scholarly journals Continuous Sliding Mode Control of Flow-Induced Vibrations

1995 ◽  
Vol 2 (5) ◽  
pp. 365-372 ◽  
Author(s):  
A. Baz
Keyword(s):  
Sliding Mode ◽  
Flexible Structures ◽  
Theoretical Models ◽  
Circular Cylinders ◽  
Design Parameters ◽  
Flow Conditions ◽  
Parameter Uncertainties ◽  
Vortex Induced Vibrations ◽  
Flow Induced Vibrations ◽  
Structural Uncertainties

Vortex-induced vibrations of flexible circular cylinders and galloping oscillations of square prisms are controlled using a robust continuous sliding mode (CSM) controller. The ability of the CSM controller in rejecting the flow-induced disturbances and accommodating parameter uncertainties is numerically demonstrated. In the present study, emphasis is placed on the development of theoretical models that describe the interaction between the flexible structures, the flow-induced excitation, and the CSM controller. In our development, the vortex-induced vibrations are based on the lift-oscillator model of Hartlen and Currie and the galloping phenomenon is described using Parkinson and Smith's model. The effectiveness of the CSM controller in suppressing the flow-induced vibrations of cylinders and square prisms is evaluated at various flow conditions and levels of structural uncertainties. The effect of the design parameters of the CSM controller on its performance is also investigated. The results obtained in the study suggest the potential of the robust control strategy presented as an important tool for rejecting undesirable and unmeasurable disturbances acting on critical structures that have considerably large parameter uncertainties.

Nonlinear Dynamics and Design of Aeroelastic Energy Harvesters

2015 ◽  
pp. 341-379
Author(s):  
Abdessattar Abdelkefi
Keyword(s):  
Wireless Sensors ◽  
Performance Enhancement ◽  
Circular Cylinders ◽  
Medical Implants ◽  
Energy Harvesters ◽  
Vortex Induced Vibrations ◽  
Flow Induced Vibrations ◽  
Self Powered ◽  
And Performance

The concept of harvesting energy from flow-induced vibrations has received a great deal of attention in the last few years. This technology would help in the replacement of small batteries that require expensive and time consuming maintenance and development of self-powered electronic devices, such as health monitoring sensors, medical implants, data transmitters, wireless sensors, and cameras. In this chapter, a particular focus is paid to the concept of harvesting energy from aeroelastic instabilities, such as flutter in airfoil sections, vortex-induced vibrations in circular cylinders, and galloping in prismatic structures. Nonlinear electroaeroelastic models for these energy harvesters are derived and validated with experimental measurements. It is shown how linear and nonlinear analyses can be used to breach traditional barriers in the design and performance enhancement of these aeroelastic energy harvesters, characterization of their behaviors, and identification of the contribution of different types of nonlinearities.

Closed-Loop Input Shaping Control of Vibration in Flexible Structures via Adaptive Sliding Mode Control

2012 ◽  
Vol 19 (2) ◽  
pp. 221-233 ◽  
Author(s):  
Ming-Chang Pai
Keyword(s):  
Closed Loop ◽  
Sliding Mode ◽  
Flexible Structures ◽  
Adaptive Sliding Mode Control ◽  
Input Shaping ◽  
Parameter Uncertainties ◽  
Residual Vibration ◽  
Shaping Technique ◽  
Control Scheme ◽  
Input Shaping Control

Input shaping technique is widely used in reducing or eliminating residual vibration of flexible structures. The exact elimination of the residual vibration via input shaping technique depends on the amplitudes and instants of impulse application. However, systems always have parameter uncertainties which can lead to performance degradation. In this paper, a closed-loop input shaping control scheme is developed for uncertain flexible structures. The algorithm is based on input shaping control and adaptive sliding mode control. The proposed scheme does not need a priori knowledge of upper bounds on the norm of the uncertainties, but estimates them by using the adaptation technique. This scheme guarantees closed-loop system stability, and yields good performance and robustness in the presence of parameter uncertainties and external disturbances as well. Furthermore, it is shown that increasing the robustness to parameter uncertainties does not lengthen the duration of the impulse sequence. Simulation results demonstrate the efficacy of the proposed closed-loop input shaping control scheme.

