scholarly journals Friction Characteristics of Synchronization Process Based on Tribo-Thermodynamics

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Hao Yan ◽  
Zhaoping Xu ◽  
Juntang Yuan ◽  
Liang Liu ◽  
Cao Tan ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Coupling Model ◽  
Maximum Temperature ◽  
Structural Coupling ◽  
Synchronization Process ◽  
Shift Quality ◽  
Compensation Control ◽  
Shift Control ◽  
Control Accuracy ◽  
Relevant Experiment

In order to improve the shift control accuracy and shift quality, the temperature and friction coefficient changing regularities of a friction cone during the synchronization process were investigated. The thermal-structural coupling model was established through tribo-thermodynamic analysis. The relevant experiment was carried out as well. The results show that the error between the experimental and simulated results is within 3%. Besides, the maximum temperature of the synchronous ring friction surface increases 1.8°C for every additional 50 N of shift force, while increases 1.1°C for every additional 200  r/min shift speed difference. Moreover, the friction coefficient declines rapidly first and then tends to be stable slowly during the synchronization process. The result of friction coefficient changing regularity lays a good theoretical basis for establishing an effective friction coefficient compensation control strategy.

scholarly journals Friction Coefficient Compensation Control in Synchronizer Synchronization Process for Transmission

2019 ◽  
Vol 9 (15) ◽  
pp. 3096 ◽  
Author(s):  
Hao Yan ◽  
Zhaoping Xu ◽  
Juntang Yuan ◽  
Meiyan Liu ◽  
Wenqing Ge
Keyword(s):  
Friction Coefficient ◽  
Sliding Friction ◽  
Control Method ◽  
Quantitative Relationship ◽  
Experimental Conditions ◽  
Synchronization Process ◽  
Shift Quality ◽  
Compensation Control ◽  
Simulation And Experiment ◽  
Synchronous Time

In the synchronization process of a synchronizer, the friction coefficient of the friction cone is changed because of friction heat. In this paper, the influence of a changing friction coefficient on shift quality was analyzed. The quantitative relationship between friction coefficient and its influencing factors was studied through a synchronizer synchronization process test bench. Based on the quantitative analysis and an optimal shift force control method, a compensation control strategy for friction coefficient was established. Moreover, the effectiveness of the compensation control was verified through simulation and experiment. The results showed that the friction coefficient was maintained near the expected value of 0.08 after the compensation control, the shifting speed difference the synchronous time was shortened by nearly 0.12 s, and the sliding friction was reduced by 4.64 J under the experimental conditions. The analysis and compensation of the friction coefficient provide a theoretical reference for improving shift quality.

scholarly journals Numerical and Experimental Study of Lightning Stroke to BIPV Modules

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 748
Author(s):  
Xiaoyan Bian ◽  
Yao Zhang ◽  
Qibin Zhou ◽  
Ting Cao ◽  
Bengang Wei
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Coupling Model ◽  
Maximum Temperature ◽  
Lightning Stroke ◽  
Study Results ◽  
Pv Modules ◽  
New Type ◽  
Metal Frame ◽  
Current Flows

Building Integrated Photovoltaic (BIPV) modules are a new type of photovoltaic (PV) modules that are widely used in distributed PV stations on the roof of buildings for power generation. Due to the high installation location, BIPV modules suffer from lightning hazard greatly. In order to evaluate the risk of lightning stroke and consequent damage to BIPV modules, the studies on the lightning attachment characteristics and the lightning energy withstand capability are conducted, respectively, based on numerical and experimental methods in this paper. In the study of lightning attachment characteristics, the numerical simulation results show that it is easier for the charges to concentrate on the upper edge of the BIPV metal frame. Therefore, the electric field strength at the upper edge is enhanced to emit upward leaders and attract the lightning downward leaders. The conclusion is verified through the long-gap discharge experiment in a high voltage lab. From the experimental study of multi-discharge in the lab, it is found that the lightning interception efficiency of the BIPV module is improved by 114% compared with the traditional PV modules. In the study of lightning energy withstand capability, a thermoelectric coupling model is established. With this model, the potential, current and temperature can be calculated in the multi-physical field numerical simulation. The results show that the maximum temperature of the metal frame increases by 16.07 °C when 100 kA lightning current flows through it and does not bring any damage to the PV modules. The numerical results have a good consistency with the experimental study results obtained from the 100 kA impulse current experiment in the lab.

