Design of torque-compensated mechanical systems with two connected identical slider-crank mechanisms

2021 ◽  
pp. 1-16
Author(s):  
Vigen Arakelian
Keyword(s):  
Root Mean Square ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Effective Means ◽  
Point Of View ◽  
Mean Square ◽  
Suggested Approach ◽  
Input Shaft ◽  
Acceleration And Deceleration ◽  
Input Torque

Abstract Balancing the torque of mechanisms designed to minimize the fluctuation of input shaft torque is an effective means of improving their dynamic performance. There are several ways of solving the problem: optimizing the distribution of the moving mass of the original mechanism; cam sub-systems that displace the balancing mass; cam-spring mechanisms; flywheels driven by non-circular gears; adding articulated dyads, linkages or redundant drivers. This paper addresses the problem of input torque compensation with the optimal connection of two identical slider-crank mechanisms. The acceleration and deceleration phases of the links of the slide-crank mechanism obviously change periodically, causing torque to fluctuate at the input shaft. This is done by minimizing the root-mean-square value of the input torque of the combined linkages. Two schemes are considered: slider-crank mechanisms with sliders moving on the same side, and on opposite sides. The prime value of this study is that it proposes an analytically tractable solution for identifying the general dynamic properties of mechanisms. Based on the ratio of link lengths, the precise relations for optimal connection of identical slider-crank mechanisms, i.e. a connection that produces the minimum root-mean-square values of the input torque, are developed. The numerical simulations illustrate the efficiency of the suggested approach. Observations show that the best solutions from the point of view of input torque minimization are obtained for the value of the coupling angle of two mechanisms around 90°.

Achievable accuracy of an azimuth obtained at short range with use of GPS and geodetic instruments

2018 ◽  
Vol 936 (6) ◽  
pp. 2-8 ◽  
Author(s):  
A.V. Sholokhov ◽  
N.I. Kotov ◽  
S.B. Berkovich ◽  
A.Y. Makhaev
Keyword(s):  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
A Priori ◽  
Measurement Data ◽  
Point Of View ◽  
Reference Points ◽  
Mean Square ◽  
Original Algorithm ◽  
Optimal Estimates

The problem of finding optimal estimates of the azimuth using the GPS coordinates is considered. The azimuth accuracy is improved through using additional measurement data of distances between reference points. It is also possible to use the measurement data of the angles between the directions to the reference points. An original algorithm for obtaining optimal estimates of azimuths is suggested. The algorithm enables to find a priori a root mean square error of the azimuth. The accuracy of the GPS coordinates, measuring distances and angles is supposed to be known. Using the algorithm, calculating azimuth accuracy was performed and the analysis of two approaches to the reference points’ location carried out. The first approach supposes the minimum number of reference points with a given precision of the azimuth. The second one is characterized by the minimum sizes of the polygon, which are the reference points. Both approaches were considered from the point of view of achieving high accuracy of finding the azimuth. As a result the possibility of finding the azimuth with root mean square error of about 1? is confirmed, when the distance between reference points is less than 400 m.

scholarly journals THE DYNAMIC PERFORMANCE ANALYSIS OF THE FOIL BEARING STRUCTURE

2013 ◽  
Vol 7 (1) ◽  
pp. 58-62 ◽  
Author(s):  
Grzegorz Żywica
Keyword(s):  
Numerical Model ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Simulation Models ◽  
Point Of View ◽  
Experimental Point ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Supporting Layer ◽  
Dynamic Performance Analysis

Abstract Foil bearings are a variety of slide bearings in which an additional set of foils is applied between journal and bush, in order to improve the selected static and dynamic properties. Engineers and researchers from all over the world investigate bearings of this type since many years - both from numerical as well as experimental point of view. Due to the complexity of construction, the reliable simulation models are all the time being searched for. This paper discusses the important stages of elaboration of the structural supporting layer numerical model of the foil bearing as well as results of verification tests. The main goal of the conducted study was assessment of reliability of the elaborated numerical model, in scope of dynamic properties. In the near future it will be used for elaboration of the numerical model of the entire foil bearing, which will take into account also phenomena in fluid-film layer. Those models will be used together to describe bearing system in operation.

