Implict torque driven gait 2D model taking account of belt velocity perturbation
Gait2DPI is one dirvatives of Gait2D model. Gait2D is a dynamic model that contains the essential elements for simulating human gait in the sagittal plane. The model has been used in earlier forms by Ackermann and van den Bogert (2010) and by Gerritsen et al. (1998). The main features of the model are:
- Seven body segments
- Fast execution
Model dynamics and outputs are twice differentiable with respect to all inputs, which is important for certain numerical methods for simulation and optimal control. The model is intended for education and basic research. The model can be used for studies such as Ackermann and van den Bogert (2010) and Geyer and Herr (2010). More information about Gait2D model can be found in gait2d_reference.pdf
Gait2DPI is an implict model, which added walking surface velocity perturbation on the base of Gait2D. This model can be used for finding optimal controller using direct collocation in perturbed standing and walking.
The only change comparing to Gait2D model is the contact model. In original Gait2D model, walking surface is assumed in static. In this gait2dpi model, x direction friction in contact model is calcuated based on the relative velocity between foot and walking surface.
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Caution:
Velocity of walking surface here is only the perturbation, not include average walking speed.
This model does not have derivative of GRF with respect of model states
The cythonized Autolev C code takes about 40 micro seconds per rhs eval under Core i5 vPro processer.
To manually build the Autolev model and make use of it in Python::
$ cd (Store Path...)/gait2dpi
$ python setup.py build_ext --inplace
See examples/run.py.