On the Synchronization of a Class of Sprott Circuits Using Variable Structure Controller

2007 ◽  
Author(s):  
Kaveh Merat ◽  
Hoda Sadeghian ◽  
Hassan Salarieh ◽  
Aria Alasty
Keyword(s):  
Boundary Layer ◽  
Sliding Mode ◽  
External Disturbance ◽  
Variable Structure ◽  
Parametric Uncertainties ◽  
Time Varying ◽  
Sliding Surface ◽  
High Quality ◽  
Variable Boundary ◽  
Chaotic Circuits

In this paper the synchronization of a class of nonlinear chaotic circuits known as Sprott Circuits is studied. The Synchronization is obtained using a variable structure method based on sliding mode control with time varying sliding surface and variable boundary layer in presence of external disturbance and parametric uncertainties. The simulation is presented to show the effectiveness of this method. The results show the high quality and good performance of the method presented in the paper for synchronization of different drive-response chaotic Sprott circuits.

scholarly journals Optimal New Sliding Mode Controller Combined with Modified Supertwisting Algorithm for a Perturbed Quadrotor UAV

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yassine El Houm ◽  
Ahmed Abbou ◽  
Moussa Labbadi ◽  
Mohamed Cherkaoui
Keyword(s):  
Sliding Mode ◽  
External Disturbance ◽  
Lyapunov Theory ◽  
Sliding Mode Controller ◽  
Time Varying ◽  
Sliding Surface ◽  
State Variables ◽  
Quadrotor Uav ◽  
The Stability ◽  
Quadrotor System

This paper deals with the design of a novel modified supertwisting fast nonlinear sliding mode controller (MSTFNSMC) to stabilize a quadrotor system under time-varying disturbances. The suggested control strategy is based on a modified supertwisting controller with a fast nonlinear sliding surface to improve the tracking performance. The paper suggests a simple optimization tool built-in MATLAB/Simulink to tune the proposed controller parameters. Fast convergence of state variables is established by using a nonlinear sliding surface for rotational and translational subsystems. The modified supertwisting controller is developed to suppress the effect of chattering, reject disturbances, and ensure robustness against external disturbance effect. The stability of the proposed controller (MSTFNSMC) is proved using the Lyapunov theory. The performance of the proposed MSTFNSMC approach is compared with the supertwisting sliding mode controller (STSMC) by numerical simulations to verify its effectiveness.

Fault Detection of an Electrohydrostatic Actuator With the SVSF Time-Varying Boundary Layer Concept

2013 ◽  
Author(s):  
S. Andrew Gadsden ◽  
Saeid R. Habibi
Keyword(s):  
Boundary Layer ◽  
Sliding Mode ◽  
Variable Structure ◽  
Estimation Methods ◽  
Gear Pump ◽  
Time Varying ◽  
Aerospace Applications ◽  
Performance Metric ◽  
Efficient Type ◽  
Predictor Corrector

The electrohydrostatic actuator (EHA) is an efficient type of actuator commonly used in aerospace applications. It makes use of a closed hydraulic circuit, a number of control valves, an electric motor, and a fluid pump (usually a type of gear pump). The smooth variable structure filter (SVSF) is a relatively new estimation strategy based on sliding mode concepts formulated in a predictor-corrector fashion. The SVSF offers a number of advantages over other traditional estimation methods, including robust and stable estimates, and an additional performance metric. A fixed smoothing boundary layer was implemented in an effort to ensure stable estimates, and is defined based on the amount of uncertainties and noise present in the estimation process. Recent advances in SVSF theory include a time-varying smoothing boundary layer. This method, known as the SVSF-VBL, offers an optimal formulation of the SVSF as well as a method for detecting changes or faults in a system. This paper implements the SVSF-VBL in an effort to detect faults in an EHA. The results are compared with traditional Kalman filter-based methods.

