scholarly journals Suppression of hydraulic transients for desalination plants based on active control synthesis

2021 ◽  
Author(s):  
Bui Duc Hong Phuc ◽  
Sam-Sang You ◽  
Hwan-Seong Kim ◽  
Sang-Do Lee
Keyword(s):  
Active Control ◽  
Sliding Mode ◽  
Control Synthesis ◽  
Hydraulic Transients ◽  
Quality Water ◽  
Sinusoidal Functions ◽  
And Performance ◽  
Hydraulic Shocks ◽  
System Sustainability ◽  
Desalination Plants

Abstract This paper proposes a control strategy to stabilize a reverse osmosis desalination system against hydraulic shocks with enhancing productivity and sustainability. First, the effects of hydraulic transients on water quality have been reviewed. The transient waves are approximated by sinusoidal functions so that their effects are incorporated into the controlled system as external disturbances. Next, the active control is implemented based on the adaptive super-twisting (STW) sliding mode control (SMC) algorithms. Then, the robust performance is guaranteed whenever the sliding variables reach the sliding surfaces in finite time despite disturbances. The STW SMC scheme is to eliminate the chattering problems for protecting the valves and to improve the convergence precision for water production. The control gains are adaptable to enable formation of an effective controller for dealing with large disturbances such as water hammer during desalination process. The simulation results reveal the superior performances on controlling water product, while eliminating shock waves. Especially, the effect of hydraulic shocks has been dramatically attenuated, hence the plant components are protected to avoid fracture. Finally, the robust stability and performance of the desalination plants are guaranteed against large disturbances to ensure the population with quality water as well as system sustainability.

scholarly journals Observer-based robust integral of the sign of the error control of class I of underactuated mechanical systems: Theory and real-time experiments

2021 ◽  
pp. 014233122110313
Author(s):  
Afef Hfaiedh ◽  
Ahmed Chemori ◽  
Afef Abdelkrim
Keyword(s):  
Real Time ◽  
Error Control ◽  
Degrees Of Freedom ◽  
Sliding Mode ◽  
Mechanical Systems ◽  
Class I ◽  
Control Input ◽  
Underactuated Mechanical Systems ◽  
Control Scheme ◽  
And Performance

In this paper, the control problem of a class I of underactuated mechanical systems (UMSs) is addressed. The considered class includes nonlinear UMSs with two degrees of freedom and one control input. Firstly, we propose the design of a robust integral of the sign of the error (RISE) control law, adequate for this special class. Based on a change of coordinates, the dynamics is transformed into a strict-feedback (SF) form. A Lyapunov-based technique is then employed to prove the asymptotic stability of the resulting closed-loop system. Numerical simulation results show the robustness and performance of the original RISE toward parametric uncertainties and disturbance rejection. A comparative study with a conventional sliding mode control reveals a significant robustness improvement with the proposed original RISE controller. However, in real-time experiments, the amplification of the measurement noise is a major problem. It has an impact on the behaviour of the motor and reduces the performance of the system. To deal with this issue, we propose to estimate the velocity using the robust Levant differentiator instead of the numerical derivative. Real-time experiments were performed on the testbed of the inertia wheel inverted pendulum to demonstrate the relevance of the proposed observer-based RISE control scheme. The obtained real-time experimental results and the obtained evaluation indices show clearly a better performance of the proposed observer-based RISE approach compared to the sliding mode and the original RISE controllers.

A fault-tolerant control scheme within adaptive disturbance observer for hypersonic vehicle

2017 ◽  
Vol 233 (3) ◽  
pp. 1071-1088 ◽  
Author(s):  
Jun Zhou ◽  
Jing Chang ◽  
Zongyi Guo
Keyword(s):  
Disturbance Observer ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
Lyapunov Theory ◽  
Sliding Mode Controller ◽  
Performance Guarantees ◽  
Uncertain Model ◽  
Control Scheme ◽  
And Performance

The paper describes the design of a fault-tolerant control scheme for an uncertain model of a hypersonic reentry vehicle subject to actuator faults. In order to improve superior transient performances for state tracking, the proposed method relies on a back-stepping sliding mode controller combined with an adaptive disturbance observer and a reference vector generator. This structure allows for a faster response and reduces the overshoots compared to linear conventional disturbance observers based sliding mode controller. Robust stability and performance guarantees of the overall closed-loop system are obtained using Lyapunov theory. Finally, numerical simulations results illustrate the effectiveness of the proposed technique.

