A study was conducted in the domain of emergency rescue operations to tackle a challenge encountered by corner module architecture intelligent electric vehicles(C-Vs).Specifically,the study addressed the issue of the ...A study was conducted in the domain of emergency rescue operations to tackle a challenge encountered by corner module architecture intelligent electric vehicles(C-Vs).Specifically,the study addressed the issue of the two front wheels getting stuck in potholes on low-adhesion roads.To overcome this obstacle,a chassis coordinated control method was introduced.Initially,a vehicle dynamic model suitable for uneven terrains was established.This model represented the vertical motion of the tire as a rigid ring and rim model.The full vehicle model accounted for suspension geometry,center of gravity(CG)transfer,and bumper blocks.Subsequently,a chassis coordinated control method was formulated,encompassing an active suspension system(ASS),traction control system(TCS),and yaw motion control system.Controllers for ASS to navigate out of potholes were designed.The relationship between the maximum driving force and posture was delineated,and the optimal suspension deflection(SD)was calculated.Building upon the designed optimal slip rate identification method,a TCS based on dynamic sliding mode control(DSMC)was developed.As both the ASS and TCS could induce yaw instability,and considering the heightened challenges posed by variations in speed and tire cornering stiffness on yaw motion control,Takagi–Sugeno(T-S)technology was employed to fuzzify both aspects.A robust SMC(RSMC)-based yaw motion control was devised,achieving coordinated control among the three systems.Finally,the results of the hardware-in-the-loop(HIL)illustrated that the coordinated control strategy enables C-Vs to escape from conditions with an adhesion coefficient of 0.3 and a pothole depth of 250 mm.展开更多
Ultraprecision machining of titanium alloy(Ti-6Al-4V)remains challenging due to its low thermal conductivity,pronounced elastic recovery,and tool-workpiece adhesion,all of which degrade surface integrity and accelerat...Ultraprecision machining of titanium alloy(Ti-6Al-4V)remains challenging due to its low thermal conductivity,pronounced elastic recovery,and tool-workpiece adhesion,all of which degrade surface integrity and accelerate tool wear.This study systematically investigates the effect of a weak magnetic field(~0.015 T)on the single-point diamond turning and microgroove machining of Ti-6Al-4V flat surfaces,microgroove arrays,and microstructures.Four machining conditions were designed to decouple the magnetic field effect:no field(nM-nM),field applied only during microgroove cutting(nM-M),field applied only during finish turning(M-nM),and field applied throughout(M-M).Theoretical analyses and experiments have demonstrated that the rotation of the conductive titanium alloy within a magnetic field induces eddy currents,generating Lorentz damping,which suppresses vibrations in Y/Z directions,enhances cutting stability,and improves surface finish.The results showed that magnetic-field assistance significantly reduces both the principal cutting forces and noise levels,and that performance under M-nM conditions surpasses that under nM-M conditions,suggesting that the finishcutting process exerts a stronger influence on the quality of microgroove machining.Microstructures machined under M-M conditions exhibit exceptional dimensional accuracy and uniformity,with groove depths approaching a nominal value of 4μm(reaching~3.98μm under the M-M conditions)and minimal burrs or microcracks forming at boundaries.The findings enhance the understanding of the magnetic field-assisted ultraprecision cutting of titanium alloys,enabling the manufacturing of high-quality micro/nanostructures for applications in aerospace,biomedicine,and optical components.展开更多
基金funded by the National Natural Science Foundation of China(No.52272407,U20A20332)the S&T Program of Hebei(No.226Z2202G)+1 种基金the Hebei Natural Science Foundation(No.E2020203174)the Science Research Project of Hebei Education Department(No.ZD2022029).
文摘A study was conducted in the domain of emergency rescue operations to tackle a challenge encountered by corner module architecture intelligent electric vehicles(C-Vs).Specifically,the study addressed the issue of the two front wheels getting stuck in potholes on low-adhesion roads.To overcome this obstacle,a chassis coordinated control method was introduced.Initially,a vehicle dynamic model suitable for uneven terrains was established.This model represented the vertical motion of the tire as a rigid ring and rim model.The full vehicle model accounted for suspension geometry,center of gravity(CG)transfer,and bumper blocks.Subsequently,a chassis coordinated control method was formulated,encompassing an active suspension system(ASS),traction control system(TCS),and yaw motion control system.Controllers for ASS to navigate out of potholes were designed.The relationship between the maximum driving force and posture was delineated,and the optimal suspension deflection(SD)was calculated.Building upon the designed optimal slip rate identification method,a TCS based on dynamic sliding mode control(DSMC)was developed.As both the ASS and TCS could induce yaw instability,and considering the heightened challenges posed by variations in speed and tire cornering stiffness on yaw motion control,Takagi–Sugeno(T-S)technology was employed to fuzzify both aspects.A robust SMC(RSMC)-based yaw motion control was devised,achieving coordinated control among the three systems.Finally,the results of the hardware-in-the-loop(HIL)illustrated that the coordinated control strategy enables C-Vs to escape from conditions with an adhesion coefficient of 0.3 and a pothole depth of 250 mm.
基金financial supports from Young Scientist Fund of National Natural Science Foundation of China(Project No.52205498/K-ZGFT)the State Key Laboratory in Hong Kong from the Innovation and Technology Commission(ITC)of the Government of the Hong Kong Special Administrative Region(HKSAR),China+2 种基金the General Research Fund(GRF)of the Research Grants Council(RGC)of the Hong Kong Special Administrative Region(HKSAR),China(Project No.PolyU 15220724)the Shenzhen Key Technology Breakthrough Project(No.Z2022N074)Shenzhen Engineering Research Center for Semiconductor-specific Equipment and the Research Committee of The Hong Kong Polytechnic University(Project code:RKWR).
文摘Ultraprecision machining of titanium alloy(Ti-6Al-4V)remains challenging due to its low thermal conductivity,pronounced elastic recovery,and tool-workpiece adhesion,all of which degrade surface integrity and accelerate tool wear.This study systematically investigates the effect of a weak magnetic field(~0.015 T)on the single-point diamond turning and microgroove machining of Ti-6Al-4V flat surfaces,microgroove arrays,and microstructures.Four machining conditions were designed to decouple the magnetic field effect:no field(nM-nM),field applied only during microgroove cutting(nM-M),field applied only during finish turning(M-nM),and field applied throughout(M-M).Theoretical analyses and experiments have demonstrated that the rotation of the conductive titanium alloy within a magnetic field induces eddy currents,generating Lorentz damping,which suppresses vibrations in Y/Z directions,enhances cutting stability,and improves surface finish.The results showed that magnetic-field assistance significantly reduces both the principal cutting forces and noise levels,and that performance under M-nM conditions surpasses that under nM-M conditions,suggesting that the finishcutting process exerts a stronger influence on the quality of microgroove machining.Microstructures machined under M-M conditions exhibit exceptional dimensional accuracy and uniformity,with groove depths approaching a nominal value of 4μm(reaching~3.98μm under the M-M conditions)and minimal burrs or microcracks forming at boundaries.The findings enhance the understanding of the magnetic field-assisted ultraprecision cutting of titanium alloys,enabling the manufacturing of high-quality micro/nanostructures for applications in aerospace,biomedicine,and optical components.
