572 questions
Advice
0
votes
1
replies
51
views
Interfacing EOM models
Right now I have a cartesian EOM with a quaternion for body->inertial. I'd like to connect it to a equinoctial eom for faster orbital propagation. Think a two stage to orbit problem with an orbital ...
- 23
0
votes
0
answers
32
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Optimization failing when trying to enforce periodicity in Dymos
I am trying to model a simplified wave energy converter with optimal control using Dymos. The linear model of the wave energy converter is characterized by mass, damping, and stiffness terms. There is ...
- 1
Best practices
0
votes
1
replies
19
views
Dymos: Change initial conditions while using a restart file
When using dm.run_problem() with the restart option, the simulation data overwrites the values that are prescribed by means of phase.set_state_val() (etc.) in the input file. If you wanted to use an ...
- 23
Best practices
0
votes
4
replies
51
views
Dymos group ODE best practices
I built a cartesian EOM with a quaternion for body_to_inertial; the EOM also calculates flight path angles, aerodynamic angles, etc. All fine and good until I started implementing aerodynamics and ran ...
- 23
0
votes
0
answers
69
views
DerivativesWarning:Design variables have no impact on the constraints or objective. Positive directional derivative for linesearch
Good afternoon!
I'm new to OpenMDAO and optimization.
I'm trying to set up a problem with mesh geometry parameterization for a structural (FEM) optimization task. I'm using TACS https://github.com/...
- 1
0
votes
0
answers
44
views
OpenMDAO: parallel derivative coloring
I have a workflow that solves an aero-elastic steady state for multiple operating conditions, coupling an aero and structural discipline using NonLinearBlockGS, nested in a parallel group, each case ...
- 58
0
votes
0
answers
33
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Cannot generate offline documentation using the instructions on git
I'm trying to generate the OpenMDA docs for offline use. I am using Python 3.8 as recommended and have a full OpenMDAO installation via pip. Here is the initial error on the command line:
/home/philip/...
- 23
0
votes
1
answer
40
views
SNOPT output from run_problem
I'm learning how to use Dymos. Coming from OTIS, I'm used to having the snopt output routed to the terminal. Is it possible to get the content of SNOPT_summary.out echoed to terminal in real time when ...
- 23
0
votes
1
answer
61
views
Output/Input coupling through groups
I'm working on a minimum lap time problem using Dymos/OpenMDAO. I've been experiencing issues with the coupling of longitudinal acceleration and normal load calculations. I've tried to couple two ...
0
votes
1
answer
46
views
Issues with HSL MC19 Equilibrium Scaling for IPOPT in OpenMDAO and Dymos
My Dymos trajectory optimization containing an implicit group converges normally while providing user scaling in dymos (ref and ref0). Using HSL MC19 for equilibrium based jacobian scaling causes the ...
- 11
1
vote
1
answer
65
views
Specifying residuals to drive to zero with a blackbox model and NewtonSolver
I'm trying to drive some gas turbine engine outputs to 0 from a simulink model (blackbox), and use an openmdao solver to achieve steady-state. I'm calling the simulink model using the MATLAB engine ...
- 11
1
vote
1
answer
93
views
OpenMDAO NEwton solver
Is it correct to say that the om.NewtonSolver() in OpenMDAO with solve_subsystems set to False would be closest to the pure monolithic Newton-Raphson solver, while solve_subsystems set to True makes ...
- 115
1
vote
0
answers
106
views
SNOPT Installation for pyOptSparse and OpenMDAO
I'm trying to install SNOPT in the pyOpySparse driver for use in OpenMDAO.
I have followed the instructions on the distributor's website for installation of the compiled libraries in Windows. I have ...
- 11
1
vote
0
answers
72
views
Issue with discretization dependent oscillating dynamics in simple steady 2D aircraft EOM
I have been struggling to get my dymos trajectory of my hybrid aircraft model to converge to physically consistent solutions.
I have reduced the model down to just the dynamics and was able to ...
- 11
0
votes
0
answers
58
views
OpenMDAO scaling to 0-1 issue
I have an issue with the pyoptsparse IPOPT driver in OpenMDAO converging at an infeasible point. I use finite difference partials and suspect that the issue may lie in the variables or objective and ...
- 115