Development of 2 Stage CVT Shift Control Algorithm to Reduce Torque Variation During 1-2 Upshift of Planetary Gear

2012 ◽  
Author(s):  
Jeongman Park ◽  
Sunghyun Ahn ◽  
Oheun Kwon ◽  
Youngho Jun ◽  
Minhyo Kim ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Shift Quality ◽  
Response Characteristics ◽  
Shift Control ◽  
Variable Transmission ◽  
Vehicle Simulator ◽  
Simulation Results ◽  
Fuzzy Control Algorithm

In this paper, a 2 stage continuously variable transmission (CVT) shift control algorithm is proposed for the 1–2 upshift of the planetary gear to achieve the shift quality. A fuzzy control algorithm is designed considering the relatively slower response characteristics of CVT. In order to evaluate the performance of the control algorithm, a 2 stage CVT vehicle simulator is developed including a dynamic model of the CVT powertrain. From the simulation results, it is found that CVT gear ratio changes faster in the inertia phase and remains constant after the inertia phase of the planetary gear shift, which provides the reduced torque variation by the proposed control algorithm.

Double-Clutch Power Shift Quality Optimization Based on Optimal Control Theory

2021 ◽  
Vol 37 (4) ◽  
pp. 677-689
Author(s):  
Guang Xia ◽  
Yueqiang Wang ◽  
Xiwen Tang ◽  
Linfeng Zhao ◽  
Jinfang Hu
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Control Strategy ◽  
Optimal Control Theory ◽  
Multiple Target ◽  
Shift Quality ◽  
Shift Control ◽  
Power Shift ◽  
Multiparameter Optimization ◽  
Differential Matrix

Highlights A power shift control strategy based on torque and speed transition, which aims to deliver multiple target and multiparameter optimization of power shift control, is proposed in this study. It can effectively solve the shift power cycle. Based on minimum optimal control theory, the optimal control of shift quality during power shifting optimizes clutch terminal oil pressure, which is determined by solving the Rebecca differential matrix equation and shift characteristics based on various stages. By aiming at the multiple target and multiparameter optimization problem of the clutch control in the power shift process, the minimum optimal control principle is applied to the shift quality optimization of the power shift. Based on the minimum optimal control theory, the optimal solution of the terminal oil pressure of the clutch is determined by solving the Rebecca differential matrix equation to improve the shift quality of the power shift process. Abstract . The dual clutch of the combined transmission of a tractor with large horsepower uses a dynamic shifting process, in which only one clutch undergoes slipping friction during the shift. A power shift control strategy based on torque and speed transition, which aims to deliver multiple target and multiparameter optimization of power shift control, is proposed in this study. Based on minimum optimal control theory, the optimal control of shift quality during power shifting optimizes clutch terminal oil pressure, which is determined by solving the Rebecca differential matrix equation and shift characteristics based on various stages. In addition, the power shift simulation model of the double clutch is established. Simulation results show that the power shift control strategy based on single slip friction can effectively avoid power flow cycle, uninterruptible tractor power shift, and adaptive resistance change. The minimum optimization theory can effectively reduce the output torque fluctuation in the dynamic shift process, reduce friction work, and improve the shift impact. Keywords: Double clutch, Heavy-horsepower tractor, Minimum theory, Power shift.

