scholarly journals Improving Disturbance-Rejection by Using Disturbance Estimator

2021 ◽  
Author(s):  
Damir Vrančić ◽  
Mikuláš Huba
Keyword(s):  
Disturbance Rejection ◽  
Pid Controller ◽  
Transfer Functions ◽  
Process Models ◽  
Tracking Performance ◽  
Fast Tracking ◽  
Tuning Method ◽  
Process Output ◽  
Process Disturbances ◽  
Disturbance Estimator

The main tasks of control in various industries are either tracking the setpoint changes or rejecting the process disturbances. While both aim at maintaining the process output at the desired setpoint, the controller parameters optimised for setpoint tracking are generally not suitable for optimal disturbance rejection. The overall control performance can be improved to some extent by using simpler 2-DOF PID controllers. Such a controller structure allows the disturbance rejection to be optimised, while it also improves the setpoint tracking performance with additional controller parameters (usually through the setpoint weighting factors). Since such 2-DOF structures are usually relatively simple, the optimization of tracking performance is usually limited to the reduction of process overshoots instead of achieving an optimal (fast) tracking response. In this chapter, an alternative approach is presented in which the parameters of the PID controller are optimised for reference tracking, while the performance of the disturbance rejection is substantially increased by introducing a simple disturbance estimator approach. The mentioned estimator requires adding two simple blocks to the PID controller. The blocks are the second-order transfer functions whose parameters, including the PID controller parameters, can be calculated analytically from the process characteristic areas (also called process moments). The advantage of such an approach is that the mentioned areas can be analytically calculated directly from the process transfer function (of any order with time delay) or from the time response of the process when the steady state of the process is changed. Both of the above calculations are absolutely equivalent. Moreover, the output noise of the controller is under control as it is considered in the design of the controller and compensator. The closed loop results on several process models show that the proposed method with disturbance estimator has excellent tracking and disturbance rejection performance. The proposed controller structure and tuning method also compare favourably with some existing methods based on non-parametric description of the process.

The magnitude optimum tuning of the PID controller: Improving load disturbance rejection by extending the controller

2017 ◽  
Vol 40 (5) ◽  
pp. 1669-1680 ◽  
Author(s):  
Jan Cvejn ◽  
Damir Vrančić
Keyword(s):  
Disturbance Rejection ◽  
Pid Controller ◽  
Stability Margin ◽  
Pid Controllers ◽  
First Order ◽  
Fast Tracking ◽  
Tuning Method ◽  
Exogenous Disturbance ◽  
Process Output ◽  
The Stability

The Magnitude Optimum (MO) tuning method for PID controllers, applied on stable and non-oscillating plants, usually gives fast tracking responses and offers very good process output disturbance-rejection performance, even if the process contains significant dead time. On the other hand, when an exogenous disturbance affects the process indirectly, for example, via the plant input, slow disturbance rejection responses may be obtained. The paper proposes a way of removing this problem by means of adding two first-order filters into the control loop, without modifying the controller parameters. The filter parameters are determined so that the disturbance lag is partially compensated and the stability margin properties of the MO tuning are preserved.

scholarly journals A Modified 2-DOF Control Framework and GA Based Intelligent Tuning of PID Controllers

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 423
Author(s):  
Gun-Baek So
Keyword(s):  
Disturbance Rejection ◽  
Pid Controller ◽  
Weighting Function ◽  
Pid Controllers ◽  
Set Point ◽  
Tuning Method ◽  
Point Tracking ◽  
Load Disturbance ◽  
Control Framework ◽  
Feedforward Controller

