Showing papers by "Swaroop Darbha published in 2001"

Assessing the benefits of coordination in automatically controlled vehicles

Abstract: We present a methodology for assessing the benefits of coordination on the safety of a platoon during emergency braking. When every following vehicle brakes at its maximum possible deceleration in response to hard braking by the lead vehicle in the platoon, it is referred to as uncoordinated braking. A braking strategy B is referred to be more beneficial than a strategy A, if strategy B leads to a larger reduction in the probability of a collision, the expected number of collisions, and the expected relative velocity at impact as compared to strategy A. The sequence of maximum deceleration of vehicles in the platoon is assumed to be a sequence of independent and identically distributed random variables; this distribution is assumed to be discrete and known. Due to coordination, the "effective" deceleration of a following vehicle may not necessarily be its maximum value. The problem of assessing the benefits of coordination can be initiated by dealing with determining the probability distribution of the "effective" deceleration of following vehicles during emergency braking. It is intuitive that the smaller the variance of this distribution, the greater the safety benefits are. We present a coordination strategy, which offers distinct safety benefits in the asymptotic cases.

Formulation of a new methodology to identify erroneous paired loop detectors

Abstract: A new algorithm was developed for screening data from paired inductive traffic loop detectors. The algorithm estimates the effective vehicle length for each vehicle that passes the paired loop detectors and computes the average vehicle length for a fixed set of vehicles, the size of the set depending upon the vehicle volume flow. Error detection is done in two steps: 1) to calibrate the effective average vehicle length range for a detector; and 2) to compare this to the effective average vehicle length computation online.

Aggregation of a Class of Large-scale, Interconnected, Nonlinear Dynamical Systems

Abstract: In this paper, the authors consider the issue of the construction of a meaningful average for a collection of nonlinear dynamical systems. Such a collection of dynamical systems may or may not have well defined ensemble averages as the existence of ensemble averages is predicated on the specification of appropriate initial conditions. A meaningful “average” dynamical system can represent the macroscopic behavior of the collection of systems and allow us to infer the behavior of such systems on an average. They can also prove to be very attractive from a computational perspective. An advantage to the construction of the meaningful average is that it involves integrating a nonlinear differential equation, of the same order as that of any member in the collection. An average dynamical system can be used in the analysis and design of hierarchical systems, and will allow one to capture approximately the response of any member of the collection.