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Michael E Hahn - One of the best experts on this subject based on the ideXlab platform.

  • low pass Filter Cutoff Frequency affects sacral mounted inertial measurement unit estimations of peak vertical ground reaction force and contact time during treadmill running
    Journal of Biomechanics, 2021
    Co-Authors: Evan M Day, Ryan S Alcantara, Michael A Mcgeehan, Alena M Grabowski, Michael E Hahn
    Abstract:

    Abstract Inertial measurement units (IMUs) are popular tools for estimating biomechanical variables such as peak vertical ground reaction force (GRFv) and foot-ground contact time (tc), often by using multiple sensors or predictive models. Despite their growing use, little is known about the effects of varying low-pass Filter Cutoff Frequency, which can affect the magnitude of force-related dependent variables, the accuracy of IMU-derived metrics, or if simpler methods for such estimations exist. The purpose of this study was to investigate the effects of varying low-pass Filter Cutoff Frequency on the correlation of IMU-derived peak GRFv and tc to gold-standard lab-based measurements. Thirty National Collegiate Athletics Association Division 1 cross country runners ran on an instrumented treadmill at a range of speeds while outfitted with a sacral-mounted IMU. A simple method for estimating peak GRFv from the IMU was implemented by multiplying the IMU’s vertical acceleration by the runner’s body mass. Data from the IMU were low-pass Filtered with 5, 10, and 30 Hz Cutoffs. Pearson correlation coefficients were used to determine how well the IMU-derived estimates matched gold-standard biomechanical estimations. Correlations ranged from very weak to moderate for peak GRFv and tc. For peak GRFv, the 10 Hz low-pass Filter Cutoff performed best (r = 0.638), while for tc the 5 Hz cut-off performed best (r = 0.656). These results suggest that IMU-derived estimates of force and contact time are influenced by the low-pass Filter Cutoff Frequency. Further investigations are needed to determine the optimal low-pass Filter Cutoff Frequency or a different method to accurately estimate force and contact time is suggested.

Roger L Simpson - One of the best experts on this subject based on the ideXlab platform.

  • 1 Experimentally Obtained Forces and Moments on Slender Bodies during Steady and Unsteady Maneuvers
    2016
    Co-Authors: Kenneth Granlund, Roger L Simpson
    Abstract:

    bzy = loadcell sensitivity for load in z-direction from registered voltage in y-direction Fy = force registered by a loadcell in loadcell y-direction fc = Filter Cutoff Frequency K’,M’,N ’ = aerodynamic moments about the body fixed coordinate system origin normalized by qL3 L = length between perpendiculars of model p,q,r = angular velocities of the body fixed coordinate system t ’ = tU∞/L = non-dimensional time u’,v’,w ’ = linear velocities in the body-fixed coordinate system normalized by U∞ U ∞ = sqrt(u2+v2+w2) = freestream velocity X’,Y’,Z ’ = aerodynamic forces in the body fixed coordinate system normalized by qL2 x,y,z = body-fixed right handed coordinate system with x forward, y to starboard and z down α = angle of attack = arcsin(w’) β = angle of sideslip = arcsin(v’) ζ = non-dimensional lengthwise coordinate from bow to stern I

  • experimentally obtained forces and moments on slender bodies during steady and unsteady maneuvers
    47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition, 2009
    Co-Authors: Kenneth Granlund, Roger L Simpson
    Abstract:

    Nomenclature bzy = loadcell sensitivity for load in z-direction from registered voltage in y-direction Fy = force registered by a loadcell in loadcell y-direction fc = Filter Cutoff Frequency K’,M’,N’ = aerodynamic moments about the body fixed coordinate system origin normalized by qL L = length between perpendiculars of model p,q,r = angular velocities of the body fixed coordinate system t’ = tU∞/L = non-dimensional time u’,v’,w’ = linear velocities in the body-fixed coordinate system normalized by U∞ U∞ = sqrt(u +v+w) = freestream velocity X’,Y’,Z’ = aerodynamic forces in the body fixed coordinate system normalized by qL x,y,z = body-fixed right handed coordinate system with x forward, y to starboard and z down α = angle of attack = arcsin(w’) β = angle of sideslip = arcsin(v’) ζ = non-dimensional lengthwise coordinate from bow to stern

Vinay Chawda - One of the best experts on this subject based on the ideXlab platform.

  • A METHOD FOR SELECTING VELOCITY Filter Cutoff Frequency FOR MAXIMIZING IMPEDANCE WIDTH PERFORMANCE IN HAPTIC INTERFACES
    2016
    Co-Authors: Vinay Chawda, Ozkan Celik, Marcia K. O’malley
    Abstract:

    This paper analyzes the effect of velocity Filtering cut-off fre-quency on the Z-width performance in haptic interfaces. Finite Difference Method (FDM) cascaded with a lowpass Filter is the most commonly used technique for estimating velocity from po-sition data in haptic interfaces. So far, there is no prescribed method for obtaining the FDM+Filter cut-off Frequency that will maximize the Z-width performance. We present a simulation based method to demonstrate that there exists such an ideal FDM+Filter cut-off Frequency, and that it can be predicted by numerical simulation. Experiments are conducted on a single degree-of-freedom linear haptic interface to validate the simula-tion results.

