WY
The WY function returns the y-component of the difference between the angular velocity vector (in radians per units of time) of marker i in ground and the angular velocity vector of marker j in ground, and expressed in the coordinate system of marker k. Marker j defaults to the global coordinate system if it is not specified. Similarly, marker k defaults to the global coordinate system if it is not specified.
Note: | The values returned by the functions have the same units defined in the UNITS statement except for angular values. All angular values are returned in radians, all angular velocities are returned in radians per units of time (as defined in the UNITS statement), all angular accelerations are returned in radians per units of time squared. Functions RTOD and DTOR may be helpful to create angular expressions involving degrees and radians. For example, the below statements create a constraint to keep the angular velocity WX(8, 9) equal to 2.5 degrees per second. UNITS/SYSTEM = MKS ! Using seconds GCON/1, FUNCTION = WX(8, 9) – 2.5*DTOR ! Convert degrees to radians |
Format
WY(i[,j][,k])
Arguments
i | The marker whose velocity is being measured. |
j | The marker with respect to which the velocity is being measured. Set j = 0, while still specifying i, if you want j to default to the global coordinate system. |
k | The marker in whose coordinate system the velocity vector is being expressed. Set k = 0 if you want the results to be calculated along the y-axis of the global coordinate system. |
Extended Definition
Mathematically, WY is calculated as follows:
where:
■
is the angular velocity vector of marker i in ground.
is the angular velocity vector of marker i in ground.■
is the angular velocity vector of marker j in ground.
is the angular velocity vector of marker j in ground.■
is the unit vector along the y-axis of marker k.
is the unit vector along the y-axis of marker k.Examples
MARKER/1236, QP=4,6,7 EU=90D,90D,90D, PART=23
MARKER/2169, PART=16
REQUEST/16
,F1=WM(1236,2169)/
,F2=WX(1236,2169,2169)/
,F3=WY(1236,2169,2169)/
,F4=WZ(1236,2169,2169)
MARKER/2169, PART=16
REQUEST/16
,F1=WM(1236,2169)/
,F2=WX(1236,2169,2169)/
,F3=WY(1236,2169,2169)/
,F4=WZ(1236,2169,2169)
In its third column, REQUEST/16 contains the y-component of the angular velocity Markers 1236 and 2169 as measured in the coordinate system of Marker 2169.
See other Velocity measures available.