VIV Basics for Subsea Spool/Jumper Design

2015 ◽  
Author(s):  
Roberto Bruschi ◽  
Lorenzo Bartolini ◽  
Caterina Molinari ◽  
Giulio C. Vignati ◽  
Luigino Vitali
Keyword(s):  
Fatigue Damage ◽  
Flow Rate ◽  
Internal Flow ◽  
Flow Conditions ◽  
Flexible Pipe ◽  
Water Project ◽  
Vortex Induced Vibrations ◽  
Spatial Configurations ◽  
Flow Induced Vibrations ◽  
Critical Components

Coming and future Deep and Ultra-Deep Water project developments involve the use of many Subsea Rigid Jumpers used to connect well heads, manifolds or riser base with Flowline End Terminations. Generally, Subsea Rigid Jumpers are short and flexible pipe sections assembled in a variety of spatial configurations to accommodate the installation tolerances, the Flowline End Terminations translation and settlement guaranteeing the continuity and the flexibility needs of the subsea pipe layout. These Subsea Rigid Jumpers are critical components as they are subject to fatigue damage due to Vortex Induced Vibrations induced by the bottom currents and/or Flow Induced Vibrations induced by the high internal flow rate, often coupled with slugging flow conditions. In this paper, a Subsea Rigid Jumper design approach based on basics of Vortex Induced Vibrations is presented, and outcomes on a few typical multi-planar Subsea Rigid Jumpers discussed.

scholarly journals Research on predictive sliding mode control strategy for horizontal vibration of ultra-high-speed elevator car system based on adaptive fuzzy

2021 ◽  
Vol 54 (3-4) ◽  
pp. 360-373
Author(s):  
Hong Wang ◽  
Mingqin Zhang ◽  
Ruijun Zhang ◽  
Lixin Liu
Keyword(s):  
Sliding Mode Control ◽  
High Speed ◽  
Sliding Mode ◽  
Mode Switching ◽  
Parameter Uncertainties ◽  
Horizontal Vibration ◽  
Adaptive Fuzzy ◽  
Mode Control ◽  
System A ◽  
Ultra High Speed

In order to effectively suppress horizontal vibration of the ultra-high-speed elevator car system. Firstly, considering the nonlinearity of guide shoe, parameter uncertainties, and uncertain external disturbances of the elevator car system, a more practical active control model for horizontal vibration of the 4-DOF ultra-high-speed elevator car system is constructed and the rationality of the established model is verified by real elevator experiment. Secondly, a predictive sliding mode controller based on adaptive fuzzy (PSMC-AF) is proposed to reduce the horizontal vibration of the car system, the predictive sliding mode control law is achieved by optimizing the predictive sliding mode performance index. Simultaneously, in order to decrease the influence of uncertainty of the car system, a fuzzy logic system (FLS) is designed to approximate the compound uncertain disturbance term (CUDT) on-line. Furthermore, the continuous smooth hyperbolic tangent function (HTF) is introduced into the sliding mode switching term to compensate the fuzzy approximation error. The adaptive laws are designed to estimate the error gain and slope parameter, so as to increase the robustness of the system. Finally, numerical simulations are conducted on some representative guide rail excitations and the results are compared to the existing solution and passive system. The analysis has confirmed the effectiveness and robustness of the proposed control method.

Research on Adaptive Backstepping Global Sliding Control for CPS

2013 ◽  
Vol 846-847 ◽  
pp. 134-138
Author(s):  
Jue Wang ◽  
Fei Li ◽  
Ye Huang ◽  
Jian Hao Wang ◽  
Hong Lin Zhang
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Flight Simulator ◽  
Position Tracking ◽  
Adaptive Backstepping ◽  
Parameter Uncertainties ◽  
Servo Systems ◽  
Mode Control ◽  
Global Sliding Mode Control ◽  
Compensation Methods

The paper studies the problem of tracking control for flight simulator servo systems, one typical CPS, with parameter uncertainties and nonlinear friction compensation. Methods of adaptive global sliding mode control and backstepping control are respectively proposed to realize the control of virtual rotational speed and position tracking. Adaptive backstepping global sliding mode control strategy for flight simulator servo systems is proposed and its stability is analyzed. Simulation results show the effectiveness of the proposed method, which could achieve the precision position tracking performance and eliminate the chattering.

scholarly journals Modification of Classical Horseshoe Spillways: Experimental Study and Design Optimization

