The Effects of Filter Cutoff Frequency on Musculoskeletal Simulations of High-Impact Movements

2018 ◽  
Vol 34 (4) ◽  
pp. 336-341 ◽  
Author(s):  
Stefan Sebastian Tomescu ◽  
Ryan Bakker ◽  
Tyson A.C. Beach ◽  
Naveen Chandrashekar
Keyword(s):  
Cutoff Frequency ◽  
High Impact ◽  
Force Platform ◽  
Contact Forces ◽  
Muscle Forces ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Lower Extremity Muscle ◽  
Joint Contact ◽  
Musculoskeletal Simulations

Estimation of muscle forces through musculoskeletal simulation is important in understanding human movement and injury. Unmatched filter frequencies used to low-pass filter marker and force platform data can create artifacts during inverse dynamics analysis, but their effects on muscle force calculations are unknown. The objective of this study was to determine the effects of filter cutoff frequency on simulation parameters and magnitudes of lower-extremity muscle and resultant joint contact forces during a high-impact maneuver. Eight participants performed a single-leg jump landing. Kinematics was captured with a 3D motion capture system, and ground reaction forces were recorded with a force platform. The marker and force platform data were filtered using 2 matched filter frequencies (10–10 Hz and 15–15 Hz) and 2 unmatched filter frequencies (10–50 Hz and 15–50 Hz). Musculoskeletal simulations using computed muscle control were performed in OpenSim. The results revealed significantly higher peak quadriceps (13%), hamstrings (48%), and gastrocnemius forces (69%) in the unmatched (10–50 Hz and 15–50 Hz) conditions than in the matched (10–10 Hz and 15–15 Hz) conditions (P < .05). Resultant joint contact forces and reserve (nonphysiologic) moments were similarly larger in the unmatched filter categories (P < .05). This study demonstrated that artifacts created from filtering with unmatched filter cutoffs result in altered muscle forces and dynamics that are not physiologic.

Design and Simulation of Switched Capacitor Filter for Speed Change Parameter Converter

2013 ◽  
Vol 562-565 ◽  
pp. 1132-1136
Author(s):  
Xiao Wei Liu ◽  
Jian Yang ◽  
Song Chen ◽  
Liang Liu ◽  
Rui Zhang ◽  
...  
Keyword(s):  
Stop Band ◽  
Cutoff Frequency ◽  
Rapid Change ◽  
Pass Band ◽  
Cmos Process ◽  
Switched Capacitor ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Time Domain

In this paper, we design a high-order switched capacitor filter for rapid change parameter converter. This design uses a structure which consists of three biquads filter sub-units. The design is a 6th-order SC elliptic low-pass filter, and the sample frequency is 250 kHz. By the MATLAB Simulink simulation, the system can meet the design requirements in the time domain. In this paper, the 6th-order switched capacitor elliptic low-pass filter was implemented under 0.5 um CMOS process and simulated in Cadence. The final simulation results show that the pass-band cutoff frequency is 10 kHz, and the maximum pass-band ripple is about 0.106 dB. The stop-band cutoff frequency is 20 kHz, and the minimum stop-band attenuation is 74.78 dB.

scholarly journals Analysis and Simulation of Active Filters Using Operational Transconductance Amplifier (OTA)

2017 ◽  
Vol 13 (15) ◽  
pp. 170
Author(s):  
Haitham K. Ali ◽  
Jihan S. Abdaljabar
Keyword(s):  
Cutoff Frequency ◽  
Current Mode ◽  
High Gain ◽  
Angular Frequency ◽  
Active Filters ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Large Bandwidth ◽  
High Output Impedance

As the transistors are continuously scaling down, it becomes necessary to reduce voltage supply and power requirements of the circuit to increase its performance and stability. Whereas, current- mode devices require less number of stages with high output impedance results in improved performance and large bandwidth as compared to voltage-mode techniques. OTA are current-mode device that takes voltage as input and produces current as output with high gain and large bandwidth. The frequency bands were parameters were determined such as the cutoff frequency (fc), the band width (BW), the quality factor (Q), and the angular frequency (Wo). In this paper the design and the simulation of the transfer function has been done by using (MATLAB) in order to obtain the frequency response for all types of filter (the low pass filter, high pass filter, band pass filter and band stop filter).

Improved Stator Flux Estimation for Direct Torque Control of Induction Motor Drives

2016 ◽  
Vol 7 (4) ◽  
pp. 1049
Author(s):  
Yahya Ahmed Alamri ◽  
Nik Rumzi Nik Idris ◽  
Ibrahim Mohd. Alsofyani ◽  
Tole Sutikno
Keyword(s):  
Induction Motor ◽  
Cutoff Frequency ◽  
Direct Torque Control ◽  
Motor Drives ◽  
Torque Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Flux Estimation ◽  
Stator Flux

<p>Stator flux estimation using voltage model is basically the integration of the induced stator back electromotive force (emf) signal. In practical implementation the pure integration is replaced by a low pass filter to avoid the DC drift and saturation problems at the integrator output because of the initial condition error and the inevitable DC components in the back emf signal. However, the low pass filter introduces errors in the estimated stator flux which are significant at frequencies near or lower than the cutoff frequency. Also the DC components in the back emf signal are amplified at the low pass filter output by a factor equals to . Therefore, different integration algorithms have been proposed to improve the stator flux estimation at steady state and transient conditions. In this paper a new algorithm for stator flux estimation is proposed for direct torque control (DTC) of induction motor drives. The proposed algorithm is composed of a second order high pass filter and an integrator which can effectively eliminates the effect of the error initial condition and the DC components. The amplitude and phase errors compensation algorithm is selected such that the steady state frequency response amplitude and phase angle are equivalent to that of the pure integrator and the multiplication and division by stator frequency are avoided. Also the cutoff frequency selection is improved; even small value can filter out the DC components in the back emf signal. The simulation results show the improved performance of the induction motor direct torque control drive with the proposed stator flux estimation algorithm. The simulation results are verified by the experimental results.</p>

scholarly journals A CMOS Low Pass Filter for SoC Lock-in-Based Measurement Devices

