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edited Dec 20, 2012 at 23:36

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First things you need to understand are "slip ratio" and the "traction circle". Slip ratio is a good approximation for tire behavior, with a non-linear relationship between angle difference and lateral tire force. It also provides you with driver torque feedback information (for force feedback steering wheel).

The super simple version of both concepts are as follows: the more angle difference between rolling direction and movement direction, the more force there is perpendicular to the rolling direction (lateral force). It reaches peak at (typically) maybe 5° to 8° and falls off from there if tire angle is increased.

The traction circle is basically a limiter that clips off any force vector that goes outside it. It models the way that heavy acceleration/braking reduces steering ability, and vice versa. The size of the traction circle (max traction force vector) scales with the force pressing the tire onto the ground.

You'd need to model the lateral (steering) force separately from the driving/braking (rotational) torque and the opposing traction force from the ground.

First things you need to understand are "slip ratio" and the "traction circle". Slip ratio is a good approximation for tire behavior, with a non-linear relationship between angle difference and lateral tire force. It also provides you with driver torque feedback information (for force feedback steering wheel).

The super simple version of both concepts are as follows: the more angle difference between rolling direction and movement direction, the more force there is perpendicular to the rolling direction (lateral force). It reaches peak at (typically) maybe 5° to 8° and falls off from there if tire angle is increased.

The traction circle is basically a limiter that clips off any force vector that goes outside it. It models the way that heavy acceleration/braking reduces steering ability, and vice versa. The size of the traction circle (max traction force vector) scales with the force pressing the tire onto the ground.

First things you need to understand are "slip ratio" and the "traction circle". Slip ratio is a good approximation for tire behavior, with a non-linear relationship between angle difference and lateral tire force. It also provides you with driver torque feedback information (for force feedback steering wheel).

The super simple version of both concepts are as follows: the more angle difference between rolling direction and movement direction, the more force there is perpendicular to the rolling direction (lateral force). It reaches peak at (typically) maybe 5° to 8° and falls off from there if tire angle is increased.

The traction circle is basically a limiter that clips off any force vector that goes outside it. It models the way that heavy acceleration/braking reduces steering ability, and vice versa. The size of the traction circle (max traction force vector) scales with the force pressing the tire onto the ground.

You'd need to model the lateral (steering) force separately from the driving/braking (rotational) torque and the opposing traction force from the ground.

answered Dec 20, 2012 at 23:31

141
6

First things you need to understand are "slip ratio" and the "traction circle". Slip ratio is a good approximation for tire behavior, with a non-linear relationship between angle difference and lateral tire force. It also provides you with driver torque feedback information (for force feedback steering wheel).

The super simple version of both concepts are as follows: the more angle difference between rolling direction and movement direction, the more force there is perpendicular to the rolling direction (lateral force). It reaches peak at (typically) maybe 5° to 8° and falls off from there if tire angle is increased.

The traction circle is basically a limiter that clips off any force vector that goes outside it. It models the way that heavy acceleration/braking reduces steering ability, and vice versa. The size of the traction circle (max traction force vector) scales with the force pressing the tire onto the ground.