CMC runing error

[Zheqi Hu]

Hi there,

When I tried to run CMC tool with RRA results, the tool failed running. And the messages can be found as

" Optimizer failed: Ipopt: Maximum iterations exceeded (status -1)
OPTIMIZATION FAILED...


CMC.computeControls: ERROR- Optimizer could not find a solution.
Unable to find a feasible solution at time = 0.1.
Model cannot generate the forces necessary to achieve the target acceleration.
Possible issues: 1. not all model degrees-of-freedom are actuated,
2. there are tracking tasks for locked coordinates, and/or
3. there are unnecessary control constraints on reserve/residual actuators."

What should I do to solve this?

What is more, I have checked the CMC troubleshooting and it states

"If CMC is failing, try increasing the maximum excitation for reserves and residuals by orders of magnitude until the simulation runs, then try working your way back down while also "relaxing" tracking weights on coordinates."

Which file should I edit to increase the maximum excitation for reserves and ersiduals?

Any advice would helpful.



Thanks
Zheqi

[Thomas Uchida]

What should I do to solve this?

There are many possible explanations. Assuming there are no upstream issues, you might first try increasing the maximum excitation for reserves and residuals. These actuators will compensate for any weak/missing muscles. The issue may become more apparent once you can get the simulation to complete and see where the reserves/residuals are high.

Which file should I edit to increase the maximum excitation for reserves and ersiduals?

The "control constraints" file. Please see the "Inputs" section of the "Getting Started with CMC" page in the Confluence documentation (http://simtk-confluence.stanford.edu:80 ... d+with+CMC).

[Ryo Ueno]

HI,

I also failed to run CMC for single leg landing task. Though I increased the isometric force to twice of gait2392 as previously reported, I think the model is still weak for landing. Then, I tried to increase maximum excitation and/or optimal force of reserves and residuals, but CMC tool always fail at the foot strike.

Please let me know any ideas to solve it.

Thank you,

Ryo