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.

scholarly journals Synchronization of Chaotic Systems with Dead Zones via Fuzzy Adaptive Variable-Structure Control

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yongbing Huangfu ◽  
Kaijuan Xue
Keyword(s):  
Chaotic Systems ◽  
Fuzzy Inference ◽  
Fuzzy Variable ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Dead Zones ◽  
Structure Control ◽  
Synchronization Problem ◽  
The Stability ◽  
Fuzzy Adaptive

This work is devoted to solving synchronization problem of uncertain chaotic systems with dead zones. Based on the Lyapunov stability theorems, by using fuzzy inference to estimate system uncertainties and by designing effective fuzzy adaptive controllers, the synchronization between two chaotic systems with dead zones is realized and a fuzzy variable-structure control is implemented. The stability is proven strictly, and all the states and signals are bounded in the closed-loop system. A simulation example is presented to test the theoretical results finally.

Enhanced Grey Variable Structure Control Methodology of Parallel-Connected DC-AC Inverters for Ultra-Precision Machining

2015 ◽  
Vol 661 ◽  
pp. 29-35
Author(s):  
En Chih Chang ◽  
Hung Liang Cheng ◽  
Chien Hsuan Chang ◽  
Jin Wei Liu ◽  
Chih Hsien Chuang ◽  
...  
Keyword(s):  
Output Voltage ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Precision Machining ◽  
Structure Control ◽  
Highly Nonlinear ◽  
Ultra Precision ◽  
The Stability ◽  
Control Methodology ◽  
Voltage Harmonics

This paper develops an enhanced grey variable structure controlled DC-AC inverter in parallel, and is suitable for the application of ultra-precision machining (UPM). The enhanced grey variable structure control methodology consists of a nonlinear sliding function (NSF) and a grey model, GM(2,1). The NSF has finite system-state convergence time, and thus the AC output voltage regulation and balanced current-sharing among the parallel modules can be achieved. However, once the loading of the UPM is a highly nonlinear condition, the chatter still exists in NSF. The chatter may cause heat losses and high voltage harmonics in parallel-connected DC-AC inverter output, and thus deteriorates the stability and reliability of the UPM. To eliminate the chatter, the control gains of the NSF can be adjusted by the use of the GM(2,1) under system uncertainty bounds are overestimated. With the enhanced methodology, the parallel-connected DC-AC inverter yields a high-quality AC output voltage with low voltage harmonics and fast dynamic response under highly nonlinear loading, thus achieving the stability and reliability of the UPM. Experimental results are performed to demonstrate the enhanced methodology.

Tracking Design of an Omni-Direction Autonomous Ground Vehicle by Hierarchical Enhancement Using Fuzzy Second-Order Variable Structure Control

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Chih-Lyang Hwang ◽  
Yunta Lee
Keyword(s):  
Tracking Error ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Second Order ◽  
Hierarchical Architecture ◽  
Switching Surface ◽  
Ground Vehicle ◽  
Structure Control ◽  
Linear Dynamic ◽  
Order Variable

Owing to the hierarchical architecture of the derived model of the omni-direction autonomous ground vehicle (OD-AGV), the virtual desired trajectory (VDT) is first designed by the first switching surface, which is set as the linear dynamic pose error of the OD-AGV. In sequence, the trajectory tracking control (TTC) is designed by the second switching surface, which is the linear dynamic tracking error of the VDT. To deal with nonlinear time-varying uncertainties including system disturbance and different ground conditions, enhanced fuzzy second-order variable structure control (EF2VSC) is designed into both VDT and TTC. Finally, the experiments for tracking the circular trajectories with different curvatures, traveling velocities, and poses of the OD-AGV are presented to validate the effectiveness and robustness of the proposed hierarchical enhancement using fuzzy second-order variable structure control (HEF2VSC).

scholarly journals Variable Structure Control of Engine Idle Speed With Estimation of Unmeasurable Disturbances

2000 ◽  
Vol 122 (4) ◽  
pp. 599-603 ◽  
Author(s):  
A. Stotsky ◽  
B. Egardt ◽  
S. Eriksson
Keyword(s):  
Engine Speed ◽  
Main Tool ◽  
Variable Structure ◽  
Time Varying ◽  
Idle Speed ◽  
Structure Control ◽  
Lyapunov Function Method ◽  
Production Delay ◽  
The Stability ◽  
Disturbance Estimator

A new controller for throttle and spark advance to control the engine speed at idle under unknown time varying disturbances is proposed in this paper. By using measurements of the engine speed the disturbance estimator is designed to reconstruct a disturbance torque. The controller is formulated so that the throttle is used as much as possible as a main tool to produce a torque and spark advance is used to compensate intake to torque production delay. The stability of the system is proved via Lyapunov function method. [S0022-0434(00)01304-6]

scholarly journals Fixed-Time Formation Control for Second-Order Disturbed Multi-Agent Systems under Directed Graph

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2295
Author(s):  
Huifen Hong ◽  
He Wang
Keyword(s):  
Formation Control ◽  
Control Method ◽  
Variable Structure ◽  
Fixed Time ◽  
Second Order ◽  
Multi Agent Systems ◽  
Structure Control ◽  
Agent Systems ◽  
Bounded Disturbances ◽  
Multi Agent

This paper investigates the fixed-time formation (FixF) control problem for second-order multi-agent systems (MASs), where each agent is subject to disturbance and the communication network is general directed. First, a FixF protocol is presented based on the backstepping technique, where the distributed cooperative variable structure control method is utilized to handle the bounded disturbances. Then, to remove the dependence of control gains on the global information, a practical adaptive FixF control is presented, where the MASs can achieve formation with a bounded error within fixed time. Finally, a numerical example is presented to validate the theoretical result.

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.

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