Tire (Friction Parameterized)

Hi all,

We have been using the Tire model with the magic formula in our team but recently decided to move towards the (Friction Parameterized) version.

However, regardless of how the initial conditions are set, we receive the same diagnostic error;

An error occurred while running the simulation and the simulation was terminated Caused by: Nonlinear solver to advance time one step failed to converge due to Linear Algebra error. Failed to solve using iteration matrix

Only way we could make it work was setting the friction coefficients ridiculously high (so to avoid slipping). I have seen another user posting a similar error (with the title AWD), however he has not received any response yet.

We tested also the "sdl_4wd_dynamics" from Simscape and get the same error.

Any suggestions and help would be appreciated.

Update: We did the same analysis by opening through version 2015b and it seems that it works just fine there. Then, the problem applies to the new 2016a version.

Thanks, regards.

Answer 1

[Martin]

The issue is that the system had an underspecified initial condition, and the tires were not able to find the right solution. In R2016a, the Vehicle Body was not appropriately setting the initial velocity of the H node. This is no longer an issue in R2016b. To resolve this in R2016a, consider other ways of specifying the initial velocity on the line connected to the H node. The simplest way would be to add a Translational Free End block from the Simscape Foundation Library. This block allows setting initial velocity of a node without effecting simulation.