Wynita M. Griggs

A “mixed” small gain and passivity theorem in the frequency domain ☆

Abstract We show that the negative feedback interconnection of two causal, stable, linear time-invariant systems, with a “mixed” small gain and passivity property, is guaranteed to be finite-gain stable. This “mixed” small gain and passivity property refers to the characteristic that, at a particular frequency, systems in the feedback interconnection are either both “input and output strictly passive”; or both have “gain less than one”; or are both “input and output strictly passive” and simultaneously both have “gain less than one”. The “mixed” small gain and passivity property is described mathematically using the notion of dissipativity of systems, and finite-gain stability of the interconnection is proven via a stability result for dissipative interconnected systems.

Interconnections of nonlinear systems with “mixed” small gain and passivity properties and associated input–output stability results

Abstract A negative feedback interconnection consisting of two causal, nonlinear systems is shown to be input–output stable when a “mixed” small gain and passivity assumption is placed on each of the systems. The “mixed” small gain and passivity property captures the well-known notions of passivity and small gain associated with systems: the property can be appropriately reduced to an input and output strictly passive system description; or alternatively, can be reduced to a description of a system with small gain. More importantly, the property captures the concept of a “blending” of the small gain and passivity ideas. This concept of “blending” can be visualized, for example, by considering linear time-invariant systems that exhibit passivity-type properties at, say, low frequencies; and lose these passivity-type properties but have small gain at high frequencies.

On Optimality Criteria for Reverse Charging of Electric Vehicles

Ever increasing expectations regarding the penetration level of electric vehicles (EVs) are driving several areas of research related to EV charging. One topic of interest treats EVs not only as controllable loads but also as storage systems, which can be used to mitigate the load on the grid during peak times by offering power. This is known as vehicle to grid (V2G). Since returning energy to the grid affects mobility patterns, V2G has an associated environmental cost. In this paper, to investigate this issue, we formulate the problem of returning electrical load to the grid as an optimization whose goal is to return the desired energy in a fashion that minimizes the cost on the environment. We show that this optimization is highly complex, and in some circumstances, the cost of V2G can be prohibitive.

A Large-Scale SUMO-Based Emulation Platform

A hardware-in-the-loop simulation platform for emulating large-scale intelligent transportation systems is presented. The platform embeds a real vehicle into SUMO, a microscopic road traffic simulation package. Emulations, consisting of the real vehicle, and potentially thousands of simulated vehicles, are run in real time. The platform provides an opportunity for real drivers to gain a feel of being in a large-scale connected vehicle scenario. Various applications of the platform are presented.

On the Design of Campus Parking Systems With QoS Guarantees

Parking spaces are resources that can be pooled together and shared, particularly when there exist complementary daytime and nighttime users. We provide solutions to two design questions. First, given a quality of service requirement, how many spaces should be set aside as contingency during the day for nighttime users? Next, how can we replace the first-come-first-served access method by one that aims for optimal efficiency while keeping user preferences private?

Parked cars as a service delivery platform

We introduce a new view of parked cars as a massive, flexible resource that is currently wasted. Given the power supply in batteries as well as computing, communication, and sensing facilities in cars in conjunction with the precise localization they can provide, parked cars have the potential to serve as a service delivery platform with a wide range of possibilities. We describe diverse applications that can be implemented using parked cars to show the flexibility of the infrastructure. Potential user groups and service providers are discussed. As an illustrative example, a simulation study of the use case of localizing persons in need of assistance is presented. Finally, the need for new algorithms and their analysis adapted to the specifics of parked cars is also highlighted.

Smart procurement of naturally generated energy (SPONGE) for PHEVs

ABSTRACT In this paper, we propose a new engine management system for hybrid vehicles to enable energy providers and car manufacturers to provide new services. Energy forecasts are used to collaboratively orchestrate the behaviour of engine management systems of a fleet of plug-in hybrid electric vehicle (PHEVs) to absorb oncoming energy in a smart manner. Cooperative algorithms are suggested to manage the energy absorption in an optimal manner for a fleet of vehicles, and the mobility simulator SUMO (Simulation of Urban MObility) is used to demonstrate the efficacy of the proposed idea.

Intelligent Speed Advising Based on Cooperative Traffic Scenario Determination

A novel system for safe speed recommendation, based on a cooperative method for vehicular density estimation and on the intelligent determination of the traffic scenario, is presented.

Alleviating a form of electric vehicle range anxiety through on-demand vehicle access

On-demand vehicle access is a method that can be used to reduce types of range anxiety problems related to planned travel for electric vehicle owners. Using ideas from elementary queueing theory, basic quality of service (QoS) metrics are defined to dimension a shared fleet to ensure high levels of vehicle access. Using mobility data from Ireland, it is argued that the potential cost of such a system is very low.

A test for determining systems with “mixed” small gain and passivity properties ☆

Abstract “Mixedness” is a property that captures elements of the notions of passivity and small gain. In the frequency domain, a linear, time-invariant system is called “mixed” if, over some frequency bands, it is strictly passive and, over the remaining frequencies, it has a gain of less than one; there exist no frequencies over which the system has neither of the notions of these properties associated with it. In this paper, a test is developed for determining whether or not a linear, time-invariant system is “mixed”.