scholarly journals Modeling and simulation of a control system of wheels of wheelset

2020 ◽  
Vol 55 (3) ◽  
pp. 73-83
Author(s):  
Andrzej Chudzikiewicz ◽  
Juraj Gerlici ◽  
Magdalena Sowińska ◽  
Anna Stelmach ◽  
Wojciech Wawrzyński
Keyword(s):  
Control System ◽  
Modeling And Simulation ◽  
Urban Areas ◽  
The Elderly ◽  
Light Rail ◽  
Bogie Frame ◽  
Passenger Rail ◽  
Rail Vehicles ◽  
Control Concept ◽  
Angular Velocities

Modern light rail vehicles, such as a tram or rail bus, due to the need to provide mobility for the elderly or disabled people and the requirements of operators operating passenger rail transport or transport in urban areas must have a 100% low floor. Structurally, this is associated with the use of wheelset with independently rotating wheels (IRW) in such vehicles. It is also possible to use a bogie structure without the use of a wheelset axle by mounting the wheels directly in the side parts of the bogie frame. This construction is more complex and will not be discussed in this article. Bearing in mind the dynamic behavior of such vehicles during operation (lateral stability, profile wear) in various driving conditions (curve traffic, crossovers) and taking into account operating costs, it becomes necessary to install wheel rotation control systems to maintain center movement mass of the wheelset around the centerline of the track. The subject of the article will be considerations on modeling and simulation of rail vehicle bogie motion with IRW sets including the wheel control system. Nominal and mathematical models of the analyzed vehicle will be presented, as well as a controlled strategy based on the comparison of the angular velocities of the wheels of the wheelset A review of works on solutions of such systems will be presented, and a control concept will be proposed. The summary contains conclusions regarding the possibility of practical use of the proposed method of steering wheels of a wheelset in the c ase of independently rotating wheels.

Rails-Next-to-Trails: A Methodology for Selecting Appropriate Safety Treatments at Complex Multimodal Intersections

2018 ◽  
Vol 2672 (10) ◽  
pp. 12-27
Author(s):  
Anna Bovbjerg Alligood ◽  
Manali Sheth ◽  
Anne Goodchild ◽  
Edward McCormack ◽  
Polina Butrina
Keyword(s):  
Urban Areas ◽  
Field Studies ◽  
The United States ◽  
Light Rail ◽  
Professional Judgment ◽  
Railroad Tracks ◽  
Rail Vehicles ◽  
Video Observations ◽  
Railroad Crossings ◽  
Disproportionate Number

There are more than 212,000 at-grade railroad crossings in the United States. Several feature paths running adjacent to the railroad tracks, and crossing a highway; they serve urban areas, recreational activities, light rail station access, and a variety of other purposes. Some of these crossings see a disproportionate number of violations and conflicts between rail, vehicles, and pedestrians and bikes. This research focuses on developing a methodology for appropriately addressing the question of treatments in these complex, multimodal intersections. The methodology is designed to be able to balance a predetermined, prescriptive approach with the professional judgment of the agency carrying out the investigation. Using knowledge and data from the literature, field studies, and video observations, a framework for selecting treatments based on primary issues at a given location is developed. Using such a framework allows the agency to streamline their crossing improvement efforts; to easily communicate and inform the public of the decisions made and their reasons for doing so; to secure stakeholder buy-in prior to starting a project or investigation; to make sure that approach and selected treatments are more standardized; and to ensure transparency in the organization to make at-grade crossings safer for pedestrians and bicyclists, without negatively impacting trains or vehicles.

scholarly journals Collision Risk Mitigating System for Light Rail Vehicles(LRV)

2016 ◽  
Vol 38 (1) ◽  
pp. 50-56
Author(s):  
Bartosz Antkowiak
Keyword(s):  
Control System ◽  
Obstacle Detection ◽  
Light Rail ◽  
Vehicle Speed ◽  
Ambient Conditions ◽  
Collision Risk ◽  
System Operation ◽  
Rail Vehicles ◽  
Braking Distance ◽  
Vehicle Positioning

Abstract This piece is dedicated tothedescription of the development of collision risk mitigating system. The proposed concept of control system is designed to enhance safety ofpassengers, a driver and other people in vicinityof light rail vehicles (tramways).The requirements were fulfilled thanks to the application of lidar sensor and feature of vehicle positioning on the track map created basingon precise measurements with the use of satellite navigation systemReal Time Kinematic. The map allows to eliminate errors of system operation and to enhance resistance to unfavorable ambient conditions, i.e.temperature or fog. The system calculates work braking distance for particular vehicle speed. In case of obstacle detection which is closer to vehicle than the calculated braking distance, the driver is informed about a collision risk with a buzzer and optical signalization. The system has already been implemented and tested.

