Steering System Ackerman Linkage geometry Road wheel geometry

Steering System Ackerman Linkage geometry Road wheel geometry

Steering System Ackerman Linkage geometry Road wheel geometry Caster Kingpin inclination Compliance effects Ackerman Steer o

L L tan-1 o R+t/2 R+t/2 i L L tan-1 i R-t/2 R-t/2 For large radii, R >> t/2 L

Ack R L R t/2 Inboard off-tracking 2 L 2R Turn Center

Ackerman Truck Steering System Straight ahead Right turn Left turn Ackerman Steer 50% Left Wheel Steer Angle (deg) 40 el l l

ra a an m P r e Ack 20 0 -50 -30 -10

10 30 -20 -40 -60 Right Wheel Steer Angle (deg) 50 Car Steering Systems Rack and pinion Steering arm Gearbox

Rack Tire rod Tire rod Gearbox Idler arm Relay link Steering arm Pitman arm Truck Steering Systems Tire rod Steering arm

Gearbox Pitman arm Drag link Compliance in Steering System K ss K ss To steering wheel Geometry at the Wheel Kingpin Axis Center of Tire Contact

Caster Angle Kingpin Inclination Angle Kinpin Offset at the Ground Lateral Inclination Angle Fzr Fzr d d sin M ( Fzl Fzr ) d sin sin

Torques from Lateral Inclination Steering Torque (in-lb) M M )d sin sin =(-F (Fzlzl + FF zrzr) d sin sin V 200 STEERING TORQUE FROM LATERAL INCLINATION ANGLE 1" Offset

10 Inclination Angle 100 0 -100 Right Wheel (600 lb) Left Wheel (800 lb) Total -200 -45 -30 -15

0 15 Steering Angle (deg) 30 45 Caster Angle Fzr Fzr

d M ( Fzl Fzr ) d sin cos d cos Torques from Caster Angle Steering Torque (in-lb) MV = (F M (zlF-xlFzr )Fdxrsin ) dcos sin cos

200 100 STEERING TORQUE FROM CASTER ANGLE 1" Offset 5 Caster Angle Left Wheel (800 lb) Total 0 -100 Right Wheel (600 lb)

-200 -45 -30 -15 0 15 Steering Angle (deg) 30 45 Lateral Force

Fyr r tan M L ( Fyl Fyr ) r tan Tractive Force Fxr d M T ( Fxl Fxr ) d 4 Wheel Steer - Low Speed

f L R Turn Center r L R = f r f

4 Wheel Steer - High Speed Four-wheel in-phase steering Only at high speed (typically above 35 mph) Rear steer angles less than front Rear steer angles limited to a few degrees f ax

r Steering System Applications Effect of steering geometry on performance Understeer (linear range) Limit cornering (non-linear range) Steering torques and feel On-center feel Torque gradients Linearity Power assist characteristics Friction and damping Evaluate effects of asymmetry Manufacturing tolerance Steering Ratio Steering Ratio = Steering wheel angle (deg) / Road wheel angle (deg) Steering ratio for cars = 15 to 20

Steering ratio for trucks = 20 to 40 Steering Ratio Assignment Design linkage geometry to meet requirement of the minimum turn radius and provide close to Ackerman geometry (X-Y plane is ok) Design steering ratio with measurements on your car

Recently Viewed Presentations

  • Online Algorithms with recourse

    Online Algorithms with recourse

    online algorithms and competitive analysis. At any time ?, maintain a solution for the current input. past decisions are irrevocable. solution should be comparable to the best offline algorithm which knows the input till time ?.
  • Graphics Systems and Models - UNR

    Graphics Systems and Models - UNR

    Fermat's Last Theorem . Andrew Wiles proved it … 350 years later. NP ≠ P. Solution will net you $1million (Clay Institute of Mathematics) The Decision to go to the Moon. President John F. Kennedy's May 25, 1961 Speech before...
  • The Greek Titans - 7A Language Arts

    The Greek Titans - 7A Language Arts

    The Greek Titans Gaia Gaia is the Earth goddess. She is the mother of the other Titans. Uranus Uranus is the sky god and first ruler. He is the husband of Gaia and together they had many offspring, including twelve...
  • MENA outlook: A view from the markets March

    MENA outlook: A view from the markets March

    Secondary enrollment remains low in Yemen and Iraq. Tertiary enrollment is generally low. February 2011 * Vulnerability to global commodity price shocks World Bank commodity price indices Headline and Food inflation (%, y/y) Note: Inflation for Bahrain, Qatar, UAE and...
  • Myth and Folktale

    Myth and Folktale

    Myth. A myth is a traditional story, religious in nature, that explains why the world is as it is. They often represent a culture's deepest beliefs.
  • Decision Making - public.navy.mil

    Decision Making - public.navy.mil

    THE DENISE WAGONER STORY THE DENISE WAGONER STORY THE DENISE WAGONER STORY THE DENISE WAGONER STORY THE DENISE WAGONER STORY Alcohol and Driving: A Bad Mix! Alcohol: Myths and Facts THE COST THE BOTTOM LINE Alcohol-induced impairment is the greatest...
  • JRN 490 Peace Journalism Lesson 1: Introduction to Peace ...

    JRN 490 Peace Journalism Lesson 1: Introduction to Peace ...

    According to Peter du Toit [2000]: "Conflict exists in a relationship when two or more parties believe their aspirations cannot be achieved simultaneously, or perceive a divergence in their values, needs or interests and purposefully employ their power in an...
  • Homework vs. Sleep

    Homework vs. Sleep

    Homework had the highest ranking for things people would do first before bed. Followed by listening to music and watching tv. Reading being the least likely thing people would do before bed.