The Relationship of Root Mean Square Value of Electromyography and Isometric Torque of Quadriceps in Normal Subjects

2016 ◽  
Vol 26 (1) ◽  
pp. 58
Author(s):  
Qiurong XIE ◽  
Zheng JIANG ◽  
Qinglu LUO ◽  
Jie LIANG ◽  
Xiaoling WANG ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Normal Subjects ◽  
Mean Square ◽  
Isometric Torque ◽  
Relationship Of ◽  
The Relationship

scholarly journals Estimation of Apple Flowering Frost Loss for Fruit Yield Based on Gridded Meteorological and Remote Sensing Data in Luochuan, Shaanxi Province, China

2021 ◽  
Vol 13 (9) ◽  
pp. 1630
Author(s):  
Yaohui Zhu ◽  
Guijun Yang ◽  
Hao Yang ◽  
Fa Zhao ◽  
Shaoyu Han ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Minimum Temperature ◽  
Price Regulation ◽  
Flowering Period ◽  
Mean Square ◽  
Prevention Measures ◽  
Agricultural Insurance

With the increase in the frequency of extreme weather events in recent years, apple growing areas in the Loess Plateau frequently encounter frost during flowering. Accurately assessing the frost loss in orchards during the flowering period is of great significance for optimizing disaster prevention measures, market apple price regulation, agricultural insurance, and government subsidy programs. The previous research on orchard frost disasters is mainly focused on early risk warning. Therefore, to effectively quantify orchard frost loss, this paper proposes a frost loss assessment model constructed using meteorological and remote sensing information and applies this model to the regional-scale assessment of orchard fruit loss after frost. As an example, this article examines a frost event that occurred during the apple flowering period in Luochuan County, Northwestern China, on 17 April 2020. A multivariable linear regression (MLR) model was constructed based on the orchard planting years, the number of flowering days, and the chill accumulation before frost, as well as the minimum temperature and daily temperature difference on the day of frost. Then, the model simulation accuracy was verified using the leave-one-out cross-validation (LOOCV) method, and the coefficient of determination (R2), the root mean square error (RMSE), and the normalized root mean square error (NRMSE) were 0.69, 18.76%, and 18.76%, respectively. Additionally, the extended Fourier amplitude sensitivity test (EFAST) method was used for the sensitivity analysis of the model parameters. The results show that the simulated apple orchard fruit number reduction ratio is highly sensitive to the minimum temperature on the day of frost, and the chill accumulation and planting years before the frost, with sensitivity values of ≥0.74, ≥0.25, and ≥0.15, respectively. This research can not only assist governments in optimizing traditional orchard frost prevention measures and market price regulation but can also provide a reference for agricultural insurance companies to formulate plans for compensation after frost.

scholarly journals Histamine Control in Raw and Processed Tuna: A Rapid Tool Based on NIR Spectroscopy

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 885
Author(s):  
Sergio Ghidini ◽  
Luca Maria Chiesa ◽  
Sara Panseri ◽  
Maria Olga Varrà ◽  
Adriana Ianieri ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Partial Least Square ◽  
Least Square ◽  
Partial Least Square Regression ◽  
Coefficient Of Determination ◽  
Mean Square ◽  
Tuna Fish ◽  
Mean Square Errors

The present study was designed to investigate whether near infrared (NIR) spectroscopy with minimal sample processing could be a suitable technique to rapidly measure histamine levels in raw and processed tuna fish. Calibration models based on orthogonal partial least square regression (OPLSR) were built to predict histamine in the range 10–1000 mg kg−1 using the 1000–2500 nm NIR spectra of artificially-contaminated fish. The two models were then validated using a new set of naturally contaminated samples in which histamine content was determined by conventional high-performance liquid chromatography (HPLC) analysis. As for calibration results, coefficient of determination (r2) > 0.98, root mean square of estimation (RMSEE) ≤ 5 mg kg−1 and root mean square of cross-validation (RMSECV) ≤ 6 mg kg−1 were achieved. Both models were optimal also in the validation stage, showing r2 values > 0.97, root mean square errors of prediction (RMSEP) ≤ 10 mg kg−1 and relative range error (RER) ≥ 25, with better results showed by the model for processed fish. The promising results achieved suggest NIR spectroscopy as an implemental analytical solution in fish industries and markets to effectively determine histamine amounts.

