Computes vehicle handling statistics such as lateral acceleration, yaw rate, roll angle, pitch angle, body sideslip angle, and longitudinal velocity in standard testing units. Lateral acceleration can be determined for vehicle roll or for suspension roll and with or without correction for gravity due to roll and pitch.
Input:
REQ/id, FUNCTION = USER(1090,bcgm,ignd,ibdy,scale,int_branch,lfbwc,lfwc,rfbwc,rfwc,lrbwc,lrwc,rrbwc,rrwc,scale)
where:
bcgm | = | test equipment transducer package location MARKER id |
ignd | = | ground reference MARKER. For models created in a coordinate system other than standard Adams Car system, origo marker should replace ignd. (origo marker represents a marker on ground in whose coordinate system the vehicle is built) |
ibdy | = | body cm MARKER |
scale | = | (optional) 1 - kph, 0 mph |
int_branch | = | (optional) internal branch id to specify correction to lateral acceleration. 1 - Ay in body frame, corrected with respect to roll and pitch (Ay as Adams measures)
2 - Ay in body frame, uncorrected (Ay as an accelerometer would measure)
3 - Ay corrected with respect to suspension roll and pitch
4 - Ay as an accelerometer would measure corrected with respect to suspension roll and pitch |
lfbwc | = | (optional) marker on body at left front wheel center MARKER id |
lfwc | = | (optional) left front wheel center MARKER id |
rfbwc | = | (optional) marker on body at right front wheel center MARKER id |
rfwc | = | (optional) right front wheel center MARKER id |
lrbwc | = | (optional) marker on body at left rear wheel center MARKER id |
lrwc | = | (optional) left rear wheel center MARKER id |
rrbwc | = | (optional) marker on body at right rear wheel center MARKER id |
rrwc | = | (optional) right rear wheel center MARKER id |
scale | = | (optional) scale factor (for example, scale = 1.0 for millimeters and for inches scale = .03937) |
Additional Notes on the int_branch Flag
Adams Car provides the user with 2 options for lateral acceleration calculation. Lateral acceleration can be output in 2 ways: with or without accelerometer gravity effects. By default (option 1) and also option 3 the acceleration is output without gravity effects. This acceleration is measured in the body reference frame. Options 2 and 4 corresponds to acceleration as an accelerometer would measure. This value is higher than that from option 1, because it contains an additional component due to angular orientation of the body, roughly equal to sin(Roll).
To modify the setting for this option modify the ay_calculation_method construction option in a standard Adams Car instrumentation subsystem file.
Lateral Acceleration Calculation Method
1. Ay in body frame, corrected with respect to roll and pitch (Ay as Adams measures)
2. Ay in body frame, uncorrected (Ay as an accelerometer would measure)
When running with the extra correlation requests, both request 1041 and request 51050 will be affected by this option. Request 51050 is used for the test accelerometer lateral acceleration.
Request File Output
Column Number Output:
1. Lateral acceleration (g's)
2. Yaw rate (deg/sec)
3. Vehicle body roll angle (deg)
4. Pitch angle (deg)
5. Vehicle sideslip angle (deg)
6. Longitudinal velocity (mph or kph)
Notes on Input and Output
This routine is very useful in model correlation studies where model results are compared to actual vehicle test data for a given maneuver. For this type of comparison, it is important to place the instrumentation MARKER at the exact location where the lateral acceleration transducer was located in the test vehicle. Parameters 7-15 are necessary only when int_branch is set to 3 or 4. In this case, the function calls string potentiometer function (user1115) to determine the suspension roll and pitch.