Modeling and Dynamic Analysis of an Electrical Helmholtz Resonator for Active Control of Resonant Noise

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Sang-Myeong Kim ◽  
Joao A. Pereira ◽  
Antonio E. Turra ◽  
Jun-Ho Cho
Keyword(s):  
Mathematical Model ◽  
Dynamic Control ◽  
Active Noise Control ◽  
Helmholtz Resonator ◽  
Single Mode ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Acoustic Cavity ◽  
Resonant Noise ◽  
The Mathematical Model

This paper describes a theoretical and experimental investigation into an electrical Helmholtz resonator (EHR): that is, an active noise control (ANC) loudspeaker used in conjunction with a microphone and a feedback controller for suppressing resonant noise in an acoustic cavity. The microphone is collocated with the loudspeaker and a band pass filter of second-order is used as the control filter inside the controller. The EHR is configured as such in order to suppress an acoustic mode that is within the volume velocity drive frequency range of the loudspeaker used. The concepts of impedance and passivity are used to develop the mathematical model as well as to study its dynamics. From these, it is theoretically shown that the EHR for single-mode suppression is an extremely low-impedance acoustic damping device that electrically realizes the pressure neutralization mechanism of a conventional Helmholtz resonator (HR). Experimental work is also presented, in which an EHR is constructed to suppress the Helmholtz mode of an acoustic cavity at about 40 Hz by more than 40 dB, to justify the mathematical model and also to verify the dynamic control mechanism.

Study on the Dynamic Control Chart of Pumping Wells

2013 ◽  
Vol 734-737 ◽  
pp. 1276-1279
Author(s):  
Jing Guang Zhu
Keyword(s):  
Mathematical Model ◽  
Boundary Conditions ◽  
Water Content ◽  
Control Chart ◽  
Dynamic Control ◽  
Scientific Basis ◽  
Leak Rate ◽  
Pump Efficiency ◽  
Pumping Wells ◽  
The Mathematical Model

In order to improve the pump efficiency of pumping wells, by means of the basic formula of pump efficiency, the mathematical model and boundary conditions of dynamic control chart is obtained, and the pump efficiency of pumping wells is drawn. Analysis shown that the pump efficiency is sensitive to the water content and pump leak rate. The higher the water content is, the higher pump efficiency is. The pump efficiency will be reduced with the increasing of pump leak rate. The dynamic control chart of class II block of A oilfield is given in the paper. After taking the measures, the pump efficiency of pumping wells is obviously improved. The dynamic control chart drawn by this method can provide a scientific basis for improving the pump efficiency of pumping wells in oilfield.

Yarn Feeding Compensation Algorithm and Implementation for Needbar Transverse Shifting of Carpet Tufting Machine

2011 ◽  
Vol 179-180 ◽  
pp. 150-155 ◽  
Author(s):  
Guang Feng Chen ◽  
Wei Bin Wang ◽  
Hao Chun Sun ◽  
Qing Qing Li
Keyword(s):  
Mathematical Model ◽  
Dynamic Control ◽  
Length Change ◽  
Compensation Scheme ◽  
Compensation Algorithm ◽  
Result Show ◽  
Carpet Tufting Machine ◽  
Control Principle ◽  
The Mathematical Model ◽  
Test Result

The needle bar transverse shifting will likely form the stop mark liked gap on the tufted carpet. This paper proposed the yarn feeding compensation scheme and illustrate implement method in detail. Through analysis the change in yarn feeding path and loop pile forming of carpet tufting machine, construct the mathematical model of length change of yarn feeding in path and usage of loop pile forming while needle bar shifting. According to the mathematical model for yarn feeding compensation, calculate the additional yarn feeding requirement. Base on jacquard control principle, dynamic control the yarn feed actuator to drive the yarn feed roller to delivery additional length yarn, and produce loop pile with predefined pile height, Test result show the compensation is feasible.

TECHNIQUE OF APPLICATION FOR PROCESSING OF LOW PASS FILTER LF SIGNALS

10.12737/7905 ◽  
2015 ◽  
Vol 7 (4) ◽  
pp. 35-38
Author(s):  
Табаков ◽  
Yu. Tabakov ◽  
Лавлинский ◽  
V. Lavlinskiy
Keyword(s):  
Mathematical Model ◽  
Block Diagram ◽  
Low Frequency ◽  
Frequency Signal ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Mathematical Model ◽  
40 Hz

The article includes a block diagram and the mathematical model for low pass filter designed for processing low frequency signal with a frequency of 10-40 Hz in order of eliminate various noises and interference.

scholarly journals Physical Mechanism of Laser Excited Acoustic Wave and its Application in Recognition of Incomplete-penetration Welding Defect

2021 ◽  
Author(s):  
Yuhua Cai ◽  
Yi Luo ◽  
Xinxin Wang ◽  
Shuqing Yang ◽  
Fuyuan Zhang ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Pulsed Laser ◽  
Acoustic Signals ◽  
Band Pass Filter ◽  
Hybrid Welding ◽  
Pass Filter ◽  
Acoustic Cavity ◽  
Physical Mechanisms ◽  
Transmission Structure ◽  
Welding Defect

Abstract Incomplete penetration is a type of welding defect that severely impacts the quality of weldments. In order to identify penetration levels in pulsed laser and plasma transferred arc (laser-PTA) hybrid welding, this paper uses structure-borne acoustic sensors to detect acoustic signals. Their characteristics are then analyzed with respect to the time and frequency domains. Acoustic signals characteristic of incomplete-penetration defects were extracted using a Butterworth band-pass filter. Physical mechanisms of laser excited acoustic wave were then studied by analyzing the correlation between incomplete-penetration defects and their characteristic acoustic signals. The results showed that acoustic signals correlating to incomplete-penetration defects have characteristic frequencies ranging from 0 to 10 kHz, which are generated by interaction between the pulsed laser beam and molten pool. An incomplete-penetration defect constitutes an acoustic cavity, which is an acoustic transmission structure. The structure of phonation sources and the acoustic cavity are affected by levels of penetration, giving rise to acoustic signals with different characteristics. In general, the study of physical mechanisms of laser excited acoustic wave lays a foundation for on-line identification of incomplete-penetration defects in laser-PTA hybrid welding.