Although a controller is well-tuned for set-point tracking, it shows poor control results for load disturbance rejection and vice versa. In this paper, a modified two-degree-of-freedom (2-DOF) control framework to solve this problem is proposed, and an optimal tuning method for the pa-rameters of each proportional integral derivative (PID) controller is discussed. The unique feature of the proposed scheme is that a feedforward controller is embedded in the parallel control structure to improve set-point tracking performance. This feedforward controller and the standard PID con-troller are combined to create a new set-point weighted PID controller with a set-point weighting function. Therefore, in this study, two controllers are used: a set-point weighted PID controller for set-point tracking and a conventional PID controller for load disturbance rejection. The parameters included in the two controllers are tuned separately to improve set-point tracking and load dis-turbance rejection performances, respectively. Each controller is optimally tuned by genetic algo-rithm (GA) in terms of minimizing the IAE performance index, and what is special at this time is that it also tunes the set-point weighting parameter simultaneously. The simulation results performed on four virtual processes verify that the proposed method shows better performance in set-point tracking and load disturbance rejection than those of the other methods.

scholarly journals Position Tracking Performance with Fine Tune Ziegler-Nichols PID Controller for Electro-Hydraulic Actuator in Aerospace Vehicle Model

2021 ◽  
Vol 2107 (1) ◽  
pp. 012064
Author(s):  
S.M. Othman ◽  
Noorhazirah Sunar ◽  
Hassrizal H.B ◽  
A.H. Ismail ◽  
M.N. Ayob ◽  
...  
Keyword(s):  
Pid Controller ◽  
External Disturbance ◽  
Viscous Friction ◽  
Fine Tuning ◽  
Tracking Performance ◽  
Position Tracking ◽  
Trial And Error ◽  
Hydraulic Actuator ◽  
Tuning Method ◽  
Non Linear System

Abstract Electro-Hydraulic Actuator (EHA) system is a third order non-linear system which is highly suffer from system uncertainties such as Coulomb friction, viscous friction and pump leakage coefficient which makes this system more complicated for the designing of the controller. The Proportional-Integral-Derivative (PID) controller has proposed in this paper to control EHA system and main problem in its application is to tune the parameter to its optimum value. Two different methods are used to tune the PID controller which are trial and error and Ziegler-Nichols method. MATLAB Simulink is used to simulate the system. In order to determine the performance of EHA system for the position tracking. 3 different of external disturbance such as 0N, 5000N and 10000N has been injected into the system. Simulation results show that the Ziegler-Nichols fine tuning method provides the better tracking performance when compared to the trial and error method for every specific disturbance setting. The Ziegler Nichols method provides better disturbance rejection as the performances indexes such as percentage overshoot, settling time and steady state error are not affected by the varying of disturbance.

Extended State Observer Based Controller Design for the Green Bank Telescope Servo System

2015 ◽  
Author(s):  
Trupti Ranka ◽  
Mario Garcia-Sanz ◽  
John M. Ford
Keyword(s):  
Disturbance Rejection ◽  
Pid Controller ◽  
Controller Design ◽  
Tracking Error ◽  
State Observer ◽  
Extended State Observer ◽  
Tracking Performance ◽  
Extended State ◽  
External Disturbances ◽  
Green Bank Telescope

The Green Bank Telescope is a large flexible structure, requiring rms tracking error ≤ 3 arcseconds against internal and external disturbances. We design an extended state observer (ESO) based controller in various configurations to improve tracking performance and increase disturbance rejection. The controllers are simulated with an experimentally validated model of the GBT. Through the simulations, the response of ESO based controllers and legacy PID controller are compared using time and frequency domain responses. We show that the ESO based controller when implemented in both position and velocity loop can give significant improvement in tracking performance and better disturbance rejection without increase in controller output.

scholarly journals Advanced Fireworks Algorithm and Its Application Research in PID Parameters Tuning

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jun-jie Xue ◽  
Ying Wang ◽  
Hao Li ◽  
Xiang-fei Meng ◽  
Ji-yang Xiao
Keyword(s):  
Pid Control ◽  
Pid Controller ◽  
Transfer Functions ◽  
Gaussian Function ◽  
Optimization Method ◽  
Pid Controllers ◽  
Fireworks Algorithm ◽  
Extremal Optimization ◽  
Tuning Method ◽  
Parameters Tuning