A new variable structure controller for robot manipulators with a nonlinear PID sliding surface

Robotica ◽  
2012 ◽  
Vol 31 (4) ◽  
pp. 503-510 ◽  
Author(s):  
Khaled R. Atia
Keyword(s):  
Boundary Layer ◽  
Pid Controller ◽  
Sliding Mode ◽  
Robot Manipulators ◽  
Variable Structure ◽  
Control Law ◽  
Robot Dynamics ◽  
Sliding Surface ◽  
The Stability ◽  
Pid Sliding Surface

SUMMARYIn this paper a new sliding mode controller for set-point control of robot manipulators is proposed. The controller does not use any part of the robot dynamics in the control law. Thus, it is structurally simpler than other sliding mode controllers where the control law uses a nominal model of the robot dynamics. The controller uses a new nonlinear Proportional-Integral-Derivative (PID) sliding surface. The stability of the controlled robot dynamics is proved. On applying the boundary-layer approach to remove chattering, a nonlinear PID controller exists inside the boundary layer. This PID controller ensures that the error tend to zero asymptotically if there is no disturbances applied to the robot dynamics.

A new design method for sliding mode controllers using a linear time-varying sliding surface

2002 ◽  
Vol 216 (6) ◽  
pp. 455-466 ◽  
Author(s):  
S Tokat ◽  
I Eksin ◽  
M Güzelkaya
Keyword(s):  
Sliding Mode ◽  
Linear Time ◽  
Design Method ◽  
External Disturbance ◽  
Geometric Interpretation ◽  
Sliding Mode Controller ◽  
Time Varying ◽  
Sliding Surface ◽  
Sliding Mode Controllers ◽  
Parameter Variations

The main objective of this study is to present a time-varying sliding surface using a new design method to improve the performance of a classical sliding mode controller that has a constant linear sliding surface. In the proposed method, the sliding surface is defined on new coordinate axes: one of the coordinates is the original sliding surface and the other one is naturally chosen as perpendicular to this axis. An important property of the proposed method is that it has a simple geometric interpretation and provides continuous movement of the sliding surface. A comparison of the proposed method against both the classical sliding mode controller and sliding mode controller with a discretely rotating sliding surface is made through simulations. Simulations are first performed on a typical second-order linear system without any disturbances and parameter variations. Next, bounded external disturbance and parameter variations are inserted into the system simulations. Results have shown that the proposed method improved the system performance, providing decreases in the reaching and settling times, and the proposed method has demonstrated more robustness to disturbances and parameter variations compared to its counterparts.

scholarly journals New Time-Varying Sliding Surface for Switching Type Quasi-Sliding Mode Control

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3811
Author(s):  
Katarzyna Adamiak ◽  
Andrzej Bartoszewicz
Keyword(s):  
Sliding Mode Control ◽  
Continuous Time ◽  
Sliding Mode ◽  
Representative Point ◽  
Time Varying ◽  
Sliding Surface ◽  
External Disturbances ◽  
Mode Control ◽  
Switching Type ◽  
Time Systems

This study considers the problem of energetical efficiency in switching type sliding mode control of discrete-time systems. The aim of this work is to reduce the quasi-sliding mode band-width and, as follows, the necessary control input, through an application of a new type of time-varying sliding hyperplane in quasi-sliding mode control of sampled time systems. Although time-varying sliding hyperplanes are well known to provide insensitivity to matched external disturbances and uncertainties of the model in the whole range of motion for continuous-time systems, their application in the discrete-time case has never been studied in detail. Therefore, this paper proposes a sliding surface, which crosses the system’s representative point at the initial step and then shifts in the state space according to the pre-generated demand profile of the sliding variable. Next, a controller for a real perturbed plant is designed so that it drives the system’s representative point to its reference position on the sliding plane in each step. Therefore, the impact of external disturbances on the system’s trajectory is minimized, which leads to a reduction of the necessary control effort. Moreover, thanks to a new reaching law applied in the reference profile generator, the sliding surface shift in each step is strictly limited and a switching type of motion occurs. Finally, under the assumption of boundedness and smoothness of continuous-time disturbance, a compensation scheme is added. It is proved that this control strategy reduces the quasi-sliding mode band-width from O(T) to O(T3) order from the very beginning of the regulation process. Moreover, it is shown that the maximum state variable errors become of O(T3) order as well. These achievements directly reduce the energy consumption in the closed-loop system, which is nowadays one of the crucial factors in control engineering.

scholarly journals Control of an IPMC Soft Actuator Using Adaptive Full-Order Recursive Terminal Sliding Mode

