scholarly journals Assessment of Real-Time Compaction Quality Test Indexes for Rockfill Material Based on Roller Vibratory Acceleration Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Tianbo Hua ◽  
Xingguo Yang ◽  
Qiang Yao ◽  
Hongtao Li
Keyword(s):  
Real Time ◽  
Rolling Process ◽  
Statistical Regression ◽  
Acceleration Signal ◽  
Rockfill Material ◽  
Field Compaction ◽  
Vibratory Acceleration ◽  
Time Test ◽  
Acceleration Analysis ◽  
Compaction Degree

Compaction quality is directly related to the structure and seepage stability of a rockfill dam. To timely and accurately test the compaction quality of the rockfill material, four real-time test indexes were chosen to characterize the soil compaction degree based on the analysis of roller vibratory acceleration, including acceleration peak value (ap), acceleration root mean square value (arms), crest factor value (CF), and compaction meter value (CMV). To determine which of these indexes is the most appropriate, a two-part field compaction experiment was conducted using a vibratory roller in different filling zones of the dam body. Data on rolling parameters, real-time test indexes, and compaction quality indexes were collected to perform statistical regression analyses. Combined with the spectrum analysis of the acceleration signal, it was found that the CF index best characterizes the compaction degree of the rockfill material among the four indexes. Furthermore, the quantitative relations between the real-time index and compaction quality index were established to determine the control criterion of CF, which can instruct the site work of compaction quality control in the rockfill rolling process.

scholarly journals Optimization of Physical Activity Recognition for Real-Time Wearable Systems: Effect of Window Length, Sampling Frequency and Number of Features

2019 ◽  
Vol 9 (22) ◽  
pp. 4833 ◽  
Author(s):  
Ardo Allik ◽  
Kristjan Pilt ◽  
Deniss Karai ◽  
Ivo Fridolin ◽  
Mairo Leier ◽  
...  
Keyword(s):  
Physical Activity ◽  
Feature Selection ◽  
Real Time ◽  
Sampling Frequency ◽  
Classification Performance ◽  
Window Length ◽  
Decision Tree Classifier ◽  
Acceleration Signal ◽  
Wearable Systems ◽  
Tree Classifier

The aim of this study was to develop an optimized physical activity classifier for real-time wearable systems with the focus on reducing the requirements on device power consumption and memory buffer. Classification parameters evaluated in this study were the sampling frequency of the acceleration signal, window length of the classification fragment, and the number of classification features, found with different feature selection methods. For parameter evaluation, a decision tree classifier was created based on the acceleration signals recorded during tests, where 25 healthy test subjects performed various physical activities. Overall average F1-score achieved in this study was about 0.90. Similar F1-scores were achieved with the evaluated window lengths of 5 s (0.92 ± 0.02) and 3 s (0.91 ± 0.02), while classification performance with 1 s were lower (0.87 ± 0.02). Tested sampling frequencies of 50 Hz, 25 Hz, and 13 Hz had similar results with most classified activity types, with an exception of outdoor cycling, where differences were significant. Using forward sequential feature selection enabled the decreasing of the number of features from initial 110 features to about 12 features without lowering the classification performance. The results of this study have been used for developing more efficient real-time physical activity classifiers.

Research on the Construction Technology of Self-Monitoring Asphalt Concrete

2021 ◽  
Vol 891 ◽  
pp. 205-210
Author(s):  
Yuan Xu
Keyword(s):  
Asphalt Concrete ◽  
Test Section ◽  
Rolling Process ◽  
Construction Technology ◽  
Self Monitoring ◽  
Mixing Effect ◽  
Steel Wheel ◽  
Mixing Method ◽  
Pavement Construction ◽  
Compaction Degree

Combined with the paving of the test section of Self-monitoring Asphalt Concrete, the electrode burying mode of pavement construction is designed according to its characteristics, and the best mixing method and spreading rolling construction technology are compared and analyzed. The results show that the construction structure of the test section is reasonable and feasible, the best mixing effect can be obtained by adding conductive phase material and asphalt at the same time, and the rolling process. The order of rubber wheel and steel wheel compaction has no significant effect on compaction degree.

scholarly journals Real-Time Human in the Loop MBS Simulation in the Fraunhofer Robot-Based Driving Simulator

2014 ◽  
Vol 61 (2) ◽  
pp. 270-285 ◽  
Author(s):  
Michael Kleer ◽  
Andrey Gizatullin ◽  
Klaus Dreßler ◽  
Steffen Müller
Keyword(s):  
Real Time ◽  
Driving Simulator ◽  
Practical Significance ◽  
Time Model ◽  
Test Drive ◽  
The Real ◽  
Transport Delay ◽  
Human In The Loop ◽  
Acceleration Signal ◽  
Time Calculation

Abstract The paper encompasses the overview of hardware architecture and the systems characteristics of the Fraunhofer driving simulator. First, the requirements of the real-time model and the real-time calculation hardware are defined and discussed in detail. Aspects like transport delay and the parallel computation of complex real-time models are presented. In addition, the interfacing of the models with the simulator system is shown. Two simulator driving tests, including a fully interactive rough terrain driving with a wheeled excavator and a test drive with a passenger car, are set to demonstrate system characteristics. Furthermore, the simulator characteristics of practical significance, such as simulator response time delay, simulator acceleration signal bandwidth obtained from artificial excitation and from the simulator driving test, will be presented and discussed.

