Disturbance Rejection Controller Design Research Articles

Modified Active Disturbance Rejection Control Design Based on Gain Scheduling for Selective Catalytic Reduction Denitrification Processes

Modified Active Disturbance Rejection Control Design Based on Gain Scheduling for Selective Catalytic Reduction Denitrification Processes

Nonlinear Active Disturbance Rejection Controller Design for Drag-Free Satellite with Two Test Massess

Nonlinear Active Disturbance Rejection Controller Design for Drag-Free Satellite with Two Test Massess

Active Disturbance Rejection Control Design with Sensitivity Constraint for Drum Water Level

The drum water level plays a crucial role in the safety and economy of heat recovery boilers. However, the control of the drum water level faces many challenges, such as external disturbances and system uncertainties. To enhance the control performance of the drum water level, a modified active disturbance rejection control (MADRC) optimized with sensitivity constraint is proposed in this paper. Firstly, the control structure of the three-element control system for the drum water level is introduced and analyzed. Based on the regular active disturbance rejection control (ADRC) structure, the structure of the MADRC is introduced and the convergence of the proposed MADRC is proven. Then a modified whale optimization algorithm (MWOA) with sensitivity constraint is applied to optimize the parameters of the MADRC. With different sensitivity constraints, the parameters of the MADRC and comparative controllers are obtained, and their control performance for tracking and disturbance rejection abilities is compared. Moreover, the ability to handle system uncertainties is analyzed. Simulation results and performance indexes show that the proposed MADRC can obtain the best tracking and disturbance rejection abilities with satisfactory robustness. The satisfactory control performance shows that the proposed MADRC has wide application potential for heat recovery boilers and other industrial processes.

Enhanced disturbance observer-based hybrid cascade active disturbance rejection control design for high-precise tracking system in application to aerospace satellite

In the control issue of the detection system for aerospace satellites, a strategy that can effectively ensure line-of-sight (LOS) stabilization of the detection system under complex environments is essential. As the essential detection part of aerospace satellites, the high-precise tracking system (HTS) can be limited in practice by disturbances and system uncertainties and usually needs to solve a disturbance suppression problem. Motivated by successful applications of the active disturbance rejection control (ADRC) in HTS, this article investigates the LOS stabilization problem for the HTS with disturbances and system nonlinearity utilizing enhanced disturbance observer-based hybrid cascade active disturbance rejection control (CADRC). A novel enhanced disturbance observer (EDOB) together with CADRC is initially designed to estimate the disturbances of the HTS, where EDOB is mainly used to compensate for the impacts of external disturbances, and the disturbances that are difficult to model are estimated by CADRC. A set of simulations and experiments, performed on an HTS, compared with the traditional method, shows that the proposed method can effectively suppress the time-varying uncertainties and non-linear friction.

On improved active disturbance rejection controller design for a pumped storage hydro unit

The pumped storage hydro unit (PSHU) shows bad dynamic performance because of the frequent switching of working conditions and the S-shaped characteristics of pump turbine. This paper proposes an improved fixed-time active disturbance rejection controller to improve the control performances and counteract the influences of uncertainties including modeling error and friction. A disturbance observer is designed to estimate the total uncertainty by using the information of the states and outputs, compensating the adverse effects of the total uncertainty actively by feed-forward principle as a result. The outstanding benefit of the disturbance observer lies in that it can be designed separately from the original controller and can enhance the performances of the PSHU without changing the original controller. Simulation results show that comparing with the conventional active disturbance rejection controller, the improved active disturbance rejection controller has better adaptability and higher robustness towards the system load disturbance, and the dynamic performance of the system is improved.

