scholarly journals Reduced-order disturbance observer based adaptive reaching law control for discretized MIMO systems with unmatched uncertainties

2021 ◽  
Author(s):  
Cong Wang ◽  
Hongwei Xia ◽  
Yanmin Wang ◽  
Shunqing Ren
Keyword(s):  
Computational Complexity ◽  
Discrete Time ◽  
Disturbance Observer ◽  
Control Algorithm ◽  
Mimo Systems ◽  
Sliding Mode ◽  
Sliding Surface ◽  
Reduced Order ◽  
Reaching Law ◽  
Unmatched Uncertainties

Abstract In this paper, an adaptive discrete-time sliding mode control based on reduced-order disturbance observer is proposed for discretized multi-input multi-output systems subjected to unmatching condition. By using the designed discrete reduced-order disturbance observer, a new sliding surface is constructed to counteract the unmatched uncertainties. Then, to guarantee a smaller width of the quasi sliding mode domain, an adaptive reaching law is developed, whose switching gain is adaptively tuned to prevent overestimation of disturbance on the premise of ensuring the reaching condition of sliding surface; meanwhile, the ranges of the quasi sliding mode band and attractiveness region are deduced. The proposed control algorithm has low computational complexity and needs no information about the upper bound of unmatched disturbance. The simulations on the control of a bank-to-turn missile demonstrate that the proposed method can effectively reject unmatched disturbance, and provide higher accuracy in comparison with traditional methods.

scholarly journals A Novel Reaching Law for Sliding Mode Control of Uncertain Discrete-Time Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Qian Xu ◽  
H. P. Du ◽  
B. He ◽  
T. H. Yan ◽  
W. H. Li ◽  
...  
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Sliding Surface ◽  
Reaching Law ◽  
Mode Control ◽  
Discrete Time Systems ◽  
Exponential Reaching Law ◽  
Time Systems

This paper proposed a new sliding mode control algorithm for discrete-time systems with matched uncertainty. The new control algorithm is characterized by a new discrete switching surface. Although the exponential reaching law can reduce oscillation, the control effectiveness will be suppressed when the rate of change of disturbance is high. The exponential reaching law cannot force the system states to approach sliding surface sk=0. In order to solve the contradiction between guaranteeing the basic property of quasi-sliding mode and reducing oscillation, a new discrete reaching law is proposed to improve the reaching process of discrete exponent reaching laws. The proposed method not only can force system state to approach the sliding surface sk=0 in less width of the switching manifold than existing studies, but also can alleviate chattering when the system representative points are near zero point. Simulation results are provided to validate the feasibility and reasonability of the method.

scholarly journals Discrete time reaching law based variable structure control for fast reaching with reduced chattering

2020 ◽  
Vol 9 (1) ◽  
pp. 51
Author(s):  
Pournami Padmalatha ◽  
Susy Thomas
Keyword(s):  
Discrete Time ◽  
Sliding Mode ◽  
Variable Structure Control ◽  
Variable Structure ◽  
The Other ◽  
Control Law ◽  
Sliding Surface ◽  
Structure Control ◽  
Reaching Law ◽  
Speed Up

In this paper, a variable structure control law is proposed for discrete time sliding mode control so as to reduce both reaching time and quasi sliding mode band reduction. This new law is composed of two different sliding variable dynamics; one to achieve fast reaching and the other to counter its effect on widening the quasi sliding mode band. This is accomplished<br />by introducing a boundary layer around the sliding surface about which the transformation of the sliding variable dynamics takes place. This provides the flexibility to choose the initial dynamics in such a way as to speed up the reaching phase and then at the boundary transform this dynamics to one that reduces the quasi sliding mode band. Thus, the law effectively<br />coalesces the advantageous traits of hitherto proposed reaching laws that succeed in either the reduction of reaching phase or the elimination of quasi sliding mode band. The effectiveness of the proposed reaching law is validated through simulations.<br /><br />

scholarly journals Terminal sliding mode control on autonomous underwater vehicle in diving motion control

2020 ◽  
Vol 20 (2) ◽  
pp. 798
Author(s):  
Nira Mawangi Sarif ◽  
Rafidah Ngadengon ◽  
Herdawatie Abdul Kadir ◽  
Mohd Hafiz A. Jalil
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Time Domain ◽  
Autonomous Underwater Vehicle ◽  
Sliding Mode ◽  
Underwater Vehicle ◽  
Terminal Sliding Mode Control ◽  
Sliding Surface ◽  
Terminal Sliding Mode ◽  
Reaching Law

