Platooning Vehicles Control for Balancing Coupling Maintenance and Trajectory Tracking - Feasibility Study Using Scale-Model Vehicles

Recently, car-sharing services using ultra-compact mobilities have been attracting attention as a means of transportation for one or two passengers in urban areas. A platooning system consisting of a manned leader vehicle and unmanned follower vehicles can reduce vehicle distributors. We have proposed a platooning system which controls vehicle motion based on the relative position and posture measured by non-contact coupling devices installed between vehicles. The feasibility of the coupling devices was validated through a HILS experiment. There are two basic requirements for realizing our platooning system; (1) all devices must remain coupled and (2) follower vehicles must be able to track the leader vehicle trajectory. Thus, this paper proposes two vehicle control method for satisfying those requirements. They are the “device coupling and trajectory tracking merging method” and the “trajectory shifting method”. The device coupling and trajectory tracking merging method consisting of a coupling keeping controller and a trajectory tracking controller. The predominant controller is chosen according to the amount of the coupling device error and the trajectory tracking error. The trajectory shifting method shifts the tracking target trajectory to keep the device coupled. The shifting amount is decided by the estimated turning radius of the leader vehicle. Platooning experiments using two 1:16 scale-model vehicles has been performed on the experiment course containing a straight section and a circular section. Experiment results revealed that the device coupling and trajectory tracking merging method can maintain the coupling of the device while limiting the trajectory tracking error to a certain range. Though the trajectory shifting method can reduce the coupling device error, it fails on both device coupling keeping and trajectory error limiting, owing to the inadequacy in estimating the turning radius of the leader.