2019 ◽  
Vol 5 (10) ◽  
pp. 2093-2109
Author(s):  
Vahid Hassanzadeh Vayghan ◽  
Ali Saber ◽  
Soroosh Mortazavian
Keyword(s):  
Hydraulic Jump ◽  
Design Parameters ◽  
Hydraulic Structures ◽  
Flow Conditions ◽  
Design Factor ◽  
Flow Passage ◽  
Water Head ◽  
Cubic Polynomial ◽  
Polynomial Models ◽  
Discharge Efficiency

Investigation of the hydraulic aspects of spillways is one of the important issues regarding hydraulic structures. This study presents a modified horseshoe spillway (MHS) constructed by adding a flow passage and an internal weir in the bed of a classical horseshoe spillway (CHS). This modification increased the discharge efficiency and eliminated the rooster-tail hydraulic jump in CHSs. Eighteen laboratory-scale MHSs in various geometric sizes, six various CHSs, and a rectangular weir of the same width were constructed and tested under the same flow conditions. Results showed that in terms of discharge efficiency and water head reduction, CHSs and MHSs were superior to the rectangular weir. Compared to CHSs, the increased discharge flowrate in MHSs due to the internal weirs could further reduce the water head and thus increased their overall efficiencies. Design parameters effecting spillways’ discharge efficiencies were investigated based on dimensional analysis. The internal to external weir length ratio in MHSs was found to be a key design factor. To determine the optimal geometric design of CHS and MHS models, cubic polynomial models considering dimensionless parameters and their interactions were fitted to the experimental results. The cubic models revealed that higher discharge efficiencies in MHSs tended to occur at relatively low water heads and high internal to external weir lengths ratios.

scholarly journals Adaptive Fast Non-Singular Terminal Sliding Mode Path Following Control for an Underactuated Unmanned Surface Vehicle with Uncertainties and Unknown Disturbances

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7454
Author(s):  
Yunsheng Fan ◽  
Bowen Liu ◽  
Guofeng Wang ◽  
Dongdong Mu
Keyword(s):  
Actuator Saturation ◽  
Sliding Mode ◽  
Path Following ◽  
Design Parameters ◽  
Real Time Control ◽  
Sideslip Angle ◽  
Terminal Sliding Mode ◽  
Unmanned Surface Vehicle ◽  
Control Approach ◽  
Unknown Disturbances

This paper focuses on an issue involving robust adaptive path following for the uncertain underactuated unmanned surface vehicle with time-varying large sideslips angle and actuator saturation. An improved line-of-sight guidance law based on a reduced-order extended state observer is proposed to address the large sideslip angle that occurs in practical navigation. Next, the finite-time disturbances observer is designed by considering the perturbations parameter of the model and the unknown disturbances of the external environment as the lumped disturbances. Then, an adaptive term is introduced into Fast Non-singular Terminal Sliding Mode Control to design the path following controllers. Finally, considering the saturation of actuator, an auxiliary dynamic system is introduced. By selecting the appropriate design parameters, all the signals of the whole path following a closed-loop system can be ultimately bounded. Real-time control of path following can be achieved by transferring data from shipborne sensors such as GPS, combined inertial guidance and anemoclinograph to the Fast Non-singular Terminal Sliding Mode controller. Two examples as comparisons were carried out to demonstrate the validity of the proposed control approach.

scholarly journals A non-linear control strategy for a PV conversion system with energy storage

2021 ◽  
Vol 297 ◽  
pp. 01023
Author(s):  
Ghizlane Traiki ◽  
Abdelmounime El Magri ◽  
Rachid Lajouad ◽  
Omar Bouattane
Keyword(s):  
Energy Storage ◽  
Energy Conversion ◽  
Control Strategy ◽  
Sliding Mode ◽  
Maximum Power ◽  
Parameter Uncertainties ◽  
Control Approach ◽  
Power Extraction ◽  
Conversion System ◽  
Energy Conversion System

A nonlinear control of a PV Energy Conversion System (PVECS) with energy storage system and maximum power extraction is presented. The control strategy is designed in two steps. Firstly, a MPPT algorithm is designed to tracking the maximum power point in variable irradiations, battery state of charge (SOC) and load changes. Then, thanks to its many advantages such as simplicity against parameter uncertainties, a Sliding Mode Control approach (SMC) is applied to control the standalone PV energy conversion system. Finally, the performances of MPPT techniques and SMC controller in the closed loop are checked using the MATLAB/SIMULINK.

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