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2-Post K&C Test - Front Rack Steering

Hi all,

I need to have a perspective on something i am currently working on: I am trying lock-to-lock steering test on 2-post assembly in adams car with suspension testrig. 

Input is 0 to 640 deg at steering wheel.

Tire using - MF-Swift.tir

Problem: I am getting very less steering torque values at driving wheel. (EPS OFF) 

My thought: It is due to tire and testrig table interaction needs to be modelled as currently it is acting like frictionless.

How to model the resistance of tire-road for 2 post kinematic and compliance tests.?

Thanks



.
[edited by: Sudhanshu Kashyap at 3:32 AM (GMT -6) on Jan 16, 2025]
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  • Unfortunately, I cannot tell you what exactly SWIFT Tire is using.

    But what you see is a result of a child variable in the tire-ude called rpf_file

    For a poster-analysis it's set to "BEDPLATE".

    For an FTire you can have a moving road basically via a roadfile containing the poster translation or via a moving part in ADAMS where the "roadfile" is attached to.

    In our case it's the contour of the poster plate.

    And maybe you'll get away without any own testrig: We had an application where the steering rod forces for parking were required. 

    First shot was a full vehicle run by a driver-xml created by the event-builder (vehicle in neutral, velocity = 0, no throtte, steering = step from ... to ... ) on a flat road with the required friction value.

    Later on it turned out that they needed something more parametric, so I created a steering-testrig and some macro/dialog box for that special application.

  • Thanks for the reply martin,

    In 2 post there is a point contact btw wheel and table. so i've created a single component torque force to represent aligning torque btw the two which is a function of tire pressure, axle load, cfactor via macros/dialog command navigator box. Now I am getting the torque values on the steering wheel around 35-40 Nm for an 700kg Axle load.(EPS OFF). 

    On the contrary i am also checking the same results with full vehicle analysis (parking effort-as you've suggested above) lets see what we get out of that.

Reply
  • Thanks for the reply martin,

    In 2 post there is a point contact btw wheel and table. so i've created a single component torque force to represent aligning torque btw the two which is a function of tire pressure, axle load, cfactor via macros/dialog command navigator box. Now I am getting the torque values on the steering wheel around 35-40 Nm for an 700kg Axle load.(EPS OFF). 

    On the contrary i am also checking the same results with full vehicle analysis (parking effort-as you've suggested above) lets see what we get out of that.

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