Lateral acceleration compensation of a vehicle based on roll angle estimation

This paper demonstrates a method for compensating the gravity component of the lateral acceleration through the estimation of the roll angle. The lateral acceleration has a direct influence on the road disturbance and suspension motion by driver´s steering input. It is difficult to differenciate the bias(gravity component) induced by the road bank disturbance and suspension motion from the actual lateral acceleration measured by a sensor. Although the roll rate sensor can estimate the roll angle via the integration, it has several limitations concerning its use. Because there is no roll rate sensor or roll angle sensor in usual vehicles and the integration may cause the sensor drift problem. In this paper, the state index that implicates whether the state of the vehicle is in the transient region or steady state region, is defined. The roll angle is estimated by integrating the suspension angle rate and kinematic roll angle through switching of the state index. The gravity component induced by roll angle is substracted from the measured lateral acceleration components. And the side-slip angle is estimated to verify the influence of the compensated lateral acceleration. These works are verified using CarSim program with variety of road environments and steering inputs.