A novel hybrid roll control strategy for partially loaded tanker trucks

In this paper, a hybrid roll control system, including passive and active roll control units, is designed to improve the roll dynamics of tanker vehicles and to reduce the lateral shifts of the liquid cargo due to lateralaccelerations. The passive control system consists of radial partitions installed inside the vehicle container. These partitions rotate in phase with the liquid cargo as one unit about the longitudinal axis of the container in response to the induced momentum forces due to the lateral acceleration excitation. Torsion dampers are fixed between the partitions and the container's front and rear walls to reduce the oscillating motion of the liquid cargo. While the passive partition dampers control the dynamics of the liquid cargo inside the container, the dampers of the vehicle suspension are switchable, generating anti-roll damping moments based on the lateral acceleration level and the container filling ratio. A dynamic roll model for a single unit road tanker, carrying a partially filled cylindrical container, is constructed taking account of the roll motions of the vehicle body, the wheel/axle assemblies and the liquid cargo. The vehicle is assumed to be moving on a smooth and flat road and subjected to a step lateral acceleration. A vector approach is developed and incorporated with the Lagrangian energy method to generate non-linear equations of motion of the vehicle. The Runge-Kutta numerical integration method has been used to solve the system non-linear differential equations of motion. PC MATLAB is used to evaluate the time domain response of both vehicle component and cargo, in terms of roll displacements, velocities and accelerations. The results showed that significant improvements are achieved in the dynamic roll response of the vehicle components and liquid cargo due to the effect of the hybrid damping potential of the proposed controllers. These improvements lead to reduce the dynamic lateral shift of the liquid cargo and hence increase the driver comfortability and vehicle safety.