This paper formulates the problem of real-time estimation of traffic state in freeway networks by means of particle filtering framework. A particle filter (PF) is developed based on a recently proposed speed-extended cell-transmission model of freeway traffic. The freeway is considered as a network of components representing different freeway stretches called segments. The evolution of the traffic in a segment is modelled as a dynamic stochastic system, influenced by states of neighbour segments. Measurements are received only at boundaries between some segments and averaged within possibly irregular time intervals. This limits the measurement update in the PF to only these time instants when a new measurement arrives, with possibly many state updates in between consecutive measurement updates. The PF performance is validated and evaluated using synthetic and real traffic data from a Belgian freeway. An Unscented Kalman filter is also presented. A comparison of the particle filter with the Unscented Kalman filter is performed with respect to accuracy and complexity.
Traffic flow on freeways is a nonlinear, many-particle phenomenon, with complex interactions between vehicles. This paper presents a stochastic model of freeway traffic at a time scale and of a level of detail suitable for on-line estimation, routing and ramp metering control. The freeway is considered as a network of interconnected components, corresponding to one-way road links consisting of consecutively connected short sections (cells). The compositional model proposed here extends the Daganzo cell transmission model by defining sending and receiving functions explicitly as random variables, and by also specifying the dynamics of the average speed in each cell. Simple stochastic equations describing the macroscopic traffic behavior of each cell, as well as its interaction with neighboring cells are obtained. This will allow the simulation of quite large road networks by composing many links. The model is validated over synthetic data with abrupt changes in the number of lanes and over real traffic data sets collected from a Belgian freeway.
List of Figures vii List of Tables ix List of Acronyms xi Nederlandse samenvatting xiii English summary xvii the two afore-mentioned distinct contributions of the proposed model-based coordinating approach namely "looking-ahead" and "communication", since the decentralized deadband approach lacks both anticipation and coordination, and the decentralized MPC approach ignores the communications with neighbors. 1 Ultra high voltage transmission voltage levels have been experimentally used at 1200 kV in the former Soviet Union and today in Kasachastan, and at 1100 kV in Japan. 1.1.3 Voltage stability Voltage stability, the main focus of this thesis, refers to the ability of a power system to maintain all its bus voltage magnitudes within a prescribed interval around the nominal bus voltages, even following a disturbance. In other words, voltage instability implies that the post-disturbance power system is unable to reach a new set of permissible steady-state voltages at some buses. A more formal definition of voltage instability is given in [6]: (2q − 1) 2 − 4(p 2 + q 2) ≥ 0 (1.7) or 1 − 4q − 4p 2 ≥ 0 This inequality represents the possible combinations of active and reactive power that the combined generation-transmission system of Fig. 1.2 can supply to the
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.