Traction Control Michael Boersma Michael LaGrand 12/10/03

Outline Methods for traction control Method studied Results Questions

Traction Control Methods Control of power to wheels Control of breaks Factors used for control – Velocity – Yaw rate – Automobile specific variables

Automobile Specifics Wheel track Wheel base Center of gravity Distance from center of gravity to axis Tire stiffness

Our Focus Controlling stability using the breaks Input factors – Vehicle velocity and angular velocity of the wheels – Driven wheel angle – Assumed vehicle constants

Our Focus II Calculated results – Estimated yaw rate – Correction factor – Desired yaw rate – Break pressure to be applied MatLAB (in progress)

Calculation of Estimated Yaw Rate Use velocity to find angular velocity of wheels Use curve radius to find driven wheel angle Use angular velocity and wheel angle to find yaw rate

Estimated Yaw Rate Results Graph of Yaw Rate vs. Curve Radius For velocities of 15, 25 and 35 MPH

Yaw Correction As the velocities become large the error in estimating the yaw rate also becomes larger A correction factor is calculated using the desired yaw rate and lateral acceleration

Break Pressure This is the break pressure applied to the wheels to keep the yaw rate in check Found using a gain factor and the difference between the estimated yaw rate and correction factor Gain factor depends of brakes (unity in our case)

Break Pressure Break Pressure vs. Curve Radius For velocity of 15 MPH

Questions? ?