Mitigation of the Effects of High Levels of High-Frequency Noise on MEMS Gyroscopes Using Microfibrous Cloth

2015 ◽  
Author(s):  
Pregassen Soobramaney ◽  
George Flowers ◽  
Robert Dean
Keyword(s):  
High Frequency ◽  
Stability Control ◽  
Harsh Environments ◽  
Vehicle Stability ◽  
Frequency Noise ◽  
High Frequency Noise ◽  
Acoustical Properties ◽  
Vehicle Stability Control ◽  
Mems Gyroscopes ◽  
Metallic Fibers

MEMS gyroscopes are being used in a variety of applications such as camcorders, vehicle stability control and game controllers. Sometimes they are used in harsh environments such as high levels of high-frequency noise. If the frequency of the noise coincides with the natural frequency of the gyroscope, the output of the latter is corrupted. Experiments were performed to demonstrate the effects of noise on MEMS gyroscopes. The focus of this research is to investigate a passive approach to attenuate the effects of noise on MEMS gyroscopes using microfibrous cloth. The candidate materials are made by intermingling and fusing micro metal fibers together using cellulose in wet-lay papermaking technique and sintering of the resulting product to remove the cellulose and bonds the metallic fibers. In this regard, four types of nickel microfibrous material were fabricated using three diameters of nickel fibers. The Delany-Bazley analytical acoustical model was used to determine the optimum acoustical properties of the material. The properties were then used to calculate the absorption coefficients of the microfibrous media. Enclosures were then designed and fabricated from these materials to evaluate the noise attenuation effects on MEMS gyroscopes. Acoustical tests performed in a reverberation room show up to 90% reduction in the amplitude of the effects of noise. The results from simulation modeling and from these experimental evaluations are presented and discussed.

An Analytical Transient Tire Model

2001 ◽  
Vol 29 (2) ◽  
pp. 108-132 ◽  
Author(s):  
A. Ghazi Zadeh ◽  
A. Fahim
Keyword(s):  
Transient Behavior ◽  
Stability Control ◽  
Vehicle Stability ◽  
Tire Model ◽  
Steering Angle ◽  
First Order ◽  
Vehicle Stability Control ◽  
Proposed Model ◽  
Depth Study ◽  
And Performance

Abstract The dynamics of a vehicle's tires is a major contributor to the vehicle stability, control, and performance. A better understanding of the handling performance and lateral stability of the vehicle can be achieved by an in-depth study of the transient behavior of the tire. In this article, the transient response of the tire to a steering angle input is examined and an analytical second order tire model is proposed. This model provides a means for a better understanding of the transient behavior of the tire. The proposed model is also applied to a vehicle model and its performance is compared with a first order tire model.

Case study: Simulation and control of high frequency noise for commercial vehicle cab considering leak

2019 ◽  
Vol 67 (4) ◽  
pp. 315-329
Author(s):  
Rongjiang Tang ◽  
Zhe Tong ◽  
Weiguang Zheng ◽  
Shenfang Li ◽  
Li Huang
Keyword(s):  
High Frequency ◽  
Commercial Vehicle ◽  
Frequency Noise ◽  
High Frequency Noise ◽  
Simulation And Control ◽  
And Control

Aerodynamic noise from an asymmetric airfoil with perforated extension plates at the trailing edge

2020 ◽  
pp. 1475472X2097838
Author(s):  
CK Sumesh ◽  
TJS Jothi
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Pore Diameter ◽  
Low Frequency ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Trailing Edge ◽  
High Frequency Noise ◽  
Displacement Thickness

This paper investigates the noise emissions from NACA 6412 asymmetric airfoil with different perforated extension plates at the trailing edge. The length of the extension plate is 10 mm, and the pore diameters ( D) considered for the study are in the range of 0.689 to 1.665 mm. The experiments are carried out in the flow velocity ( U∞) range of 20 to 45 m/s, and geometric angles of attack ( αg) values of −10° to +10°. Perforated extensions have an overwhelming response in reducing the low frequency noise (<1.5 kHz), and a reduction of up to 6 dB is observed with an increase in the pore diameter. Contrastingly, the higher frequency noise (>4 kHz) is observed to increase with an increase in the pore diameter. The dominant reduction in the low frequency noise for perforated model airfoils is within the Strouhal number (based on the displacement thickness) of 0.11. The overall sound pressure levels of perforated model airfoils are observed to reduce by a maximum of 2 dB compared to the base airfoil. Finally, by varying the geometric angle of attack from −10° to +10°, the lower frequency noise is seen to increase, while the high frequency noise is observed to decrease.

Vehicle Stability Control Through Predictive and Optimal Tire Saturation Management

2012 ◽  
Author(s):  
Justin Sill ◽  
Beshah Ayalew
Keyword(s):  
Stability Control ◽  
Vehicle Stability ◽  
Distribution Problem ◽  
Scale Separation ◽  
Torque Distribution ◽  
Hydraulic Hybrid ◽  
Time Scale Separation ◽  
Vehicle Stability Control ◽  
Natural Time ◽  
Set Up

This paper presents a predictive vehicle stability control (VSC) strategy that distributes the drive/braking torques to each wheel of the vehicle based on the optimal exploitation of the available traction capability for each tire. To this end, tire saturation levels are defined as the deficiency of a tire to generate a force that linearly increases with the relevant slip quantities. These saturation levels are then used to set up an optimization objective for a torque distribution problem within a novel cascade control structure that exploits the natural time scale separation of the slower lateral handling dynamics of the vehicle from the relatively faster rotational dynamics of the wheel/tire. The envisaged application of the proposed vehicle stability strategy is for vehicles with advanced and emerging pure electric, hybrid electric or hydraulic hybrid power trains featuring independent wheel drives. The developed predictive control strategy is evaluated for, a two-axle truck featuring such an independent drive system and subjected to a transient handling maneuver.

Bayesian deconvolution of gamma‐ray logs

Geophysics ◽  
1987 ◽  
Vol 52 (11) ◽  
pp. 1535-1546 ◽  
Author(s):  
Ping Sheng ◽  
Benjamin White ◽  
Balan Nair ◽  
Sandra Kerford
Keyword(s):  
High Frequency ◽  
Gamma Ray ◽  
Simulated Data ◽  
Field Measurements ◽  
Bayesian Optimization ◽  
Frequency Noise ◽  
High Frequency Noise ◽  
Data Application ◽  
Gamma Ray Detector ◽  
Gamma Ray Log

The spatial resolution of gamma‐ray logs is defined by the length 𝓁 of the gamma‐ray detector. To resolve thin beds whose thickness is less than 𝓁, it is generally desirable to deconvolve the data to reduce the averaging effect of the detector. However, inherent in the deconvolution operation is an amplification of high‐frequency noise, which can be a detriment to the intended goal of increased resolution. We propose a Bayesian statistical approach to gamma‐ray log deconvolution which is based on optimization of a probability function which takes into account the statistics of gamma‐ray log measurements as well as the empirical information derived from the data. Application of this method to simulated data and to field measurements shows that it is effective in suppressing high‐frequency noise encountered in the deconvolution of gamma‐ray logs. In particular, a comparison with the least‐squares deconvolution approach indicates that the incorporation of physical and statistical information in the Bayesian optimization process results in optimal filtering of the deconvolved results.

Mixed H∞/H2 Output Feedback Stability Control for Dual-Motor Independent Drive Electric Vehicle

2013 ◽  
Vol 658 ◽  
pp. 602-608 ◽  
Author(s):  
Cheng Lin ◽  
Chun Lei Peng
Keyword(s):  
Electric Vehicle ◽  
Output Feedback ◽  
Stability Control ◽  
Vehicle Stability ◽  
Robust Performance ◽  
Output Feedback Controller ◽  
Vehicle Stability Control ◽  
Feedback Stability ◽  
Simulation Results ◽  
Yaw Moment

This paper presents the design of mixed H∞/H2Output Feedback Controller for Independent Drive Electric Vehicle Stability Control. It generates yaw moment by applying driving intervention at front Independent driving wheels according to the vehicle states. The performance of the proposed controller is evaluated through a series of simulations under different velocity and different mass. The simulation results show that the controller can help vehicle against a certain range of uncertainty (speeds and loads) and get excellent robust performance.

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