The FZ measure returns the z-component of the net translational force acting on marker i, represented in the coordinate system of marker k. All force and constraint elements acting between markers i and j are included in the calculation of the force. If j is not specified, FZ measures the sum of all force and constraint elements acting on marker i. If k not specified or if k=0 the force is represented in the GROUND coordinate system. To specify k without specifying j use j=0.
Format
FZ(i[,j][,k])
Arguments
i | An integer that specifies the identifier of the marker at which the magnitude of the net force is to be calculated. Objects using marker i (for example, SFORCE, JOINT) must be active. |
j | A second integer that specifies a marker identifier. All forces acting between the [i,j] pair are to be included in the calculation. Set j = 0 or do not specify if you are interested in all forces acting on marker i, for example, FZ(i,0,k) will compute the sum of all forces acting on marker i. |
k | An integer that specifies the identifier of a marker (coordinate system) in which the z-component of the force is to be returned. k defaults to the global coordinate system when it is not specified. |
Examples
SFORCE/1, I=23, J=11, TRANSLATION, ACTIONONLY
, FUNCTION=STEP5(FZ(34), -1.5, -200, 1.5, 200)
This SFORCE statement defines a translational, action-only, nonlinear force. The force is directed along the z-axis of Marker 11. The value of the force is a 5
th order step function (see
STEP5). The independent variable for the STEP5 function is FZ(34), the net force acting along the global z-axis at Marker 34. Since no j marker is specified, only action-only forces acting at Marker 34 are included in the calculation of FZ().