Development of Integrated Chassis Control for Limit Handling 2016-01-1638
This paper presents the integrated chassis control(ICC) of four-wheel drive(4WD), electronic stability control(ESC), electronic control suspension(ECS), and active roll stabilizer(ARS) for limit handling. The ICC consists of three layers: 1) a supervisor determines target vehicle states; 2) upper level controller calculates generalized forces; 3) lower level controller, which is contributed in this paper, optimally allocates the generalized force to chassis modules. The lower level controller consists of two integrated parts, 1) longitudinal force control part (4WD/ESC) and 2) vertical force control part (ECS/ARS). The principal concept of both algorithms is optimally utilizing the capability of the each tire by monitoring tire saturation, with tire combined slip. By monitoring tire saturation, 4WD/ESC integrated system minimizes the sum of the tire saturation, and ECS/ARS integrated system minimizes the variance of the tire saturation. However, with only minimizing the sum of tire saturation in 4WD/ESC, the performance of the algorithm is inconsistent against gain and vehicle state, i.e., lateral acceleration and velocity. Thus, the allocation guideline, which guides the control input in the vicinity of the guideline, is designed. Meanwhile, to reduce workload of the 4WD/ESC, the ECS/ARS integrated system generates the additional yaw moment based on relationship between lateral and vertical tire forces. The performance of the algorithm has been investigated via computer simulation. It has been shown that the proposed ICC algorithm effectively keeps stability and maneuverability of the vehicle. In addition, the simulation results show that the 4WD/ESC keeps tire slip within stable region and ECS/ARS reduces yaw rate oscillation.