  • a method for selecting velocity Filter Cutoff Frequency for maximizing impedance width performance in haptic interfaces
    Volume 2: Control Monitoring and Energy Harvesting of Vibratory Systems; Cooperative and Networked Control; Delay Systems; Dynamical Modeling and Diag, 2013
    Co-Authors: Vinay Chawda, Ozkan Celik, Marcia K Omalley
    Abstract:

    This paper analyzes the effect of velocity Filtering cut-off Frequency on the Z-width performance in haptic interfaces. Finite Difference Method (FDM) cascaded with a lowpass Filter is the most commonly used technique for estimating velocity from position data in haptic interfaces. So far, there is no prescribed method for obtaining the FDM+Filter cut-off Frequency that will maximize the Z-width performance. We present a simulation based method to demonstrate that there exists such an ideal FDM+Filter cut-off Frequency, and that it can be predicted by numerical simulation. Experiments are conducted on a single degree-of-freedom linear haptic interface to validate the simulation results.Copyright © 2013 by ASME

Evan M Day - One of the best experts on this subject based on the ideXlab platform.

  • low pass Filter Cutoff Frequency affects sacral mounted inertial measurement unit estimations of peak vertical ground reaction force and contact time during treadmill running
    Journal of Biomechanics, 2021
    Co-Authors: Evan M Day, Ryan S Alcantara, Michael A Mcgeehan, Alena M Grabowski, Michael E Hahn
    Abstract:

    Abstract Inertial measurement units (IMUs) are popular tools for estimating biomechanical variables such as peak vertical ground reaction force (GRFv) and foot-ground contact time (tc), often by using multiple sensors or predictive models. Despite their growing use, little is known about the effects of varying low-pass Filter Cutoff Frequency, which can affect the magnitude of force-related dependent variables, the accuracy of IMU-derived metrics, or if simpler methods for such estimations exist. The purpose of this study was to investigate the effects of varying low-pass Filter Cutoff Frequency on the correlation of IMU-derived peak GRFv and tc to gold-standard lab-based measurements. Thirty National Collegiate Athletics Association Division 1 cross country runners ran on an instrumented treadmill at a range of speeds while outfitted with a sacral-mounted IMU. A simple method for estimating peak GRFv from the IMU was implemented by multiplying the IMU’s vertical acceleration by the runner’s body mass. Data from the IMU were low-pass Filtered with 5, 10, and 30 Hz Cutoffs. Pearson correlation coefficients were used to determine how well the IMU-derived estimates matched gold-standard biomechanical estimations. Correlations ranged from very weak to moderate for peak GRFv and tc. For peak GRFv, the 10 Hz low-pass Filter Cutoff performed best (r = 0.638), while for tc the 5 Hz cut-off performed best (r = 0.656). These results suggest that IMU-derived estimates of force and contact time are influenced by the low-pass Filter Cutoff Frequency. Further investigations are needed to determine the optimal low-pass Filter Cutoff Frequency or a different method to accurately estimate force and contact time is suggested.

A Baschirotto - One of the best experts on this subject based on the ideXlab platform.

  • a 255 mhz programmable gain amplifier and low pass Filter for ultra low power impulse radio uwb receivers
    IEEE Transactions on Circuits and Systems, 2012
    Co-Authors: S Damico, M De Blasi, M De Matteis, A Baschirotto
    Abstract:

    A 90 nm-CMOS power-optimized analog baseband chain for ultra-low-power impulse-radio ultra-wideband (IR-UWB) receivers is presented. The proposed device merges the functions of a programmable gain amplifier (PGA) and a low-pass Filter (LPF). It consists of the cascade of three biquadratic cells made up by opamps in a series-shunt configuration, which features high input impedance, low load effects in the cascade blocks, and better Frequency response. The opamp parameters are included in the overall biquad transfer function. This allows getting very low power performance, since the opamp bandwidth is not required to be much larger than the Filter Cutoff Frequency. Moreover, the current consumption is optimized according to the selected gain level (1.3 mA at 0 dB-gain up to 1.9 mA at 40 dB-gain). The PGA features a 0-40 dB programmable gain range with a 5 dB gain-step. The LPF performs a sixth-order 255 MHz low-pass Frequency response. For the overall chain the IIP3 is 14 dBm at 0 dB gain, while the input referred noise is 12.5 nV/√Hz at 40 dB gain.

  • a 1 2 v 30 4 dbm oip3 reconfigurable analog baseband channel for umts wlan transmitters
    IEEE Transactions on Circuits and Systems, 2006
    Co-Authors: N Ghittori, A Vigna, P Malcovati, S Damico, A Baschirotto
    Abstract:

    This paper presents a reconfigurable universal mobile telecommunication systems [(UMTS) and wireless local area network (WLAN) mode)] analog baseband transmitter channel composed of a current steering digital-analog converter (DAC), a transimpedance stage, and a low-pass reconstruction Filter. The device operates from a single 1.2-V supply voltage while guaranteeing the high-linearity UMTS/WLAN standard requirements. It can be digitally programmed to process WLAN 802.11a/b/g and UMTS signals, by adjusting the DAC conversion Frequency and the low-pass Filter Cutoff Frequency. For the WLAN mode, the DAC operating Frequency and the Filter bandwidth are set to 100 and 11 MHz, respectively, while for the UMTS mode, they are equal to 50 and 2.11 MHz. The device is realized in a 1.2-V 0.13-mum standard CMOS technology. The die area occupation, equal to 0.9mm2, has been minimized by optimizing the component sharing for the two operation modes. The proposed circuit achieves a 30.4 dBm third-order output referred intermodulation intercept point (OIP3) for the WLAN mode, and a 31.5 dBm-OIP3 when configured for the UMTS mode, while the spurious-free dynamic range is 58 dB for WLAN mode, and 60 dB for UMTS mode. The power consumption is optimized according to the operation mode and is 19.44 mW in WLAN mode and 16.8 mW in UMTS mode