Proportional-Integral-Derivative (PID) controller is one of the most widely used controllers for its property of simplicity and practicability. In order to design high-quality performances PID controllers, an Advanced Fireworks (AFW) algorithm based on self-adaption principle and bimodal Gaussian function is proposed, which is built to optimize the PID controller by parameters tuning. Firstly, a compound index of optimization performance is formulated, and then the extremal optimization method of PID control system is proposed. Secondly, a PID parameters tuning model combined with AFW is built. At last, 5 typical transfer functions are simulated to obtain optimal parameters by AFW and contrast tuning method, such as Ziegler-Nichols method, Enhanced Fireworks (EFW) algorithm, and Particle Swarm Optimization (PSO). Simulation results show that AFW are effective and are easily implemented methods to solve PID control problems of different transfer functions.

Tracking of periodic reference signal: A parameterized finite dimensional repetitive control approach

2017 ◽  
Vol 40 (13) ◽  
pp. 3640-3650 ◽  
Author(s):  
Ujjwal Mondal ◽  
Anindita Sengupta ◽  
Naiwrita Dey
Keyword(s):  
Disturbance Rejection ◽  
Pid Controller ◽  
Transfer Functions ◽  
Repetitive Control ◽  
Reference Signal ◽  
Input Output ◽  
Prime Factorization ◽  
Control Approach ◽  
Finite Dimensional ◽  
Reference Input

This paper is concerned with the development of a Modified Finite Dimensional Repetitive Control (MFDRC) system. Conventional FDRC is modified through parameterization of the controller using co-prime factorization. The proposed method of controller design specifies the input output characteristics beforehand, ensuring highly accurate tracking and disturbance rejection property of the system subjected to periodic reference input. Another problem is the stabilization issues in the input–output and the disturbance rejection characteristics of a conventional repetitive control system with respect to the periodic reference input owing to have infinite number of poles in the transfer function of it. It is desirable that the transfer functions from both the reference input and the disturbance to the output have a finite number of poles and that will be taken care of in the proposed scheme of MFDRC design depicted in this paper. The performance of designed controller has been validated in steps applied to a laboratory based servo system. Comparisons are done using conventional PID controller, FDRC-based PID controller and MFDRC to show advantage, disadvantage or limitation of applied control scheme.

scholarly journals High-Order Filtered PID Controller Tuning Based on Magnitude Optimum

Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1340
Author(s):  
Damir Vrančić ◽  
Mikuláš Huba
Keyword(s):  
A Priori ◽  
Higher Order ◽  
Process Models ◽  
Pid Controllers ◽  
Tuning Method ◽  
Output Noise ◽  
Pid Controller Tuning ◽  
Output Time ◽  
Tuning Methods ◽  
Measured Input

The paper presents a tuning method for PID controllers with higher-order derivatives and higher-order controller filters (HO-PID), where the controller and filter orders can be arbitrarily chosen by the user. The controller and filter parameters are tuned according to the magnitude optimum criteria and the specified noise gain of the controller. The advantages of the proposed approach are twofold. First, all parameters can be obtained from the process transfer function or from the measured input and output time responses of the process as the steady-state changes. Second, the a priori defined controller noise gain limits the amount of HO-PID output noise. Therefore, the method can be successfully applied in practice. The work shows that the HO-PID controllers can significantly improve the control performance of various process models compared to the standard PID controllers. Of course, the increased efficiency is limited by the selected noise gain. The proposed tuning method is illustrated on several process models and compared with two other tuning methods for higher-order controllers.

scholarly journals Active Disturbance Rejection Control for Position Tracking of Electro-Hydraulic Servo Systems under Modeling Uncertainty and External Load

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 20
Author(s):  
Manh Hung Nguyen ◽  
Hoang Vu Dao ◽  
Kyoung Kwan Ahn
Keyword(s):  
Angular Velocity ◽  
Disturbance Rejection ◽  
Lyapunov Theory ◽  
Tracking Performance ◽  
System Stability ◽  
Position Tracking ◽  
Parametric Uncertainties ◽  
Active Disturbance Rejection Control ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control

