PiG with functional knee joint axes only
This project adds functional knee joint axes determination (SARA) only to the default Vicon PlugInGait model. It works together with the old Vicon Workstation system and allows to control the usage of the motion phases, which are used for the estimation by setting of events.
In the gait trials the lateral knee markers are projected onto the functional knee joint axes and the knee joint center is determined based on the clinical measurement of the knee width. Than the femur coordinate system is constructed equivalent to the original PiG. Keep in mind that this coordinate system does not have the functional axis as one of its axes. The axes are defined by cross products to achive orthoganal systems and have the longitudinal femur axes included.
The proximal tibia (anatomical) coordinate systems are defined by PiG virtual markers.
Preconditions
- It is assumed, that the Vicon PiG is processed for the static calibration trial and all gait trials, before processing with this model. Vicon PiG processing is not needed for the dynamic calibration trials.
- Additional markers on the shank are needed. Have a look at the follwing markerset picture
- Specific dynamic calibration movements with knee flexion; events to define the phases used by the estimation.
- Specific eclipse entries. Have a look at the following table and screenshot.