Opened 12 years ago
Last modified 7 years ago
#1929 assigned defect
Multibody USR and SSR joints have wrong initialization values
| Reported by: | Bruno Scaglioni | Owned by: | Willi Braun |
|---|---|---|---|
| Priority: | high | Milestone: | 2.0.0 |
| Component: | Backend | Version: | trunk |
| Keywords: | Cc: |
Description
ModelicaTest.MultiBody.FourbarVariants.JointUSR and
ModelicaTest.MultiBody.FourbarVariants.JointSSR models simulate with wrong results, this is due to wrong initialization of some variables including derivatives of state variables, see for example j2.a in JointUSR or
Body1.w_a[1]
Body1.z_a[1]
Body2.v_0[2]
Body2.a_0[2]
in joints.SSR
The initial conditions and values for the states are completely specified in the models but OMC wrongly computes the initial value of some variables in the USR and SSR joints.
Change History (16)
comment:1 by , 12 years ago
| Owner: | changed from to |
|---|---|
| Status: | new → assigned |
comment:2 by , 12 years ago
| Resolution: | → fixed |
|---|---|
| Status: | assigned → closed |
follow-up: 4 comment:3 by , 12 years ago
| Resolution: | fixed |
|---|---|
| Status: | closed → reopened |
The models are still initialized different to Dymola.
comment:4 by , 12 years ago
Replying to wbraun:
The models are still initialized different to Dymola.
It would be very helpful, if you can also say what actually initialized different. Just to make work more efficient.
follow-up: 6 comment:5 by , 12 years ago
OpenModelica: ModelicaTest.MultiBody.FourbarVariants.JointSSR
Warning: Parameter jointSSR.rod1.rodLength has no value, and is fixed during initialization (fixed=true), using available start value (start=1.0) as default value
is different to Dymola, where jointSSR.rod1.rodLength is initialized with 1.04881.
comment:6 by , 12 years ago
Replying to lochel:
OpenModelica: ModelicaTest.MultiBody.FourbarVariants.JointSSR
Warning: Parameter jointSSR.rod1.rodLength has no value, and is fixed during initialization (fixed=true), using available start value (start=1.0) as default value
is different to Dymola, where jointSSR.rod1.rodLength is initialized with 1.04881.
OpenModelica: ModelicaTest.MultiBody.FourbarVariants.JointSSR
jointSSR.rod1.rodLength is now correctly initialized with 1.04881
OpenModelica: ModelicaTest.MultiBody.FourbarVariants.JointUSR
is properly initialized according to the test ModelicaTest.MultiBody.FourbarVariants.JointUSR_init.mos
comment:8 by , 10 years ago
| Owner: | changed from to |
|---|---|
| Status: | reopened → assigned |
It seems that the example ModelicaTest.MultiBody.FourbarVariants.JointUSR misses an event somehow and produces therefore wrong simulation results.
The other example (ModelicaTest.MultiBody.FourbarVariants.JointSSR) fails during compilation while generating a symbolic jacobian matrix. (That issue is also reported in other tickets.)
Originally, this ticket was about initialization issues, but I think we should not close it until both models simulate as expected.
comment:9 by , 10 years ago
| Milestone: | 1.9.1 → 1.9.2 |
|---|
This ticket was not closed for 1.9.1, which has now been released. It was batch modified for milestone 1.9.2 (but maybe an empty milestone was more appropriate; feel free to change it).
comment:10 by , 10 years ago
| Milestone: | 1.9.2 → 1.9.3 |
|---|
Milestone changed to 1.9.3 since 1.9.2 was released.
comment:15 by , 8 years ago
| Milestone: | 1.11.0 → 1.12.0 |
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Milestone moved to 1.12.0 due to 1.11.0 already being released.
comment:16 by , 7 years ago
| Milestone: | 1.12.0 → 2.0.0 |
|---|
Initialization works fine using the new initialization method (+d=solveinitialsystem). Simulation results are still wrong.