A Mathematical Model for Control of an Autonomous Vehicle Convoy

This paper describes the modeling of a two-vehicle convoy and the design of a vehicle following controller that tracks the trajectory of the vehicle ahead with prescribed inter-vehicle distance. Kinematic equations of the system are formulated applying standard robotic methodology. We consider autonomous vehicle following without any information obtained from road infrastructure or communicated from the lead vehicle. Assuming that the leader linear and angular velocities, as well the curvature radius of the path traveled by the lead vehicle, are unknown constant parameters, an adaptive tracking controller is proposed. With only the current inter-vehicle relative position and orientation available for feedback control, the control velocities of the following vehicle are computed using the leader velocity estimates obtained from the dynamic (adaptive) part of the proposed controller. For constant velocity maneuvers of the leader, at steady state, the two-vehicle convoy will travel concentric arcs of same radii with prescribed inter-vehicle spacing. For time-varying lead vehicle velocities, the proposed controller achieves ultimate boundness of the closed-loop system in error coordinate. Various simulation results demonstrating the performance of the controller are included. Key-Words: Autonomous vehicle convoy, vehicle following, kinematic model, nonlinear adaptive control