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Modeling on-demand AWD



  • Greetings,
    has anyone modeled an on-demand AWD vehicle? I have a vehicle which is predominantly RWD and if the the rear wheels begin to lose traction, the vehicle goes into AWD mode. The front drive will remain engaged until the torque requirement goes away (i.e. rear wheels regain traction). Seems to me that there is no straight forward way of modeling this within ANVEL. However, I'm not so sure about achieving this using Python? Has anyone tried something like this? Any help is appreciated. Thanks in advance.



  • This issue can addressed through the GUI by going into your vehicle's motor components, as shown below.

    0_1524084903387_TransferCase.PNG

    Inside of the transfer case component(which controls the power to the front and rear axles), if you click on the drop down for OutputMode, you will see None, First Only, Second Only, and the default Both. Depending on your transfer case definition in your vehicle definition file, "First Only" and "Second Only" refers to output1 and output2 respectively in the below XML snippet.

    <transferCase efficiency="0.89" name="transferCase" output1="rearAxle" output2="frontAxle" slip="10" type="locking">
    	<ratio value="1.0"/>			
    	<ratio value="2.72"/>			
    </transferCase>
    

    So in this case, First Only would be RWD, Second Only would be FWD and Both would be AWD.
    Since this is a changeable property in the properties menu, you can also manipulate these values through the External API at run time.

    What that might look like using Python through the External API:

    transferCase = anvel.GetObjectDescriptorByTypeAndName("TorqueSplitter", "transferCase")
    anvel.SetProperty(transferCase.id, "OutputMode", "2") # 2 is the index in the list which corresponds to Second Only
    

    For more information on transfer cases and power trains in general, please refer to https://wiki.anvelsim.com/index.php/Generic_Powertrain .