Periodic Reporting for period 1 - PADECOT (PArtial Differential Equation model-based COntrol of Traffic flow)
Periodo di rendicontazione: 2017-05-01 al 2019-04-30
Arguably, highway traffic is one of the main means of transportation in modern megalopolises. The continuously increasing traffic demand has led to severe degradation of the available infrastructure, which manifests itself through, increased travel times, reduced safety, increased discomfort, high fuel consumption, and increased harmful emissions, costing several billion euros every year. Extending the road infrastructure is an obvious solution to this problem, which, however, is rather expensive and, in most cases, virtually not realizable. In contrast, real-time traffic flow control has been proved to be a viable, practically feasible, and low-cost alternative.
Besides being intuitively expected that, on a macroscopic level (i.e. when considering a "population" of vehicles and not each individual vehicle), the traffic flow dynamics may be compared to fluid flows, traffic flow evidently may be quantified utilizing, at each point in time, information from each particular location (e.g. on a highway stretch). For these reasons, continuum (in time and space) dynamical systems, i.e. Partial Differential Equation (PDE) systems, constitute perhaps the most recognizable form of a macroscopic description of the traffic flow dynamics, as they provide not only an accurate and elegant description, but also retain the distributed nature of traffic flow. Exploiting the detailed description of the traffic flow dynamics using PDEs, a new framework is introduced for control and estimation of traffic flow in highways, which capitalizes on PDE control tools and which doesn't rely on model reduction or any discrete approximations (apart, only, from the implementation stage), thus also offering provable stability guarantees.
Specifically, in the new methodology, feedforward and feedback control designs are developed, based on continuum in time and space traffic-flow models, which assign to the traffic flow the desired shape, with an a priori prescribed convergence rate and for any initial traffic profile. In certain cases, the novel control and estimation algorithms employ measurements/actuation only at the entries and exits of the highway, thus requiring minimum amount of information and actuation capabilities. The designs are accompanied with tools for verification that are introduced, which provide quantified actual performance guarantees and robustness margins of the proposed algorithms. The methodologies are validated in simulation, using fictitious and real data of traffic.
Besides being intuitively expected that, on a macroscopic level (i.e. when considering a "population" of vehicles and not each individual vehicle), the traffic flow dynamics may be compared to fluid flows, traffic flow evidently may be quantified utilizing, at each point in time, information from each particular location (e.g. on a highway stretch). For these reasons, continuum (in time and space) dynamical systems, i.e. Partial Differential Equation (PDE) systems, constitute perhaps the most recognizable form of a macroscopic description of the traffic flow dynamics, as they provide not only an accurate and elegant description, but also retain the distributed nature of traffic flow. Exploiting the detailed description of the traffic flow dynamics using PDEs, a new framework is introduced for control and estimation of traffic flow in highways, which capitalizes on PDE control tools and which doesn't rely on model reduction or any discrete approximations (apart, only, from the implementation stage), thus also offering provable stability guarantees.
Specifically, in the new methodology, feedforward and feedback control designs are developed, based on continuum in time and space traffic-flow models, which assign to the traffic flow the desired shape, with an a priori prescribed convergence rate and for any initial traffic profile. In certain cases, the novel control and estimation algorithms employ measurements/actuation only at the entries and exits of the highway, thus requiring minimum amount of information and actuation capabilities. The designs are accompanied with tools for verification that are introduced, which provide quantified actual performance guarantees and robustness margins of the proposed algorithms. The methodologies are validated in simulation, using fictitious and real data of traffic.
PADECOT's work and results may be categorized into two different categories, methodological and testing work/results. Within the former category, PADECOT developed novel algorithms for feedback control and estimation of traffic flow, capitalizing on realistic models of traffic flow via Partial Differential Equations (PDEs). In addition, PADECOT introduced tools for analysis, verifying the performance of the developed strategies. Within the latter category, PADECOT developed software codes for implementation and validation of the developed control and estimation algorithms in simulation, using fictitious traffic data. In addition, further validation, using real traffic data, was performed of the effectiveness of a specific traffic estimation algorithm that was developed, which showed that accurate traffic state estimation can be achieved.
