Adaptive constrained sliding mode control of uncertain nonlinear fractional-order input affine systems

2019 ◽  
Vol 26 (5-6) ◽  
pp. 318-330
Author(s):  
Tahmine V Moghaddam ◽  
Seyyed K Yadavar Nikravesh ◽  
Mohammad A Khosravi
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Nonlinear Function ◽  
Lyapunov Theory ◽  
Adaptive Sliding Mode Control ◽  
Mode Control ◽  
Adaptive Laws ◽  
Chattering Free ◽  
System States

This paper addresses asymptotic stabilization of uncertain nonlinear fractional-order systems with bounded inputs in the presence of model uncertainties and external disturbances. To develop the idea, it is assumed that the upper bound of perturbations is a nonlinear function of the pseudostates norm in which its coefficients are unknown and are obtained via proposed adaptive laws. The main contribution of this paper is to develop a new bounded fractional-order chattering free adaptive sliding mode control in which the system states converge to the sliding surface at a predefined finite time. The stability of the closed-loop system with the proposed control scheme is guaranteed by the Lyapunov theory. Furthermore, for more clarification, a comparison with the classical integer-order case is also presented; finally, some practical simulation results are provided to show the effectiveness of the proposed control algorithm.

scholarly journals On Chattering-Free Dynamic Sliding Mode Controller Design

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jeang-Lin Chang
Keyword(s):  
Sliding Mode Control ◽  
Controller Design ◽  
Sliding Mode ◽  
Control Law ◽  
Mode Control ◽  
Chattering Free ◽  
Dynamic Sliding Mode Control ◽  
System States ◽  
Dynamic Sliding Mode ◽  
Free Dynamic

For a class of linear MIMO uncertain systems, a dynamic sliding mode control algorithm that avoids the chattering problem is proposed in this paper. Without using any differentiator, we develop a modified asymptotically stable second-order sliding mode control law in which the proposed controller can guarantee the finite time convergence to the sliding mode and can show that the system states asymptotically approach to zero. Finally, a numerical example is explained for demonstrating the applicability of the proposed scheme.

scholarly journals Fractional Order Adaptive Fast Super-Twisting Sliding Mode Control for Steer-by-Wire Vehicles with Time-Delay Estimation

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2424
Author(s):  
Yong Yang ◽  
Yunbing Yan ◽  
Xiaowei Xu
Keyword(s):  
Time Delay ◽  
Sliding Mode Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Time Delay Estimation ◽  
Lyapunov Theory ◽  
Delay Estimation ◽  
Mode Control ◽  
Model Free ◽  
Steer By Wire

It is difficult to model and determine the parameters of the steer-by-wire (SBW) system accurately, and the perturbation is variable with complex and changeable tire–road conditions. In order to improve the control performance of the vehicle SBW system, an adaptive fast super-twisting sliding mode control (AFST-SMC) scheme with time-delay estimation (TDE) is proposed. The proposed scheme uses TDE to acquire the lumped dynamics in a simple way and establishes a practical model-free structure. Then, a fractional order (FO) sliding mode surface and a fast super-twisting sliding mode control structure were designed on the basic super-twisting sliding mode to ensure fast convergence and high control accuracy. Since the uncertain boundary information of the actual system is unknown, a novel adaptive algorithm is proposed to regulate the control gain based on the control errors. Theoretical analysis concerning system stability is given based on the Lyapunov theory. Finally, the effectiveness of the method is verified through comparative experiments. The results show that the proposed TDE-AFST-FOSMC control scheme has the advantages of model-free, fast response and high accuracy.

Sliding mode observer-based fractional-order proportional–integral–derivative sliding mode control for electro-hydraulic servo systems

2020 ◽  
Vol 234 (10) ◽  
pp. 1887-1898 ◽  
Author(s):  
Cheng Cheng ◽  
Songyong Liu ◽  
Hongzhuang Wu
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Lyapunov Theory ◽  
Sliding Mode Observer ◽  
Proportional Integral Derivative ◽  
Servo Systems ◽  
Proportional Integral ◽  
Mode Control ◽  
Hydraulic Servo

This paper proposes an observer-based sliding mode control method for electro-hydraulic servo systems with uncertain nonlinearities, external disturbances, and immeasurable states. The mathematical model is built based on the principle of electro-hydraulic servo systems. Owing to its highly robustness and finite time properties, the sliding mode observer is chosen and designed to estimate the velocity and the equivalent pressure online only using the position feedback. Then, in order to tackle the chattering problem of conventional sliding mode control and increase the control accuracy, a novel second-order sliding mode control scheme is proposed based on the fractional-order proportional–integral–derivative sliding surface and the state observer. The stability of the overall system is proved by Lyapunov theory. Finally, the detailed simulations are conducted, which include the comparative analysis of control performance with other methods and the study of observation performance.

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