scholarly journals Adaptive versus Conventional Positive Position Feedback Controller to Suppress a Nonlinear System Vibrations

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 255
Author(s):  
N. A. Saeed ◽  
Emad Mahrous Awwad ◽  
Talaat Abdelhamid ◽  
Mohammed A. El-Meligy ◽  
Mohamed Sharaf
Keyword(s):  
Mathematical Model ◽  
Natural Frequency ◽  
Nonlinear Vibrations ◽  
Excitation Frequency ◽  
External Excitation ◽  
Main System ◽  
Positive Position Feedback ◽  
Position Feedback ◽  
Excitation Force ◽  
External Excitation Frequency

The nonlinear vibration control of a nonlinear dynamical system modeled as the well-known Duffing oscillators is investigated within this article. The conventional Positive Position Feedback (PPF) controller is proposed to mitigate the considered system nonlinear vibrations. The whole system mathematical model is analyzed by applying the multiple time scales perturbation method. The slow-flow modulation equations that govern the oscillation amplitudes of both the main system and controller are derived. The stability analysis is investigated based on Lyapunov’s first method. The effects of the different control parameters on both the main system and controller are explored. The obtained analytical and numerical results illustrated that the PPF controller can eliminate the main system nonlinear vibrations once the controller natural frequency is tuned to be the same value as the external excitation frequency, otherwise, the controller adds excessive vibrational energy to the main system rather than suppressing it. In addition, the PPF controller can destabilize the main system motion when excited by strong excitation force. Therefore, a modified version of the PPF controller named the Adaptive Positive Position Feedback (APPF) controller is proposed to overcome the main drawbacks of the conventional PPF controller. The idea is to track the external excitation frequency using an adaptive frequency measurement technique to update continuously the PPF controller natural frequency to become the same value of the excitation frequency. Based on this strategy, the system mathematical model is analyzed again by making the controller’s natural frequency equal to the external excitation frequency. The obtained analytical and numerical simulations showed that the adaptive positive position feedback controller can suppress the main system nonlinear vibration close to zero regardless of the excitation force amplitude and excitation frequency.

Structural Analysis and Optimization of Combine Harvester Frame

2014 ◽  
Vol 490-491 ◽  
pp. 629-632
Author(s):  
Fu Qiang Li ◽  
Shou Rong Liu ◽  
En Rong Mao ◽  
Bin Xie ◽  
Li Xiang Zhang
Keyword(s):  
Structural Analysis ◽  
Natural Frequency ◽  
Excitation Frequency ◽  
Paper Analysis ◽  
External Excitation ◽  
Parameterized Model ◽  
Combine Harvester ◽  
Strength And Stiffness ◽  
External Excitation Frequency ◽  
Ansys Workbench

Parameterized model of combine harvester frame is created using the DM module of ANSYS Workbench in this paper. Analysis on the strength and stiffness of the frame is implemented to estimate its safety and economy. According to the analysis result, optimization is made to save material appropriately. Modal analysis of the frame is proceeded to study its natural frequency and compare it with external excitation frequency.

Resonance Modelling and Control in Structures by Means of Magnetorheological Dampers

2010 ◽  
Author(s):  
Mario F. Letelier ◽  
Dennis A. Siginer ◽  
Juan S. Stockle ◽  
Cristian Herrera
Keyword(s):  
Natural Frequency ◽  
Resonance Effect ◽  
Excitation Frequency ◽  
Magnetorheological Dampers ◽  
External Excitation ◽  
External Forces ◽  
And Control ◽  
External Excitation Frequency

Many structures such as automobile bodies, bridges and buildings are subjected to external forces due to the nature of the environment in which they exist. When the external excitation frequency is similar to the structure’s natural frequency a resonance effect is generated, increasing the energy and the amplitude of the oscillation, often causing catastrophic situations. This paper presents a method to decrease such resonant oscillations using magnetorheological dampers.

