Engine mount system affects the automobile NVH performance.Active mounts would achieve excellent vibration isolation and relative displacement control performance in a broad frequency bandwidth by outputting controlle...Engine mount system affects the automobile NVH performance.Active mounts would achieve excellent vibration isolation and relative displacement control performance in a broad frequency bandwidth by outputting controlled force to the mounting system.The actuator and control method of the active mounts determine the system performance.In this paper,an active mount based on the smart material,i.e.,Terfenol-D rod,is proposed,which mainly includes three parts:rubber spring,magnetostrictive actuator(MA),and hydraulic amplification mechanism(HAM).Dynamic model of the active mount is correspondingly established.A state feedback control method based on x-LMS(Least-Mean-Square)algorithm is proposed as well.Specifically,with the consideration of the unmeasurable state parameters in the active mounting system,an x-LMS state feedback controller with the system state as the reference signal is constructed by employing Sage-Husa Kalman filter to realize the state estimation of the active mounting system.Then a detailed analysis of the proposed control method is conducted,with deriving iterative formula of tap-weight vector.Sequentially,the problem of the dependence on the excitation signal in the x-LMS algorithm is addressed.The feasibility and capability of the proposed control method are verified and evaluated by simulation of a two-degree-offreedom active mounting system.展开更多
Efficient regenerative braking of electric vehicles(EVs)can enhance the efficiency of an energy storage system(ESS)and reduce the system cost.To ensure swift braking energy recovery,it is paramount to know the upper l...Efficient regenerative braking of electric vehicles(EVs)can enhance the efficiency of an energy storage system(ESS)and reduce the system cost.To ensure swift braking energy recovery,it is paramount to know the upper limit of the regenerative energy during braking.Therefore,this paper,based on 14 typical urban driving cycles,proposes the concept and principle of confidence interval of“probability event”and“likelihood energy”proportion of braking.The critical speeds of EVs for braking energy recovery are defined and studied through case studies.First,high-probability critical braking speed and high-energy critical braking speed are obtained,compared,and analyzed,according to statistical analysis and calculations of the braking randomness and likelihood energy in the urban driving cycles of EVs.Subsequently,a new optimized ESS concept is proposed under the frame of a battery/ultra-capacitor(UC)hybrid energy storage system(HESS)combined with two critical speeds.The battery/UC HESS with 9 UCs can achieve better regenerative braking performances and discharging performances,which indicates that a minimal amount of UCs can be used as auxiliary power source to optimize the ESS.After that,the efficiency regenerative braking model,including the longitudinal dynamics,motor,drivetrain,tire,and wheel slip models,is established.Finally,parameters optimization and performance verification of the optimized HESS are implemented and analyzed using a specific EV.Research results emphasize the significance of the critical speeds of EVs for regenerative braking.展开更多
The superior performance of active vibration control systems largely depends on the four-quadrant controllable execution capability in the available force-velocity diagram of active actuators.Although semi-active vibr...The superior performance of active vibration control systems largely depends on the four-quadrant controllable execution capability in the available force-velocity diagram of active actuators.Although semi-active vibration control systems have the advantages of low energy consumption,simple structure,and high reliability,the system performance is not comparable to active control systems,due to the partial capability in only the first and third quadrants.On the basis of the comprehensive advantages of active and semi-active actuators,to reform the design philosophy of semi-active actuators to realize pseudo-active actuators that have both mechanical properties of active actuators and energy consumption advantages of semi-active actuators,that is,new semi-active actuators with four-quadrant controllable execution capability,will very likely cause a revolution in the related fields of mechanical design and system control.The basic design principle of pseudo-active actuators that use semi-active controllable actuators to achieve active actuator performance in the way of conceptual analysis is proposed.The proposed pseudo-active actuators should consist of two half-four-quadrant actuators,that is,one is for the first and third quadrants and the other one for the second and fourth quadrants.This study employs two semi-active controllable damping actuators and one mechanical compensation mechanism.One of the actuators provides the damping force in the first and third quadrants,and the other one combining with the mechanical compensation mechanism is for the second and fourth quadrants.A global mathematical model of the proposed actuator is established to describe the four different operational modes of the proposed actuator.It is proved that the two operational modes of the proposed actuator can realize active vibration control,and a case study of realizing active control is presented.The other two operational modes are compared with the conventional two-degree-of-freedom model.More specifically,the application cases of the pseudo-active operational mode of the proposed actuator in the quarter-car/body-powertrain suspension system are given,a pseudo-active suspension named dual-hook automobile suspension is presented.Furthermore,an equivalent expression of the electrical network is given for the mechanical network under different operational modes of the proposed actuator.展开更多
基金National Natural Science Foundation of China(Grant No.52272392)Fundamental Research Funds for the Central Universities of China(Grant No.JD2019JGPY0018).
