LTS Output Variable Listing - Milliken Research Associates, Inc.

LTS Output Variable Listing  - Milliken Research Associates, Inc.
MRA
Lap Time Simulation User’s Manual
August 28, 2001
Chapter 9
Program Output
When LTS is run, several output files are generated:
•
Standard print output goes to the *.out file.
•
Spreadsheet-formatted output data goes to several files that are always named tmp1.prn,
tmp2.prn, tmp3.prn and etc. See Section 9.2 for more detail.
•
Plot output (for use with the LTG.EXE program) goes to the *.plt file.
•
Optionally, a series of files are written by LTS for import into Pi Research Ltd Analysis
Software (Version 6.6.2 or higher).
•
Optionally, a series of files are written by LTS for use by Track Master 2000 software.
User controllable input/output filenames are read from the LTS.INP file. In the command line
(DOS-box) version, to change car, track or tire data for a run, simply edit this file and change the
appropriate input filename (and output filenames, to save previous output data). In the Windows
version LTS.INP is changed through on-screen selections. See Chapter 3 for more detail on the
LTS.INP file.
9.1 Output (Print) File Description
The print file (*.out) is a standard DOS-ASCII data file that can be viewed/edited with any text
editor (or programmer’s editor). This file documents a single LTS run and is primarily intended for
debugging purposes. The print file can be directed to a printer with the DOS PRINT command as
needed. Note that the file contains lines longer that 80 columns; therefore either a 132 column
printer should be used or an 80 column printer should be in “compressed mode” — see your printer
manual.
With the Windows front end, an icon for the print file appears on the main screen after a single
LTS run is made. The print file can be viewed by double clicking on this icon, assuming that the
.out file type (extension) has been previously associated with an application (a text editor).
Input Documentation and Output Summary
The print file contains several sections that document the input and summarize the output:
LTS Version 3.11
— 155 —
Chapter 9
August 28, 2001
Lap Time Simulation User’s Manual
MRA
1.
An echo of the comment lines and data from the input files.
2.
A block of data calculated from the car inputs — this may be useful in sorting out input
data problems. Included is: total weight, CG locations (sprung and unsprung), other
dimensional data and calculated spring rate data.
3.
An echo of the comment lines from the tire datafile and a tire data listing.
4.
An echo of the comment lines from the track file and a calculation of the position and
heading at the end of the track, relative to the starting section. Section-by-section track
geometry data is included in the station output data.
5.
If there were any convergence errors reported by the solver, they are printed in this location.
6.
Lap time and average speed for this simulation run.
Cutoff Point Output Data
A list of all acceleration/braking transition points (or cutoff points) on the track is given next. This
list includes the following:
sta
Station number after which the transition occurs.
vprime
Speed at the transition point — mph.
lprime
Distance from the beginning of the section to the transition point — ft.
tpwr
Time spent under power from the start of the section to the transition point
— sec.
tbrk
Time spent under braking from the transition point to the beginning of the
next station — sec.
Station Output Data
The output printed by the program at each station on the track includes a description of the track
section geometry and a number of vehicle operational variables at that point on the track. This data
is given in a multi-line format to allow it to fit within the 132 column limit of most printers.
The printed data for each station (not necessarily in this order) includes:
seg
The segment number within which the station resides. The first segment
printed is the segment number associated with the start/finish line (isf in
the track data file).
sta
The station number. Recall that each segment may contain more than one
station. This number reflects the cumulative number of stations from the
Chapter 9
— 156 —
LTS Version 3.11
MRA
Lap Time Simulation User’s Manual
August 28, 2001
beginning of the track data set but are printed in sequence from the S/F
line.
frc
Tire/ground friction multiplier for this station. This is the product of the
global friction multiplier (uglob) and the local friction multiplier
(sfrc(sta)).
ba
Bank angle of the station, positive for the right side of the track down —
deg.
ga
Grade angle of the station, positive for uphill — deg.
bounce
Inverse of the vertical radius of the station. Positive for a dip (increase in
normal load), negative for a bump (decrease in normal load). Units are
1/ft.
rad
Plan view path radius at this station, positive for a RH turn — ft.
dist
Cumulative distance from the S/F line — ft.
time
Cumulative time from the S/F line — sec.
v
Forward speed of the car along the path, at the start of the section — mph.
ax
Acceleration in the x direction. This is the rate of change of “v” along the
path with respect to time. Positive values increase speed — g’s. This is
not equivalent to a body fixed accelerometer.
ay
Acceleration perpendicular to the path and in the ground. This is the
lateral acceleration that would be measured by an accelerometer mounted
at the c.g. of the car corrected for yaw rate, yaw angle, pitch angle and
absolute roll angle — g’s.
v0a
This is the car speed along the path at which ax = 0. Assumed to be the
maximum speed at which the car can traverse the station. Due to
aerodynamic and sideslip drag, driving forces must exist to maintain
ax = 0. For straights or very large radius sections, an approximate value is
used representing the power limited speed of the car — mph.
bal
Brake or power balance. The fraction of the x-force that is applied by the
rear wheels. For negative x-force, it appears as a negative number. It is
+1.0 for a rear drive car under power; -0.25 for braking with 25% of the
braking force at the rear.
phi
Car roll angle (positive right side down) — deg.
