Mitigation of Gear Mesh-Frequency Noise Using a Hydrostatic Bearing

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Zamir A. Zulkefli ◽  
Maurice L. Adams
Keyword(s):  
Frequency Noise ◽  
Driving Frequency ◽  
Low Frequencies ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Hydrostatic Bearing ◽  
Gear Mesh ◽  
Hydrostatic Bearings ◽  
Low Pass ◽  
Filtering Effect

A proposed solution to reducing gear mesh-frequency vibrations in a gear-set involves the utilization of hydrostatic bearings placed in series, load wise, with the main support bearing. The hydrostatic bearings are expected to utilize its low pass filtering effect of the vibrational energies to prevent its transmission from the shaft to the gear housing where it would be emitted as noise. The present investigation examines the frequency response of a single-recess circular hydrostatic bearing under applied sinusoidal loads. The results show that as the driving frequency increases, the filtering effect of the hydrostatic bearing increases. The exhibited behavior is similar to the behavior of a low pass filter: negligible filtering effect at low frequencies, the filtering effect increasing from 0% to 90% over the midfrequencies range and the filtering effect remaining at the maximum value as the frequencies of the applied signals continue to increase. This observed behavior is expected to play a central role in the proposed gear mesh-frequency vibration mitigation system.

scholarly journals Improved harmonic detection method based on ip-iq theory

2021 ◽  
Vol 261 ◽  
pp. 01028
Author(s):  
Zhisen Yao ◽  
Guige Gao
Keyword(s):  
Detection Method ◽  
Phase Error ◽  
Response Speed ◽  
Detection Accuracy ◽  
Harmonic Detection ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
In Series ◽  
Filtering Effect

Based on the traditional ip-iq harmonic detection theory, the accuracy of harmonic detection is easily affected by the phase-locked loop (PLL) output phase error, and the single low-pass filter (LPF) detection accuracy and filtering effect cannot be simultaneously. In this paper, an improved harmonic detection method based on the second-order generalized integrator-frequency locked loop (SOGI-FLL) technique is proposed to generate sine and cosine signals with the same frequency as the grid voltage; The traditional low-pass filter and average filter are used in series to improve the response speed and accuracy. Through theoretical analysis of the improved harmonic detection method and simulation in MATLAB environment, the theory and simulation results prove the effectiveness of the improved method.

Construction of a High-Pass Digital Filter from a Low-Pass Digital Filter

1994 ◽  
Vol 10 (4) ◽  
pp. 374-381 ◽  
Author(s):  
Stephen D. Murphy ◽  
D. Gordon E. Robertson
Keyword(s):  
Digital Filter ◽  
Low Frequency ◽  
Frequency Noise ◽  
Band Pass Filter ◽  
Low Frequency Noise ◽  
Pass Filter ◽  
Low Pass Filter ◽  
High Pass Filter ◽  
Low Pass ◽  
High Pass

To remove low-frequency noise from data such as DC-bias from electromyo-grams (EMGs) or drift from force transducers, a high-pass filter was constructed from a low-pass filter of known characteristics. A summary of the necessary steps required to transform the low-pass digital were developed. Contaminated EMG and force platform data were used to test the filter. The high-pass filter successfully removed the low-frequency noise from the EMG signals. The high-pass filter was then cascaded with the low-pass filter to produce a band-pass filter to enable simultaneous high- and low-frequency noise reduction.

Flicker Sensitivity as a Function of Eccentricity

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 327-327 ◽  
Author(s):  
A N Raninen ◽  
J Rovamo
Keyword(s):  
Matched Filter ◽  
Temporal Frequency ◽  
Internal Noise ◽  
Modulation Transfer ◽  
Low Frequencies ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Neural Noise ◽  
Low Pass ◽  
High Pass

We determined DeLange curves with and without external temporal noise at eccentricities of 0 – 70 deg by measuring flicker sensitivity at 1 – 45 Hz for sharp-edged M-scaled spots with an equiluminous surround. Without noise, flicker sensitivity at high frequencies increased with eccentricity but remained unchanged at low frequencies. In strong noise, flicker sensitivity was independent of eccentricity. The only exception was 70 deg where sensitivity was reduced at 1 – 3 Hz with and without noise. The data at each eccentricity are well described by our flicker-sensitivity model (Rovamo et al, 1996 Vision Research36 3767 – 3774) comprising (i) low-pass filtering by the modulation transfer function (MTF) of the retina, (ii) filtering in direct proportion to temporal frequency by the high-pass MTF of the retina and subsequent neural visual pathways, (iii) addition of white internal neural noise, and (iv) detection by a temporal matched filter. When interpreted in the context of the model, our results mean that while the high-pass filter and the magnitude of internal noise remained unchanged across eccentricities, the bandwith of the low-pass filter increased with eccentricity and at 70 deg eccentricity the efficiency of the detecting mechanism in the brain was reduced at 1 – 3 Hz. The increase in the bandwidth of the low-pass filter is in agreement with the eccentricity-dependent changes in the retinal function as revealed by the electroretinogram (ERG).

