320 likes | 1.03k Views
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.
E N D
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