Traction ControlMichael BoersmaMichael LaGrand12/10/03

OutlineMethods for traction control Method studiedResultsQuestions

Traction Control MethodsControl of power to wheelsControl of breaksFactors used for controlVelocityYaw rateAutomobile specific variables

Automobile SpecificsWheel trackWheel baseCenter of gravityDistance from center of gravity to axisTire stiffness

Our FocusControlling stability using the breaksInput factorsVehicle velocity and angular velocity of the wheelsDriven wheel angleAssumed vehicle constants

Our Focus IICalculated resultsEstimated yaw rateCorrection factorDesired yaw rateBreak pressure to be appliedMatLAB (in progress)

Calculation of Estimated Yaw RateUse velocity to find angular velocity of wheelsUse curve radius to find driven wheel angleUse angular velocity and wheel angle to find yaw rate

Estimated Yaw Rate ResultsGraph of Yaw Rate vs. Curve RadiusFor velocities of 15, 25 and 35 MPH

Yaw CorrectionAs the velocities become large the error in estimating the yaw rate also becomes largerA correction factor is calculated using the desired yaw rate and lateral acceleration

Break PressureThis is the break pressure applied to the wheels to keep the yaw rate in checkFound using a gain factor and the difference between the estimated yaw rate and correction factorGain factor depends of brakes (unity in our case)

Break PressureBreak Pressure vs. Curve RadiusFor velocity of 15 MPH

Questions??