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Hello, I am studying ergonomics at university.

I am currently using Opensim to study the amount of muscle power exerted in the pedaling motion of a bicycle.

And I am having trouble with the setting about the pedal load during pedaling exercise.
I would like to apply a force from the pedals when I step on them. Any suggestions?
For example, it's like setting gears on a bicycle.

I am using a translator.

It is unclear what data you may or may not have, so here are a few thoughts:

1. It would be best to use measured external forces to the model with a tracking algorithm, such as Static Optimization or Computed Muscle Control. The external forces would include pedal forces, seat forces, and handlebar forces. You could then follow some of the examples (such as gait1018 or gait2392 included with the installation).
2. If you don't have measured external forces, you might have to use some constraints to generate forces at the pedals and seat, and then validate that the forces generated are good enough for your work. You could see this preliminary work as a starting example (this model is too simple to use for research): https://simtk-confluence.stanford.edu/d ... ling+Model

It sounds like you may have an idea of what forces you want to apply at the pedals, so you might be able to create ExternalLoads files (as seen in the gait1018 and gait2392 examples), and then add a constraint at the seat to apply forces there.

Thank you for reply Mr. Carmichael.

My lab only have the data obtained from motion capture.
https://youtu.be/4TMWHgjjd8A

For #1, how do I create an external load file? In the tutorial, it looks like you are just editing a file that originally exists.
For #2, does that mean adding actuators or muscles?

I'm new to Opensim, so I don't know much about it.

Yuya.

For #1, you can use the external loads file as a template for how to generate your own file (using MATLAB, Python, Excel, etc.)
For #2, we have a separate class of components called Constraints (in addition to the Actuators and Muscles). You may want to continue working through some of the tutorials and examples since you are newer to OpenSim (https://simtk-confluence.stanford.edu/d ... +Tutorials) as well as our Overview page to give you a sense of available tools (https://simtk-confluence.stanford.edu/d ... +Workflows). With the examples and tutorials, the advanced examples that involve modifying a model (the first three advanced examples) could be helpful to get you more comfortable with models.