scholarly journals Control of desalination plants using sliding mode scheme with state observer

2021 ◽  
Author(s):  
Bui Duc Hong Phuc ◽  
Sam-Sang You ◽  
Hwan-Seong Kim ◽  
Sang-Do Lee
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Sliding Mode ◽  
Water Productivity ◽  
State Observer ◽  
The State ◽  
State Variables ◽  
Mode Control ◽  
Product Water ◽  
Desalination Plants

Abstract This paper deals with real-time control with observer to manipulate desalination plants as well as to monitor system states for smart operations. The controller plays an important role in achieving stabilization of reverse osmosis (RO) systems to guarantee the desired water product and concentration. The super-twisting (STW) sliding mode control (SMC) algorithm guarantees performance while reducing chattering. Supposing that all the state variables are not available by sensors, the observer is implemented to provide state estimation. Since smart operations depend on control algorithm and sensor availability, the proposed strategy provides robustness to ensure the water productivity even under uncertainties or under failure of sensors. The robustness is guaranteed by active controller where 80% of disturbance is eliminated in product water flow and that of product water quality is approximately 95%. As well, the state observer can produce precise predictions of the unmeasured states. Sliding mode control with observer provides the system with stability, while assuring better performances against uncertainties. Finally, the active controller with state estimator can guarantee a robust control strategy and monitoring system to extend the life of the filters and membranes, while ensuring sustainability. This control strategy is highly recommended for smart operations of desalination plants.

scholarly journals Sliding Mode Control Based on Observer for a Class of State-Delayed Switched Systems with Uncertain Perturbation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Zhaolan He ◽  
Xue Wang ◽  
Zongwei Gao ◽  
Jingjie Bai
Keyword(s):  
Sliding Mode Control ◽  
Switched Systems ◽  
Sliding Mode ◽  
Estimation Error ◽  
Matching Condition ◽  
State Observer ◽  
Sliding Surface ◽  
State Variables ◽  
Parameter Uncertainties ◽  
Mode Control

This paper is concerned with a state observer-based sliding mode control design methodology for a class of continuous-time state-delayed switched systems with unmeasurable states and nonlinear uncertainties. The advantages of the proposed scheme mainly lie in which it eliminates the need for state variables to be full accessible and parameter uncertainties to be satisfied with the matching condition. Firstly, a state observer is constructed, and a sliding surface is designed. By matrix transformation techniques, combined with Lyapunov function and sliding surface function, a sufficient condition is given to ensure asymptotic stability of the overall closed-loop systems composed of the observer dynamics and the estimation error dynamics. Then, reachability of sliding surface is investigated. At last, an illustrative numerical example is presented to prove feasibility of the proposed approaches.

scholarly journals A Reference Trajectory Based Discrete Time Sliding Mode Control Strategy

2019 ◽  
Vol 29 (3) ◽  
pp. 517-525 ◽  
Author(s):  
Andrzej Bartoszewicz ◽  
Katarzyna Adamiak
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Control Strategy ◽  
Control Method ◽  
Sliding Mode ◽  
Reference Trajectory ◽  
State Variables ◽  
Reaching Law ◽  
Mode Control ◽  
Sliding Motion

Abstract This study presents a new, reference trajectory based sliding mode control strategy for disturbed discrete time dynamical systems. The desired trajectory, which is generated externally according to an existing switching type reaching law, determines the properties of the emerging sliding motion of the system. It is proved that an appropriate choice of the trajectory generator parameters ensures the existence of the quasi-sliding motion of the system according to the definition by Gao et al. (1995) in spite of the influence of disturbances. Moreover, the paper shows that the application of the desired trajectory based reaching law results in a significant reduction in the quasi-sliding mode band width and errors of all state variables. Therefore, in comparison with Gao’s control method, the system’s robustness is increased. The paper also presents an additional modification of the reaching law, which guarantees a further reduction in the quasi-sliding mode band in the case of slowly varying disturbances. The results are confirmed with a simulation example.

Response Variance Reduction of a Nonlinear Mechanical System via Sliding Mode Control

1998 ◽  
Vol 120 (3) ◽  
pp. 801-805 ◽  
Author(s):  
J. Q. Sun ◽  
Qing Xu
Keyword(s):  
Sliding Mode Control ◽  
Target Tracking ◽  
Mechanical System ◽  
Variance Reduction ◽  
Sliding Mode ◽  
The State ◽  
State Variables ◽  
Mode Control ◽  
Response Variance ◽  
Special Cases

An analysis of a target tracking mechanical system subject to random base excitations is presented in this paper. Sliding mode controls are proposed to minimize the random error of target tracking. Two special cases are studied. In the first case, it is assumed that all the system parameters are known and the state variables are measurable. A sliding mode control is then determined. This highly idealized example reveals the effect of sliding mode control parameters on the reduction of response variance and provides a benchmark for designing a robust controller that deals with systems with unknown parameters. The second case deals with a robust sliding mode control where some parameters of the system are assumed to fall in a known range of values. The proposed controls are proven stable in the mean square sense. The statistical aspects of the controlled system are studied by considering the first and second order moments of the state variables. The equations for these moments are derived and solved by using the method of Gaussian closure in order to investigate the variance reduction performance of the controls.

scholarly journals An extended state observer-based full-order sliding mode control for robotic joint actuated by antagonistic pneumatic artificial muscles

2021 ◽  
Vol 18 (1) ◽  
pp. 172988142098603
Author(s):  
Daoxiong Gong ◽  
Mengyao Pei ◽  
Rui He ◽  
Jianjun Yu
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
State Observer ◽  
Extended State Observer ◽  
Artificial Muscles ◽  
Extended State ◽  
Robot System ◽  
Mode Control ◽  
Physical Experiments ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are expected to play an important role in endowing the advanced robot with the compliant manipulation, which is very important for a robot to coexist and cooperate with humans. However, the strong nonlinear characteristics of PAMs hinder its wide application in robots, and therefore, advanced control algorithms are urgently needed for making the best use of the advantages and bypassing the disadvantages of PAMs. In this article, we propose a full-order sliding mode control extended state observer (fSMC-ESO) algorithm that combines the ESO and the fSMC for a robotic joint actuated by a pair of antagonistic PAMs. The fSMC is employed to eliminate the chattering and to guarantee the finite-time convergence, and the ESO is adopted to observe both the total disturbance and the states of the robot system, so that we can inhibit the disturbance and compensate the nonlinearity efficiently. Both simulations and physical experiments are conducted to validate the proposed method. We suggest that the proposed method can be applied to the robotic systems actuated by PAMs and remarkably improve the performance of the robot system.

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