Hybrid Controller

[Eric Hu]

Hi Dr. Geijtenbeek,

I hope you having a wonderful day! I was wondering if a hybrid controller, one that superimposes a feed forward controller with a feedback controller, can be developed within SCONE. I noticed that just using the feedback reflex controller from the "Examples" does not produce similar muscle activations as the experimental data that I have collected. Additionally, I attempted to develop an open loop feed forward controller that maps out the muscle activations using the Raise Fall Functions. The measure that I created was set to mimic the kinematics and grfs from my experimental data, but the results showed noticeable errors. My main 2 concerns are whether this idea can be created within SCONE and is it logical to create a this hybrid controller given the function of the optimizer.

If talking about this issue instead of typing is easier for you, please let me know. I'd be happy to hop on a call.

Thank you so much,

Eric

[Thomas Geijtenbeek]

Yes, you can certainly use a feedforward controller in combination with a feedback controller in SCONE.

However, if your goal is to replicate experimental data, then you are probably better of using direct collocation / OpenSim Moco.

[Eric Hu]

Hi Dr. Geijtenbeek,

Thank you so much for your response. I was wondering if a weighted combination of the two controllers is possible to describe the activation of certain muscles? This would help me merge these controllers together a little bit more seamlessly than just superimposing them together.

This replication step is a part of my goal. Later on, I would like to predict the torque of an ankle actuator using a Spline Lua code I created, and I believe SCONE can help me with this process.

Thank you,
Eric

[Thomas Geijtenbeek]

If you have multiple controllers operating simultaneously, their control signals are indeed always added together. There is no method to automatically use a weighted combination.