control the robot manipulator. The proposed control strategy has three main phases. First, converting the cartesian space trajectory to joint space. Second, the FOARDC is developed to ensure good tracking in the joint space. The FOADRC uses the extended state observer (ESO) to estimate the disturbances and the fractional-order PD as a feedback controller. Finally, the forward kinematic is used to convert the real joint space trajectory to cartesian space coordination. Experimental results show that the FOADRC has better performance than the traditional ADRC.

Evaluation of the Disturbance Rejection Performance of an Aerial Manipulator

This study mainly focuses on the control of a hexacopter platform that is equipped with a two degree-of-freedom robot arm. The designed control system rejects the disturbances to the attitude dynamics of the hexacopter which are mainly caused by the motion of the robot arm. For this purpose, Active Disturbance Rejection Control (ADRC) is implemented and its disturbance rejection capabilities are investigated. The equations of motion of the hexacopter with a two degree-of-freedom robot arm are derived by using the Newton-Euler approach. Flight tests are utilized to compare the performance of the third order ADRC with that of the cascaded PID (P-PID) controller which is one of the mostly used controllers in commercial multicopter systems. In addition, second and the third order ADRC performances are compared as well. Regulatory and disturbance rejection characteristics of the hexacopter are compared using several performance criteria. It is shown that third order ADRC has a better performance when disturbance acts in both the roll and pitch axes.

Active disturbance rejection based MPPT control for wind energy conversion system under uncertain wind velocity changes

The tip speed ratio regulation based maximum power point tracking (MPPT) control for the wind energy conversion system (WECS) is studied in this paper. Challenges imposed by uncertain changes in wind velocity and unmodelled system dynamics are considered. A first order active disturbance rejection controller (ADRC) is designed to tackle this problem. Based on the platform of the high-power (2-MW) rigid-drive-train squirrel-cage induction generator-based wind energy conversion system (WECS), a simulation study is carried out by comparing with the performance of a well-tuned published PI (proportional–integral) speed controller, and the results show that the proposed first order ADRC controller exhibits better tracking performance and adaptability for uncertain wind velocity changes. There are only two controller parameters, namely, ωo and ωc, to tune, and control adaptability can be held without parameters resetting or extractable mechanical power reducing, proving the effectiveness of the proposed ADRC approach for the WECS MPPT problem.

Fractional Order Nonlinear Feedback Controller Design for PMSM Drives

Fractional order integral is introduced into active disturbance rejection controller (ADRC) to establish the structure of fractional order proportional integral controller (FPI). Fractional order ADRC (FADRC) is designed by replacing the nonlinear state error feedback control law using nonlinear function combination in ADRC with FPI, which can combine the high performance of ADRC estimating disturbances with the characteristics of fractional order calculus more really describing the physical object and spreading the stable region of the system parameters. The proposed FADRC is applied to permanent magnet synchronous motor (PMSM) speed servo system in order to improve robustness of system against the disturbances. Compared with ADRC, simulation results verify that the proposed control method has given very good robust results and fast speed tracking performance.

A Nonlinear Control Method of Steering Angle Following Used in Steer-by-Wire System

In this paper, active disturbance rejection control method is used to implement the steering angle following control of steer-by-wire system for the simplification of controller designing. The dynamic model of steering performing system is established, and then a second order active disturbance rejection controller is designed to control the steering angle. On the electric vehicle with steer-by-wire system, the angle following test of steering performing system is carried out under the control of the second order active disturbance rejection controller. The results show that the designed active disturbance rejection controller can restrain the effect of system resistant force on the accuracy of angle following and meet the requirement of steer-by-wire system to the steering angle following function. At the same time, there isn’t necessary to get the accurate data of steering system and the design process of controller becomes simple with adopting active disturbance rejection control method.