Developing Guidelines for Crashworthiness of Light Rail Vehicles in Mixed Fleet Operations

2002 ◽  
Author(s):  
Steven W. Kirkpatrick ◽  
Martin P. Schroeder ◽  
Juan Carlos Valde´s Salazar
Keyword(s):  
Structural Integrity ◽  
Safety Concern ◽  
Light Rail ◽  
Passenger Rail ◽  
Rail Vehicles ◽  
Increased Risk ◽  
Crashworthiness Design ◽  
Computer Crash ◽  
Parametric Analyses ◽  
Risk Parameters

As new passenger rail cars are introduced into existing rail fleets, the potential structural for incompatibility between cars in a collision is a safety concern. Crush damage that occurs when dissimilar strength vehicles collide is concentrated in the weaker vehicle. In a serious collision the deformation of the weaker vehicle could be sufficiently large to intrude into the occupied volume of the operator or passenger compartments. As a result, the strength incompatibility has the potential for increased risk of injury for passengers in the weaker vehicle. The design strategy of many modern rail vehicles is to reduce vehicle weight and incorporate crashworthiness design features to improve safety. This is in contrast to an older design approach where strength requirements, such as a high buff strength, were included to ensure structural integrity. The objective of this study is to assess the collision risk for a mixed rail fleet of different vehicle designs. Collision safety is investigated for three different vehicle types. The crash scenarios investigated include vehicle to vehicle collisions between newly designed cars, between older designed cars, and between a mix of new and old designs. To quantify risk, parameters such as cab crush strength, occupant volume strength, and collision speed are varied in computer crash simulations to uncover potential safety problems associated with mixed car operation. Results from these parametric analyses are presented and utilized to guide the development of new crashworthiness specifications for mixed fleet operation.

scholarly journals Daily Stimulation and Cognitive Functioning: The Importance of the Participation of Healthy Older People in Cognitively Demanding Everyday Activities

2014 ◽  
Vol 4 (3) ◽  
pp. 309-319
Author(s):  
José Antonio Labra Pérez ◽  
Julio Menor
Keyword(s):  
Cognitive Functioning ◽  
Urban Areas ◽  
Ad Hoc ◽  
The Elderly ◽  
Protective Mechanism ◽  
Everyday Activity ◽  
Neuropsychological Measures ◽  
Rural And Urban Areas ◽  
Everyday Activities ◽  
Rural And Urban

The participation of the elderly in cognitively demanding activities is considered an enhancing factor of cognitive function. However, the life cycle psychosocial variables such as education and type of profession also influence in cognitive functioning. The objective of this study is to analyze the relationship between daily stimulation and cognitive functioning in a sample of healthy older adults, controlling the effects of education and the type of profession. The study involved 164 adults over 60 years, from rural and urban areas, with different levels of education and professional level which were assessed with an extensive battery of neuropsychological measures, as well as in an inventory of everyday activities built ad hoc. The results show that different cognitively demanding everyday activities are related to with cognitive processes, both fluids and crystallized. Furthermore, it was found that daily stimulation plays an important role in cognitive functioning outside of education and the type of profession performed. Overall, the results of this study shows the importance of everyday activity as a protective mechanism against cognitive decline, as well as the need to adopt a model of active aging

scholarly journals Maternal depression and loss of children under the one-child family planning policy in China: a cross-sectional study of 300 000 women

BMJ Open ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. e048554
Author(s):  
Hanyu Wang ◽  
Eric Frasco ◽  
Jie Shang ◽  
Minne Chen ◽  
Tong Xin ◽  
...  
Keyword(s):  
Family Planning ◽  
Maternal Depression ◽  
Urban Areas ◽  
The Elderly ◽  
Population Based ◽  
Cross Sectional Study ◽  
Only Child ◽  
Cross Sectional ◽  
Live Births ◽  
Child Group