VERTICAL VIBRATION CHARACTERISTICS OF A HIGH-TEMPERATURE SUPERCONDUCTING MAGLEV VEHICLE SYSTEM

2013 ◽  
Vol 27 (15) ◽  
pp. 1362022 ◽  
Author(s):  
JING JIANG ◽  
KE CAI LI ◽  
LI FENG ZHAO ◽  
JIA QING MA ◽  
YONG ZHANG ◽  
...  
Keyword(s):  
High Temperature ◽  
Vibration Frequency ◽  
Excitation Frequency ◽  
Vertical Vibration ◽  
External Excitation ◽  
Maglev Vehicle ◽  
Vehicle System ◽  
High Temperature Superconducting Maglev ◽  
External Excitation Frequency ◽  
Maglev Vehicle System

The vertical vibration characteristics of a high-temperature superconducting maglev vehicle system are investigated experimentally. The displacement variations of the maglev vehicle system are measured with different external excitation frequency, in the case of a certain levitation gap. When the external vibration frequency is low, the amplitude variations of the response curve are small. With the increase of the vibration frequency, chaos status can be found. The resonance frequencies with difference levitation gap are also investigated, while the external excitation frequency range is 0–100 Hz. Along with the different levitation gap, resonance frequency is also different. There almost is a linear relationship between the levitation gap and the resonance frequency.

Vibration characteristics analysis and structure optimization of air-pressure subsoiler

2021 ◽  
pp. 095745652110526
Author(s):  
Hongjie Su ◽  
Hongmei Cui ◽  
Feiyu Li ◽  
Chaolun Yideer ◽  
Yaxiong Zhu ◽  
...  
Keyword(s):  
Natural Frequency ◽  
Structural Reliability ◽  
Excitation Frequency ◽  
Structure Optimization ◽  
Time Domain Analysis ◽  
Vibration Characteristics ◽  
Air Pressure ◽  
Excitation Source ◽  
External Excitation ◽  
Actual Production

Aiming at the problems of strong vibration, inconsistent subsoiling depth and high failure rate of air-pressure subsoiler, air-pressure subsoiler vibration characteristics was studied. In order to decrease the vibration, For the first time, the vibration characteristics of air-pressure subsoiler were obtained by modal analysis and vibration test. The vibration characteristics of the whole air-blown subsoiler are analyzed Through time domain analysis, it is found that the vibration acceleration of four deep loosening shovel is inconsistent. When the diesel engine is started, it is easy to cause inconsistent subsoiler depth. Then, by analyzing the vibration characteristics of the whole air-pressure subsoiler, it can be known that the external excitation source of the air-blown subsoiler is close to its own natural frequency. In order to avoid resonance caused by the vibration frequency of the external excitation source being close to the natural frequency of the air-pressure subsoiler, and to reduce the inconsistency of the subsoil depth, we optimize the design of air-pressure subsoiler. Instead of diesel engines, the steering gear box is connected with tractor power output shaft to provide power. The modal simulation of the optimized air-pressure subsoiler shows that the first-order natural frequency is obviously improved and the external excitation frequency is successfully avoided. It not only avoids resonance, reduces the damage of resonance components, but improves the service life of the subsoiler, greatly improves the structural reliability of the air-pressure subsoiler, at the same time, removes the main external excitation source, which greatly reduces the vibration in actual production and the inconsistency of subsoiling, which is of great significance in actual production. It provides a reference for the research of vibration characteristics, resonance avoidance and structure optimization of agricultural equipment.

scholarly journals Dynamic Analysis of Excavator Arm Used for Breaking Operation

CONVERTER ◽  
2021 ◽  
pp. 19-31
Author(s):  
Weizhang Wang, Kun Yang, Zengmei Song
Keyword(s):  
Working Condition ◽  
Excitation Frequency ◽  
External Excitation ◽  
Low Frequencies ◽  
High Frequencies ◽  
Software Analysis ◽  
Finite Element Software ◽  
Practical Operation ◽  
Working Device ◽  
External Excitation Frequency

