| Tires as the only unit to connect the body with the road, in addition to the air force,almost all the external forces acted on vehicles are from the tire and road contact force. Thefirst is based on accurate modeling of the vehicle dynamics model for accurate modeling ofthe contact force to the tires and the road. Model of the traditional wheel tire forcecalculation does not consider the rim and the matrix of elastic connection, and thus cannot bedynamic calculation of the tire ground at the slip, and can not reflect the flexibility of the tirecasing on the power transfer.In addition, the premise of research on non-level road vehicle dynamics and the vehiclemodel simulation is a mathematical expression to non-level road and the establishment of thedetection method of the tire ground point location information. Therefore, based on thedynamic calculation of the tire slip rate, build a dynamics model considering the dynamicwheel of the matrix, while creating a model of non-level road and the road surface contactdetection algorithm in order to meet the non-level road vehicle dynamics model simulationon the road information input requirements. The main work and conclusions are as follows:1. The model of the dynamic wheel based on a ground point to the dynamic calculationof the tire slip rate is established. The model describes the mechanical properties of tirenon-steady state conditions by taking into account the flexibility to connect and establish thedynamics of the six degrees of freedom of the matrix, dynamically calculating the slip of thetire ground between the matrix and rims. The modeling process is divided into two parts: thesystem of rigid ring dynamics and the system of the tire statics. Rigid ring dynamics systemsimplifies the tire carcass as a rigid ring model, and the sidewall and inflatable elastic as thesix spring-dampers which connects the rigid ring and the rim. Through the establishment ofthe dynamics of a rigid ring complete six degrees of freedom; dynamically calculate the slipof the tire ground imprinted is acquired. Through the establishment of six spring-dampers model, describing the filtering effect of the flexibility of the carcass is obtained. Through theestablishment of contact between the tire and the road model and friction model of tirestatics system, calculating the tire and the ground contact force is achieved.In order to simulate the driving of the low velocity zone and "Stand Still" and otheroperating conditions, the friction model establishes static and dynamic friction separationalgorithm, dividing friction force into friction static friction and dynamic friction accordingto certain rules, as well as adopting different methods of calculation. Among them, the staticfriction force is calculated according to external power (six spring-damping force); whiledynamic friction is obtained by using the steady-state tire model. To calculate the dynamicfriction, the steady-state interpolation tire model is created. The main parameters of thedynamic wheel model are the six stiffness of the tire carcass. This paper presents the solutionmethod of the matrix stiffness, and applies the suspension K&C test data to calculate.2. Based on the requirements of describing for a new generation of vehicle dynamicssimulation platform on the road, a non-level road model is established. Based on the S-Lcoordinate system and table structure of stored road information, road model is divided intopavement discrete points mesh, the description of the road surface is established, and accessto the tire ground detection algorithm is studied.3. Finally, the non-level road dynamic wheel model is simulated to verify the results ofthe dynamic wheel model on the flat road surface as well as on a non-level road. The resultsshowed that: the non-level road dynamic wheel model is computationally efficient and canbe used for real-time simulation of vehicle dynamics, and of high precision in describing thesteady-state mechanical properties of the tire, and can better describe the mechanicalproperties of the dynamic tire, and has a higher accuracy on the road surface expression aswell.Through this research, the model of the tire-ground system for the pre-developmentphase is established. The model is of high accuracy, with few parameters while each with aclear physical meaning, easily obtained, and of high computational efficiency. Therefore, itcan be applied to real-time simulation of vehicle dynamics to improve vehicle modelsimulation accuracy. |
