This routine computes the error between a desired quanity and an instantanous quanity. The "quanity" may be displacement, velocity, acceleration or force between an "I" marker and a "J" marker along the shadow of the X axis of the "I" marker on the ground plane. The calling diffsub/diff computes the integral of the error. The desired quantity is set by the user in a spline statement or as a constant. If the desired quantity is set in a spline statement, the quantity can vary with time. Typically this routine works in conjunction with Traction Controller (PI) and Braking Controllers.
DIFF/id, IC = 0.0
, FUN=USER (1102, spid, imot, bm, gm )
where:
id | = | Diff statement id |
spid | = | A positve value specifies the id of spline representing the desired quantity with respect to time. A negative values specifies a constant value. |
imot | = | Type of quatity whose error is to be determined :
1 - Translational displacement
2 - Translational velocity
3 - Translational acceleration
4 - Translational force |
bm | = | I marker whose quatity is measured with respect to base marker. |
gm | = | Base marker |