Modified Cooperative Adaptive Cruise Control Strategy for Optimizing Cooperative Driving in Freeway Weaving Segments

Abstract

This paper comprehensively investigates the feasibility of a modified cooperative adaptive cruise control (CACC) strategy to support car platooning in freeway weaving segments. Firstly, to improve the system response to cut-out and cut-in disturbance, the control structure of the typical original CACC system was modified and a synthesis control structure was designed that integrates the feedforward control module to the conventional feedback CACC system. Based on the modified control structure, a variable acceleration limited (VAL) control algorithm is proposed, which is specifically applied in the feedforward control model to suppress the propagation of the cut-in and cut-out disturbances in the CACC platoon. To investigate the performance of the VAL-CACC strategy, a series of comparative simulation experiments were carried out under simulated freeway weaving areas. In these tested scenarios, the occurance of frequent lane changing is considered, and the cut-out and cut-in disturbance of the CACC platoon are investigated, respectively. The obtained experimental results revealed that, compared with the original CACC system, the proposed VAL-CACC strategy can ameliorate the acceleration fluctuation amplitude, reducing it by 12.5% in the tested cut-out scenario. On the other hand, in the cut-in comparative experiments, it is found out that the VAL-CACC strategy can more significantly reduce by about 48.33% the jitter amplitude caused by the merging-in behavior of the non-platooned vehicle. These results demonstrate that the proposed synthesis VAL-CACC strategy can dramatically improve the CACC platoon’s ability to resist cut-in and cut-out disturbances.