Disturbance rejection controller design based on nonlinear with fuzzy approximation technique for a tidal turbine system

In this work, a novel disturbance rejection controller based on a nonlinear fractional order proportional integral derivative with fuzzy (NLFOPIDF) approximation and an adaptive law technique for a 160 kW two horizontal axis parts tidal turbine model is proposed. The tidal turbine system encounters gigantic unknown uncertainties with external and internal disturbances induced by fatigue forces and non-uniform operative thrust and turbulence deviations caused by the effect of wind and wave movements. The main working purpose of the tidal turbine system is to extract the maximum power generated by obtaining and tracking the optimal turbine speed. To track the optimal speed turbine, two controller loops are synthesized for the tidal turbine dynamics (outer loop) and current dynamics in the q-axis component (inner loop). The stability and convergence are verified for the outer and inner loops using a candidate Lyapunov function. An approximation fuzzy function is proposed to estimate the nonlinear dynamics of the tidal turbine system, and an adaptive technique is applied to adapt the tidal turbine system against the variation in nonlinear dynamics. The results demonstrate that the NLFOPIDF controller is superior to other works in optimal power generation and optimal turbine speed tracking. Moreover, this controller can be used to achieve the maximum power coefficients to get the optimal power generation.

Heuristic algorithms based optimal tuning of FOLQI controller for quadruple tank process under disturbance conditions

Design of centralised disturbance rejection controllers for an highly interacting MIMO quadruple tank process is tedious. Recently, centralised disturbance rejection Fractional Order LQI (FOLQI) controller is designed for such system to meet the desired specifications with better performance than various disturbance rejection controllers that are available in the literature. In this paper, an optimisation problem is formulated to obtain the optimal parameters of FOLQI controller providing minimum control effort by applying various widely used heuristic methods like Cuckoo Search (CS), Accelerated Particle Swarm Optimisation (APSO) and FireFly (FF) algorithms. A detailed simulation study is carried out to compare the performance of the FOLQI and Integer Order LQI (IOLQI) controllers obtained by these heuristic algorithms under disturbance and parameter uncertainty conditions. From the simulation study it is inferred that (i) FOLQI controller provides better time domain specifications % Mp, ts and J in comparison to IOLQI controllers and (ii) FF tuned FOLQI and IOLQI controllers provide better robustness characteristics compared to CS and APSO tuned controllers.

Disturbance rejection controller design based on adaptive nonlinear FOPID controller and chaotic WOA with a neuro-fuzzy approximation for URV robot

This paper presents an adaptive neuro-fuzzy-based nonlinear fractional order proportional integral derivative (ANF-NLFOPID) controller to stabilize six degrees of freedom (6-DOF) underwater robotic vehicle (URV). Generally, the stability of the URV system is jammed due to internal and external variations related to unknown uncertainties and disturbances in the URV model, which lead to trajectory tracking problems. Thus, to solve unknown uncertainties and disturbances problems, an ANF network is proposed to estimate unknown uncertainties and disturbances. At the same time, an NLFOPID controller is proposed to minimize the error effect generated by the variation of the URV model parameters. Considering the unknown and unpredictable behavior of the URV system in the presence of uncertainties and disturbances, the ANF-NLFOPID controller parameters are tuned continuously using an improved whale optimization algorithm based on chaotic theory (IWOA-CT). The main working principle of the IWOA-CT is to solve the local minimum (optimum) problem and achieve the global optimum points to deliver the best parameter values for the ANF-NLFOPID controller. A simulation and experimental results are conducted to measure the performance of the ANF-NLFOPID controller compared to other existing works. MATLAB software is used to simulate four trajectory tracking cases, where the first case proved the superiority of the ANF-NLFOPID controller by 52.559%, 70.028%, and 73.83%, the second case shows that the ANF-NLFOPID improves the trajectory tracking performance by 34.399%, 46.094%, and 59.143%, the third case demonstrates the effectiveness of the ANF-NLFOPID controller by 41.922%, 51.205%, and 62.252%, and the fourth case shows that the ANF-NLFOPID enhance the overall trajectory tracking efficiency by 29.356%, 38.413%, and 44.795% compared to adaptive neural network-based nonlinear FOPID (ANNFOPID), adaptive fuzzy-based nonlinear PID (AFNLPID), and disturbance rejection based on adaptive neural network (DR-ANN) controllers respectively. In the end, the experimental results were conducted using a real-world URV model and showed that the ANF-NLFOPID controller presents superior in solving trajectory tracking problems compared to the ANNFOPID controller.

