Non-pneumatic tire appears to have advantages over traditional pneumatic tire in terms of flat proof and maintenance free.A mechanical elastic wheel(MEW) with a non-pneumatic elastic outer ring which functions as air ...Non-pneumatic tire appears to have advantages over traditional pneumatic tire in terms of flat proof and maintenance free.A mechanical elastic wheel(MEW) with a non-pneumatic elastic outer ring which functions as air of pneumatic tire was presented.The structure of MEW was non-inflatable integrated configuration and the effect of hinges was accounted for only in tension. To establish finite element model of MEW, various nonlinear factors, such as geometrical nonlinearity, material nonlinearity and contact nonlinearity, were considered. Load characteristic test was conducted by tyre dynamic test-bed to obtain force-deflection curve. And the finite element model was validated through load characteristic test. Natural dynamic characteristics of the MEW and its influencing factors were investigated based on the finite element model. Simulation results show that the finite element model closely matched experimental wheel. The results also show that natural frequency is related to ground constraints, material properties, loads and torques. Influencing factors as above obviously affect the amplitude of mode of vibration, but have little effect on mode of vibration shape. The results can provide guidance for experiment research, structural optimization of MEW.展开更多
Machining and installation errors are unavoidable in mechanical structures. However, the effect of errors on radial stiffness of the mechanical elastic wheel(ME-Wheel) is not considered in previous studies. To this en...Machining and installation errors are unavoidable in mechanical structures. However, the effect of errors on radial stiffness of the mechanical elastic wheel(ME-Wheel) is not considered in previous studies. To this end, the interval mathematical model and interval finite element model of the ME-Wheel were both established and compared with bench test results. The intercomparison of the influence of the machining and installation errors on the ME-Wheel radial stiffness revealed good consistency among the interval mathematical analysis, interval finite element simulation,and bench test results. Within the interval range of the ME-Wheel machining and installation errors, parametric analysis of the combined elastic rings was performed at different initial radial rigidity values. The results showed that the initial radial stiffness of the flexible tire body significantly influenced the ME-Wheel radial stiffness, and the inverse relationship between the hinge unit length or suspension hub and the radial stiffness was nonlinear. The radial stiffness of the ME-Wheel is predicted by using the interval algorithm for the first time, and the regularity of the radial stiffness between the error and the load on the ME-Wheel is studied, which will lay the foundation for the exact study of the ME-Wheel dynamic characteristics in the future.展开更多
Aiming at the issue of yaw and rollover stability control for off-road vehicles with non-pneumatic mechanical elastic wheel(MEW),an integrated control system based on fuzzy differential braking is developed.By simplif...Aiming at the issue of yaw and rollover stability control for off-road vehicles with non-pneumatic mechanical elastic wheel(MEW),an integrated control system based on fuzzy differential braking is developed.By simplifying the structure of the MEW,a corresponding fitting brush tire model is constructed and its longitudinal and lateral tire force expressions are set up,respectively.Then,a nonlinear vehicle simulation model with MEW is established to validate the proposed control scheme based on Carsim.The designed yaw and rollover control system is a two-level structure with the upper additional moment controller,which utilizes a predictive load transfer ratio(PLTR)as the rollover index.In order to design the upper integrated control algorithm,fuzzy proportional-integral-derivative(PID)is adopted to coordinate the yaw and rollover control,simultaneously.And the lower control allocator realizes the additional moment to the vehicle by differential braking.Finally,a Carsim-simulink co-simulation model is constructed,and simulation results show that the integrated control system could improve the vehicle yaw and roll stability,and prevent rollover happening.展开更多
Conventional pneumatic tires exhibit disadvantages such as puncture,blowout at high speed,pressure maintenance,etc.Owing to these structural inevitable weaknesses,non?pneumatic tires have been developed and are invest...Conventional pneumatic tires exhibit disadvantages such as puncture,blowout at high speed,pressure maintenance,etc.Owing to these structural inevitable weaknesses,non?pneumatic tires have been developed and are investigated.A non?pneumatic mechanical elastic wheel(NPMEW)is introduced and investigated as a function of static radical stiffness characteristics and contact behavior.A bench test method is utilized to improve the riding comfort and the traction traffic ability of NPMEW based on tire characteristics test rig,and the static radical stiffness characteristics and the contact behavior of NPMEW are compared with that of an insert supporting run?flat tire(ISRFT).The vertical force?deformation curves and deformed shapes and contact areas of the NPMEW and ISRFT are obtained using a set of vertical loads.The contact behavior is evaluated using extracted geometrical and mechanical feature parameters of the two tires.The results indicate that the NPMEW appears to exhibit considerably high radical stiffness,and the numerical value is dependent on the mechanical characteristic of the flexible tire body and hinge units.NPMEW demonstrates more uniform contact pressure than ISRFT within a certain loading range,and it can efficiently mitigate the problem of stress concentration in ISRFT shoulder under heavy load and enhance the wear resistance and ground grip performances.展开更多
基金Project(NHA13002)supported by Explore Research Project of the General Armament Department,ChinaProject(11072106)supported by the National Natural Science Foundation of China
文摘Non-pneumatic tire appears to have advantages over traditional pneumatic tire in terms of flat proof and maintenance free.A mechanical elastic wheel(MEW) with a non-pneumatic elastic outer ring which functions as air of pneumatic tire was presented.The structure of MEW was non-inflatable integrated configuration and the effect of hinges was accounted for only in tension. To establish finite element model of MEW, various nonlinear factors, such as geometrical nonlinearity, material nonlinearity and contact nonlinearity, were considered. Load characteristic test was conducted by tyre dynamic test-bed to obtain force-deflection curve. And the finite element model was validated through load characteristic test. Natural dynamic characteristics of the MEW and its influencing factors were investigated based on the finite element model. Simulation results show that the finite element model closely matched experimental wheel. The results also show that natural frequency is related to ground constraints, material properties, loads and torques. Influencing factors as above obviously affect the amplitude of mode of vibration, but have little effect on mode of vibration shape. The results can provide guidance for experiment research, structural optimization of MEW.
