A System Level Study of the Longitudinal Control of a Platoon of Vehicles

Abstract

This paper presents a preliminary system study of a longitudinal control law for a platoon of nonidentical vehicles using a simplified nonlinear model for the vehicle dynamics. This study advances the art of automatic longitudinal control for a platoon of vehicles in the sense that it considers longer platoons composed of nonidentical vehicles; furthermore, the longitudinal control laws presented in this study take advantage of communication possibilities not available in the recent past. We assume that for i = 1, 2, . . . vehicle i knows at all times vl and al (the velocity and acceleration of the lead vehicle) in addition to the distance between vehicle i and the preceding vehicle, i − 1. A control law is developed and is tested on a simulation of a platoon of 16 vehicles where the lead vehicle increases its velocity at a rate of 3 m.s−2; it is shown that the distance between successive vehicles does not change by more than 0.12 m in spite of variations in the masses of the vehicles (from the nominal), of communication delay and of noise in measurements.

Throttle and Brake Control Systems for Automatic Vehicle Following

“…More complicated vehicle models were used in the design of automatic vehicle following controllers in [6,9] where constant intervehicle spacing is desired at all speeds. In order to achieve platoon stability with desired constant intervehicle spacing, vehicle-to-vehicle communication was shown to be necessary [9,10].…”

“…More complicated vehicle models were used in the design of automatic vehicle following controllers in [6,9] where constant intervehicle spacing is desired at all speeds. In order to achieve platoon stability with desired constant intervehicle spacing, vehicle-to-vehicle communication was shown to be necessary [9,10]. In [5], it was shown that under a constant time headway policy, the stability of the dynamics of a platoon of vehicles could be achieved without vehicle-to-vehicle communication, provided the throttle and brake controllers are designed appropriately.…”

Cooperative adaptive cruise control, design and experiments

“…Comparing this to the string stability definitions in [9], [11]- [14], amplification of oscillations in the vehicle state is considered, rather than oscillations in the distance error. As a result, the definition of string stability (14) targets preventing so-called shockwave behavior, rather than preventing collisions.…”

“…1 [9]. Furthermore, heterogeneous traffic is considered, i.e., vehicles with different characteristics [4], [10], and delay in the communicated signal is taken into account [6], [7], [11]. Finally, the communication will be implemented as a feedforward signal.…”

Fault-tolerant control for automated highway systems

“…In [5], it was shown that feedback linearization techniques may be used to achieve stable operation of a platoon of vehicles with constant intervehicle spacing if information about the lead vehicle was available to each following vehicle, while later in [6] the effects of communication losses between vehicles were considered. The controller proposed herein allows for the incorporation of lead vehicle information, however, we show that it is not required to provide a safe driving environment.…”