Several results' dissemination activities performed within PADECOT, among them i) 8 journal and 7 conference papers were published, to leading control theory and transportation journals/conferences, ii) the fellow participated to 11 conferences/workshops delivering presentations related to the project's results, iii) the fellow delivered 16 invited seminars in renowned institutions, iv) the fellow organized a workshop on the research topic of PADECOT that included 9 invited presentations and 30 participants, v) a webpage frequently updated was created exclusively devoted to PADECOT, vi) the fellow participated to 3 public engagement events and one social media dissemination activity (through the "Fellow of the Week" program), vii) the fellow gave an interview in the local newspaper and advertised PADECOT in the bulletin of Greek transportation engineers.
Besides defining new research directions on traffic and PDE control, via its methodological developments, the exploitation of PADECOT's results includes the following specific activities i) an ERC Starting Grant 2020 proposal prepared and submitted (currently under review) entitled "Secure control of infinite-dimensional systems with application to vehicular traffic", ii) a proposal entitled "Smart integrated management system for electric vehicles charging stations" was also prepared and submitted (currently under review), iii) some of the traffic state estimation algorithms developed within PADECOT (included in a journal paper) were further tested and evaluated (by researchers in the HI) in detailed, microscopic simulation (within a Horizon 2020 ICT project), iv) the fellow has investigated the possibility of collaboration with automotive companies and traffic authorities, via meetings and discussions with researchers, for further exploitation of the developed algorithms, through field implementation and demonstration.
Several results' dissemination activities performed within PADECOT, among them i) 8 journal and 7 conference papers were published, to leading control theory and transportation journals/conferences, ii) the fellow participated to 11 conferences/workshops delivering presentations related to the project's results, iii) the fellow delivered 16 invited seminars in renowned institutions, iv) the fellow organized a workshop on the research topic of PADECOT that included 9 invited presentations and 30 participants, v) a webpage frequently updated was created exclusively devoted to PADECOT, vi) the fellow participated to 3 public engagement events and one social media dissemination activity (through the "Fellow of the Week" program), vii) the fellow gave an interview in the local newspaper and advertised PADECOT in the bulletin of Greek transportation engineers.
Besides defining new research directions on traffic and PDE control, via its methodological developments, the exploitation of PADECOT's results includes the following specific activities i) an ERC Starting Grant 2020 proposal prepared and submitted (currently under review) entitled "Secure control of infinite-dimensional systems with application to vehicular traffic", ii) a proposal entitled "Smart integrated management system for electric vehicles charging stations" was also prepared and submitted (currently under review), iii) some of the traffic state estimation algorithms developed within PADECOT (included in a journal paper) were further tested and evaluated (by researchers in the HI) in detailed, microscopic simulation (within a Horizon 2020 ICT project), iv) the fellow has investigated the possibility of collaboration with automotive companies and traffic authorities, via meetings and discussions with researchers, for further exploitation of the developed algorithms, through field implementation and demonstration.
All of the traffic flow control and estimation methodologies introduced within PADECOT constitute the starting point for the development of new research results and for the establishment of new research directions. Besides the new knowledge produced and the scientific impact of the developed results, influencing the numerous researchers currently working on traffic flow control-related problems, the introduced control and estimation methodologies have a potential impact in the society in general, affecting millions of people facing daily the ramifications of a continuously degrading traffic infrastructure, manifested as excessive delays, accidents, fuel consumption, emissions. This is attributed to the fact that the novel designs, when implemented in practice, have the potential of significantly improving the traffic conditions, offering low-cost, viable, and practically feasible solutions to several traffic problems. The potential traffic improvements include mitigation of traffic congestion and/or its negative consequence, decrease of travel times, decrease of fuel consumption, as well as increased safety and comfort. In turn, the positive effects of this improvement may be reflected in the society via significant costs reduction (e.g. from fuel consumption) and quality improvement of daily transportation.