文摘Engine mount system affects the automobile NVH performance.Active mounts would achieve excellent vibration isolation and relative displacement control performance in a broad frequency bandwidth by outputting controlled force to the mounting system.The actuator and control method of the active mounts determine the system performance.In this paper,an active mount based on the smart material,i.e.,Terfenol-D rod,is proposed,which mainly includes three parts:rubber spring,magnetostrictive actuator(MA),and hydraulic amplification mechanism(HAM).Dynamic model of the active mount is correspondingly established.A state feedback control method based on x-LMS(Least-Mean-Square)algorithm is proposed as well.Specifically,with the consideration of the unmeasurable state parameters in the active mounting system,an x-LMS state feedback controller with the system state as the reference signal is constructed by employing Sage-Husa Kalman filter to realize the state estimation of the active mounting system.Then a detailed analysis of the proposed control method is conducted,with deriving iterative formula of tap-weight vector.Sequentially,the problem of the dependence on the excitation signal in the x-LMS algorithm is addressed.The feasibility and capability of the proposed control method are verified and evaluated by simulation of a two-degree-offreedom active mounting system.
基金the Major Scientific and Technological Projects of Anhui Province(Grant No.17030901065)for its support to this research.
文摘Efficient regenerative braking of electric vehicles(EVs)can enhance the efficiency of an energy storage system(ESS)and reduce the system cost.To ensure swift braking energy recovery,it is paramount to know the upper limit of the regenerative energy during braking.Therefore,this paper,based on 14 typical urban driving cycles,proposes the concept and principle of confidence interval of“probability event”and“likelihood energy”proportion of braking.The critical speeds of EVs for braking energy recovery are defined and studied through case studies.First,high-probability critical braking speed and high-energy critical braking speed are obtained,compared,and analyzed,according to statistical analysis and calculations of the braking randomness and likelihood energy in the urban driving cycles of EVs.Subsequently,a new optimized ESS concept is proposed under the frame of a battery/ultra-capacitor(UC)hybrid energy storage system(HESS)combined with two critical speeds.The battery/UC HESS with 9 UCs can achieve better regenerative braking performances and discharging performances,which indicates that a minimal amount of UCs can be used as auxiliary power source to optimize the ESS.After that,the efficiency regenerative braking model,including the longitudinal dynamics,motor,drivetrain,tire,and wheel slip models,is established.Finally,parameters optimization and performance verification of the optimized HESS are implemented and analyzed using a specific EV.Research results emphasize the significance of the critical speeds of EVs for regenerative braking.
基金The authors wish to acknowledge the Fundamental Research Funds for the Central Universities(No.JD2019JGPY0018)for the support of this study.
文摘The superior performance of active vibration control systems largely depends on the four-quadrant controllable execution capability in the available force-velocity diagram of active actuators.Although semi-active vibration control systems have the advantages of low energy consumption,simple structure,and high reliability,the system performance is not comparable to active control systems,due to the partial capability in only the first and third quadrants.On the basis of the comprehensive advantages of active and semi-active actuators,to reform the design philosophy of semi-active actuators to realize pseudo-active actuators that have both mechanical properties of active actuators and energy consumption advantages of semi-active actuators,that is,new semi-active actuators with four-quadrant controllable execution capability,will very likely cause a revolution in the related fields of mechanical design and system control.The basic design principle of pseudo-active actuators that use semi-active controllable actuators to achieve active actuator performance in the way of conceptual analysis is proposed.The proposed pseudo-active actuators should consist of two half-four-quadrant actuators,that is,one is for the first and third quadrants and the other one for the second and fourth quadrants.This study employs two semi-active controllable damping actuators and one mechanical compensation mechanism.One of the actuators provides the damping force in the first and third quadrants,and the other one combining with the mechanical compensation mechanism is for the second and fourth quadrants.A global mathematical model of the proposed actuator is established to describe the four different operational modes of the proposed actuator.It is proved that the two operational modes of the proposed actuator can realize active vibration control,and a case study of realizing active control is presented.The other two operational modes are compared with the conventional two-degree-of-freedom model.More specifically,the application cases of the pseudo-active operational mode of the proposed actuator in the quarter-car/body-powertrain suspension system are given,a pseudo-active suspension named dual-hook automobile suspension is presented.Furthermore,an equivalent expression of the electrical network is given for the mechanical network under different operational modes of the proposed actuator.
