Stepwise spatial coordinate changes after FW

[Alexandra Yurova]

Hello,

what can cause sudden jumps of translational coordinate (one of DoF in the model), computed by Forward Dynamics tool?

Are there any constraints to be set to make this function smooth?

Regards,
Alexandra

[Thomas Uchida]

Perhaps you could provide some information about the model, the motion, whether there are any controllers in the model, etc.? If this is a translational coordinate, the "jump" is only about 3 mm.

[Alexandra Yurova]

Patella movement during knee flexion is considered. Patellofemoral joint has 5DoF, there are no controllers. Even if rotation angle of patella around femur is a prescribed function of time (which is linear), there still occurs a jump in this function (see attachment) after FD and in patella's translation correspondingly.