The control strategy is firstly the first braking power according to the fuzzy control algorithm, considering the speed, the battery SOC and the battery maximum charging power limit to obtain the maximum braking speed...The control strategy is firstly the first braking power according to the fuzzy control algorithm, considering the speed, the battery SOC and the battery maximum charging power limit to obtain the maximum braking speed, thus the secondary distribution of the hydraulic braking torque. Then the brake control strategy can reduce the impact of the EV braking mode conversion process, and meet the braking demand and brake safety, which proves the effectiveness of the control strategy. In order to ensure the braking stability of the vehicle and further improve the energy utilization rate of electric vehicles, the vehicle speed refueling controller, battery charging state and braking force are used as the energy variables, and the braking force distribution coefficient is taken as the output variable. The braking power distribution coefficient is recommended, considering the stability requirements of the engine, battery, and braking system, to distribute mechanical braking and engine regeneration to the front and rear axles of the machine. Simulation of the developed regenerative braking strategy is analyzed and incorporated into the AVL cruise park model. The results show that this strategy improves braking stability and comfort over the classical ECE curve control strategy, increasing FTP75 by 17.22% compared to the classical ECE curve control strategy展开更多
To improve the braking safety of automobiles, the author studied the effect of differential brake on the stabilities. To analyze the mechanical characteristics of differential brake, automotive subsystem models were b...To improve the braking safety of automobiles, the author studied the effect of differential brake on the stabilities. To analyze the mechanical characteristics of differential brake, automotive subsystem models were built by applying ADAMS/CAR, and automotive mechanics simulation model was built by setting the main subsystems such as body, engine and brake. The simulation model studied the distribution mode of three kinds of differential brake, and beeline braking stability and turning braking stability were simulated. It shows that differential brake can amend turning shortage of automobile brake and improve its braking stability, but the effect of automobile mass on its braking stability is great. So the distribution mode of braking force and the effect of mass change should be considered while differential brake is applied.展开更多
Based on the modal coupling theory,the rotor and stator contact stiffness and axial relative velocity are considered to build an electric aircraft brake dynamic system model in this study.Both the complex modal analys...Based on the modal coupling theory,the rotor and stator contact stiffness and axial relative velocity are considered to build an electric aircraft brake dynamic system model in this study.Both the complex modal analysis and transient dynamic analysis methods are used to study the aircraft brake squeal performance and vibratory mechanism.The unstable vibration modes indicate that the out-of-plane vibration plays an important role and the feed-in energy is larger than the output energy in the brake rotor–stator module so that brake squeal takes place.Then the influences of the contact stiffness,friction damping and frictional coefficient on the brake squeal system are carried out,laying the foundation for the three proposed vibration suppression methods.Results show that the coefficient negative-slope condition will intensify the vibration.Also,a linear relationship between the squeal factor and the frictional coefficient is obtained to provide a guidance to predict squeal stability under more conditions.Vibration reduction design shows that adding a damping layer to the brake mechanism and chamfering the edge of braking stators both can reduce brake squeal effectively,while slotting braking stators is invalid in aircraft braking system.展开更多
文摘The control strategy is firstly the first braking power according to the fuzzy control algorithm, considering the speed, the battery SOC and the battery maximum charging power limit to obtain the maximum braking speed, thus the secondary distribution of the hydraulic braking torque. Then the brake control strategy can reduce the impact of the EV braking mode conversion process, and meet the braking demand and brake safety, which proves the effectiveness of the control strategy. In order to ensure the braking stability of the vehicle and further improve the energy utilization rate of electric vehicles, the vehicle speed refueling controller, battery charging state and braking force are used as the energy variables, and the braking force distribution coefficient is taken as the output variable. The braking power distribution coefficient is recommended, considering the stability requirements of the engine, battery, and braking system, to distribute mechanical braking and engine regeneration to the front and rear axles of the machine. Simulation of the developed regenerative braking strategy is analyzed and incorporated into the AVL cruise park model. The results show that this strategy improves braking stability and comfort over the classical ECE curve control strategy, increasing FTP75 by 17.22% compared to the classical ECE curve control strategy
基金Western Countries,Traffic IT Projects Traffic (No.200431800048)
文摘To improve the braking safety of automobiles, the author studied the effect of differential brake on the stabilities. To analyze the mechanical characteristics of differential brake, automotive subsystem models were built by applying ADAMS/CAR, and automotive mechanics simulation model was built by setting the main subsystems such as body, engine and brake. The simulation model studied the distribution mode of three kinds of differential brake, and beeline braking stability and turning braking stability were simulated. It shows that differential brake can amend turning shortage of automobile brake and improve its braking stability, but the effect of automobile mass on its braking stability is great. So the distribution mode of braking force and the effect of mass change should be considered while differential brake is applied.
基金This study was funded by the National Natural Science Foundation of China(Grant 51905264)the China Postdoctoral Science Foundation Funded Project(Grants 2019M650115,2019M661818 and 2020T130298)+1 种基金the National Defense Outstanding Youth Science Foundation(Grant 2018-JCJQ-ZQ-053)the Fundamental Research Funds for the Central Universities(Grant NF2O18OO1)and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Based on the modal coupling theory,the rotor and stator contact stiffness and axial relative velocity are considered to build an electric aircraft brake dynamic system model in this study.Both the complex modal analysis and transient dynamic analysis methods are used to study the aircraft brake squeal performance and vibratory mechanism.The unstable vibration modes indicate that the out-of-plane vibration plays an important role and the feed-in energy is larger than the output energy in the brake rotor–stator module so that brake squeal takes place.Then the influences of the contact stiffness,friction damping and frictional coefficient on the brake squeal system are carried out,laying the foundation for the three proposed vibration suppression methods.Results show that the coefficient negative-slope condition will intensify the vibration.Also,a linear relationship between the squeal factor and the frictional coefficient is obtained to provide a guidance to predict squeal stability under more conditions.Vibration reduction design shows that adding a damping layer to the brake mechanism and chamfering the edge of braking stators both can reduce brake squeal effectively,while slotting braking stators is invalid in aircraft braking system.
