Given a car configuration with a length of L and width of W. If you can give the top left wheel an angle of A to turn A degree how do you derive the angle of top right wheel for turning . I know that the bottom left angle will just be complimentary of the top left wheel and bottom right wheel is complimentary of top right wheel. This is a swerve drive system so i can control each wheel angle.
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$\begingroup$ Lots of simikar questions on here, here is just one : engineering.stackexchange.com/a/3079/10902 $\endgroup$– Solar MikeCommented Apr 25, 2018 at 5:52
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$\begingroup$ A diagram would help. Knowing the reference point for the angles would also help. $\endgroup$– FredCommented Apr 25, 2018 at 12:10
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1 Answer
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Most road vehicle steering is based on Ackerman geometry
Put simply the plane of each steered wheel should be perpendicular to a straight line from the centre of rotation the wheel to the centre of the tuning circle.
Normally this is achieved by a mechanical linkage where the steering arms point along a line from the wheel pivot point to the centre of the rear axle. With independent steered wheels you need to translate that geometry to whatever control system you are using.
In practice there are several factors which might make you deviate from pure Ackerman steering, suspension often doesn't travel in a perfectly vertical line and you may want non-zero camper, castor and toe-in in the suspension geometry for various reasons.
Also pneumatic tyres tend to operate with a small slip angle on turning as a result of the finite stiffness of the side wall of the tyre, which is how the turning force is generated.
Modeling and analysing this in detail get very complex very quickly and there is no single 'correct' solution as it will depend on a whole variety if interrelated factors and will often end up being some compromise.
answered Apr 25, 2018 at 9:43