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Vehicle dynamics is the study ofvehicle motion, e.g., how a vehicle's forward movement changes in response to driver inputs, propulsion system outputs, ambient conditions, air/surface/water conditions, etc.Vehicle dynamics is a part ofengineering primarily based onclassical mechanics.It may be applied formotorized vehicles (such as automobiles),bicycles and motorcycles,aircraft, andwatercraft.
The aspects of a vehicle's design which affect the dynamics can be grouped into drivetrain and braking, suspension and steering, distribution of mass, aerodynamics and tires.
Some attributes relate to thegeometry of thesuspension,steering andchassis. These include:
Some attributes or aspects of vehicle dynamics are purely due tomass and its distribution. These include:
Some attributes or aspects of vehicle dynamics are purelyaerodynamic. These include:
Some attributes or aspects of vehicle dynamics can be attributed directly to thetires. These include:
Some attributes or aspects of vehicle dynamics are purelydynamic. These include:
The dynamic behavior of vehicles can be analysed in several different ways.[1] This can be as straightforward as a simplespring mass system, through a three-degree of freedom (DoF) bicycle model, to a large degree of complexity using amultibody system simulation package such asMSC ADAMS orModelica. As computers have gotten faster, and software user interfaces have improved, commercial packages such as CarSim have become widely used in industry for rapidly evaluating hundreds of test conditions much faster than real time. Vehicle models are often simulated withadvanced controller designs provided assoftware in the loop (SIL) with controller design software such asSimulink, or with physical hardware in the loop (HIL).
Vehicle motions are largely due to the shear forces generated between the tires and road, and therefore the tire model is an essential part of the math model. In current vehicle simulator models, the tire model is the weakest and most difficult part to simulate.[2] The tire model must produce realistic shear forces during braking, acceleration, cornering, and combinations, on a range of surface conditions. Many models are in use. Most are semi-empirical, such as thePacejka Magic Formula model.
Racing car games or simulators are also a form of vehicle dynamics simulation. In early versions many simplifications were necessary in order to get real-time performance with reasonable graphics. However, improvements in computer speed have combined with interest in realistic physics, leading todriving simulators that are used for vehicle engineering using detailed models such as CarSim.
It is important that the models should agree with real world test results, hence many of the following tests are correlated against results from instrumented test vehicles.
Techniques include:
{{cite book}}:|last= has generic name (help) Vehicle dynamics and chassis design from a race car perspective.