Prediction of Knee Joint Contact Forces From External Measures Using Principal Component Prediction and Reconstruction

2018 ◽  
Vol 34 (5) ◽  
pp. 419-423 ◽  
Author(s):  
Christopher M. Saliba ◽  
Allison L. Clouthier ◽  
Scott C.E. Brandon ◽  
Michael J. Rainbow ◽  
Kevin J. Deluzio
Keyword(s):  
Knee Joint ◽  
Knee Osteoarthritis ◽  
Real Time ◽  
Contact Force ◽  
Haptic Feedback ◽  
Principal Component ◽  
Contact Forces ◽  
Statistical Regression ◽  
Joint Contact Force ◽  
Joint Contact

Abnormal loading of the knee joint contributes to the pathogenesis of knee osteoarthritis. Gait retraining is a noninvasive intervention that aims to reduce knee loads by providing audible, visual, or haptic feedback of gait parameters. The computational expense of joint contact force prediction has limited real-time feedback to surrogate measures of the contact force, such as the knee adduction moment. We developed a method to predict knee joint contact forces using motion analysis and a statistical regression model that can be implemented in near real-time. Gait waveform variables were deconstructed using principal component analysis, and a linear regression was used to predict the principal component scores of the contact force waveforms. Knee joint contact force waveforms were reconstructed using the predicted scores. We tested our method using a heterogenous population of asymptomatic controls and subjects with knee osteoarthritis. The reconstructed contact force waveforms had mean (SD) root mean square differences of 0.17 (0.05) bodyweight compared with the contact forces predicted by a musculoskeletal model. Our method successfully predicted subject-specific shape features of contact force waveforms and is a potentially powerful tool in biofeedback and clinical gait analysis.

scholarly journals Design and real-time test of a hybrid energy storage system in the microgrid with the benefit of improving the battery lifetime

2018 ◽  
Vol 218 ◽  
pp. 470-478 ◽  
Author(s):  
Jianwei Li ◽  
Rui Xiong ◽  
Hao Mu ◽  
Bertrand Cornélusse ◽  
Philippe Vanderbemden ◽  
...  
Keyword(s):  
Energy Storage ◽  
Real Time ◽  
Storage System ◽  
Energy Storage System ◽  
Battery Lifetime ◽  
Hybrid Energy ◽  
Hybrid Energy Storage ◽  
Hybrid Energy Storage System ◽  
Time Test

VIBRATORY ACTIVITY INVESTIGATION OF GRINDING MACHINE ELECTRIC SPINDLES

2021 ◽  
Vol 2021 (6) ◽  
pp. 23-29
Author(s):  
Erik Gasparov ◽  
Lana Gasparova ◽  
Gevorg Markosyan
Keyword(s):  
Spectrum Analysis ◽  
Dynamic Properties ◽  
Harmonic Oscillation ◽  
Rotation Frequency ◽  
Linear Increase ◽  
Acceleration Signal ◽  
Spindle Unit ◽  
Spindle Rotation ◽  
Vibratory Acceleration ◽  
The Impact

The purpose of this work is to support dynamic properties of spindle units in grinding machines. For this there are problems under solution for the definition of the origin of the constituents in the spindle unit vibratory activity by means of the linear increase of electric spindle rotation frequency, obtaining and analyzing a vibratory acceleration signal for the possibility to determine a preload. The vibratory acceleration signal was investigated through a spectrum analysis method. A scientific novelty of investigation consists in the substantiation of possibility to determine a preload by means of the spectrum analysis of a vibration acceleration signal at the linear increase of spindle rotation frequency that is at starting. It gives, in its turn, a possibility for the automated estimate of the spindle unit state before cutting beginning. In the experimental way there are obtained temporal realizations of the vibratory acceleration signal at different efforts of the preload. A high-speed grinding motor-spindle is as a basic element of the bench, which was investigated through the methods of testing diagnostics in the operation. In the bench design there were made some alterations. The bench was supplemented with the systems essential to support motor-spindle full operation, in particular: with systems of lubrication, cooling and drive control. There was revealed a large number of harmonics multiple to 50 Hz, which tells of the connection with the frequency of power supply circuit. Their coincidence with the own frequencies of the spindle unit results in the considerable increase of their amplitudes. To increase dynamic quality one should avoid the cases of the coincidence of switching frequencies and circuit harmonics with own frequencies of the electric spindle. It is also necessary to bring a form of power voltage to a pure harmonic oscillation to decrease the impact of a drive electromagnetic field upon dynamic characteristics of the spindle unit.

Velocity Estimation of Embedded Mobile Robot in Structured Man-Made Environments

2014 ◽  
Vol 592-594 ◽  
pp. 2215-2219
Author(s):  
D. Elayaraja ◽  
R. Ramesh ◽  
S. Ramabalan
Keyword(s):  
Mobile Robot ◽  
Real Time ◽  
Velocity Estimation ◽  
Road Surface ◽  
Test Environment ◽  
The Real ◽  
Logic Control ◽  
Road Surfaces ◽  
Surface Sand ◽  
Time Test

It is proposed to determine the velocity of the embedded mobile robot in a real world test environment .The test environment considered in this work is the man-made road surfaces like cement road surface, sand road surface, Bituminous Thar road surface, Grass road surface and loose gravel road surfaces etc. First, fuzzy logic control of velocity estimation a mobile robot is done using Matlab for the different surfaces. Then the real time tests on the different surfaces were carried out. The simulated values are compared with the test values. The comparison showed that the simulation values were close to the real time test values.

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