Vicon ProCalc Force Vector Tutorial
- Former user (Deleted)
- Gisela Roberts
About this tutorial
In ProCalc 1.4 and later, force plate data became more integrated than in previous versions of ProCalc. The functions and calculation methods that were introduced enable the researcher to calculate spatial relationships between the position and orientation of the force vector, and other 3D entities such as trajectories.
This tutorial shows a potential use case for these features.
About the data for this tutorial
To follow this tutorial, navigate to C:\Program Files\Vicon\ProCalc\Help and unzip the ProCalc Tutorials Data file. Choose a path or directory that has sufficient read/write permissions and that you can remember and access easily (eg, C:\Users\Public\Documents\Vicon). If you have completed a ProCalc tutorial in the past, you may have already completed this step.
For this tutorial, we will use the Force Vector session. Within this folder, there is one trial (Static.c3d).
To access the trials in ProCalc, ensure you have a hierarchy that looks like the following example, though the specific path will depend on the location of your extracted data.
Features covered in this tutorial
These new features were introduced in ProCalc 1.4 and are described in this tutorial:
- The Center of Pressure (CoP) point for the force plate
- The force vector
- Calculating the shortest line between two other lines
Example research questions
Postural research is often concerned with answering questions about a person's symmetry when standing, walking, or performing other common movements. For example, it may be of interest to measure how asymmetric a person's standing posture is.
If the motion measurement lab has both a 3D Vicon system and one or more force plates, several useful calculations can be made.
This tutorial looks at the following measurements:
- The position of the CoP compared to the position of the feet. Does the person lean more on one foot than the other?
- The position of the ground reaction force vector compared to the pelvis inter-ASIS line. Does the person lean forwards, backwards, or sideways?
Further uses of the new functionality
This tutorial demonstrates how you can use data from force plates to calculate static parameters, but the new functionality could also be used for dynamic variables (for example, if you are interested in the moment arms from the ground reaction force relative to a joint center), or to define events (for example, the peak force event).