Active disturbance rejection controller design for harmonic suppression in MPC optimal control based on harmonic state space modeling

SummaryThis paper proposes a harmonic suppression strategy for photovoltaic‐voltage source converters (PV‐VSC). The proposed method utilizes a harmonic state space (HSS) model‐combine model predictive control (MPC) algorithm, which provides a comprehensive representation of the global characteristics of AC/DC harmonic coupling impedance in photovoltaic systems. The HSS‐based converter model operates as a linear time‐varying periodic system, which allows for the implementation of MPC to optimize the HSS equation. This optimization yields voltage increments across various harmonic orders, providing feedforward compensation for the current controller. By incorporating feedback signals into the current control, harmonic compensation is achieved, resulting in improved power quality. Furthermore, a decoupled proportional resonance‐linear adaptive disturbance rejection control (PR‐LADRC) is employed to effectively mitigate steady‐state errors and decrease total harmonic distortion in the presence of DC‐side disturbances. This is accomplished by decoupling the disturbance observer from the controller and integrating the increment feedback signal derived from the MPC‐HSS. Finally, the efficacy of the proposed method and the analysis results are corroborated through numerical simulations.

An active disturbance rejection control design for the distillation process with input saturation via quantitative feedback theory

The distillation process is a major contributor to high energy consumption in the petrochemical industry. It is a complex multivariable system with input saturation, and its control problem is a critical factor that affects process energy efficiency. To address these control challenges, a new active disturbance rejection control (ADRC) design is proposed for the distillation process. The design includes a saturation compensation element with an integral structure and a nonlinear error feedback component with switched gain. The proposed control structure is effective in helping the system exit saturation in time, resulting in better dynamic performance than traditional ADRC. Additionally, a parameter tuning strategy based on quantitative feedback theory (QFT) is proposed to achieve the desired performance. The closed-loop stability conditions are analyzed using the describing functions technique to ensure the robust stability of the system. Finally, the proposed control structure and corresponding tuning strategy are applied to the distillation process. A numerical simulation and a simulation based on Aspen Plus confirm its superiority over traditional control structures. The proposed ADRC design with input saturation compensation has clear potential in the application of the distillation process.

Modified ADRC Design of Permanent Magnet Synchronous Motor Based on Improved Memetic Algorithm

In this paper, a novel modified auto disturbance rejection control (ADRC) design of a permanent magnet synchronous motor based on the improved memetic algorithm (IMA) is proposed. Firstly, there is an obvious system ripple caused by the defect that the optimal control function used in traditional ADRC cannot be differentiable and smooth at the segment point; aiming at weakening the system ripple effectively, the proposed method constructs a novel differentiable and smooth optimal control function to modify the ADRC design. Furthermore, aiming at improving the integration parameters optimization effect effectively, a novel improved memetic algorithm is proposed for obtaining the optimal parameters of ADRC. Specifically, an IMA with high-quality balance based on an adaptive nonlinear decreasing strategy for the convergence factor, Gaussian mutation mechanism, improved learning mechanism with the high-quality balance between competitive and opposition-based learning (OBL) and an elite set maintenance mechanism based on fusion distance is proposed so that these strategies can improve the optimization precision by a large margin. Finally, the experiment results of the PMSM speed control practical cases show that the ADRC based on IMA has an apparent better optimization effect than that of fuzzy PI, traditional ADRC based on the genetic algorithm and an improved ADRC based on improved moth-flame optimization.

