This document discusses Ackermann steering geometry which aims to avoid tire slip when turning a vehicle by ensuring the inner wheel turns through a greater angle than the outer wheel. It explains that at high speeds, tires must develop lateral forces to counteract lateral acceleration and slip angles will be present at each wheel. The tire's cornering force is related to its slip angle through its cornering stiffness up to around 5 degrees of slip angle.

1. VEHICLE DYNAMICS
BY
G.SARATH REDDY

2. STEADY STATE HANDLING CHARACTERISTICS
HOW TO HANDLE THE VEHICLE….?
• Ackermann Steering Geometry

3. ACKERMANN STEERING GEOMETRY
• Ackermann steering geometry is a geometric arrangement of linkages in the
steering of a car or other vehicle designed to solve the problem of wheels on the
inside and outside of a turn needing to trace out circles of different radii.
• The use of such geometry helps reduce tyre temperatures during high-speed
cornering but compromises performance in low speed .
• The intention of Ackermann geometry is to avoid the need for tyre to slip
sideways when following the path around a curve.

4. • As the rear wheels are fixed, this centre point must be on a line extended from
the rear axle
• Intersecting the axes of the front wheels on this line as well requires that the
inside front wheel is turned, when steering, through a greater angle than the
outside wheel .

5. Where
t = tread
L = wheel base
𝛿o= steer angle of the outside
wheel in a turn
𝛿I = steer angle of the inside
wheel in a turn
R = Radius of turn

8. High Speed Cornering
• High speed cornering produces different equations with respect to
low speed cornering.
• Tires must develop significant lateral forces to counteract the lateral
acceleration.
• Slip angles will be present at each wheel

9. Tire Cornering Forces
• Under cornering conditions,in which the tire must develop a lateral
forces, the tire will also experience lateral slips as it rolls.
• The angle between the direction of heading and its direction of travel
is called slip angle.
• Below about 5˚ slip relationship is linear
Where ; Cα — cornering stiffness