Integrated Real-Time Transit Signal Priority Control for High-Frequency Segregated Transit Services

2015 ◽  
Vol 2533 (1) ◽  
pp. 28-38 ◽  
Author(s):  
Felipe Delgado ◽  
Juan Carlos Muñoz ◽  
Ricardo Giesen ◽  
Nigel H. M. Wilson
Keyword(s):  
Real Time ◽  
Control Strategy ◽  
High Frequency ◽  
Control Strategies ◽  
Transit Signal Priority ◽  
Operational Conditions ◽  
Traffic Lights ◽  
Wide Range ◽  
Transit Services ◽  
Capacity Constrained

Bus bunching affects transit operations by increasing passenger waiting time and variability. To tackle this phenomenon, a wide range of control strategies has been proposed. However, none of them have considered station and interstation control together. In this study station and interstation control were tackled to determine the optimal vehicle control strategy for various stops and traffic lights in a single service transit corridor. The strategy minimized the total time that users must devote to making a trip, taking into account delays for transit and general traffic users. Based on a high-frequency, capacity-constrained, and unscheduled service (no timetable) for which real-time information about bus position (GPS) and bus load (automated passenger counter) is available, this study focused on strategies for traffic signal priority in the form of green extension considered together with holding buses at stops and limiting passenger boarding at stops. The decisions on transit signal priority were made according to a rolling horizon scheme in which effects over the whole corridor were considered in every single decision. The proposed strategy was evaluated in a simulated environment under different operational conditions. Results showed that the proposed control strategy achieves reductions in the excess delay for transit users close to 61.4% compared with no control, while general traffic increases only by 1.5%.

Efficiency of a turbidity-based, real-time control strategy applied to a retention tank: a simulation study

2011 ◽  
Vol 64 (7) ◽  
pp. 1533-1539 ◽  
Author(s):  
C. Lacour ◽  
C. Joannis ◽  
M. Schuetze ◽  
G. Chebbo
Keyword(s):  
Real Time ◽  
Flow Rate ◽  
Control Strategy ◽  
Control Strategies ◽  
Dynamic Control ◽  
Real Time Control ◽  
The Third ◽  
Time Control ◽  
Wide Range ◽  
Two Parameters

This paper compares several real-time control (RTC) strategies for a generic configuration consisting of a storage tank with two overflow facilities. Two of the strategies only make use of flow rate data, while the third also introduces turbidity data in order to exercise dynamic control between two overflow locations. The efficiency of each strategy is compared over a wide range of system setups, described by two parameters. This assessment is performed by simulating the application of control strategies to actual measurements time series recorded on two sites. Adding turbidity measurements into an RTC strategy leads to a significant reduction in the annual overflow pollutant load. The pollutant spills spared by such a control strategy strongly depend on the site and on the flow rate based strategy considered as a reference. With the datasets used in this study, values ranging from 5 to 50% were obtained.

scholarly journals Transport modeling: An artificial immune system approach

2006 ◽  
Vol 16 (1) ◽  
pp. 3-30
Author(s):  
Dusan Teodorovic ◽  
Jovan Popovic ◽  
Panta Lucic
Keyword(s):  
Immune System ◽  
Real Time ◽  
Traffic Control ◽  
System Approach ◽  
Artificial Immune System ◽  
Control Strategies ◽  
Transportation Systems ◽  
Artificial Immune ◽  
Real Time Traffic ◽  
Wide Range

This paper describes an artificial immune system approach (AIS) to modeling time-dependent (dynamic, real time) transportation phenomenon characterized by uncertainty. The basic idea behind this research is to develop the Artificial Immune System, which generates a set of antibodies (decisions, control actions) that altogether can successfully cover a wide range of potential situations. The proposed artificial immune system develops antibodies (the best control strategies) for different antigens (different traffic "scenarios"). This task is performed using some of the optimization or heuristics techniques. Then a set of antibodies is combined to create Artificial Immune System. The developed Artificial Immune transportation systems are able to generalize, adapt, and learn based on new knowledge and new information. Applications of the systems are considered for airline yield management, the stochastic vehicle routing, and real-time traffic control at the isolated intersection. The preliminary research results are very promising.

scholarly journals 4D imaging of sub-second dynamics in pore-scale processes using real time synchrotron x-ray tomography

