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Steer angles are different for same Rack Travel in Suspension analysis and Full vehicle analysis.

dmvachhani
Dear all,
 
Rightnow I am going through one problem and that needs to investigate as soon as possible.
 
I have optimized the hardpoints to get the desired steer angles for 85mm rack travel at suspension level.
 
---- Suspension Level Analysis
Now, While I am running steering analysis at suspension level, I am getting following results.
Inner_Wheel_Angle = 42.5deg (Optimized Value)
Outer_Wheel_Angle = 35.6deg
 
---- Full Vehicle Analysis
Now, when I have used the same suspension in my full vehicle and running Turn Diameter event, I am getting following results with same rack travel.
Inner_Wheel_Angle = 43.5deg
Outer_Wheel_Angle = 35.0deg
 
Then I have adjusted the rack travel to get Inner_Wheel_Angle = 42.5 deg but then Outer_Wheel_Angle is reduced to 34.2 deg.
 
----
So now my confusion is why full vehicle event showing me different steer angles for same rack travel ?
 
Also, why outer angle is different for same inner angle in full vehicle event compare to suspension level analysis ?
 
Just to note, I am running the full vehicle event at very slow speed and using PAC tire model but I guess same geometry should give the same result.
 
It will be very helpful to have your comments on this confusion.
Thank you very much in advance.
 
Regards,
Darshan
 
Parents
  • 0
    Thank you very much Jesper for clear answer !!
    Yes, it seems same as you said and it's fully convincible.
     
    But to take clear understandings, I have tried few observations as below.
     
    As I have relation between wheel travel and steer angles from suspension analysis, I tried to run both the simulation kinematically at low speed and I am expecting that wheel angle should change within certain range based on the relation with wheel travel.
     
    But what I found is that wheel angle changes are higher and not following the relation with wheel travel. So, it made me to take doubts on my models or techniques.
     
    OR Is there any way I can accurately predict the Turning Radius at early stage using suspension analysis ?
     
    Regards,
    Darshan
     
Reply
  • 0
    Thank you very much Jesper for clear answer !!
    Yes, it seems same as you said and it's fully convincible.
     
    But to take clear understandings, I have tried few observations as below.
     
    As I have relation between wheel travel and steer angles from suspension analysis, I tried to run both the simulation kinematically at low speed and I am expecting that wheel angle should change within certain range based on the relation with wheel travel.
     
    But what I found is that wheel angle changes are higher and not following the relation with wheel travel. So, it made me to take doubts on my models or techniques.
     
    OR Is there any way I can accurately predict the Turning Radius at early stage using suspension analysis ?
     
    Regards,
    Darshan
     
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