In this paper, an active disturbance rejection control is designed to improve the position tracking performance of an electro-hydraulic actuation system in the presence of parametric uncertainties, non-parametric uncertainties, and external disturbances as well. The disturbance observers (Dos) are proposed to estimate not only the matched lumped uncertainties but also mismatched disturbance. Without the velocity measurement, the unmeasurable angular velocity is robustly calculated based on the high-order Levant’s exact differentiator. These disturbances and angular velocity are integrated into the control design system based on the backstepping framework which guarantees high-accuracy tracking performance. The system stability analysis is analyzed by using the Lyapunov theory. Simulations based on an electro-hydraulic rotary actuator are conducted to verify the effectiveness of the proposed control method.

scholarly journals Optimal Fractional-Order Active Disturbance Rejection Controller Design for PMSM Speed Servo System

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 262
Author(s):  
Pengchong Chen ◽  
Ying Luo ◽  
Yibing Peng ◽  
Yangquan Chen
Keyword(s):  
Fractional Order ◽  
Disturbance Rejection ◽  
Pid Controller ◽  
External Disturbance ◽  
Servo System ◽  
Stable Region ◽  
Speed Tracking ◽  
Active Disturbance Rejection ◽  
Load Disturbance ◽  
Tuning Strategy

In this paper, a fractional-order active disturbance rejection controller (FOADRC), combining a fractional-order proportional derivative (FOPD) controller and an extended state observer (ESO), is proposed for a permanent magnet synchronous motor (PMSM) speed servo system. The global stable region in the parameter (Kp, Kd, μ)-space corresponding to the observer bandwidth ωo can be obtained by D-decomposition method. To achieve a satisfied tracking and anti-load disturbance performance, an optimal ADRC tuning strategy is proposed. This tuning strategy is applicable to both FOADRC and integer-order active disturbance rejection controller (IOADRC). The tuning method not only meets user-specified frequency-domain indicators but also achieves a time-domain performance index. Simulation and experimental results demonstrate that the proposed FOADRC achieves better speed tracking, and more robustness to external disturbance performances than traditional IOADRC and typical Proportional-Integral-Derivative (PID) controller. For example, the JITAE for speed tracking of the designed FOADRC are less than 52.59% and 55.36% of the JITAE of IOADRC and PID controller, respectively. Besides, the JITAE for anti-load disturbance of the designed FOADRC are less than 17.11% and 52.50% of the JITAE of IOADRC and PID controller, respectively.

scholarly journals An MEA-Tuning Method for Design of the PID Controller

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Yongli Zhang ◽  
Lijun Zhang ◽  
Zhiliang Dong
Keyword(s):  
Pid Controller ◽  
Industrial Process ◽  
Optimal Solution ◽  
Design Feature ◽  
Parameter Tuning ◽  
Parallel Structure ◽  
Evolutionary Information ◽  
Tuning Method ◽  
Efficiency And Effectiveness ◽  
Global Optimal

The optimization and tuning of parameters is very important for the performance of the PID controller. In this paper, a novel parameter tuning method based on the mind evolutionary algorithm (MEA) was presented. The MEA firstly transformed the problem solutions into the population individuals embodied by code and then divided the population into superior subpopulations and temporary subpopulations and used the similar taxis and dissimilation operations for searching the global optimal solution. In order to verify the control performance of the MEA, three classical functions and five typical industrial process control models were adopted for testing experiments. Experimental results indicated that the proposed approach was feasible and valid: the MEA with the superior design feature and parallel structure could memorize more evolutionary information, generate superior genes, and enhance the efficiency and effectiveness for searching global optimal parameters. In addition, the MEA-tuning method can be easily applied to real industrial practices and provides a novel and convenient solution for the optimization and tuning of the PID controller.

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