Effects of Brake Actuator Error on Vehicle Dynamics and Stability

In this paper the effects of rear brake imprecision on vehicle braking performance and yaw dynamics are investigated for a vehicle with individually controlled brake actuators. The effects of side to side brake force imbalance on vehicle yaw rate and path deviation during straight line braking and in braking in turn maneuvers are examined through analysis, simulations and vehicle testing. These effects are compared to the influences of disturbances encountered during normal driving such as side winds and bank angles of the road. The loss of brake efficiency due to imprecision in generating actuating force is evaluated for different types of vehicles and different levels of vehicle deceleration. Requirements regarding path deviation during straight line braking and braking efficiency on low friction surfaces were found to lead to the most stringent specifications for actuator accuracy in realizing the desired braking forces.