Integrated switched-capacitor low-pass filter with combined anti-aliasing decimation filter for low frequencies

1982 ◽  
Vol 17 (6) ◽  
pp. 1024-1029 ◽  
Author(s):  
D.C. von Grungen ◽  
R. Sigg ◽  
M. Ludwig ◽  
U.W. Brugger ◽  
G.S. Moschytz ◽  
...  
Keyword(s):  
Switched Capacitor ◽  
Low Frequencies ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Decimation Filter

Pulse-shape distortion introduced by broadband deconvolution

1992 ◽  
Vol 82 (1) ◽  
pp. 238-258
Author(s):  
Stuart A. Sipkin ◽  
Arthur L. Lerner-Lam
Keyword(s):  
Transfer Function ◽  
Ground Motion ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequencies ◽  
Pass Filter ◽  
Long Period ◽  
High Pass Filter ◽  
Low Pass ◽  
High Pass

Abstract The availability of broadband digitally recorded seismic data has led to an increasing number of studies using data from which the instrument transfer function has been deconvolved. In most studies, it is assumed that raw ground motion is the quantity that remains after deconvolution. After deconvolving the instrument transfer function, however, seismograms are usually high-pass filtered to remove low-frequency noise caused by very long-period signals outside the frequency band of interest or instabilities in the instrument response at low frequencies. In some cases, data must also be low-pass filtered to remove high-frequency noise from various sources. Both of these operations are usually performed using either zero-phase (acausal) or minimum-phase (causal) filters. Use of these filters can lead to either bias or increased uncertainty in the results, especially when taking integral measures of the displacement pulse. We present a deconvolution method, based on Backus-Gilbert inverse theory, that regularizes the time-domain deconvolution problem and thus mitigates any low-frequency instabilities. We apply a roughening constraint that minimizes the long-period components of the deconvolved signal along with the misfit to the data, emphasizing the higher frequencies at the expense of low frequencies. Thus, the operator acts like a high-pass filter but is controlled by a trade-off parameter that depends on the ratio of the model variance to the residual variance, rather than an ad hoc selection of a filter corner frequency. The resulting deconvolved signal retains a higher fidelity to the original ground motion than that obtained using a postprocess high-pass filter and eliminates much of the bias introduced by such a filter. A smoothing operator can also be introduced that effectively applies a low-pass filter. This smoothing is useful in the presence of blue noise, or if inferences about source complexity are to be made from the roughness of the deconvolved signal.

A New Parabolic Sliding Mode Filter Augmented by a Linear Low-Pass Filter and Its Application to Position Control

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Myo Thant Sin Aung ◽  
Zhan Shi ◽  
Ryo Kikuuwe
Keyword(s):  
Position Control ◽  
Sliding Mode ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Optical Encoder ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Response Characteristics ◽  
Low Pass ◽  
Dc Servomotor

This paper proposes a new sliding mode filter augmented by a linear low-pass filter (LPF) for mitigating the effect of high-frequency noise. It is based on the derivation of three new variants of Jin et al.'s (2012, “Real-Time Quadratic Sliding Mode Filter for Removing Noise,” Adv. Rob., 26(8–9), pp. 877–896) parabolic sliding mode filter (J-PSMF) and investigation on their frequency-response characteristics. The new filter is developed by augmenting one of the variants of J-PSMF by a second-order linear LPF. It has better balance between the noise attenuation and signal preservation than both linear LPFs and J-PSMF. The effectiveness of the new filter is experimentally evaluated on a direct current (DC) servomotor equipped with an optical encoder. This paper also shows the application of the proposed filter to a positioning system under PDD2 (proportional, derivative, and second derivative) control, which successfully realizes the noise attenuation and the nonovershooting response simultaneously.

Design of Programmable Wideband Low Pass Filter with Continuous-Time/Discrete-Time Hybrid Architecture

2017 ◽  
Vol E100.C (10) ◽  
pp. 858-865 ◽  
Author(s):  
Yohei MORISHITA ◽  
Koichi MIZUNO ◽  
Junji SATO ◽  
Koji TAKINAMI ◽  
Kazuaki TAKAHASHI
Keyword(s):  
Discrete Time ◽  
Continuous Time ◽  
Hybrid Architecture ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass
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