Fuzzy Adaptive Controller for Uncertain Multivariable Nonlinear Systems with Both Sector Nonlinearities and Dead-Zones

2015 ◽  
pp. 334-363
Author(s):  
Abdesselem Boulkroune
Keyword(s):  
Nonlinear Systems ◽  
Positive Definite ◽  
Loop Control ◽  
Dead Zones ◽  
Gain Matrix ◽  
Control Gain ◽  
Loop Control System ◽  
The Stability ◽  
Sector Nonlinearities ◽  
Fuzzy Adaptive

This chapter presents two fuzzy adaptive variable structure controllers for a class of uncertain multi-input multi-output nonlinear systems with actuator nonlinearities (i.e. with sector nonlinearities and dead-zones). The design of the first controller concerns systems with symmetric and positive definite control-gain matrix, while the design of the second one is extended to the case of non-symmetric control-gain matrix thanks to an appropriate matrix decomposition, namely the product of a symmetric positive-definite matrix, a diagonal matrix with diagonal entries +1 or -1, and a unity upper triangular matrix. An appropriate adaptive fuzzy-logic system is used to reasonably approximate the uncertain functions. A Lyapunov approach is adopted to derive the parameter adaptation laws and prove the stability of the closed-loop control system. Finally, some simulation results are carried out to show the effectiveness of the proposed controllers.

Fuzzy Adaptive Controller for Uncertain Multivariable Nonlinear Systems with Both Sector Nonlinearities and Dead-Zones

2017 ◽  
pp. 1127-1155
Author(s):  
Abdesselem Boulkroune
Keyword(s):  
Nonlinear Systems ◽  
Positive Definite ◽  
Loop Control ◽  
Dead Zones ◽  
Gain Matrix ◽  
Control Gain ◽  
Loop Control System ◽  
The Stability ◽  
Sector Nonlinearities ◽  
Fuzzy Adaptive

This chapter presents two fuzzy adaptive variable structure controllers for a class of uncertain multi-input multi-output nonlinear systems with actuator nonlinearities (i.e. with sector nonlinearities and dead-zones). The design of the first controller concerns systems with symmetric and positive definite control-gain matrix, while the design of the second one is extended to the case of non-symmetric control-gain matrix thanks to an appropriate matrix decomposition, namely the product of a symmetric positive-definite matrix, a diagonal matrix with diagonal entries +1 or -1, and a unity upper triangular matrix. An appropriate adaptive fuzzy-logic system is used to reasonably approximate the uncertain functions. A Lyapunov approach is adopted to derive the parameter adaptation laws and prove the stability of the closed-loop control system. Finally, some simulation results are carried out to show the effectiveness of the proposed controllers.

Fuzzy Adaptive Controller for Uncertain Multivariable Nonlinear Systems with Both Sector Nonlinearities and Dead-Zones

Fuzzy Systems ◽  
2017 ◽  
pp. 487-515 ◽  
Author(s):  
Abdesselem Boulkroune
Keyword(s):  
Nonlinear Systems ◽  
Positive Definite ◽  
Loop Control ◽  
Dead Zones ◽  
Gain Matrix ◽  
Control Gain ◽  
Loop Control System ◽  
The Stability ◽  
Sector Nonlinearities ◽  
Fuzzy Adaptive

This chapter presents two fuzzy adaptive variable structure controllers for a class of uncertain multi-input multi-output nonlinear systems with actuator nonlinearities (i.e. with sector nonlinearities and dead-zones). The design of the first controller concerns systems with symmetric and positive definite control-gain matrix, while the design of the second one is extended to the case of non-symmetric control-gain matrix thanks to an appropriate matrix decomposition, namely the product of a symmetric positive-definite matrix, a diagonal matrix with diagonal entries +1 or -1, and a unity upper triangular matrix. An appropriate adaptive fuzzy-logic system is used to reasonably approximate the uncertain functions. A Lyapunov approach is adopted to derive the parameter adaptation laws and prove the stability of the closed-loop control system. Finally, some simulation results are carried out to show the effectiveness of the proposed controllers.

Backstepping Control for Synchronizing Fractional-Order Chaotic Systems

2018 ◽  
pp. 129-165
Author(s):  
Amina Boubellouta
Keyword(s):  
Fractional Order ◽  
Control Method ◽  
Nonlinear Function ◽  
Backstepping Control ◽  
Projective Synchronization ◽  
Loop Control ◽  
Loop Control System ◽  
The Stability ◽  
Synchronization Scheme ◽  
Fuzzy Adaptive

In this chapter, one develops a fuzzy adaptive backstepping control-based projective synchronization scheme of a class of uncertain fractional-order nonlinear systems with unknown external disturbances. In each step, an uncertain nonlinear function is online modeled via a fuzzy logic system, and a virtual control term is determined based on the fractional Lyapunov stability. At the final step, a fuzzy adaptive control law ensuring the convergence of the projective synchronization error as well as the stability of the closed-loop control system is derived. Numerical simulations given at the end of this chapter confirm well the effectiveness of the proposed control method.

