On Robust Control of Fractional Order Plants: Invariant Phase Margin

2015 ◽  
Vol 10 (5) ◽  
Author(s):  
Mohammad Hossein Basiri ◽  
Mohammad Saleh Tavazoei
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Phase Margin ◽  
Crossover Frequency ◽  
Large Uncertainty ◽  
Robust Controller ◽  
Numerical Examples

Recently, a robust controller has been proposed to be used in control of plants with large uncertainty in location of one of their poles. By using this controller, not only the phase margin and gain crossover frequency are adjustable for the nominal case but also the phase margin remains constant, notwithstanding the variations in location of the uncertain pole of the plant. In this paper, the tuning rule of the aforementioned controller is extended such that it can be applied in control of plants modeled by fractional order models. Numerical examples are provided to show the effectiveness of the tuned controller.

scholarly journals The Robust Control and Synchronization of a Class of Fractional-Order Chaotic Systems with External Disturbances via a Single Output

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Runzi Luo ◽  
Haipeng Su
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Chaos Control ◽  
Chaotic Systems ◽  
Sufficient Conditions ◽  
External Disturbances ◽  
Numerical Examples ◽  
Single Output ◽  
Lorenz Chaotic System ◽  
Control And Synchronization

This paper investigates the stabilization and synchronization of a class of fractional-order chaotic systems which are affected by external disturbances. The chaotic systems are assumed that only a single output can be used to design the controller. In order to design the proper controller, some observer systems are proposed. By using the observer systems some sufficient conditions for achieving chaos control and synchronization of fractional-order chaotic systems are derived. Numerical examples are presented by taking the fractional-order generalized Lorenz chaotic system as an example to show the feasibility and validity of the proposed method.

Phase-constrained fractional order PIλ controller for second-order-plus dead time systems

2016 ◽  
Vol 39 (8) ◽  
pp. 1225-1235 ◽  
Author(s):  
Kai Chen ◽  
Rongnian Tang ◽  
Chuang Li
Keyword(s):  
Fractional Order ◽  
Dead Time ◽  
Open Loop ◽  
Second Order ◽  
Phase Constraint ◽  
Phase Margin ◽  
Crossover Frequency ◽  
Tuning Method ◽  
The Stability ◽  
Stability Line

In this paper we propose a phase-constrained fractional order [Formula: see text] controller based on a second-order-plus dead time process and a new tuning method. The design is derived in several constraints: a flat phase constraint, a gain crossover frequency and a phase margin. With the specified phase margin, it can reach the corresponding upper boundary of gain crossover frequency and the stability region. The complete surface of stabilizing controllers is achieved by guaranteeing the open-loop system to fulfil the pre-set phase margin. Afterwards, a stability line on the relative stable surface can then be obtained. For a set of controllers on the stability line, the flat phase constraint is used to make sure the uniqueness of the designed controller. The effectiveness of the proposed method is illustrated with several numerical examples.

Fractional Order Proportional Derivative (FOPD) and FO[PD] Controller Design for Networked Position Servo Systems

2009 ◽  
Author(s):  
Yongshun Jin ◽  
YangQuan Chen ◽  
Chunyang Wang ◽  
Ying Luo
Keyword(s):  
Fractional Order ◽  
Controller Design ◽  
Phase Margin ◽  
Crossover Frequency ◽  
Pd Controller ◽  
Servo Systems ◽  
Integer Order ◽  
Simulation Results ◽  
Position Servo ◽  
The Given

This paper considers the fractional order proportional derivative (FOPD) controller and fractional order [proportional derivative] (FO[PD]) controller for networked position servo systems. The systematic design schemes of the networked position servo system with a time delay are presented. It follows from the Bode plot of the FOPD system and the FO[PD] that the given gain crossover frequency and phase margin are fulfilled. Moreover, the phase derivative w.r.t. the frequency is zero, which means that the closed-loop system is robust to gain variations at the given gain crossover frequency. However, sometimes we can not get the controller parameters to meet our robustness requirement. In this paper, we have studied on this situation and presented the requirement of the gain cross frequency, and phase margin in the designing process. For the comparison of fractional order controllers with traditional integer order controller, the integer order proportional integral differential (IOPID) was also designed by using the same proposed method. The simulation results have verified that FOPD and FO[PD] are effective for networked position servo. The simulation results also reveal that both FOPD controller and FO[PD] controller outperform IO-PID controller for this type of system.

