Nonlinear spacing policy based vehicle platoon control for local string stability and global traffic flow stability

Adaptive Cruise Control (ACC) aims to increase traffic throughput and traffic safety. A typical application of ACC vehicles is creating a platoon system, in which a series of vehicles moves longitudinally in an automated manner. For platooning vehicles, we need to define the inter-vehicle spacing policy and the control law for each and every vehicle. In this work, a new nonlinear spacing policy and a linear feedback controller related to the policy are proposed to achieve string stability and traffic flow stability. Moreover, we show that the proposed policies provide a higher traffic flow capacity compared with a conventionally used constant time gap policy. Finally, a generalized linear feedback controller is used to derive a more relaxed condition for ensuring string stability requirement.