Fractional-order Active Disturbance Rejection 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.

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.

Control method for permanent magnet synchronous motor based on fractional active disturbance rejection

To improve the response speed and anti-interference ability of a permanent magnet synchronous motor (PMSM), a PMSM control method based on fractional-order active disturbance rejection control (FOADRC) is proposed in this study. First, a fractional-order tracking differentiator (FOTD) and fractional-order extended state observer (FOESO) are designed using the fractional calculus. According to the response speed of the FOTD and the observation effect of the FOESO, a new fastest function and new nonlinear function are designed. Second, a fractional-order active disturbance rejection (FOADR) controller is built based on the new FOTD, new FOESO, and nonlinear feedback control law, and its stability is proven. Finally, the superiority and effectiveness of the proposed strategy are verified through a simulation and experiments.

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.

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 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.