2016 ◽  
Author(s):  
Katherine J. Dobson ◽  
Sophia B. Coban ◽  
Sam A. McDonald ◽  
Joanna Walsh ◽  
Robert Atwood ◽  
...  
Keyword(s):  
Real Time ◽  
High Frequency ◽  
High Speed ◽  
Motion Blur ◽  
Transport Processes ◽  
Fluid Distribution ◽  
Pore Scale ◽  
X Ray ◽  
Wide Range ◽  
In Situ Experiments

Abstract. A variable volume flow cell has been integrated with state-of-the-art ultra-high speed synchrotron x-ray tomography imaging. The combination allows the first real time (sub-second) capture of dynamic pore (micron) scale fluid transport processes in 4D (3D + time). With 3D data volumes acquired at up to 20 Hz, we perform in situ experiments that capture high frequency pore-scale dynamics in 5–25 mm diameter samples with voxel (3D equivalent of a pixel) resolution of 2.5 to 3.8 µm. The data are free from motion artefacts, can be spatially registered or collected in the same orientation making them suitable for detailed quantitative analysis of the dynamic fluid distribution pathways and processes. The method presented here are capable of capturing a wide range of high frequency non equilibrium pore-scale processed including wetting, dilution, mixing and reaction phenomena, without sacrificing significant spatial resolution. As well as fast streaming (continuous acquisition) at 20 Hz, it also allows larger-scale and longer term experimental runs to be sampled intermittently at lower frequency (time-lapse imaging); benefiting from fast image acquisition rates to prevent motion blur in highly dynamic systems. This marks a major technical breakthrough for quantification of high frequency pore scale processes: processes that are critical for developing and validating more accurate multiscale flow models through spatially and temporally heterogeneous pore networks.

New Control Strategy for High-Frequency Digital Inverter Power Supply

2013 ◽  
Vol 772 ◽  
pp. 443-447
Author(s):  
Yi Wang Wang
Keyword(s):  
Induction Heating ◽  
Control Strategy ◽  
Power Supply ◽  
High Frequency ◽  
Effective Control ◽  
Strong Nonlinearity ◽  
Wide Range ◽  
Inverter Power Supply ◽  
Control Technologies ◽  
High Frequency Induction

The inverter power supply system has strong nonlinearity and parameter variability, especially in the non-linear loads, conventional control technology is difficult to achieve effective control and get the ideal control effect. Aiming at the control requirements of single-phase high-frequency induction heating inverter supply power control applications, uses a novel multiple and composite control technologies to achieve rapid power modulation control of inverter. The components and design principles of proposed control system were introduced in detail. The inverter power system model based on the new control strategy has been built, and inverter prototype used for high-frequency induction heating was designed. The experimental results show that the proposed control method to obtain better dynamic characteristics than the conventional control technologies, and has good advantages of system steady-state accuracy, robustness and control qualities, which has wide range of application.

A New Approach to Gas Control Simulation

2006 ◽  
Author(s):  
Richard G. Carter ◽  
Henry H. Rachford ◽  
Todd F. Dupont
Keyword(s):  
Steady State ◽  
Real Time ◽  
Control Strategy ◽  
Control Strategies ◽  
Mathematical Optimization ◽  
Hydraulic Simulation ◽  
New Approach ◽  
Look Ahead ◽  
Gas Control ◽  
Transient Loads

Gas Pipelines are usually designed to operate in steady state, but in practice most pipelines deliver transient loads. Transient loads degrade total delivery capacity and lose revenue. This paper uses simple examples to quantify such losses and shows how to keep from losing more in practice. The challenge to pipeline operators is to minimize lost capacity by choosing opportunities wisely and exercising skillful control. Look-forward hydraulic simulation has long been used to evaluate spot transportation opportunities and their impact on prior delivery commitments. Gas Control tests control strategies with simulation using a “What-if Study”: If a load appears, “What if we respond this way?” The control selection is often driven by the number of alternate strategies that can be analyzed in the time available for a decision. Thus, while the selected strategy might be reasonable, it may not be optimal for the pipeline company, just the best they had time to try. Through studying example events, this paper describes a completely new approach to What-if Studies. It introduces the use of real-time transient optimization technology to allow the engineer, operator, or even the marketer to get answers for the completely different “What-if” question, namely “What control strategy is best if the network must respond to a specific event?” This replaces manual-iterative look-ahead simulations by mathematical optimization. For each possible load event this cutting-edge technology presents the highest-profit strategy, if one is feasible. Moreover, if delivering the load is infeasible it can determine the alternate strategy that makes the most profit, such as which loads to shed, when, and by how much.