Intersession reliability of GPS-based and accelerometer-based physical variables in small-sided games with and without the offside rule

2021 ◽  
pp. 175433712098764
Author(s):  
Igor Junio de Oliveira Custódio ◽  
Gibson Moreira Praça ◽  
Leandro Vinhas de Paula ◽  
Sarah da Glória Teles Bredt ◽  
Fabio Yuzo Nakamura ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Global Positioning System ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Mean Square ◽  
Physical Demands ◽  
Intraclass Correlation Coefficients ◽  
Total Distance ◽  
Global Positioning ◽  
High Level

This study aimed to analyze the intersession reliability of global positioning system (GPS-based) distances and accelerometer-based (acceleration) variables in small-sided soccer games (SSG) with and without the offside rule, as well as compare variables between the tasks. Twenty-four high-level U-17 soccer athletes played 3 versus 3 (plus goalkeepers) SSG in two formats (with and without the offside rule). SSG were performed on eight consecutive weeks (4 weeks for each group), twice a week. The physical demands were recorded using a GPS with an embedded triaxial accelerometer. GPS-based variables (total distance, average speed, and distances covered at different speeds) and accelerometer-based variables (Player Load™, root mean square of the acceleration recorded in each movement axis, and the root mean square of resultant acceleration) were calculated. Results showed that the inclusion of the offside rule reduced the total distance covered (large effect) and the distances covered at moderate speed zones (7–12.9 km/h – moderate effect; 13–17.9 km/h – large effect). In both SSG formats, GPS-based variables presented good to excellent reliability (intraclass correlation coefficients – ICC > 0.62) and accelerometer-based variables presented excellent reliability (ICC values > 0.89). Based on the results of this study, the offside rule decreases the physical demand of 3 versus 3 SSG and the physical demands required in these SSG present high intersession reliability.

scholarly journals GNINA 1.0: molecular docking with deep learning

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Andrew T. McNutt ◽  
Paul Francoeur ◽  
Rishal Aggarwal ◽  
Tomohide Masuda ◽  
Rocco Meli ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Root Mean Square ◽  
Root Mean Square Deviation ◽  
Computational Cost ◽  
Scoring Function ◽  
Binding Pocket ◽  
Protein Docking ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Autodock Vina

AbstractMolecular docking computationally predicts the conformation of a small molecule when binding to a receptor. Scoring functions are a vital piece of any molecular docking pipeline as they determine the fitness of sampled poses. Here we describe and evaluate the 1.0 release of the Gnina docking software, which utilizes an ensemble of convolutional neural networks (CNNs) as a scoring function. We also explore an array of parameter values for Gnina 1.0 to optimize docking performance and computational cost. Docking performance, as evaluated by the percentage of targets where the top pose is better than 2Å root mean square deviation (Top1), is compared to AutoDock Vina scoring when utilizing explicitly defined binding pockets or whole protein docking. Gnina, utilizing a CNN scoring function to rescore the output poses, outperforms AutoDock Vina scoring on redocking and cross-docking tasks when the binding pocket is defined (Top1 increases from 58% to 73% and from 27% to 37%, respectively) and when the whole protein defines the binding pocket (Top1 increases from 31% to 38% and from 12% to 16%, respectively). The derived ensemble of CNNs generalizes to unseen proteins and ligands and produces scores that correlate well with the root mean square deviation to the known binding pose. We provide the 1.0 version of Gnina under an open source license for use as a molecular docking tool at https://github.com/gnina/gnina.

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