Effects of interval friction coefficients on the differential mechanism dynamics

2022 ◽  
pp. 095440702110689
Author(s):  
Wassim Lafi ◽  
Fathi Gharbi ◽  
Ali Akrout ◽  
Mohamed Haddar
Keyword(s):  
Friction Coefficient ◽  
Sliding Friction ◽  
Dynamic Performance ◽  
Mathematical Formulation ◽  
Reference Method ◽  
Least Square Method ◽  
Least Square ◽  
Mesh Stiffness ◽  
Scanning Method ◽  
Differential Mechanism

The presence of a differential mechanism is fundamental in most automotive applications. Its importance stems from allowing a vehicle to take a curve. The differential should be well-lubricated to ensure its smooth operation and mitigate its vibration level. With lubrication conditions deteriorating over time, the sliding friction coefficient becomes difficult to predict its accurate value. Thus, scrutinizing the dynamic performance of the mechanism with deterministic sliding friction can be misleading. This paper aims to investigate the dynamic performance of the automotive differential with the presence of interval sliding friction. To this end, a 3D dimensional model of automotive differential with time-varying mesh stiffness (TVMS) and bearing flexibility is proposed. The influence of sliding friction on TVMS for straight bevel gear is revealed. The Newton-Euler formulation is used to derive the dynamic equations governing the motions of the automotive differential with friction. The Chebyshev inclusion function and the least square method are used to deal with the interval mathematical formulation of the model. The scanning method is used as a reference method in this paper. There are quite similarities between the results derived by the scanning method and that of the interval process method. The reliability analysis of the differential is conducted. The outcome of this research shows that any variation of the sliding friction can alter the dynamic performance of the differential significantly. The differential is more sensitive to the friction coefficient between the ring gear and the drive pinion and between the left-side gear and two planets. The findings should make an important contribution to the analysis of the differential mechanism.

Effects of the interval geometric deviation and crowning parameters on the automotive differential dynamics

2021 ◽  
pp. 146441932110394
Author(s):  
Wassim Lafi ◽  
Fathi Djemal ◽  
Ali Akrout ◽  
Lassaad Walha ◽  
Mohamed Haddar
Keyword(s):  
Gear Tooth ◽  
Dynamic Performance ◽  
Gear System ◽  
Time Step ◽  
Scanning Method ◽  
Wheel Drive ◽  
Applied Torque ◽  
Differential Mechanism ◽  
Geometric Deviation ◽  
Potential Energy Method

A differential mechanism is an essential component in the majority of automotive applications. Its vitality stems from the fact that it allows a wheel-drive vehicle to take a curve safely. On the other hand, it can ratchet up the vibration in the wheel-drive vehicle due to the excessive gear tooth deflection from applied torque. Some gear tooth modifications can increase or decrease the level of vibration in the mechanism. So far, very little attention has been paid to the effects of the uncertain geometric deviation of the tooth profile and uncertain crowning parameters on the dynamic performance of the mechanism. This study aims to investigate the impacts of these uncertain parameters on the gear systems’ dynamic performance. To this end, the nonlinear interval model of the differential mechanism is proposed. The mesh stiffness for straight bevel gear is modelled through the potential energy method and slice theory, while bearing stiffness elements are calculated at each time step. A refined computational algorithm is proposed to deal with any gear system with multiple interval variables. The scanning method is used as a reference method in this paper. The main outcomes of this study are that the crowning design can slightly reduce the vibration in the mechanism, and the profile errors can increase its vibration level excessively. Besides, the results derived from the refined algorithm show similarities to those determined by the scanning method, and the study shows that the refined algorithm can handle any gear system with uncertain static or time-varying parameters.

scholarly journals Friction Characteristics of Post-Tensioned Tendons of Full-Scale Structures Based on Site Tests

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Haoyun Yuan ◽  
Yuan Li ◽  
Bin Zhou ◽  
Shuanhai He ◽  
Peizhi Wang
Keyword(s):  
Friction Coefficient ◽  
Quantile Regression ◽  
Least Square Method ◽  
Regression Method ◽  
Full Scale ◽  
Least Square ◽  
Friction Characteristics ◽  
Bayesian Quantile Regression ◽  
Prestressing Force ◽  
Quantile Regression Method

In the design of prestressing concrete structures, the friction characteristics between strands and channels have an important influence on the distribution of prestressing force, which can be considered comprehensively by curvature and swing friction coefficients. However, the proposed friction coefficient varies widely and may lead to an inaccurate prestress estimation. In this study, four full-scale field specimens were established to measure the friction loss of prestressing tendons with electromagnetic sensors and anchor cable dynamometers to evaluate the friction coefficient. The least square method and Bayesian quantile regression method were adopted to calculate the friction coefficient, and the results were compared with that in the specifications. Field test results showed that Bayesian quantile regression method was more effective and significant in the estimation of the friction coefficient.

Investigation on adaptive method of torque characteristic in dual clutch transmission during launch phase

2020 ◽  
Vol 234 (3) ◽  
pp. 568-584
Author(s):  
Hongtao Hao ◽  
Tongli Lu ◽  
Jianwu Zhang ◽  
Wenjie Ding
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Sliding Friction ◽  
Least Square Method ◽  
Adaptive Method ◽  
Least Square ◽  
Dual Clutch Transmission ◽  
Engine Torque ◽  
Simulation And Experiment ◽  
Application Potential

To reduce sliding friction work and clutch judder, an adaptive method of torque characteristic in dual clutch transmission during launch phase is presented in this paper. The proposed approach provides a tool to identify the change of torque characteristic and adapt it in real time. Firstly, to reduce the influence of the error between the nominal engine torque and the actual engine torque, the estimator based on the extended Kalman filter is designed to estimate the transmitted torque of the dual-clutch transmission during launch phase. Furthermore, the torque characteristic adaptive method is presented by a combination of the estimator with the improved Least Square Method. Then, based on the established driveline model of the dual-clutch transmission, the torque characteristic adaptive method during launch phase is validated by MATLAB/Simulink. Finally, in order to further evaluate the application potential of the adaptive method, the experiments are conducted on a production vehicle equipped with the wet dual-clutch transmission. The simulation and experiment results show that the proposed algorithms work well.

Simulation and Research for Gas Boiler Based on the Vague Set PID

2014 ◽  
Vol 556-562 ◽  
pp. 2101-2104
Author(s):  
Gang Zhao ◽  
Jian Li
Keyword(s):  
Dynamic Performance ◽  
Least Square Method ◽  
Equation Model ◽  
Hot Water ◽  
Least Square ◽  
Vague Set ◽  
Pid Algorithm ◽  
Static Performance ◽  
Self Tuning ◽  
The Difference

Gas hot water boiler is widely used as heating equipment in everyday life. Because gas hot water boiler has the characteristics of nonlinear, large inertia and disturbances, so it is particularly important to build a precise mathematical model. Then the difference equation model of the system is identified by the least square method according to the collected data in this paper. Writing M file in the MATLAB software to get the continuous transfer function, and setting up Vague Set PID simulation, fuzzy self-tuning PID simulation and conventional PID algorithm in SIMULINK. By comparing among the three kinds of adjusting method, We get that Vague Set PID not only in regulation time, overshoot and effect of dynamic performance is superior compared the other two controller models , but also enhance the robustness and adaptability of the system, has a good dynamic, static performance..

Modeling and compensation control of asymmetric hysteresis in a pneumatic artificial muscle

2017 ◽  
Vol 28 (19) ◽  
pp. 2769-2780 ◽  
Author(s):  
Lina Hao ◽  
Hui Yang ◽  
Zhiyong Sun ◽  
Chaoqun Xiang ◽  
Bangcan Xue
Keyword(s):  
Dynamic Performance ◽  
Artificial Muscle ◽  
Least Square Method ◽  
Least Square ◽  
Model Parameters ◽  
Pneumatic Artificial Muscle ◽  
Proportional Integral Derivative ◽  
Proportional Integral Derivative Controller ◽  
Proportional Integral ◽  
Control Precision

Pneumatic artificial muscle is a novel compliance actuator, and it has many excellent actuator characteristics, such as high power density, safety, and compliance. However, it also has strong nonlinear and asymmetric hysteresis, which makes the accurate trajectory control for a pneumatic artificial muscle very difficult. In this article, the pressure/length hysteresis of a pneumatic artificial muscle was analyzed via an isotonic test. And then, it was described using extended unparallel Prandtl–Ishlinskii model, and the model parameters were identified by an adaptive weight particle swarm optimization with a mutation portion algorithm. For the comparison, the classical Prandtl–Ishlinskii was also considered, and its parameters were identified by least square method. Based on the hysteresis model built by extended unparallel Prandtl–Ishlinskii model, an integral inverse compensator was proposed, and then a proportional–integral–derivative controller with the integral inverse compensator (integral inverse-proportional–integral–derivative) was designed. The simulations and experiments validated that the integral inverse-proportional–integral–derivative controller has good dynamic performance. Compared with conventional proportional–integral–derivative controller without a hysteresis compensator, the control precision of integral inverse-proportional–integral–derivative controller is improved by 43.86%.

Direct Assessment of Effective Renal Plasma Flow from Renoscintigraphy with a Gamma Camera and an On-Line Computer

1981 ◽  
Vol 20 (06) ◽  
pp. 274-278
Author(s):  
J. Liniecki ◽  
J. Bialobrzeski ◽  
Ewa Mlodkowska ◽  
M. J. Surma
Keyword(s):  
Count Rate ◽  
Renal Plasma Flow ◽  
Early Period ◽  
Least Square Method ◽  
Least Square ◽  
Uptake Coefficient ◽  
Positive Linear Correlation ◽  
On Line ◽  
Best Fit ◽  
Plasma Activity

A concept of a kidney uptake coefficient (UC) of 131I-o-hippurate was developed by analogy from the corresponding kidney clearance of blood plasma in the early period after injection of the hippurate. The UC for each kidney was defined as the count-rate over its ROI at a time shorter than the peak in the renoscintigraphic curve divided by the integral of the count-rate curve over the "blood"-ROI. A procedure for normalization of both curves against each other was also developed. The total kidney clearance of the hippurate was determined from the function of plasma activity concentration vs. time after a single injection; the determinations were made at 5, 10, 15, 20, 30, 45, 60, 75 and 90 min after intravenous administration of 131I-o-hippurate and the best-fit curve was obtained by means of the least-square method. When the UC was related to the absolute value of the clearance a positive linear correlation was found (r = 0.922, ρ > 0.99). Using this regression equation the clearance could be estimated in reverse from the uptake coefficient calculated solely on the basis of the renoscintigraphic curves without blood sampling. The errors of the estimate are compatible with the requirement of a fast appraisal of renal function for purposes of clinical diagknosis.

PENGARUH KNOWLEDGE MANAGEMENT, KOMPETENSI, MOTIVASI TERHADAP KINERJA KARYAWAN

2015 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Miftahol Arifin
Keyword(s):  
Knowledge Management ◽  
Linear Regression ◽  
Significant Influence ◽  
Employee Performance ◽  
Least Square Method ◽  
Least Square ◽  
Analysis Tool ◽  
Ordinary Least Square ◽  
Competence Motivation ◽  
Performance Analyze

The purpose of this research is to analyze the influence of knowledge management on employee performance, analyze the effect of competence on employee performance, analyze the influence of motivation on employee performance). In this study, samples taken are structural employees PT.centris Kingdom Taxi Yogyakarta. The analysis tool in this study using multiple linear regression with Ordinary Least Square method (OLS). The conclusion of this study showed that the variables of knowledge management has a significant influence on employee performance, competence variables have an influence on employee performance, motivation variables have an influence on employee performance, The analysis showed that the variables of knowledge management, competence, motivation on employee performance.Keywords: knowledge management, competence, motivation, employee performance.

An Application of the Least Square Method to the Ship Maneuverability Identification

1973 ◽  
Vol 1973 (134) ◽  
pp. 173-181
Author(s):  
Takeo Koyama ◽  
Takane Watanabe ◽  
Iwao Watanabe
Keyword(s):  
Least Square Method ◽  
Least Square ◽  
Ship Maneuverability

Peristaltic Carreau-Yasuda nanofluid flow and mixed heat transfer analysis in an asymmetric vertical and tapered wavy wall channel

2020 ◽  
Vol 1 (1) ◽  
pp. 128-140 ◽  
Author(s):  
Mohammad Hatami ◽  
◽  
D Jing ◽  
Keyword(s):  
Heat Transfer ◽  
Least Square Method ◽  
Weissenberg Number ◽  
Least Square ◽  
Heat Transfer Analysis ◽  
Phase Method ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Nanoparticles Concentration ◽  
The Right

In this study, two-phase asymmetric peristaltic Carreau-Yasuda nanofluid flow in a vertical and tapered wavy channel is demonstrated and the mixed heat transfer analysis is considered for it. For the modeling, two-phase method is considered to be able to study the nanoparticles concentration as a separate phase. Also it is assumed that peristaltic waves travel along X-axis at a constant speed, c. Furthermore, constant temperatures and constant nanoparticle concentrations are considered for both, left and right walls. This study aims at an analytical solution of the problem by means of least square method (LSM) using the Maple 15.0 mathematical software. Numerical outcomes will be compared. Finally, the effects of most important parameters (Weissenberg number, Prandtl number, Brownian motion parameter, thermophoresis parameter, local temperature and nanoparticle Grashof numbers) on the velocities, temperature and nanoparticles concentration functions are presented. As an important outcome, on the left side of the channel, increasing the Grashof numbers leads to a reduction in velocity profiles, while on the right side, it is the other way around.

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