Prescribed coordinate not working:
Posted: Mon Mar 30, 2020 11:27 am
Hi,
My model has several degrees of freedom and I prescribed one of the generalized coordinates and saved the model. The section of the model file displaying information on that coordinate is shown below:
After integrating the model I realized that the coordinate does not follow the prescribed path prescribed for it above. Am I missing something else in doing this? I note that neither OpenSim documentation nor any previous forum posting contains any successful example of prescribing generalized coordinates in this way.
Thanks.
Musa
My model has several degrees of freedom and I prescribed one of the generalized coordinates and saved the model. The section of the model file displaying information on that coordinate is shown below:
Code: Select all
<coordinates>
<Coordinate name="walkerToGround_coord_0">
<!--The value of this coordinate before any value has been set. Rotational coordinate value is in radians and Translational in meters.-->
<default_value>0</default_value>
<!--The speed value of this coordinate before any value has been set. Rotational coordinate value is in rad/s and Translational in m/s.-->
<default_speed_value>0</default_speed_value>
<!--The minimum and maximum values that the coordinate can range between. Rotational coordinate range in radians and Translational in meters.-->
<range>-5 5</range>
<!--Flag indicating whether or not the values of the coordinates should be constrained to the current (e.g. default) value, above.-->
<locked>false</locked>
<!--If specified, the coordinate can be prescribed by a function of time. It can be any OpenSim Function with valid second order derivatives.-->
<prescribed_function>
<SimmSpline>
<x> 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1</x>
<y> 0 0.0075 0.0175 0.0325 0.05 0.065 0.0825 0.095 0.1 0.1 0.1</y>
</SimmSpline>
</prescribed_function>
<!--Flag indicating whether or not the values of the coordinates should be prescribed according to the function above. It is ignored if the no prescribed function is specified.-->
<prescribed>true</prescribed>
</Coordinate>
</coordinates>
Thanks.
Musa