Controlled Freezing of Nonideal Solutions With Application to Cryosurgical Processes

1991 ◽  
Vol 113 (4) ◽  
pp. 430-437 ◽  
Author(s):  
H. M. Budman ◽  
J. Dayan ◽  
A. Shitzer
Keyword(s):  
Cooling Rate ◽  
Freezing Process ◽  
Data Sets ◽  
Tracking Accuracy ◽  
Loop Control ◽  
Set Point ◽  
New Device ◽  
Loop Control System ◽  
The Stability ◽  
Controlled Freezing

Success of a cryosurgical procedure, i.e., maximal cell destruction, requires that the cooling rate be controlled during the freezing process. Standard cryosurgical devices are not usually designed to perform the required controlled process. In this study, a new cryosurgical device was developed which facilitates the achievement of a specified cooling rate during freezing by accurately controlling the probe temperature variation with time. The new device has been experimentally tested by applying it to an aqueous solution of mashed potatoes. The temperature field in the freezing medium, whose thermal properties are similar to those of biological tissue, was measured. The cryoprobe temperature was controlled according to a desired time varying profile which was assumed to maximize necrosis. The tracking accuracy and the stability of the closed loop control system were investigated. It was found that for most of the time the tracking accuracy was excellent and the error between the measured probe temperature and the desired set point is within ±0.4°C. However, noticeable deviations from the set point occurred due to the supercooling phenomenon or due to the instability of the liquid nitrogen boiling regime in the cryoprobe. The experimental results were compared to those obtained by a finite elements program and very good agreement was obtained. The deviation between the two data sets seems to be mainly due to errors in positioning of the thermocouple junctions in the medium.

Research on INS-Aided GNSS Carrier Tracking Loop in High Dynamic Circumstance

2013 ◽  
Vol 464 ◽  
pp. 215-221
Author(s):  
Xin Long Wang ◽  
Chuan Jun Li ◽  
Xing Cheng Li
Keyword(s):  
Dynamic Environment ◽  
Coupled System ◽  
Tracking Performance ◽  
Tracking Loop ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Tightly Coupled ◽  
High Dynamic ◽  
The Stability

GNSS receiver will produce a large Doppler shift in high dynamic environment, thus causing lock-lose of the tracking loop. INS-aided GNSS tightly coupled system can improve tracking performance in high dynamic environment by introducing the Doppler information estimated by INS. Through analyzing by the theory of closed loop control system theory and numerical simulation of the INS-aided carrier tracking loop, the results show that INS-aided carrier tracking loop can obviously improve the stability of carrier tracking performance and anti-jamming ability of the satellite navigation receiver in high dynamic circumstance.

scholarly journals Research on Discretization PI Control Technology of Single-Phase Grid-Connected Inverter with LCL Filter

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Jianke Li ◽  
Jinquan Wang ◽  
Ye Xu ◽  
Jianting Li ◽  
Jingjing Chen ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Numerical Algorithms ◽  
Switching Frequency ◽  
Lcl Filter ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Grid Connected Inverter ◽  
The Stability ◽  
The Cost

Compared with L-type filter, LCL-type filter is more suitable for high-power low-switching frequency applications with reducing the inductance, improving dynamic performance. However, the parameter design for the LCL filter is more complex due to the influence of the controller response performance of the converter. If the harmonic current around switching frequency can be fully suppressed, it is possible for inverter to decrease the total inductance as well as the size and the cost. In this paper, the model of the LCL filter is analyzed and numerical algorithms are adopted to analyze the stability of the closed-loop control system and stable regions are deduced with different parameters of LCL filter. Then, the minimum sampling frequencies are deduced with different conditions. Simulation and experimental results are provided to validate the research on the generating mechanism for the unstable region of sampling frequency.

scholarly journals Fuzzy Adaptive Variable Structure Control of Second-Order Robotic Manipulators with Dead Zones

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Songyu Wang ◽  
Xianmin Hou
Keyword(s):  
Fuzzy Systems ◽  
Variable Structure ◽  
Second Order ◽  
Theoretical Derivation ◽  
Controlled System ◽  
Dead Zones ◽  
Structure Control ◽  
Adaptive Laws ◽  
The Stability ◽  
Fuzzy Adaptive

In this study, with respect to certain second-order robotic systems with dead zones, a fuzzy adaptive variable structure controller (VSC) is implemented. Some suitable adaptive fuzzy systems are used to estimate uncertain functions. Based on Lyapunov stability theorems, parameter adaptive laws are designed, and it is proven that all signals involved will remain bounded and the stability of the controlled system is also guaranteed. Our controller is effective for the system with or without sector nonlinearity. Finally, a simulation example is presented to illustrate the correctness of the theoretical derivation.

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