Study on Uninterrupted Shift Transmission Shift Strategy Based on Fuzzy Control

2013 ◽  
Vol 791-793 ◽  
pp. 668-671
Author(s):  
Ke Gang Zhao ◽  
Hao Chang ◽  
Yong Liang Hu ◽  
Wei Hao Yao
Keyword(s):  
Fuzzy Control ◽  
Control Strategy ◽  
Experimental Results ◽  
Control Technology ◽  
Shift Quality ◽  
Shift Control ◽  
Shift Strategy ◽  
Fuzzy Control Strategy

Uninterrupted Shift Transmission (UST) is a novel vehicle transmission and which is introduced as the research object in this paper. It realizes torque uninterrupted shift by controlling dual multimode controlled shifter (MCS) modes and synchronizers. Fuzzy control technology is adopted in shift control strategy in order to improve its shift quality. Experimental results show that the fuzzy control strategy can improve the shift quality of UST effectively.

scholarly journals Thermo-Structural Behaviour Prediction of the Nose Cap of a Hypersonic Vehicle Based on Multifield Coupling

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xuewen Sun ◽  
Haibo Yang ◽  
Tao Mi
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Principal Stress ◽  
Structural Model ◽  
Coupling Model ◽  
Maximum Principal Stress ◽  
Hypersonic Vehicle ◽  
Structural Behaviour ◽  
Structural Coupling ◽  
Initial Stage

The analysis of thermo-structural behaviour is crucial to the nose cap of a hypersonic vehicle under aerothermodynamic loads. Considering chemical nonequilibrium of the flow field, heat transfer, and deformation of the structure, a fluid-thermal-structural coupling model of the typical nose cap was established. The coupling relation between the flow field and nose cap was analyzed. The results show that the fluid-thermal-structural model can effectively predict the response of the nose cap under a hypersonic environment. The highest temperature and the peak of maximum principal stress appear at the front of the nose cap at an initial stage. As time goes on, the highest temperature increases gradually and the peak of maximum principal stress decreases after reaching a certain value. The position of the peak of maximum principal stress gradually moves to the inside of the nose cap and eventually stabilizes. With the increase in the Mach number, the highest temperature and the peak of maximum principal stress of the nose cap increase. The fluid-thermal-structural coupling model can provide guidance for the optimal design of the nose cap of a hypersonic vehicle.

scholarly journals Analysis and experiment of HMT stationary shift control considering the effect of oil bulk modulus

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402096832
Author(s):  
Xueliang Li ◽  
Lu Zhang ◽  
Shujun Yang ◽  
Nan Liu
Keyword(s):  
Experimental Study ◽  
Bulk Modulus ◽  
Control Method ◽  
Simulation Analysis ◽  
Continuously Variable Transmission ◽  
Mechanical Transmission ◽  
Reverse Time ◽  
Shift Quality ◽  
Shift Control ◽  
Variable Transmission

In order to improve the shift quality of hydro-mechanical continuously variable transmission, the effect of tangent bulk modulus and different control methods on the shift quality were analyzed. Theoretical analysis and experimental study on the tangent bulk modulus of oil were carried out to obtain the effect law of air content on the tangent bulk modulus of oil. A four-cavity model of a closed hydraulic circuit was established based on a two-stage arithmetic type hydro-mechanical transmission. By means of simulation analysis and experimental study, the effect of the tangent bulk modulus of oil on the shift quality is studied. The lean control method of reasonably controlling displacement ratio and prolonging the reverse time of load torque is put forward. The results show that this method can reduce the fluctuations of the speed of the fixed displacement motor and the oil pressure of the original low-pressure side. This method can also improve the shift quality and provide reference for the study of the shift process of hydro-mechanical continuously variable transmission.