Vibration Control of a Translating Beam With an Active Control Strategy on the Basis of the Fuzzy Sliding Mode Control

2013 ◽  
Author(s):  
Liming Dai ◽  
Lin Sun
Keyword(s):  
Sliding Mode Control ◽  
Vibration Control ◽  
Active Control ◽  
Control Strategy ◽  
Sliding Mode ◽  
Nonlinear Dynamic System ◽  
Fuzzy Sliding Mode Control ◽  
Mode Control ◽  
Fuzzy Sliding Mode ◽  
Active Control Strategy

An active control strategy is developed for nonlinear vibration control of an axially translating beam applied in engineering field. The control strategy is established on the basis of Fuzzy Sliding Mode Control. The nonlinear model governing the beam system is described with a six-degree nonlinear dynamic system. Corresponding to the multi-degree nonlinear system, the active control strategy is developed. The proposed control strategy is proven to be effective in controlling and stabilizing the nonlinear motions especially chaotic motion of the beam.

Adaptive nonlinear observer–based sliding mode control of robotic manipulator for handling an unknown payload

2020 ◽  
pp. 095965182096946
Author(s):  
Guiying Li ◽  
Shuyang Wang ◽  
Zhigang Yu
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Design Procedure ◽  
Nonlinear Observer ◽  
Control Synthesis ◽  
Unknown Constant ◽  
Nonlinear Disturbance Observer ◽  
Mode Control ◽  
Nonlinear Disturbance

This article presents the control synthesis of robotic manipulators with an unknown constant payload. A novel nonlinear disturbance observer with an adaptive scheme is designed to estimate the external force induced by the unknown constant payload. A general design procedure for designing the gain of the nonlinear observer is developed rather than the time-consuming trials and error to choose proper gain. The nonlinear observer gain is designed using an adaptive technique to extend the applicability of the disturbance observer. The stability of the proposed observer is established using Lyapunov method under certain conditions. The proposed nonlinear disturbance observer will be integrated with the sliding mode control to substantially alleviate the chattering problem. Also, simulation results are presented to verify the effectiveness of the proposed methods.

Non-linear optimal fuzzy control synthesis for robust output tracking of uncertain micro-electro-mechanical systems

2016 ◽  
Vol 39 (8) ◽  
pp. 1146-1160 ◽  
Author(s):  
Alireza Modirrousta ◽  
Mostafa Shokrian Zeini ◽  
Tahereh Binazadeh
Keyword(s):  
Fuzzy Control ◽  
Sliding Mode ◽  
Reference Signal ◽  
Mechanical Systems ◽  
Control Synthesis ◽  
Sliding Mode Controller ◽  
Micro Electro Mechanical Systems ◽  
Output Tracking ◽  
Non Linear ◽  
Variable Universe Fuzzy Control

This paper considers the output tracking problem for micro-electro-mechanical systems (MEMS) under uncertainties and external disturbances. The robust non-linear controllers are designed by two methods. The first method consists of a backstepping strategy combined with a first-order sliding mode controller. Also, in order to reduce the chattering effect and to improve the robustness of the proposed scheme, a new variable universe fuzzy control action with an adaptive coefficient is used instead of the signum function in the switching control law. In the proposed fuzzy scheme, the centres of the output membership functions are optimized via three heuristic optimization algorithms including the artificial bee colony (ABC) algorithm, ant colony optimization (ACO) and particle swarm optimization (PSO). In the second method, a class of second-order sliding mode controller is combined with the backstepping strategy. The second controller includes the proposed optimal fuzzy controllers of the first method. The stability of the closed-loop systems in both approaches are proved via the Lyapunov stability criterion and the conditions of stabilization are provided by linear matrix inequalities (LMIs). Numerical simulations are carried out to verify the theoretical results and to demonstrate the robust performance of the proposed controller in output tracking of the time-varying reference signal.

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