scholarly journals Research on Urban Traffic Signal Control Systems Based on Cyber Physical Systems

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Li-li Zhang ◽  
Qi Zhao ◽  
Li Wang ◽  
Ling-yu Zhang
Keyword(s):  
Real Time ◽  
Control Strategy ◽  
Road Traffic ◽  
Control Strategies ◽  
Traffic Signal ◽  
Signal Control ◽  
Traffic Signal Control ◽  
General Control ◽  
Urban Road ◽  
New System

In this paper, we present a traffic cyber physical system for urban road traffic signal control, which is referred to as UTSC-CPS. With this proposed system, managers and researchers can realize the construction and simulation of various types of traffic scenarios, the rapid development, and optimization of new control strategies and can apply effective control strategies to actual traffic management. The advantages of this new system include the following. Firstly, the fusion architecture of private cloud computing and edge computing is proposed for the first time, which effectively improves the performance of software and hardware of the urban road traffic signal control system and realizes information security perception and protection in cloud and equipment, respectively, within the fusion framework; secondly, using the concept of parallel system, the depth of real-time traffic control subsystem and real-time simulation subsystem is realized. Thirdly, the idea of virtual scene basic engine and strategy agent engine is put forward in the system design, which separates data from control strategy by designing a general control strategy API and helps researchers focus on control algorithm itself without paying attention to detection data and basic data. Finally, considering China, the system designs a general control strategy API to separate data from control strategy. Most of the popular communication protocols between signal controllers and detectors are private protocols. The standard protocol conversion middleware is skillfully designed, which decouples the field equipment from the system software and achieves the universality and reliability of the control strategy. To further demonstrate the advantages of the new system, we have carried out a one-year practical test in Weifang City, Shandong Province, China. The system has been proved in terms of stability, security, scalability, practicability and rapid practice, and verification of the new control strategy. At the same time, it proves the superiority of the simulation subsystem in the performance and simulation scale by comparing the different-scale road networks of Shunyi District in Beijing and Weifang City in Shandong Province. Further tests were conducted using real intersections, and the results were equally valid.

scholarly journals Dynamic Aeroelastic Response of Stall-Controlled Wind Turbine Rotors in Turbulent Wind Conditions

2021 ◽  
Vol 11 (15) ◽  
pp. 6886
Author(s):  
Sara Jalal ◽  
Fernando Ponta ◽  
Apurva Baruah ◽  
Anurag Rajan
Keyword(s):  
Wind Turbines ◽  
Economies Of Scale ◽  
Control Strategies ◽  
Oscillatory System ◽  
Oscillatory Behavior ◽  
Reduced Order ◽  
Operational Conditions ◽  
Wind Speeds ◽  
Wide Range ◽  
Generating Capacity

With the current global trend of the wind turbines to be commissioned, the next generation of state-of-the-art turbines will have a generating capacity of 20 MW with rotor diameters of 250 m or larger. This systematic increase in rotor size is prompted by economies-of-scale factors, thereby resulting in a continuously decreasing cost per kWh generated. However, such large rotors have larger masses associated with them and necessitate studies in order to better understand their dynamics. The present work regarding the aeroelastic behavior of stall-controlled rotors involves the study of the frequency content and time evolution of their oscillatory behavior. A wide range of experiments were conducted to assess the effects of rapid variations on the rotor’s operational conditions. Various gust conditions were tested at different wind speeds, which are represented by pulses of different intensities, occurring suddenly in an otherwise constant wind regime. This allowed us to observe the pure aero-elasto-inertial dynamics of the rotor’s response. A reduced-order characterization of the rotor’s dynamics as an oscillatory system was obtained on the basis of energy-transfer principles. This is of fundamental interest for researchers and engineers working on developing optimized control strategies for wind turbines. It allows for the critical elements of the rotor’s dynamic behavior to be described as a reduced-order model that can be solved in real time, an essential requirement for determining predictive control actions.