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5173 ◽  
Author(s):  
Jorge Pérez-Bailón ◽  
Belén Calvo ◽  
Nicolás Medrano
Keyword(s):  
Dynamic Range ◽  
Current Trend ◽  
Cutoff Frequency ◽  
Oxide Semiconductor ◽  
Constant Current ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Compact Size ◽  
Low Pass ◽  
Lock In

This paper presents a fully integrated Gm–C low pass filter (LPF) based on a current steering Gm reduction-tuning technique, specifically designed to operate as the output stage of a SoC lock-in amplifier. To validate this proposal, a first-order and a second-order single-ended topology were integrated into a 1.8 V to 0.18 µm CMOS (Complementary Metal-Oxide-Semiconductor) process, showing experimentally a tuneable cutoff frequency that spanned five orders of magnitude, from tens of mHz to kHz, with a constant current consumption (below 3 µA/pole), compact size (<0.0140 mm2/pole), and a dynamic range better than 70 dB. Compared to state-of-the-art solutions, the proposed approach exhibited very competitive performances while simultaneously fully satisfying the demanding requirements of on-chip portable measurement systems in terms of highly efficient area and power. This is of special relevance, taking into account the current trend towards multichannel instruments to process sensor arrays, as the total area and power consumption will be proportional to the number of channels.

The Design of Gm-C Low-Pass Filter for Micromachined Gyroscope

2014 ◽  
Vol 609-610 ◽  
pp. 1072-1076
Author(s):  
Qiu Ye Lv ◽  
Chong He ◽  
Wen Jie Fan ◽  
Yu Feng Zhang ◽  
Xiao Wei Liu
Keyword(s):  
Process Model ◽  
Stop Band ◽  
Cutoff Frequency ◽  
Harmonic Distortion ◽  
Cmos Process ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Simulation Results ◽  
Micromachined Gyroscope

In this Paper, a 4th-Order Low-Pass Gm-C Filter is Presented. for the Design of Operational Tranconductance Amplifier(OTA), it Adopts the Techniques of Current Division and Current Cancellation. these Techniques can Help to Achieve a Low Transconductance Value. for the Architecture of the 4th-Order Gm-C Filter, it Consists of Two Biquads. the Two Biquads are Cascade Connected. the Gm-C Low-Pass Filter has been Implemented under 0.5 μm CMOS Process Model. the Final Simulation Results Show the Cutoff Frequency of the Filter is 100Hz and the Stop-Band Attenuation is Larger than 60dB. the Power Consumption is Lower than 1mW and the Total Harmonic Distortion(THD) is -55dB.

The Method on Acceleration Extraction from Strapdown Airborne Scalar Gravimeter Based on Flight Dynamics

2012 ◽  
Vol 591-593 ◽  
pp. 2152-2156 ◽  
Author(s):  
Shao Kun Cai ◽  
Kai Dong Zhang ◽  
Mei Ping Wu ◽  
Yang Ming Huang
Keyword(s):  
Measurement Errors ◽  
Cutoff Frequency ◽  
Flight Dynamics ◽  
Error Model ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

Combining with the error model of strapdown airborne scalar gravimetry, the paper analyses the natural motions of the aircraft, and then discusses how those natural motions of the aircraft influence the airborne scalar gravimetry. The spectra characteristic of measurement errors of the strapdown airborne scalar gravimetry can be obtained, and its relation with natural motions of the aircraft is demonstrated. As a result, we can determine the cutoff frequency of low-pass filter through the characteristic of the natural motions of the aircraft, the cutoff frequency is very important for acceleration extraction from the strapdown airborne scalar gravimeter.

Evaluation of Predicted Knee Joint Muscle Forces During Gait Using an Instrumented Knee Implant

2008 ◽  
Author(s):  
Justin W. Fernandez ◽  
Hyung J. Kim ◽  
Massoud Akbarshahi ◽  
Jonathan P. Walter ◽  
Benjamin J. Fregly ◽  
...  
Keyword(s):  
Contact Forces ◽  
In Vivo Studies ◽  
Muscle Forces ◽  
Model Calculations ◽  
Musculoskeletal Models ◽  
Model Predictions ◽  
Joint Contact ◽  
Knee Muscle

Many studies have used musculoskeletal models to predict in vivo muscle forces at the knee during gait [1, 2]. Unfortunately, quantitative assessment of the model calculations is often impracticable. Various indirect methods have been used to evaluate the accuracy of model predictions, including comparisons against measurements of muscle activity, joint kinematics, ground reaction forces, and joint moments. In a recent study, an instrumented hip implant was used to validate calculations of hip contact forces directly [3]. The same model was subsequently used to validate model calculations of tibiofemoral loading during gait [4]. Instrumented knee implants have also been used in in vitro and in vivo studies to quantify differences in biomechanical performance between various TKR designs [5, 6]. The main aim of the present study was to evaluate model predictions of knee muscle forces by direct comparison with measurements obtained from an instrumented knee implant. Calculations of muscle and joint-contact loading were performed for level walking at slow, normal, and fast speeds.

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