Reduced Order Based Active Disturbance Rejection Controller Design with Applications

Active disturbance rejection control (ADRC) has emerged as a well-addressed controller design technique in recent years. It is a suitable replacement for the error-based feedback PID controller design approaches. The ADRC constitutes two controller design techniques: linear active disturbance rejection control (LADRC) and generalized active disturbance rejection control (GADRC). The LADRC design approach requires minimal information about the plant, while in the GADRC approach, detailed information about the plant is needed. For higher-order plants, the design of ADRC controllers and extended state observers may be pretty complex and costlier. So, the performance analysis of the higher order plant becomes difficult. Therefore, to make the controller simpler, it is always advantageous to reduce the controller size. This paper proposes reduced order linear active disturbance rejection control (ROLADRC), and reduced order generalized active disturbance rejection control (ROGADRC) techniques instead of full-order LADRC and GADRC approaches. The stability equation method (SEM) and other widespread model order reduction (MOR) methods are utilized to reduce the order of the plant. Further, ROLADRC and ROGADRC are compared with existing control techniques in the literature. The effectiveness of the proposed scheme is tested on the sun tracker system (STS) for position control and power systems for load frequency control (LFC).

Active disturbance rejection controller design for alleviation of gust-induced aeroelastic responses

This paper develops an active disturbance rejection control technology that uses the equivalent input disturbance (EID) approach to reduce the aeroelastic vibrations and structural loads caused by wind gusts. The influence of gust disturbance is evaluated by the EID estimator and actively compensated in the control input channel, giving a high disturbance rejection performance of the aeroelastic system. The suitable design of the state observer and low-pass filter is essential for the disturbance estimation and rejection. However, the conventional low-pass filter simply specified by a cutoff frequency may lead to a degraded estimation performance. To this end, a new structure of low-pass filter is proposed, and the design algorithms for the observer gain and filter parameters are also given. By specifying bandwidth constraints, the control system with guaranteed performance can be automatically generated. Numerical results show that for the acceleration measurement-based control, the proposed design method can achieve better disturbance estimation performance than that obtained by the conventional one, resulting in smaller gust responses. Finally, the proposed design method is further extended to the folding wing parameter-varying system. A parameterized version of the EID-based controller is constructed by using the concept of gain-scheduling. It is demonstrated that the gust responses can be significantly reduced in the entire range of folding angle. This study provides an effective solution for gust alleviation of the aeroelastic system with fixed or variable configurations.

A two stage Active Disturbance Rejection Control design for under-actuated nonlinear systems

A two-stage Active Disturbance Rejection Control (ADRC) design procedure is presented for the output trajectory tracking control problem in Single Input Single Output (SISO) nonlinear systems. Aside from the given scalar system output, the plant is assumed to exhibit a second, physically measurable, internal scalar output variable. The system output is controlled in an ADRC manner from an implicit static, or dynamic, nonlinear feedback controller using, in general, a nonlinear differential expression of the internal output variable. A desired internal output trajectory is thus generated. The internal output variable, in turn, is controlled from the original input and forced to track the desired trajectory synthesized in the previous step by the auxiliary controller. Each ADRC controller design is based on a simplified model of the corresponding subsystem, usually relegating interaction variables and additive nonlinearities to be part of a local (total) disturbance input term. The control scheme is reduced to a set of linear ADRC controllers with, possibly, cancellation of nonlinear input gains which are assumed to be known. Two illustrative aerospace examples are presented where the proposed procedure is illustrated via digital computer simulations.

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.

Fractional-Order Active Disturbance Rejection Controller Design for Large Radio Telescope Antenna

large radio telescope antennas are required in current astronomical research and deep space communication applications. The wind disturbance becomes a serious problem with an increase in the size of the antennas. Based on the typical antenna model, this work aims to design a fractional-order active disturbance rejection controller (FOADRC) for improving the accuracy of the antenna pointing mechanism in wind disturbance. First, the fractional-order active disturbance rejection control scheme is chosen to estimate and compensate both the wind disturbance and other uncertain mechanical dynamics. Afterwards, the relationship between the parameters of fractional-order extended state observer and the performance of disturbance suppression and noise immunity is revealed. The stability of fractional-order extended state observer is proved under similar assumptions as an integer order extended state observer. In addition, a stability region boundary calculation method is presented to simplify the parameter setting procedure. Finally, we perform simulations to verify the superiority of FOADRC in the antenna control system under wind disturbance. The results demonstrate that FOADRC has a good capability of resisting wind disturbance; at the same time, it limits the response overshoot and converges faster compared to other industrial controllers.

