Comfort And Stability Analysis Of Articulated Steering Vehicles

The working environment of the articulated steering vehicle(ASV)is complicated and poor,When the vehicle is running on a non-structural pavement,the uneven ground causes severe vibration shock;especially the ASV generally contains the working device,the working device posture and shovel of load change frequently further aggravated the vibration of the vehicle.In addition,the center of gravity of the ASV is higher,the front and the rear frames are deflected in the process of turning,and the center of gravity of the whole machine shifts laterally,which will reduce the stability of the vehicle,the vibration of the vehicle will further reduce the stability of the vehicle.Due to the restriction of the vehicle vibration and stability,the ASV has to reduce the speed in the process of driving and operation,which seriously affecting its mobility and operating efficiency.Therefore,how to effectively reduce the vibration and improve the stability are the key factors of the ASV in the development of high performance and high quality.In order to improve the comfort of the ASV,the engine mount,tire damping,cab and seat mount are proposed to isolate vibration,but all these methods can not effectively isolate the vibration,the driver's body vibration level still exceeds the international standard health guide warning area.This study was supported by the National Natural Science Foundation of China(Grant No.51505177),Ride comfort and operation stability of the ASV with Hydro-pneumatic Suspension are studied.Specific work is as follows:Taking the typical articulated steering wheel loader as an example,according to the selected ASV model,the structure of the suspension system was designed.Based on the ideal gas equation and the fluid mechanics theory,the mathematical model of the components of the Hydro-pneumatic suspension system was established.The stiffness and damping models of the non-connected and connected Hydro-pneumatic suspension systems were established.The relationship between the components of the wheel loader was analyzed.The multi-body dynamics software Recurdyn was used to build the virtual prototype model of the loader,and the method of simulation analysis is clarified.Based on the established mathematical model,the stiffness and damping simulation model of the Hydro-pneumatic suspension system was established by the software Matlab / Simulink.The stiffness and damping characteristics of the Hydro-pneumatic suspension system were analyzed by simulation.The effects of Hydro-pneumatic suspension parameters,such as the initial charge pressure and volume of the accumulator,the diameter of the damping hole,the diameter of the suspension cylinder and the weight of the suspension,on the stiffness and damping characteristics of the Hydro-pneumatic suspension system were studied.The responses of Hydro-pneumatic suspension for displacement and frequency were also studied.The time-domain incentive model of the road was established,the total root mean square(RMS)of weighed acceleration was taken as the evaluation index of vehicle ride comfort,and the influence of Hydro-pneumatic suspension parameters on vehicle ride comfort was studied.The acceleration characteristics of X,Y and Z direction of the vehicle were calculated when the wheel loader travelled at different speed,and the RMS values of the total weighted acceleration were calculated.The influence of different Hydro-pneumatic system on the ride comfort of the vehicle was analyzed.The analysis showed that the Hydro-pneumatic suspension system could significantly reduce the vibration and improve the ride comfort of the vehicle.The vertical acceleration,roll angle,LTR,pitch angle and the bucket vertical displacement were taken as the driving and working stability evaluation indexes,and the typical driving and working conditions were selected to study the performance of the wheel loader when turning on a flat road,passing over obstacles,scooping and unloading crushed rock.The simulation results showed that the Hydro-pneumatic suspension system could reduce the vertical acceleration of the wheel loader when passing over obstacles.The X-style Hydro-pneumatic suspension system could guarantee the stability of the vehicle when driving and operating.In summary,this paper took the wheel loader as the study object,a new type of wheel loader with Hydro-pneumatic suspension system was designed.The mathematical model of non-connected and connected Hydro-pneumatic suspension system were established,and the stiffness and damping characteristics were analyzed.Ride comfort of the vehicle when driving on the road was studied.The influence of the Hydro-pneumatic suspension system on the stability of the loader was analyzed when driving and operating.The research work of this paper provided the basis for the development of the hydrodynamic suspension system of the ASV,which had important significance to improve the ride comfort and working efficiency of the ASV.