Why does the example "Three axle tractor towing a trailer" model a difference in the normal loads on the different axles?

I was testing out the "Three-Axle Tractor Towing a Trailer" and observed that there was a difference in the normal loads on the front, middle and rear axles of the trailer. I thought that in actual vehicles, the load leveling device ensures that the load is the same on all three trailer axles.

 

Could I get some clarification on this?

Answer 1

[MathWorks Support Team]

As of MATLAB R2020a, the Vehicle Dynamics Blockset three axle vehicle models assume fully independent suspensions in both the 3DOF and 6DOF implementations.