Optimal integral–proportional derivative controller design for input load disturbance rejection of time delay integrating processes

One of the commonly encountered type of processes in industry is integrating systems. For this type of processes, tuning formulas to calculate optimally integral–proportional derivative controller parameters to reject input load disturbance, which is an important problem in process control, are presented here. Simple tuning formulas are provided to set the integral–proportional derivative controller parameters for rejection of input load disturbance of integrating plus first order plus dead time and double integrating plus first order plus dead time processes. Time-weighted integral performance indices are exploited to derive optimal formulas for input load disturbance rejection. Achieved formulas for integral–proportional derivative tuning contain only process transfer function parameters. To show benefits and usefulness of the suggested design approach, simulation examples are imparted. Furthermore, comparisons to some available design approaches are given to reveal the superior performance of the suggested design method. In addition, proposed design method is experimentally validated by controlling a cart position.

Composite disturbance rejection and tracking control design for fuzzy model based systems with cyber attacks

This paper addresses the output tracking control problem and lumped disturbance rejections for nonlinear cyber-physical systems described by fuzzy model systems with parametric uncertainties, external disturbances and cyber attacks. Especially, to assure both the robust tracking and lumped disturbance estimation performances, an uncertainty and disturbance estimator (UDE)-based modified repetitive control (MRC) protocol is devised for the addressed control system. In detail, the impact of unpredictable factors, such as disturbances and uncertainties in the system model is robustly tackled by the UDE method with an appropriate filter. To be specific, the MRC protocol is amalgamated into the UDE technique for estimating the changes that occur in the afore-said unpredictable factors to ensure the asymptotic tracking performance of the system under study. Notably, to improve the tracking precision, the parallel distributed compensation strategy and the estimated lumped disturbance signal are incorporated into the control design. Meanwhile, the cyber attacks are depicted in this study as a stochastic variable that adheres to the Bernoulli distribution. Further, the required controller gain matrices are determined to affirm the robust asymptotic tracking performances with the aid of Lyapunov stability theory. Eventually, the method proposed in this paper is validated through the simulation results with two numerical examples, which include the continuous stirred tank reactor (CSTR) plant model. Further, the result reveals that the proposed control law provides the minimum tracking error when compared with an existing work.

Predictor-based phase-lead active disturbance rejection control design for industrial processes with input delay

For industrial processes subject to input delay, a predictor-based phase-lead active disturbance rejection control (ADRC) scheme is proposed in this article for improving disturbance rejection performance by introducing a phase-lead module for feedback control. First, an extended state observer (ESO) in combination with a generalized delay-free output predictor is presented to estimate the delay-free system state together with load disturbance lumped with process uncertainties. To reduce the phase lag caused by not only ESO but also the delay-free output predictor, a phase-lead module is then added into the disturbance observation channel so as to expedite disturbance estimation and thus improve the disturbance rejection performance. Consequently, the ESO gain vector and feedback controller are analytically designed by specifying the desired poles for the observer and the closed-loop system, respectively. Moreover, a digital implementation of the proposed scheme is presented to facilitate the practical applications, followed by a robust stability analysis of the closed-loop system based on the small gain theorem. Illustrative examples from the literature are used to demonstrate the effectiveness and merits of the proposed method over the existing methods.

Disturbance rejection and robust tracking control design for turbofan systems

The intention of this work is to analyse the issues of multiple disturbance estimation and rejection as well as robust tracking control design for turbofan systems subject to input gain perturbations. A standard generalized extended state observer is developed to estimate both the state disturbances and output measurement disturbances, simultaneously. Therewith, a modified repetitive controller is utilized with generalized extended state observer to track the states of the turbofan system accurately. Then, a new composite control strategy is developed by incorporating the estimates obtained via generalized extended state observer in modified repetitive controller to attenuate the effect of disturbances. Based on the pole placement technique, the observer gain is calculated and in accordance with Lyapunov stability theory, a set of sufficient conditions which ensures the robust asymptotic stability of the considered turbofan system is derived in the form of linear matrix inequalities. Moreover by offering the numerical examples with simulation results, the superiority of developed control strategy is validated.