基金Supported by National Natural Science Foundation of China(Grant No.11672127)Major Exploration Project of the General Armaments Department of China(Grant No.NHA13002)+1 种基金Fundamental Research Funds for the Central Universities of China(Grant No.NP2016412,NP2018403,NT2018002)Jiangsu Provincial Innovation Program for Graduate Education and the Fundamental Research Funds for the Central Universities of China(Grant No.KYLX16_0330)
文摘Machining and installation errors are unavoidable in mechanical structures. However, the effect of errors on radial stiffness of the mechanical elastic wheel(ME-Wheel) is not considered in previous studies. To this end, the interval mathematical model and interval finite element model of the ME-Wheel were both established and compared with bench test results. The intercomparison of the influence of the machining and installation errors on the ME-Wheel radial stiffness revealed good consistency among the interval mathematical analysis, interval finite element simulation,and bench test results. Within the interval range of the ME-Wheel machining and installation errors, parametric analysis of the combined elastic rings was performed at different initial radial rigidity values. The results showed that the initial radial stiffness of the flexible tire body significantly influenced the ME-Wheel radial stiffness, and the inverse relationship between the hinge unit length or suspension hub and the radial stiffness was nonlinear. The radial stiffness of the ME-Wheel is predicted by using the interval algorithm for the first time, and the regularity of the radial stiffness between the error and the load on the ME-Wheel is studied, which will lay the foundation for the exact study of the ME-Wheel dynamic characteristics in the future.
基金Project(11672127)supported by the National Natural Science Foundation of ChinaProject(NHAl3002)supported by the Major Exploration Project of the General Armaments Department of China+1 种基金Project(KYCX17_0240)supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province,ChinaProjects(NP2016412,NP2018403,NT2018002)supported by the Fundamental Research Funds for the Central Universities,China
文摘Aiming at the issue of yaw and rollover stability control for off-road vehicles with non-pneumatic mechanical elastic wheel(MEW),an integrated control system based on fuzzy differential braking is developed.By simplifying the structure of the MEW,a corresponding fitting brush tire model is constructed and its longitudinal and lateral tire force expressions are set up,respectively.Then,a nonlinear vehicle simulation model with MEW is established to validate the proposed control scheme based on Carsim.The designed yaw and rollover control system is a two-level structure with the upper additional moment controller,which utilizes a predictive load transfer ratio(PLTR)as the rollover index.In order to design the upper integrated control algorithm,fuzzy proportional-integral-derivative(PID)is adopted to coordinate the yaw and rollover control,simultaneously.And the lower control allocator realizes the additional moment to the vehicle by differential braking.Finally,a Carsim-simulink co-simulation model is constructed,and simulation results show that the integrated control system could improve the vehicle yaw and roll stability,and prevent rollover happening.
基金supported in part by the National Natural Science Foundations of China (Nos.51605215, 11672127)the National Science Foundations for Post-Doctoral Scientists of China (Nos.2018M630593, 2019T120450)+1 种基金Research Foundations of Nanjing Institute of Technology (Nos. QKJ201707, PTKJ201702)the Qing Lan Project
文摘Conventional pneumatic tires exhibit disadvantages such as puncture,blowout at high speed,pressure maintenance,etc.Owing to these structural inevitable weaknesses,non?pneumatic tires have been developed and are investigated.A non?pneumatic mechanical elastic wheel(NPMEW)is introduced and investigated as a function of static radical stiffness characteristics and contact behavior.A bench test method is utilized to improve the riding comfort and the traction traffic ability of NPMEW based on tire characteristics test rig,and the static radical stiffness characteristics and the contact behavior of NPMEW are compared with that of an insert supporting run?flat tire(ISRFT).The vertical force?deformation curves and deformed shapes and contact areas of the NPMEW and ISRFT are obtained using a set of vertical loads.The contact behavior is evaluated using extracted geometrical and mechanical feature parameters of the two tires.The results indicate that the NPMEW appears to exhibit considerably high radical stiffness,and the numerical value is dependent on the mechanical characteristic of the flexible tire body and hinge units.NPMEW demonstrates more uniform contact pressure than ISRFT within a certain loading range,and it can efficiently mitigate the problem of stress concentration in ISRFT shoulder under heavy load and enhance the wear resistance and ground grip performances.