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 33
Author(s):  
Romina Zarrabi Ekbatani ◽  
Ke Shao ◽  
Jasim Khawwaf ◽  
Hai Wang ◽  
Jinchuan Zheng ◽  
...  
Keyword(s):  
Sliding Mode ◽  
External Disturbance ◽  
Tracking Error ◽  
Working Environment ◽  
Parametric Uncertainties ◽  
Metal Composite ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Positioning Accuracy ◽  
Soft Actuator

The ionic polymer metal composite (IPMC) actuator is a kind of soft actuator that can work for underwater applications. However, IPMC actuator control suffers from high nonlinearity due to the existence of inherent creep and hysteresis phenomena. Furthermore, for underwater applications, they are highly exposed to parametric uncertainties and external disturbances due to the inherent characteristics and working environment. Those factors significantly affect the positioning accuracy and reliability of IPMC actuators. Hence, feedback control techniques are vital in the control of IPMC actuators for suppressing the system uncertainty and external disturbance. In this paper, for the first time an adaptive full-order recursive terminal sliding-mode (AFORTSM) controller is proposed for the IPMC actuator to enhance the positioning accuracy and robustness against parametric uncertainties and external disturbances. The proposed controller incorporates an adaptive algorithm with terminal sliding mode method to release the need for any prerequisite bound of the disturbance. In addition, stability analysis proves that it can guarantee the tracking error to converge to zero in finite time in the presence of uncertainty and disturbance. Experiments are carried out on the IPMC actuator to verify the practical effectiveness of the AFORTSM controller in comparison with a conventional nonsingular terminal sliding mode (NTSM) controller in terms of smaller tracking error and faster disturbance rejection.

scholarly journals Tracking Control of Variable Structure System Using Variable Boundary Layer

2001 ◽  
Vol 5 (6) ◽  
pp. 338-345
Author(s):  
Heejin Lee ◽  
Keyword(s):  
Boundary Layer ◽  
Tracking Control ◽  
Linear Time ◽  
Variable Structure ◽  
Second Order ◽  
Initial State ◽  
Variable Boundary ◽  
Variable Structure Systems ◽  
Variable Structure System ◽  
Arbitrary Initial State

In this paper, a new scheme is presented for the accurate tracking control of the second-order variable structure systems using the variable boundary layer. Up to now, variable structure controller(VSC) applying the variable boundary layer did not remove chattering from an arbitrary initial state of the system trajectory because VSC has used the fixed sliding surface. But, by using the linear time-varying sliding surfaces, the scheme has the robustness against chattering from all states. The suggested method can be applied to the second-order nonlinear systems with parameter uncertainty and extraneous disturbances, and have better tracking performance than the conventional method.To demonstrate the advantages of the proposed algorithm, it is applied to a two-link manipulator.

scholarly journals Chattering-Free Single-Phase Robustness Sliding Mode Controller for Mismatched Uncertain Interconnected Systems with Unknown Time-Varying Delays

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 282 ◽  
Author(s):  
Cong-Trang Nguyen ◽  
Thanh Long Duong ◽  
Minh Quan Duong ◽  
Duc Tung Le
Keyword(s):  
Single Phase ◽  
Sliding Mode ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Sliding Mode Controller ◽  
Time Varying ◽  
Structure Control ◽  
Time Varying Delay ◽  
Chattering Free ◽  
Varying Delay

Variable structure control with sliding mode can provide good control performance and excellent robustness. Unfortunately, the chattering phenomenon investigated due to discontinuous switching gain restricting their applications. In this paper, a chattering free improved variable structure control (IVSC) for a class of mismatched uncertain interconnected systems with an unknown time-varying delay is proposed. A sliding function is first established to eliminate the reaching phase in traditional variable structure control (TVSC). Next, a new reduced-order sliding mode estimator (ROSME) without time-varying delay is constructed to estimate all unmeasurable state variables of plants. Then, based on the Moore-Penrose inverse approach, a decentralized single-phase robustness sliding mode controller (DSPRSMC) is synthesized, which is independent of time delays. A DSPRSMC solves a complex interconnection problem with an unknown time-varying delay term and drives the system’s trajectories onto a switching surface from the initial time instance. Particularly, by applying the well-known Barbalat’s lemma, the chattering phenomenon in control input is alleviated. Moreover, a sufficient condition is established by using an appropriate Lyapunov theory and linear matrix inequality (LMI) method such that a sliding mode dynamics is asymptotically stable from the beginning time. Finally, a developed method is validated by numerical example with computer simulations.

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