Research on Vehicle Height Dynamic Control

2013 ◽  
Vol 791-793 ◽  
pp. 672-675
Author(s):  
Hui Xin Song ◽  
Cui Fen Li ◽  
You Shan Hou ◽  
Chao Wang ◽  
Chun Ming Shao
Keyword(s):  
Mathematical Model ◽  
Ride Comfort ◽  
Dynamic Control ◽  
Pneumatic Suspension ◽  
The Mathematical Model

In order to achieve the target of control vehicle height in running state,we designed a control schematic of which practicability was analyzed. By using AMEsim software, we established the mathematical model of the charging and releasing oil to simulate the performance of a 1/4 vehicle with hydro-pneumatic suspension. From the result, we get the conclusion that charging and releasing oil in running state has tiny effect on ride comfort, and stability of the vehicles.

scholarly journals Analysis, Mathematical Model and Simulation Tests of the Unmanned Aerial Vehicle Control System

2019 ◽  
Vol 24 ◽  
pp. 01005
Author(s):  
Lucjan Setlak ◽  
Rafał Kowalik
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Unmanned Aerial Vehicle ◽  
Dynamic Control ◽  
Vehicle Control ◽  
Model And Simulation ◽  
Aerial Vehicle ◽  
The Subject ◽  
Dynamic Control System ◽  
The Mathematical Model

The subject of this paper is to analyze, create a dynamic mathematical model and, on this basis, conduct simulation tests of the control system used in unmanned aerial vehicles. The key objective of the work is to develop a mathematical model of a control system based on the conducted studies of P, PI and PID regulators. The summary of this article are selected simulation tests of the proposed unmanned aerial vehicle (UAV) control system based on the analysis performed, the mathematical model developed for the dynamic control system and based on them, drawing practical conclusions.

scholarly journals A Study on the Effect of the Contact Point and the Contact Force of a Glass Fiber under End-Face Polishing Process

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Ying-Chien Tsai ◽  
Guang-Miao Huang ◽  
Shin-Wei Cheng ◽  
Cheng-An Hsu ◽  
Innchyn Her
Keyword(s):  
Mathematical Model ◽  
Glass Fiber ◽  
Contact Force ◽  
Contact Point ◽  
Coupling Efficiency ◽  
Single Mode ◽  
Contact Forces ◽  
Initial Contact ◽  
Fiber Core ◽  
The Mathematical Model

The offset between the center lines of the polished end-face and the fiber core has a significant effect on coupling efficiency. The initial contact point and the contact force are two of the most important parameters that induce the offset. This study proposes an image assistant method to find the initial contact point and a mathematical model to estimate the contact force when fabricating the double-variable-curvature end-face of single mode glass fiber. The repeatability of finding the initial contact point via the vision assistant program is 0.3 μm. Based on the assumption of a large deflection, a mathematical model is developed to study the relationship between the contact force and the displacement of the lapping film. In order to verify the feasibility of the mathematical model, experiments, as well as DEFORM simulations, are carried out. The results show that the contact forces are alomst linearly proportional to the feed amounts of the lapping film and the errors are less than 9%. By using the method developed in this study, the offset between the grinding end-face and the center line of the fiber core is within 0.15 to 0.35 μm.

scholarly journals Theoretical and Experimental Study on Nonlinear Failure of an MEMS Accelerometer under Dual Frequency Acoustic Interference

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 945
Author(s):  
Peng Guo ◽  
Jiayu Zhang ◽  
Lihui Feng ◽  
Jianmin Cui ◽  
Chaoyang Xing
Keyword(s):  
Mathematical Model ◽  
Damping Ratio ◽  
Maximum Amplitude ◽  
Dual Frequency ◽  
Maximum Acceleration ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Mathematical Model ◽  
Frequency Sweeping

In order to quantitatively study the interfered output of the accelerometer under an acoustic injection attack, a mathematical model for fitting and predicting the accelerometer output was proposed. With ADXL103 as an example, an acoustic injection attack experiment with amplitude sweeping and frequency sweeping was performed. In the mathematical model, the R-squared coefficient was R2 = 0.9990 in the acoustic injection attack experiment with amplitude sweeping, and R2 = 0.9888 with frequency sweeping. Based on the mathematical model, the dual frequency acoustic injection attack mode was proposed. The difference frequency signal caused by the nonlinear effect was not filtered by the low-pass filter. At a 115 dB sound pressure level, the maximum acceleration bias of the output was 4.4 m/s2 and the maximum amplitude of fluctuation was 4.97 m/s2. Two kinds of methods of prevention against acoustic injection attack were proposed, including changing the damping ratio of the accelerometer and adding a preposition low-pass filter.

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