ObjectivesThis study aims to explore the association between maternal depression and the loss of the only child under the family-planning (FP) policy.DesignCross-sectional data from a Chinese population-based study were analysed.SettingPopulation from 10 (5 rural and 5 urban) areas in China.ParticipantsAround 300 000 females were included in the study. The FP group was defined as women with one or two live births. Those with no surviving child were classified into the loss-of-only-child group. The non-FP group included women who had more than two live births. Logistic regression was used to assess the relationship between major depressive disorder (MDD) and family types, after stratification and adjustment.OutcomeMDD was assessed using the Composite International Diagnostic Inventory.ResultsThe odds of MDD are 1.42 times higher in the FP group in general (OR=1.42, 95% CI: 1.28 to 1.57), as opposed to the non-FP group. In particular, the odds of MDD are 1.36 times greater in the non-loss-of-only-child group (OR=1.36, 95% CI: 1.21 to 1.51) and 2.80 (OR=2.80, 95% CI: 0.88 to 8.94) times greater in the loss-of-only-child group, compared with the non-FP group. The associations between FP groups and MDD appeared to be stronger in the elderly population, in those who were married, less educated and those with a higher household income. The association was found progressively stronger in those who lost their only child.ConclusionsPeople in the FP group, especially those who lost their only child, are more susceptible to MDD than their counterparts in the non-FP group. Mental health programmes should give special care to those who lost their only child and take existing social policies and norms, such as FP policies, into consideration.

scholarly journals Green and Blue Space Availability and Self-Rated Health among Seniors in China: Evidence from a National Survey

2021 ◽  
Vol 18 (2) ◽  
pp. 545
Author(s):  
Chensong Lin ◽  
Longfeng Wu
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Empirical Studies ◽  
National Level ◽  
The Elderly ◽  
Coverage Ratio ◽  
Self Rated Health ◽  
Health Promoting ◽  
Major River ◽  
Urban And Rural Areas

Many empirical studies have shown evidence of multiple health benefits provided by green and blue spaces. Despite the importance of these spaces, investigations are scarce in details for blue spaces rather than green. Moreover, most research has focused on developed regions. A limited number of studies on blue spaces can be found in China with a focus on the city level. Outcomes have been mixed due to varying research scales, methodologies, and definitions. This study relies on a national-level social survey to explore how the self-rated health (SRH) of senior individuals is associated with local green and blue space availability in urban and rural areas. Results indicate that the coverage ratio of overall green spaces and waterbodies around a resident’s home have marginal effects on SRH status in both urban and rural areas. In urban areas, living close to a park can is marginally beneficial for older people’s health. Regarding different types of blue spaces, the presence of a major river (within 0.3–0.5 km) or coastline (within 1 km and 1–5 km) in the vicinity of home negatively affects SRH among the elderly in urban areas. Close proximity to lakes and other types of waterbodies with a water surface larger than 6.25 ha did not significantly influence SRH. These findings not only evaluate general health impacts of green/blue space development on senior populations across the county but inform decision makers concerning the health-promoting qualities and features of different green/blue spaces to better accommodate an aging population in the era of urbanization.

A Hydraulic Control System Design for Change-Wheel Garage of Light Rail Based on PLC

2012 ◽  
Vol 233 ◽  
pp. 76-79
Author(s):  
Yong Gang Yang ◽  
Jun Sun ◽  
Meng Tao Yang
Keyword(s):  
Control System ◽  
System Design ◽  
Servo Control ◽  
Light Rail ◽  
Control System Design ◽  
Hydraulic Control ◽  
Plc Control ◽  
Servo Control System ◽  
Hydraulic Servo ◽  
Hydraulic Control System

This paper introduces the hydraulic control system design for the change-wheel garage of Chongqing light rails through analysis of three-stage cylinder synchronization circuit for lifting bodies, and optimizing the design of the slewing mechanism with respect to the hydraulic servo control system of digital cylinder. The results improved the smoothness in the process of changing wheel lifting and the rotary accuracy of the rotary mechanism. Design on the PLC control system of the system is also included as part of this paper.

Modeling and Simulation of Improved Vector Control System for PMSM

2014 ◽  
Vol 548-549 ◽  
pp. 819-823
Author(s):  
Xi Juan Wang ◽  
Tao Zhou ◽  
Jing Xiao Feng ◽  
Yu Peng Pei
Keyword(s):  
Control System ◽  
Control Theory ◽  
Modeling And Simulation ◽  
Vector Control ◽  
System Model ◽  
Excellent Performance ◽  
Matlab Simulink ◽  
Ac Motor ◽  
Control System Model ◽  
Vector Control System

In the AC control system, vector control theory is very popular as it makes the AC motor achieve the performance as perfect as DC motor [1]. In the paper, the vector control theory is briefly introduced, and then a vector control system model is builded in the matlab/simulink, and the SVPWM technique is adopted. The results show that the improved vector control sytem of PMSM has a excellent performance.

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