Ground contact of human model

[George Mastorakis]

Hi,
I'm trying to use the model from (Induced Accelerations-based controller for balance), but it seems that the ground does not hold the body as it fells down. Please see attached image. How can I change this behaviour?

Thanks

[Dimitar Stanev]

Hi,

This model uses contact spheres on the foot to estimate the ground reaction force and applies these forces on the model. If you run the model in a forward manner, you need to predict and apply joint torques (or muscle forces) that counter the effect of the ground reaction forces and also to balance without falling.

[George Mastorakis]

Alright, so the ground is just for visualisation purposes. It doesn't have any impact on the human model, unless I configure the model to do so.

[Dimitar Stanev]

The ground does not do anything on its own. What you have on the above picture is a contact geometry plane. Also there are contact spheres on the foot (if I remember correct) and internally during forward simulation they are tracked for collision. When a collision occurs, a reaction force is estimated an applied to the foot points. Unfortunately, when you run forward dynamics you are not aware of what joint torques you need to apply to counter these forces and balance without falling and that is why you need a controller.

[George Mastorakis]

Thanks Jim. As you figured out, is just my first week using the software. One final question re this model: How can I identify the force that pushes the human model backwards? There isn't any documentation unfortunately.