Phase-lag-free low pass filter with higher-order sensors and its application in motion control

2016 ◽  
Author(s):  
Dapeng Tian ◽  
Huijun Gao
Keyword(s):  
Motion Control ◽  
Higher Order ◽  
Phase Lag ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

scholarly journals Higher-Order Sliding Mode Observer for Speed and Position Estimation in PMSM

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Suneel K. Kommuri ◽  
Kalyana C. Veluvolu ◽  
M. Defoort ◽  
Yeng C. Soh
Keyword(s):  
Sliding Mode ◽  
Permanent Magnet Synchronous Motor ◽  
Estimation Method ◽  
Higher Order ◽  
Position Estimation ◽  
Accurate Estimation ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Three Phase ◽  
Low Pass

This paper presents a speed and position estimation method for the permanent magnet synchronous motor (PMSM) based on higher-order sliding mode (HOSM) observer. The back electromotive forces (EMFs) in the PMSM are treated as unknown inputs and are estimated with the HOSM observer without the need of low-pass filter and phase compensation modules. With the estimation of back EMFs, an accurate estimation of speed and rotor position can be obtained. Further, the proposed method completely eliminates chattering. Experimental results with a 26 W three-phase PMSM demonstrate the effectiveness of the proposed method.

Statistics of fine-scale velocity in turbulent plane and circular jets

1982 ◽  
Vol 119 ◽  
pp. 55-89 ◽  
Author(s):  
R. A. Antonia ◽  
B. R. Satyaprakash ◽  
A. K. M. F. Hussain
Keyword(s):  
Streamwise Velocity ◽  
Higher Order ◽  
Pass Filter ◽  
Low Pass Filter ◽  
A Value ◽  
Circular Jets ◽  
Low Pass ◽  
Number Variation ◽  
Turbulent Plane ◽  
Velocity Derivative

Higher-order statistics of the streamwise velocity derivative have been measured on the centre-line of turbulent plane and circular jets. The instrumentation and sources of error are discussed to establish the accuracy of the data and convergence of statistics. The optimum setting for the low-pass filter cut-off was found to be 1·75 times the Kolmogorov frequency fK, in contrast with the majority of previous investigations where it was set equal to fK. The magnitude of the constant μ in Kolmogorov's revised hypothesis is obtained using statistics derived from the instantaneous velocity derivative or its squared value. The correlation and spectrum of fluctuations of the squared velocity derivative and the Reynolds-number variation of the skewness and flatness factors of the velocity derivative are consistent with μ ≃ 0·2, while the most popular value used is 0·5. Second-order moments of the locally averaged dissipation, assumed proportional to the squared streamwise velocity derivative, and breakdown coefficients also suggest a value of μ of about 0·2. Higher-order correlations and spectra of the dissipation are in closer agreement with the Novikov-Stewart or β-model than with Kolmogorov's lognormal model. Higher-order moments of locally averaged values of the dissipation rate are more closely represented by the lognormal than the β-model.

A ZERO PHASE-LAG HOMODYNE DEMODULATION TECHNIQUE FOR SYNCHRONOUS MEASUREMENT APPLICATIONS AND ITS FPGA IMPLEMENTATION

2005 ◽  
Vol 14 (04) ◽  
pp. 771-791 ◽  
Author(s):  
B. DAM ◽  
K. BANERJEE ◽  
K. MAJUMDAR ◽  
R. BANERJEE ◽  
D. PATRANABIS
Keyword(s):  
A Priori ◽  
Phase Error ◽  
Time Lag ◽  
Fpga Implementation ◽  
Phase Lag ◽  
Processor Time ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Square Wave ◽  
Low Pass

A simple homodyne direct digital demodulation technique that is insensitive to sensor induced phase-error and its innovative FPGA implementation are presented here. This novel demodulation scheme does not need a low pass filter; thereby the inherent filter time lag is eliminated. A direct digital read-out of the demodulated signal, i.e., the measurand value, is obtained through analog-to-digital conversion of the modulated signal at an instant that coincides with its peak. This peak sampling eliminates the processor time required in quadrature demodulators to obtain the measurand from the in-phase and quadrature components. For this purpose a quadrature square wave is first generated from the reference carrier. Digital measures of carrier time period and sensor induced time lag/lead are used to ensure that the rising edges of this quadrature square wave coincide with the peak instants of the modulated signal. The required sampling instants for digitization of the modulated signal are generated in synchronism with its rising edges. The digital read-out of the measurand is directly obtained without taking recourse to the standard sequence of multiplication, low-pass filtering and the subsequent processing common in existing synchronous phase-sensitive demodulators. With an a priori knowledge of the sensor-type used, this innovative FPGA-based implementation accommodates sensors introducing lagging or leading phase-shift in the modulated carrier.

scholarly journals Eye movement dynamics in the dogfish

1983 ◽  
Vol 105 (1) ◽  
pp. 297-303 ◽  
Author(s):  
J. C. Montgomery
Keyword(s):  
Eye Movement ◽  
Sea Water ◽  
Stimulus Frequency ◽  
Abducens Nerve ◽  
Phase Lag ◽  
Movement Detector ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Stimulation Of

A method is described of obtaining the relationship between electrical stimulation of the abducens nerve and horizontal eye movement in the dogfish. The stump of the VIth nerve was stimulated intracranially in a fish in which the brain had been removed, but in which the circulation remained intact, and the gills were perfused with sea water. Horizontal rotation of the eye was monitored with an opto-electronic movement detector. Eye rotation was linearly related to stimulus frequency in the 0–20 Hz range, and was maximal at frequencies above 40 Hz. Stimulation of the VIth nerve, with a pulse train whose frequency was modulated sinusoidally between 0 and 20 Hz, produced sinusoidal eye movements. The frequency response of the system approximates a first order low pass filter with a characteristic frequency of 0.23 Hz, and an additional phase lag equivalent to a time delay of approximately 50 ms.

scholarly journals Fuzzy Self-tuning Tracking Differentiator for Motion Measurement Sensors and Application in Wide-Bandwidth High-accuracy Servo Control

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 948 ◽  
Author(s):  
Yang Gao ◽  
Dapeng Tian ◽  
Wang
Keyword(s):  
Noise Suppression ◽  
Low Frequency ◽  
Phase Lag ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Motion Measurement ◽  
Frequency Information ◽  
Tracking Differentiator ◽  
Low Pass ◽  
Self Tuning

Sensor differential signals are widely used in many systems. The tracking differentiator (TD) is an effective method to obtain signal differentials. Differential calculation is noise-sensitive. There is the characteristics of low-pass filter (LPF) in the TD to suppress the noise, but phase lag is introduced. For LPF, fixed filtering parameters cannot achieve both noise suppression and phase compensation lag compensation. We propose a fuzzy self-tuning tracking differentiator (FSTD) capable of adaptively adjusting parameters, which uses the frequency information of the signal to achieve a trade-off between the phase lag and noise suppression capabilities. Based on the frequency information, the parameters of TD are self-tuning by a fuzzy method, which makes self-tuning designs more flexible. Simulations and experiments using motion measurement sensors show that the proposed method has good filtering performance for low-frequency signals and improves tracking ability for high-frequency signals compared to fixed-parameter differentiator.

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