Steering simulation issue
Steering simulation issue
(OP)
Hello,
I have encountered an issue and I was wondering whether you can help me with it.
I have a front axle assembly with a steering system trying to run a suspension analysis:steering. The steering consists of a steering wheel that goes to a steering lever through a reduction box. Now, if I set up the reduction at 10 and run an analysis from -100 to 100 degrees, the simulation runs just fine. If I set up the reduction at 1 and run the analysis from -10 to 10deg, the simulation fails pointing out a following error:
Static equilibrium analysis has not been successful.
The maximum number of iterations 25, has been reached.
For the last attempted iteration:
The equation with the largest error was model.testrig.controller_steering Comp = 0 Error = 0.000000
The variable receiving the largest increment was model.testrig.jostra_steering_part Comp = 3 Delta = 9.099849.
This means I try to run the simulation with the same inputs, only difference is the reduction. I checked the pvs_max_steering_torque and angles, and both should be within the limits. I don't see any other inputs that might cause the simulation to fail.
Do you have any tips?
Thanks a lot!
Sincerely,
Vojtech
I have encountered an issue and I was wondering whether you can help me with it.
I have a front axle assembly with a steering system trying to run a suspension analysis:steering. The steering consists of a steering wheel that goes to a steering lever through a reduction box. Now, if I set up the reduction at 10 and run an analysis from -100 to 100 degrees, the simulation runs just fine. If I set up the reduction at 1 and run the analysis from -10 to 10deg, the simulation fails pointing out a following error:
Static equilibrium analysis has not been successful.
The maximum number of iterations 25, has been reached.
For the last attempted iteration:
The equation with the largest error was model.testrig.controller_steering Comp = 0 Error = 0.000000
The variable receiving the largest increment was model.testrig.jostra_steering_part Comp = 3 Delta = 9.099849.
This means I try to run the simulation with the same inputs, only difference is the reduction. I checked the pvs_max_steering_torque and angles, and both should be within the limits. I don't see any other inputs that might cause the simulation to fail.
Do you have any tips?
Thanks a lot!
Sincerely,
Vojtech
Talk To Other Members
RE: Steering simulation issue
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Steering simulation issue
thanks for your reply.
I don't know how to run a static funnel with the A/CAR simulation as there is nothing much in the .acf file.
preferences/solver=CXX
preferences/list,status=on
control/ routine=acarSDM::con950, function=user(950,35,37,1,2,18,20,1,3,2,3,34,36,2,3,34,36,1,1,0,0,0)
simulate/static, end=251.000000, steps=250
!
stop
Could you explain how to do it please? Nevertheless, the MAXIT at 400 helps with the steering simulation. I attached the wheel steering angles in the function of the steering wheel angle to the attachment. Now there are 2 successful runs with and without reduction.
However, I also noticed an issue when running other static simulations, for example the parallel wheel travel. Unless I set the reduction above certain value I get an error when the PWT is set to start with the wheels without the contact with the testrig. It helps when I completely lock the steeering system (add 0 motion to the steering joint) or remove the steering subsystem completely. The error message ends with following:
Begin Simulation
****** Performing Quasi-Static Simulation ******
Simulation Step Function Cumulative CPU Slvr
Time Size Evaluations Steps Taken time type
___________ ___________ ___________ ___________ ________ ___
9.00000E-01 1.00000E-01 125 10 1.17 1
Time: 9.498712739E-01.
QSTATIC: Step Size Too Small: 6.119229265E-06
End Simulation
Simulation failed
Begin Static Solution
STATICS: Original static solver will be used with the Sparse linear solver.
Static Solution converged in 2 iterations
Residual imbalance is less than 0.00000E+00
End Static Solution
command: simulate/static, end=251.000000, steps=250
Begin Simulation
****** Performing Quasi-Static Simulation ******
Simulation Step Function Cumulative CPU Slvr
Time Size Evaluations Steps Taken time type
___________ ___________ ___________ ___________ ________ ___
9.49871E-01 0.00000E+00 0 0 1:30 1
Time: 9.498712739E-01.
QSTATIC: Step Size Too Small: 6.104739471E-05
End Simulation
Simulate status=-124
command: !
command: stop
Termination status=0
Terminating Adams Car usersubs...
Finished -----
Elapsed time = 113.29s, CPU time = 112.48s, 99.29%
Analysis failed!
Please check the error messages to determine the cause.
Thanks again for the support Greg.
Sincerely,
Vojtech
RE: Steering simulation issue
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Steering simulation issue
I was advised to by the MSC support to check the following link:
https://simcompanion.hexagon.com/customers/s/artic...
Then to set environment variable MSC_SD_STTRQ_MAX which limits the maximum steering torque for any simulation done in Adams. But still no success. I'm still in contact with the support, I will post the solution here if I'm successful. Seems to me like an internal A/CAR issue.
Thank you Greg for your time.
Sincerely,
Vojtech
RE: Steering simulation issue
Just to come back on the issue I was facing. I received a feedback from Adams support. The issue seems to be really in the solver settings. Changing the stability parameter from 1e-5 to 1e-7 solves the problem I have. I cannot tell if there is something else I can do within the model to avoid changing the solver's setting.
Thanks a lot for your time.
Have a nice day,
Vojtech
RE: Steering simulation issue
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?