Driver Resulting in Solver Failure

User: "draucis"
Altair Community Member
Updated by draucis

Hello,

Earlier I posted a question about the solver failing due to custom inertia values. Now that thing is sorted out, but the new thing is I am modeling with a detailed rider now, the solver is failing and sometimes not solving at all without error, so when I deactivate the driver, the solver works fine and when I activate it gives an error. I tried to simplify my model by adding a simple rider instead of the detailed one, but the error is still there. the error I get is the menitoned below. I have not edited the driver and have taken the default values for mass and inertia.

WARNING: Akima-interpolation -> Data out of bounds Spline id:0
         Future messages for Spline will be suppressed.
WARNING: Akima-interpolation -> Data out of bounds Spline id:0
         Future messages for Spline will be suppressed.
 Time=1.202E+00; Order=2; H=5.000E-04 [Max Phi=3.336E-07]
WARNING: [DASPK] The nonlinear system solver in the time integration could not converge
 .....
WARNING: EvaluateResidual failed (NaN encountered)! Future warnings will be suppressed.
         Residual idx=2214, GS/310001 X1
ERROR: [DASPK] IRES = -2 was encountered and control is being returned to the calling program
 .....

 DAE SOLVER STATISTICS (DASPK-Index3)
 ------------------------------------------------
 Number of solution steps                 = 1341
 Number of residue evaluations            = 445
 Number of jacobian computations          = 516
 Number of error test failures            = 4
 Number of nonlinear convergence failures = 31


WARNING: Repeated abnormal return from integrator!

ERROR: At time=1.254E+00 the integrator failed to proceed.

after this there is list of probable causes.

Regards 

Draucis

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    User: "Jagadeesh R"
    Altair Employee
    Accepted Answer
    Updated by Jagadeesh R

    hi Draucis,

    The modified model is attached here.

    The issue was not with inertia values. The powertrain solver variables and rear monoshock suspension properties needed changes to run events

    1] Edited FMU vehicle speed and throttle inputs. Vehicle velocity needed in FMU control should be in m/s. throttle value is in %.

    2] Propulsion torque which is coming form FMU need to be changed to model units so multiplied by 1000 in solver variable within Electric powertrain.

    Note: You can refer help document and library/example models to verify the unit system followed in FMU control and within motionview model.

    3] Observed rear monoshock suspension motion ratio, stiffness and preload value issues. I have moved back and up just to solve the model with edited powertrain parameters. Please consider correct stiffness, preload values for the monospring spring based on required motion ratio.