Integrated Adaptive Cruise Control design considering the optimization of switching between throttle and brake

Abstract

In the Adaptive Cruise Control (ACC) system, the switching between throttle and brake is critical, and the threshold switching logic is used in most existing references, which will possibly cause the frequent switching, resulting in the mechanical damage of vehicle components, fluctuations of the vehicle dynamics, increased fuel consumption, un-comfort and un-satisfaction from passengers and car owners. In this paper, the integrated ACC controller that optimizes the switching between throttle and brake is designed. The ACC system, which consists of the continuous-time vehicle longitudinal dynamics (throttle and brake models) and the discrete-event dynamics (logic switching rule between throttle and brake), is modeled in Mixed Logic Dynamical (MLD) approach. Then the ACC controller is designed in Model Predictive Control (MPC) framework, and the requirements of spacing control, rear-end collision avoidance (safety), optimal switching between throttle and brake, and vehicle capabilities are considered as the control objectives and constraints, respectively. In MPC framework, the ACC controller design is finally transformed to an online Mixed-Integer Quadratic Programming (MIQP). The simulation results show that the proposed ACC controller shows good ability in following the preceding vehicle, prevents rear-end collisions, and it outperforms the traditional ACC controller with the threshold switching rule for providing the smoother vehicle dynamics, less switching between throttle and brake, and more comfortable traveling.