scholarly journals 4-D imaging of sub-second dynamics in pore-scale processes using real-time synchrotron X-ray tomography

Solid Earth ◽  
2016 ◽  
Vol 7 (4) ◽  
pp. 1059-1073 ◽  
Author(s):  
Katherine J. Dobson ◽  
Sophia B. Coban ◽  
Samuel A. McDonald ◽  
Joanna N. Walsh ◽  
Robert C. Atwood ◽  
...  
Keyword(s):  
Real Time ◽  
High Frequency ◽  
High Speed ◽  
Motion Blur ◽  
Transport Processes ◽  
Fluid Distribution ◽  
Pore Scale ◽  
X Ray ◽  
Wide Range ◽  
In Situ Experiments

Abstract. A variable volume flow cell has been integrated with state-of-the-art ultra-high-speed synchrotron X-ray tomography imaging. The combination allows the first real-time (sub-second) capture of dynamic pore (micron)-scale fluid transport processes in 4-D (3-D + time). With 3-D data volumes acquired at up to 20 Hz, we perform in situ experiments that capture high-frequency pore-scale dynamics in 5–25 mm diameter samples with voxel (3-D equivalent of a pixel) resolutions of 2.5 to 3.8 µm. The data are free from motion artefacts and can be spatially registered or collected in the same orientation, making them suitable for detailed quantitative analysis of the dynamic fluid distribution pathways and processes. The methods presented here are capable of capturing a wide range of high-frequency nonequilibrium pore-scale processes including wetting, dilution, mixing, and reaction phenomena, without sacrificing significant spatial resolution. As well as fast streaming (continuous acquisition) at 20 Hz, they also allow larger-scale and longer-term experimental runs to be sampled intermittently at lower frequency (time-lapse imaging), benefiting from fast image acquisition rates to prevent motion blur in highly dynamic systems. This marks a major technical breakthrough for quantification of high-frequency pore-scale processes: processes that are critical for developing and validating more accurate multiscale flow models through spatially and temporally heterogeneous pore networks.

Real Time Estimation and Prediction of Wave Excitation Forces on a Heaving Body

2015 ◽  
Author(s):  
Bradley A. Ling ◽  
Belinda A. Batten
Keyword(s):  
Real Time ◽  
Control Strategies ◽  
Average Power ◽  
Time Estimation ◽  
Wave Climate ◽  
Domain Model ◽  
Recursive Least Squares ◽  
Levelized Cost Of Electricity ◽  
Wide Range ◽  
Excitation Force

Wave energy converters (WECs) face many technical challenges before becoming a cost-competitive source of renewable energy. The levelized cost of electricity could be decreased by implementing real-time control strategies to increase average power produced by a WEC. These control strategies typically require knowledge of the immediate future excitation force, caused by the waves. This paper presents a disturbance prediction methodology that is independent of the local wave climate and can be implemented on a wide range of devices. A time-domain model of a generic heaving WEC is developed with the Cummins equations. The model is simulated with measured water surface elevation data collected off the Oregon Coast. A simplified linear frequency-invariant state-space model is used in conjunction with a Kalman filter to estimate the current excitation force with measurements of the WEC’s motion. Future excitation forces are then predicted multiple steps in the future with a recursive least squares filter. The results show this approach makes accurate predictions of excitation force over short time horizons (up to 15 seconds), but accurate predictions become infeasible for longer horizons.

Empirical Demonstration of Acausal Control Strategies for Wave Energy Converters

2013 ◽  
Author(s):  
James Eder ◽  
James Bretl ◽  
Kathleen Edwards
Keyword(s):  
Real Time ◽  
Wave Energy ◽  
Control Strategy ◽  
Control Strategies ◽  
Complex Conjugate ◽  
Optimal Control Strategy ◽  
Wave Energy Converters ◽  
Wave Elevation ◽  
Linear Damping ◽  
Empirical Demonstration

The benefit of acausal control strategies for Wave Energy Convertors (WECs) is empirically demonstrated in a wave tank. An upstream wave gage is used to provide real time predictions of the wave elevation at the WEC’s location. Using a sub-optimal control strategy based upon complex conjugate control, these predictions are used to generate real time force commands for the Power Take Off (PTO) system. Empirical comparisons are made between the acausal control strategy and a simple linear damping approach.

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