<p>In this study, mechanism for reducing chattering in discrete conventional Sliding Mode Controller (DSMC) for Autonomous Underwater Vehicle (AUV) was designed in discrete time domain. The combination of reaching law approach and discrete Terminal Sliding Mode Control (DTSMC) scheme was employed to alleviate chattering effect caused by Quasi Sliding Mode (QSM). First, 6 DOF NPS AUV II equation of motion is linearized to diving mode subsystem. Second, linear sliding surface in discrete time domain is designed and Reaching Law Based (RLB) is employed to the control law. Thirdly, discrete nonlinear sliding surface, specifically DTSMC is designed to reduce chattering phenomena and improved precision control simultaneously. Finally, comparative experimental results are presented to illustrate the effectiveness and advantages of the nonlinear sliding surface. (9 pt).</p>

A Novel Variable Exponential Discrete Time Sliding Mode Reaching Law

2021 ◽  
pp. 1-1
Author(s):  
Xigang Chen ◽  
Yangmin Li ◽  
Haifeng Ma ◽  
Hui Tang ◽  
Yanlin Xie
Keyword(s):  
Discrete Time ◽  
Sliding Mode ◽  
Reaching Law

scholarly journals Reaching Law Based Sliding Mode Control of Sampled Time Systems

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1882
Author(s):  
Piotr Leśniewski ◽  
Andrzej Bartoszewicz
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
Rate Of Change ◽  
Reaching Law ◽  
Mode Control ◽  
Sliding Motion ◽  
Control Precision ◽  
Continuous Time Systems ◽  
Time Systems

In this paper, discrete time reaching law-based sliding mode control of continuous time systems is considered. In sliding mode control methods, usually the assumption of bounded absolute values of disturbances is used. However in many cases, the rate of change of the disturbance is also bounded. In the presented approach, this knowledge is used to improve the control precision and reduce the undesirable chattering. Another advantage of the proposed method is that the disturbance does not have to satisfy the matching conditions. In the paper two new reaching laws are analyzed, one of them ensures the switching quasi-sliding motion and the other the non-switching motion. For both of them, the robustness is assessed by calculating the quasi-sliding mode band width, as well as the greatest possible state error values. Specifically, the state errors are not considered only at the sampling instants, as is usual for discrete time systems, but the bounds on the continuous values “between” the sampling instants are also derived. Then, the proposed approaches are compared and analyzed with respect to energy expenditure of the control signal.

scholarly journals Event-triggered Discrete-time Sliding Mode Control for High-order Systems via Reduced-order Model Approach

2020 ◽  
Vol 53 (2) ◽  
pp. 6207-6212
Author(s):  
Kiran Kumari ◽  
Bijnan Bandyopadhyay ◽  
Johann Reger ◽  
Abhisek K. Behera
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
High Order ◽  
Reduced Order Model ◽  
Order Model ◽  
Reduced Order ◽  
Mode Control ◽  
Event Triggered ◽  
Model Approach

Terminal sliding mode control of permanent magnet synchronous motor based on the reaching law

2019 ◽  
Vol 234 (7) ◽  
pp. 849-859
Author(s):  
Peikun Zhu ◽  
Yong Chen ◽  
Meng Li
Keyword(s):  
Sliding Mode Control ◽  
Permanent Magnet ◽  
Parameter Uncertainty ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Terminal Sliding Mode ◽  
Reaching Law ◽  
Mode Control

Aiming at the parameter uncertainty and load torque disturbance of permanent magnet synchronous motor system, a terminal sliding mode control algorithm for permanent magnet synchronous motor based on the reaching law is proposed. First, a sliding mode control algorithm for sliding mode reaching law is proposed, which can dynamically adapt to the changes in system state. Second, a sliding mode disturbance observer is designed to estimate the lumped disturbance in real time and to compensate the controller for disturbance. On this basis, an online identification method based on disturbance observer for viscous friction coefficient and moment of inertia is used to reduce the influence of parameter uncertainty on the control system. Simulation and experimental results show the effectiveness of the method.

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