Finding ackerman measurement 1

[hertzky]

Can anybody tell me what the ackerman would equate to in this drawing? Thanks.

 

[hertzky]

Uploaded the pic, but don't see it....

 

[patprimmer]

What drawing was my question.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[carnage1]

since we are on the topic does anyone have some standard formulas for ackerman percentage vs. steering geometry? I tried to derive them myself but got pretty bogged down and thought someone must have done it already. I have not been able to find a diagram with accompanying equations in the texts I have available.

 

[GregLocock]

"The Automotive Chassis Engineering Principles
J. Reimpell H. Stoll J. W. Betzler.
ISBN 978-0-7680-0657-5 "

Has a very thorough discussion of how you get from the difference in front wheel steer angles (aka wheel cut angles aka steering error aka delta toe) to Ackermann.

Working out the steer angle error can only be done simply for very simple geometries, otherwise you need to consider 3d angles. If you have a double wishbone geometry then wishbon.bas will work them out.







Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[GregLocock]

% Ackerman = ( ai - ao ) / ( aic - aoc )


where: ai
=
inside wheel steer angle

ao
=
outside wheel steer angle

aic
=
inside wheel steer angle required to have the wheel plane perpendicular line intersect a line passing through the rear axle at the center point between where the inside tire perpendicular intersects the axle line and where the outside tire perpendicular intersects the line.

aoc
=
outside wheel steer angle required to have the wheel plane perpendicular line intersect a line passing through the rear axle at the center point between where the inside tire perpendicular intersects the axle line and where the outside tire perpendicular intersects the line.




Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[carnage1]

Thanks Greg, the equation should give me enough to start with and ill see if I can hunt up a copy of Ren and Stimpy.