Power Shift Control of High-Power Tractor Based on Pattern Search

2020 ◽  
Vol 36 (4) ◽  
pp. 565-578
Author(s):  
Guang Xia ◽  
Xinghai Yu ◽  
Xiwen Tang ◽  
Linfeng Zhao ◽  
Baoqun Sun
Keyword(s):  
Evaluation System ◽  
Sliding Wear ◽  
Pattern Search ◽  
Shift Quality ◽  
Evaluation Indexes ◽  
Shift Control ◽  
Output Torque ◽  
Power Shift ◽  
Factor Evaluation ◽  
Three Factor

Highlights This article presents a multiobjective optimization function of power shift quality that uses the calculation formulas of sliding wear work, impact degree, and output torque derived from the analysis of split-phase dynamics. The calculation formulas of impact degree, sliding wear work, and output torque of each phase are derived, and a three-factor evaluation system of power shift quality is constructed. A pattern-search-based optimization method of power shift quality is proposed on the basis of the three-factor evaluation system of power shift quality. The power shift control based on pattern search algorithm optimizes the shift quality evaluation indexes and effectively improves the power shift quality of high-power tractors. Abstract . This study conducts a dynamic analysis of power shift by analyzing the key influencing factors of power shift quality. The power shift process is divided into low gear torque, sliding wear, and high gear torque phases. The calculation formulas of impact degree, sliding wear work, and output torque of each phase are derived, and a three-factor evaluation system of power shift quality is constructed. A pattern-search-based optimization method of power shift quality is proposed on the basis of the three-factor evaluation system of power shift quality. A multi-objective optimization function of shift quality is constructed using the linear change law expression of clutch oil pressure and the calculation of shift quality evaluation indexes of each phase. The multi-objective function is pretreated using a weighted coefficient method, and the change rule of clutch oil pressure is accurately optimized. Simulation and experimental results show that the power shift control based on pattern search algorithm optimizes the evaluation indexes of each shift quality and effectively improves the power shift quality of high-power tractors. Keywords: Pattern search, Power shift, Shift quality, Split-phase dynamics.

Nonlinear Friction Compensation of a Flexible Robotic Joint with Harmonic Drive

2017 ◽  
Vol 868 ◽  
pp. 39-44
Author(s):  
Peng Fei Zeng ◽  
Ge Dong Jiang ◽  
Chuang Zou ◽  
Xian Zhang ◽  
Cheng Xuan Xie
Keyword(s):  
Control Strategies ◽  
Industrial Robot ◽  
Friction Compensation ◽  
Nonlinear Friction ◽  
Harmonic Drive ◽  
Stribeck Effect ◽  
Compensation Control ◽  
Polynomial Fit ◽  
Feedback Compensation ◽  
Control Accuracy

To suppress the abrupt and unexpected turning velocity fluctuation of the industrial robot under the condition of trajectory tracking, a flexible robotic joint experimental setup with the harmonic drive was established. The measured friction with Stribeck effect and velocity were modeled by a simple polynomial fit method. Two friction compensation control strategies of feedforward and feedback were designed. The friction compensation experiments were carried out on the dSPACE system, the good restraint effect of fluctuation on the turning velocity was verified and the control accuracy of feedback compensation control strategy proved better.

Method of Compensation Control for Shaking Table

2011 ◽  
Vol 199-200 ◽  
pp. 1397-1404
Author(s):  
Zhen Bao Li ◽  
Zhen Yun Tang ◽  
Jin Bao Ji ◽  
Xiao Liang Li ◽  
Da Xing Zhou ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Variable Parameter ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Stability And Control ◽  
Compensation Control ◽  
Narrow Bandwidth ◽  
The Stability ◽  
And Control ◽  
Control Accuracy

This paper presents the defects existing in shaking table control including the overshoot of displacement under low-middle frequency input using three variable parameter controls, the narrow bandwidth resulting from the performance of servo-valve and low accuracy of seismic wave reproduction because of specimen and table interaction. The effects of these factors on the stability and control accuracy of shaking table are discussed, and then the reasons of these problems existing are analyzed. The aim of this paper is to improve the stability and control accuracy of shaking table, thus, some corresponding strategies for compensation control are proposed. And a series of shaking table tests with one-story frame and two-story frame for verifying the validity of compensation control algorithm are performed.

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