New fixed-time sliding mode control for a mismatched second-order system

2020 ◽  
pp. 014233122095230
Author(s):  
Guo Jianguo ◽  
Yang Shengjiang
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Initial Conditions ◽  
Nonlinear Function ◽  
Fixed Time ◽  
Second Order ◽  
Order System ◽  
Time Stability ◽  
Mode Control ◽  
Mismatched Uncertainties

A fixed-time sliding mode control (FTSMC) method is proposed for a second-order system with mismatched uncertainties in this paper. A new sliding mode, which is insensitive to the mismatched disturbance, is present to eliminate the effect of mismatched uncertainties by adopting the differentiable nonlinear function, and to obtain the fixed time stability independent of initial conditions by using the fraction-order function. In order to improve the performance of control system, the extended disturbance-observer-based fixed-time sliding mode control (EDO-FTSMC) approach is investigated to obtain the fixed-time stability subject to the mismatched uncertainties. Finally, the performance of the proposed control method is illustrated to compare other control approaches with numerical simulation results and application examples.

scholarly journals Continuous Prescribed-Time Sliding Mode Control with A Prescribed-Time ESO for Second-Order Nonlinear Systems with Mismatched Disturbance

2021 ◽  
Author(s):  
Xiaozhe Ju ◽  
Feng Wang ◽  
Yingzi Guan ◽  
Shihao Xu
Keyword(s):  
Nonlinear Systems ◽  
Sliding Mode Control ◽  
Sliding Mode ◽  
Fixed Time ◽  
Second Order ◽  
Order System ◽  
Practical Applications ◽  
Mode Control ◽  
System States ◽  
Mismatched Disturbances

Abstract This paper aims to settle the continuous prescribed-time stabilization problem of second-order nonlinear systems with mismatched disturbances. A continuous prescribed-time sliding mode control (CPTSMC) method with a prescribed-time extended state observer (PTESO) is proposed. The PTESO can precisely estimate the unknown states and disturbances, with its upper bound for the settling time (UBST) prescribed by only one parameter more tightly than existing finite-time or fixed-time ESOs. Furthermore, as a common concern for ESOs, the peaking value problem is well addressed. Then, a novel prescribed-time convergent form with little conservatism and simple tuning procedures is designed, and the internal mechanism in acquiring higher transient performance is explicitly researched. By using the estimated states and disturbances, the CPTSMC makes system states converge in a chattering-alleviated manner following the novel prescribed-time form. In addition to proving that the UBST of the whole system is tightly prescribed by only one design parameter, we show the continuity of the CPTSMC and the boundedness of all system signals, which are vital for practical applications. Ultimately, numerical simulations on the second-order system and a DC motor servo verify the efficiency of the proposed control system.

Chattering Reduction of Sliding Mode Control by Adopting Nonlinear Saturation Function

2010 ◽  
Vol 143-144 ◽  
pp. 53-61 ◽  
Author(s):  
Ning Bo Cheng ◽  
Li Wen Guan ◽  
Li Ping Wang ◽  
Jian Han
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Tracking Error ◽  
Nonlinear Function ◽  
Order System ◽  
Nonlinear Saturation ◽  
Simple Method ◽  
Mode Control ◽  
Computation Efficiency ◽  
Saturation Function

This paper proposes a simple method dealing with chattering phenomenon of sliding mode control. Instead of using a linear function to smooth the discontinuous control when the system is within the boundary layer, the controller adopts a smooth nonlinear function which we call a nonlinear saturation function (nsat function). Compared with the conventional linear saturation function (sat function), the nsat function can be constructed arbitrarily and shall satisfy eight conditions. Seven of the conditions are used to get a better effect in reducing chattering and one is used to keep a fast response performance by adjusting one constant parameter . As the nsat function can be specified by , it can be calculated in advance; this makes the nsat function of high computation efficiency and makes it acceptable in real time control systems. One candidate nsat function is constructed by adopting a hyperbolic tangent function and it is adopted in the simulations running on a second order system. Simulation results show that the nsat function also results in a smaller tracking error.

Sliding Mode Control for a Minimum Phase Unstable Second Order System

2014 ◽  
Vol 573 ◽  
pp. 285-290 ◽  
Author(s):  
B. Senthil Kumar ◽  
K.Suresh Manic
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Second Order ◽  
Stirred Tank ◽  
Order System ◽  
Minimum Phase ◽  
Robust Controller ◽  
Mode Control ◽  
Linear And Nonlinear ◽  
Nonlinear Plants

Sliding Mode Control is a robust Controller for Linear and Nonlinear plants where uncertainty in the model exists.Convetional controllers such as PID, Lead-lag Compensators do not to compensate for the uncertainties due to modeling and rejection to either matched or unmatched disturbances .The proposed method for controlling Unstable Second Order System with a zero by padmashree et al2 is taken from the literature for a Jacketed Continous Stirred-Tank Reactor.Introduction

scholarly journals New adaptive sliding mode control for a mismatched second-order system using an extended disturbance observer

2018 ◽  
Vol 41 (1) ◽  
pp. 276-284 ◽  
Author(s):  
Jianguo Guo ◽  
Yuchao Liu ◽  
Jun Zhou
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Second Order ◽  
Adaptive Sliding Mode Control ◽  
Order System ◽  
Adaptive Sliding Mode ◽  
Disturbance Estimation ◽  
Mode Control ◽  
Mismatched Disturbance

An adaptive sliding mode control (ASMC) approach for a second-order system based on an extended disturbance observer (EDO) is proposed in this paper for systems with mismatched uncertainties. The EDO-based ASMC method is investigated to eliminate the effect of mismatched disturbance by using a novel adaptive sliding surface consisting of the disturbance estimation. The proposed method exhibits the following two attractive features: Firstly, the proposed adaptive sliding mode with disturbance estimation is insensitive to the mismatched disturbance; that is, the asymptotical stability of the adaptive sliding mode can be guaranteed in the presence of the disturbance estimation error of the EDO. Secondly, the chattering in traditional sliding mode control methods is eliminated by using an adaptive term the adaptive parameter. Compared with the disturbance-observer-based sliding mode control and the EDO-based modified sliding mode control method, numerical simulation results and application examples show that the proposed approach is robust, has the best dynamic performance and eliminates chattering.

Sign in / Sign up

Export Citation Format

Share Document