Fractional order robust control based on Bode's ideal transfer function

2008 ◽  
Vol 42 (6-8) ◽  
pp. 999-1014 ◽  
Author(s):  
Abdelbaki Djouambi ◽  
Abdelfatah Charef ◽  
Alina Voda-Besancon
Keyword(s):  
Robust Control ◽  
Transfer Function ◽  
Fractional Order ◽  
Bode’S Ideal Transfer Function

A computationally efficient adaptive robust control scheme for a quad-rotor transporting cable-suspended payloads

2021 ◽  
pp. 095441002110136
Author(s):  
Nasim Ullah ◽  
Irfan Sami ◽  
Wang Shaoping ◽  
Hamid Mukhtar ◽  
Xingjian Wang ◽  
...  
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Adaptive Robust Control ◽  
Computationally Efficient ◽  
Control Scheme ◽  
Control Schemes ◽  
Adaptive Laws ◽  
Unknown Disturbances ◽  
The Stability

This article proposes a computationally efficient adaptive robust control scheme for a quad-rotor with cable-suspended payloads. Motion of payload introduces unknown disturbances that affect the performance of the quad-rotor controlled with conventional schemes, thus novel adaptive robust controllers with both integer- and fractional-order dynamics are proposed for the trajectory tracking of quad-rotor with cable-suspended payload. The disturbances acting on quad-rotor due to the payload motion are estimated by utilizing adaptive laws derived from integer- and fractional-order Lyapunov functions. The stability of the proposed control systems is guaranteed using integer- and fractional-order Lyapunov theorems. Overall, three variants of the control schemes, namely adaptive fractional-order sliding mode (AFSMC), adaptive sliding mode (ASMC), and classical Sliding mode controllers (SMC)s) are tested using processor in the loop experiments, and based on the two performance indicators, namely robustness and computational resource utilization, the best control scheme is evaluated. From the results presented, it is verified that ASMC scheme exhibits comparable robustness as of SMC and AFSMC, while it utilizes less sources as compared to AFSMC.

scholarly journals Performance Evaluation of Fractional Order Pid and Sliding Mode Control with Optimization Tuning Access

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1448-1454
Keyword(s):  
Fractional Order ◽  
Pid Controller ◽  
World Economy ◽  
Sliding Mode ◽  
Proportional Integral Derivative ◽  
Robust Controller ◽  
The Past ◽  
Control Schemes ◽  
Different Types ◽  
Fractional Order Pid

The statistical analyses in the past showing the important properties of the electrohydraulic actuator (EHA) system, especially in the growth of the world economy. Dealing with the existing drawback in the EHA system, various types of control schemes have been introduced in the past. In this paper, to produce a more insightful view of the performance and the capabilities of the controller, three different types of controllers have been designed and compared. The favourite controller in the industry field, which is the proportional-integral-derivative (PID) controller will be first introduced. Follow by the improved PID controller, named Fractional Order (FO-PID) controller will be designed. Then, the prominent robust controller in the control field, called sliding mode controller (SMC) will be established. Instead of obtaining the controller’s parameters without any appropriate technique, the well-known tuning technique in computer science, named particle swarm optimization (PSO) will be utilized. Referring to the performances produced by these controllers, it can be concluded that the SMC is capable to generate most desired control performance that produced the highest accuracy with the smallest error in the analyses.

scholarly journals Controllability of Flow-Conservation Transportation Networks with Fractional-Order Dynamics

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Wei Chen ◽  
Bo Zhou
Keyword(s):  
Theoretical Analysis ◽  
Fractional Derivative ◽  
Exact Solutions ◽  
Fractional Order ◽  
Location Problem ◽  
Transportation Networks ◽  
Qr Decomposition ◽  
Rank Condition ◽  
Numerical Examples ◽  
Flow Conservation

In this paper, we adapt the fractional derivative approach to formulate the flow-conservation transportation networks, which consider the propagation dynamics and the users’ behaviors in terms of route choices. We then investigate the controllability of the fractional-order transportation networks by employing the Popov-Belevitch-Hautus rank condition and the QR decomposition algorithm. Furthermore, we provide the exact solutions for the full controllability pricing controller location problem, which includes where to locate the controllers and how many controllers are required at the location positions. Finally, we illustrate two numerical examples to validate the theoretical analysis.

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