Application of fuzzy control system to autonomous vehicle platoon

Abstract

This work aims to explore a simplified approach using the Fuzzy logic control system to control homogeneous vehicle platoon to achieve velocity and string stability while keeping a constant inter-vehicular gap. String stability can be affected by unknown uncertainties such as truck incapacitation, delay of platoons and inability to maintain a constant inter-vehicular gap. This paper addresses the problem of string stability, that is inability of vehicles to maintain a constant inter-vehicular gap. To address this problem, a Fuzzy Logic Cooperative Adaptive Cruise Control scheme was developed to ensure string stability, reduced catch-up time and robust enough to implement different maneuvers such as catch-up strategy, slow-down strategy, and lane-change. A triangular membership function was used for Distance, Velocity and Acceleration. A three-vehicle platoon setup was developed using Fuzzy Logic controller for lead vehicle and two follower vehicles. The lead vehicle is controlled by 5 rules with velocity as input and acceleration output. While the follower vehicles were governed by 2-inputs (distance and velocity) and acceleration as output, having a total of 25 fuzzy rules as captured in the rule matrix lookup table. The platoon system shows a good string stability margin of less than 5 seconds and inter-vehicular distance gap stability of about 2 seconds maximum. The results obtained shows the effectiveness of the developed controller in terms of time taken to attain string stability. The approach developed increases platoon stability at a faster time. The design, development and evaluation are carried out using MATLAB modeling environment.