So far excavator retrofitting breaking hammer is commonly applied to impact breaking operation on rock, mountain and building body in engineering field. In practical operation fracture of the movable excavator arm frequently occurs. This thesis, in terms of dynamics, considers the breaking machine under three typical working conditions and aims at respective load solutions for the hinge point of the movable arm under each working condition. Modal analysis and harmonic response for the movable arm is conducted by means of finite element software. Analysis shows that the movable arm would not resonate at relatively high frequencies and external excitation load affects the movable arm noticeably at low frequencies. Damping increase of the working device of the breaking machine is needed to enable the external excitation frequency to avoid the primary and secondary inherent frequencies, and thus reduce the resonation opportunity of the movable arm.

Study of Hydrostatic Pump Created Under Liquid Sloshing in a Rectangular Tank Subjected to External Excitation

2016 ◽  
Vol 08 (01) ◽  
pp. 1650004 ◽  
Author(s):  
Abdallah Bouabidi ◽  
Zied Driss ◽  
Mohamed Salah Abid
Keyword(s):  
Numerical Simulation ◽  
Excitation Frequency ◽  
Liquid Sloshing ◽  
Experimental Results ◽  
Experimental Setup ◽  
Liquid Motion ◽  
External Excitation ◽  
Sinusoidal Movement ◽  
Rectangular Tank ◽  
External Excitation Frequency

The aim of this work is to study the hydrostatic pump created under liquid sloshing in a rectangular tank partially filled with liquid. A numerical simulation was performed to predict the liquid motion in the tank. The apparition of the compression and the depression zones due to the liquid motion was presented and analyzed. An experimental setup with sinusoidal movement was developed to study the hydrostatic pump. The hydrostatic pump is created using a mixing element. The experimental results show that the compression and the depression zones can create the hydrostatic pump. The effect of the connecting chamber value was studied for different values of external excitation frequency. The pump depends considerably on the dimension of the connecting zone between the two volumes. For the different connecting chamber values, the pumped quantity increase with the increase of the frequency.

Structural Optimization of Mine Hoisting Skip Underframe Based on Modal Analysis

2013 ◽  
Vol 850-851 ◽  
pp. 208-211
Author(s):  
Yi Jie Zhang ◽  
Ling Qiong Kong ◽  
Huan Zou
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
3D Model ◽  
Excitation Frequency ◽  
Element Model ◽  
External Excitation ◽  
Modal Test ◽  
Parameterized Model ◽  
The Finite Element Model ◽  
External Excitation Frequency

Aiming at the problems of vibration and noise appeared in the work of lifting the skip underframe of the mine, a parameterized model of the underframe of skip is established by taking advantage of UG. And a finite element modal analysis is done by leading 3D model into the ANSYS, and the credibility of the finite element model is verified by combining the modal test. On the basis of comparing the characteristics of the external excitation frequency, the dynamic characteristics of the underframe of skip are evaluated and the structure is optimized. The results of the optimization indicate that: not only the modal frequency of the first eight orders of the ship underframe has avoided the range of external excitation frequency, with a smooth mode of vibration, avoiding the occurrence of sympathetic vibration effectively, but it has lost a weight of 10.6%, achieving an improvement of the hoisting capacity of the skip equipment. This research is of important reference to the technical transformation of skip equipment for some mine enterprise.

Nonlinear positive position feedback control for mitigation of nonlinear vibrations

2019 ◽  
Vol 132 ◽  
pp. 457-470 ◽  
Author(s):  
G. Zhao ◽  
A. Paknejad ◽  
G. Raze ◽  
A. Deraemaeker ◽  
G. Kerschen ◽  
...  
Keyword(s):  
Feedback Control ◽  
Nonlinear Vibrations ◽  
Positive Position Feedback ◽  
Position Feedback
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