LTS Version 3.11
— 157 —
Chapter 9
August 28, 2001
Lap Time Simulation User’s Manual
MRA
usep
Power usage. The percentage of available engine power that is being
used. Under full power, 1.0. Under braking, it is negative and provides a
measure of braking horsepower relative to peak engine power.
usef
percentage of current front axle force (in the plane of the road) to the
maximum force available from the front tires.
user
percentage of current rear axle force (in the plane of the road) to the
maximum force available from the rear tires.
del
Front wheel reference steer angle. This is the steering wheel angle
divided by the overall steering ratio — deg.
bet
Car sideslip angle — deg.
fzlf
Left front tire normal force — lb.
fzrf
Right front tire normal force — lb.
fzlr
Left rear tire normal force — lb.
fzrr
Right rear tire normal force — lb.
fylf
Left front tire lateral force — lb.
fyrf
Right front tire lateral force — lb.
fylr
Left rear tire lateral force — lb.
fyrr
Right rear tire lateral force — lb.
fxlf
Left front driving force — lb.
fxrf
Right front driving force — lb.
fxlr
Left rear driving force — lb.
fxrr
Right rear driving force — lb.
fslipd
Front axle tire sideslip drag. This represents the sum of the front tire side
force components along the path — lb.
rslipd
Rear axle tire sideslip drag — lb.
alplf
Left front tire slip angle — deg.
alprf
Right front tire slip angle — deg.
alplr
Left rear tire slip angle — deg.
Chapter 9
— 158 —
LTS Version 3.11
MRA
Lap Time Simulation User’s Manual
August 28, 2001
alprr
Right rear tire slip angle — deg.
SMhcg
Sprung mass CG height above ground — in.
theta
Pitch attitude, positive pitch angle is nose up — deg.
power
Engine power output at the current station — hp.
engrpm
Engine speed at the current station — rpm
gear
Transmission gear (for standard transmission) or transmission gear ratio
(for cvt) at current station. Note that for a standard transmission a gear of
0 will occur at a station for which the shift time is greater than the time
required to traverse the section.
vaero
Apparent wind speed (car speed plus ambient wind speed) — mph
psiaero
Apparent wind angle (per SAE aero axis) — deg.
fxa
Aerodynamic drag force acting on the car — lb.
fzfa
Front aerodynamic lift force (positive for downforce) — lb.
fzra
Rear aerodynamic lift force (positive for downforce) — lb.
fyfa
Front aero side force (positive to right) — lb.
fyra
Rear aero side force (positive to right) — lb.
mxaero
Aero rolling moment (positive right side down) — lb. ft.
gamlf
Left front wheel inclination angle — deg.
gamrf
Right front wheel inclination angle — deg.
gamlr
Left rear wheel inclination angle — deg.
gamrr
Right rear wheel inclination angle — deg.
qlf
Left front wheel rotational speed — rad./sec.
qrf
Right front wheel rotational speed — rad./sec.
qlr
Left rear wheel rotational speed — rad./sec.
qrr
Right rear wheel rotational speed — rad./sec.
helf
Left front effective radius — in.
LTS Version 3.11
— 159 —
Chapter 9
August 28, 2001
Lap Time Simulation User’s Manual
herf
Right front effective radius — in.
helr
Left rear effective radius — in.
herr
Right rear effective radius — in.
MRA
Note: If effective radius data (REI and KRE) are not supplied, these radii
outputs default to free radius (unloaded radius).
tqlf
Left front wheel driving torque — lb-ft.
tqrf
Right front wheel driving torque — lb-ft.
tqlr
Left rear wheel driving torque — lb-ft.
tqrr
Right rear wheel driving torque — lb-ft.
atlf
Left front aligning torque — lb-ft.
atrf
Right front aligning torque — lb-ft.
atlr
Left rear aligning torque — lb-ft.
atrr
Right rear aligning torque — lb-ft.
fsalf
Left front shock force — lb.
fsarf
Right front shock force — lb.
fsalr
Left rear shock force — lb.
fsarr
Right rear shock force — lb.
shdlf
Left front shock displacement — in.
shdrf
Right front shock displacement — in.
shdlr
Left rear shock displacement — in.
shdrr
Right rear shock displacement — in.
silf
Left front longitudinal slip ratio — %
sirf
Right front longitudinal slip ratio — %
silr
Left rear longitudinal slip ratio — %
sirr
Right front longitudinal slip ratio — %
Chapter 9
— 160 —
LTS Version 3.11
MRA
Lap Time Simulation User’s Manual
August 28, 2001
uself
Percentage of left front tire capability used — %
userf
Percentage of right front tire capability used — %
uselr
Percentage of left rear tire capability used — %
userr
Percentage of right rear tire capability used — %
hilf
Left front loaded radius — in.
hirf
Right front loaded radius — in.
hilr
Left rear loaded radius — in.
hirr
Right rear loaded radius — in.
ulf
Left front wheel center longitudinal velocity — ft./sec.
urf
Right front wheel center longitudinal velocity — ft./sec.
ulr
Left rear wheel center longitudinal velocity — ft./sec.
urr
Right rear wheel center longitudinal velocity — ft./sec.
delwlf
Left front wheel center ride travel. Positive for jounce, negative for
rebound - in.
delwrf
Right front wheel center ride travel. Positive for jounce, negative for
rebound - in.
delwlr
Left rear wheel center ride travel. Positive for jounce, negative for
rebound - in.
delwrr
Right rear wheel center ride travel. Positive for jounce, negative for
rebound - in.
LTS Version 3.11
— 161 —
Chapter 9
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement