Profile Optimization of Table Top Speed Hump for Speed Control

2011 ◽  
Author(s):  
Theunis R. Botha ◽  
Pieter S. Els ◽  
Petronella E. Uys ◽  
Rudolf Bester
Keyword(s):  
Urban Areas ◽  
World Wide ◽  
Ride Comfort ◽  
Vehicle Control ◽  
Vehicle Speed ◽  
Loss Of Control ◽  
Vehicle Model ◽  
Gradient Based ◽  
Profile Optimization ◽  
Set Up

Speed bumps are the most commonly used measure to control speeding in urban areas world wide. Specifications on profiles and dimensions are largely based on road tests. Studies into speed bumps, directed at evaluating their effectiveness in reducing accidents and their environmental impact, have brought some negative aspects concerning speed bumps to light. These aspects include incidents of spinal and neck injury or loss of control while speeding over speed bumps. Observations have also shown that speeding over certain speed bumps often result in an improvement in ride comfort, thus negating the effectiveness of speed bumps as a measure to control speeding. This paper addresses these aspects by considering the optimization of a speed bump’s profile. The profile is optimized by means of a validated non-linear four degree of freedom vehicle model, as well as the gradient based LFOPC optimization algorithm. The optimized profile allows for increased ride comfort at speeds at and below the designed speed. The ride comfort decreases with an increase in vehicle speed while the vehicle response remains within boundaries set up to reduce the possibility of injury or loss of vehicle control.

scholarly journals Raised Pedestrian Crossings: Analysis of Their Characteristics on a Road Network and Geometric Sizing Proposal

2019 ◽  
Vol 9 (14) ◽  
pp. 2844 ◽  
Author(s):  
Loprencipe ◽  
Moretti ◽  
Pantuso ◽  
Banfi
Keyword(s):  
Urban Areas ◽  
Ride Comfort ◽  
International Standards ◽  
Motor Vehicles ◽  
Whole Body ◽  
Vehicle Speed ◽  
Traffic Calming ◽  
Dynamic Performances ◽  
Vertical Accelerations ◽  
Pedestrian Crossing

In urban areas traffic-calming strategies and pedestrian friendly measures are often adopted to reduce the adverse impacts of motor vehicles on vulnerable users. This study surveyed 24 raised pedestrian crossings (RPCs) to examine their geometrical and functional characteristics. Geometric characteristics, location, administrative and effective vehicle speed, and the whole-body vibration acceleration induced to vehicle occupants while they are passing over, were considered. In addition to the analysis of the field data, geometrical and functional criteria to design RPCs were carried out. Particularly, two design approaches have been considered. In the first one, RPC provides a designated route across a carriageway raised to the same level, or close to the same level, as the sidewalks that provide access to the pedestrian crossing. In such condition, an RPC is not a traffic-calming device and its design should satisfy geometrical and comfort criteria for designing roads. The results from the surveys demonstrated that less than 10% of RPCs guarantee ride comfort. According to the second design approach, an RPC acts both as a marked pedestrian feature and as a traffic-calming device (i.e., it is trapezoidal in shape with sharp edges). The analysis of the vertical accelerations on vehicle occupants reveal that more than 90% of the surveyed RPCs comply with geometrical and dynamic criteria for speed tables. Extreme variations concerning the observed geometrical characteristics of RPCs and the modelled dynamic performances have been observed: It results in noneffective treatments. Therefore, the results of this study would contribute to providing geometric best practices for overcoming the regulation gap in this subject, and designing RPCs according to international standards.

Fuzzy Control of Tracked Vehicle’s Semi-Active Suspension System Based on LMS

2014 ◽  
Vol 602-605 ◽  
pp. 1313-1316 ◽  
Author(s):  
Xiao Dong Gao ◽  
Liang Gu ◽  
Ji Fu Guan ◽  
Jun Feng Gao
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Ride Comfort ◽  
Fuzzy Controller ◽  
Active Suspension ◽  
Adaptive Control System ◽  
Vehicle Model ◽  
Tracked Vehicle ◽  
Change Rate ◽  
Set Up

A half tracked vehicle model was established based on LMS, a co-simulation interface between control algorithm of MATLAB and physical model of LMS was set up. Fuzzy controller with PID regulator was proposed to achieve controlling strategy based on half tracked vehicle model. With suspension stroke and its change rate as input parameters of fuzzy controller, the dynamic adjusting parameters of PID controller are acquired through fuzzy controller, then a semi-active suspension vehicle adaptive control system was formed. The simulation result shows that the adaptive control system can effectively coordinate the contradiction acceleration and dynamic travel in different bands, the ride comfort tracked vehicle is significantly improved.

scholarly journals Dynamic Characteristics Analysis of ISD Suspension System under Different Working Conditions

Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1345
Author(s):  
Xiaopeng Li ◽  
Fanjie Li ◽  
Dongyang Shang
Keyword(s):  
Ride Comfort ◽  
Vibration Reduction ◽  
Suspension System ◽  
Dynamic Responses ◽  
Vehicle Body ◽  
Vehicle Speed ◽  
Vehicle Model ◽  
System A ◽  
Characteristics Analysis ◽  
Road Excitation

The “inerter-spring-damper” (ISD) suspension system is a suspension system composed of an inerter, spring, and damper. To study the ride comfort and stability of the vehicle by using the ISD suspension system, a vehicle model with ISD suspension is established in this paper. The vehicle model including vertical, pitch, roll, and yaw motion of the vehicle body. Based on the vehicle model, the differential equation of motion with ISD suspension is obtained. The dynamic responses of the ISD suspension system are investigated by using different road excitations. At the same time, the influence of coupled excitation and single excitation on the vibration reduction performance of the ISD suspension system is studied. Then, the dynamic responses of ISD suspension and passive suspension are compared, and the improvement of comprehensive vibration reduction performance of ISD suspension system is quantitatively analyzed. The numerical results illustrate the ISD suspension has the optimal vehicle speed under different road excitations, and the comprehensive vibration reduction performance of the ISD suspension is the best when driving at the optimal vehicle speed. Under different types of road excitation, ISD suspension shows excellent comprehensive vibration reduction performance. ISD suspension is more suitable for vibration reduction of complex roads than that of a single road.

scholarly journals The Control of an Active Seat Suspension Using an Optimised Fuzzy Logic Controller, Based on Preview Information from a Full Vehicle Model

Vibration ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 20-40 ◽  
Author(s):  
Abdulaziz Alfadhli ◽  
Jocelyn Darling ◽  
Andrew Hillis
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Ride Comfort ◽  
Vertical Direction ◽  
Front Axle ◽  
Rule Base ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Vehicle Model ◽  
Full Vehicle

The use of suspension preview information obtained from a quarter vehicle model (QvM) to control an active seat has been shown by the authors to be very promising, in terms of improved ride comfort. However, in reality, a road vehicle will be subjected to disturbances from all four wheels, and therefore the concept of preview enhanced control should be applied to a full vehicle model. In this paper, different preview scenarios are examined, in which suspension data is taken from all or limited axles. Accordingly, three control strategies are hypothesized—namely, front-left suspension (FLS), front axle (FA), and four wheel (4W). The former utilises suspension displacement and velocity preview information from the vehicle suspension nearest to the driver’s seat. The FA uses similar preview information, but from both the front-left and front-right suspensions. The 4W controller employs similar preview information from all of the vehicle suspensions. To cope with friction non-linearities, as well as constraints on the active actuator displacement and force capabilities, three optimal fuzzy logic controllers (FLCs) are developed. The structure of each FLC, including membership functions, scaling factors, and rule base, was sequentially optimised based on improving the seat effective amplitude transmissibility (SEAT) factor in the vertical direction, using the particle swarming optimisation (PSO) algorithm. These strategies were evaluated in simulation according to ISO 2631-1, using different road disturbances at a range of vehicle forward speeds. The results show that the proposed controllers are very effective in attenuating the vertical acceleration at the driver’s seat, when compared with a passive system. The controller that utilised suspension preview information from all four corners of the car provided the best seat isolation performance, independent of vehicle speed. Finally, to reduce the implementation cost of the “four suspension” controller, a practical alternative is developed that requires less measured preview information.

scholarly journals Research on Model Predictive Control for Automobile Active Tilt Based on Active Suspension

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 671
Author(s):  
Jialing Yao ◽  
Meng Wang ◽  
Zhihong Li ◽  
Yunyi Jia
Keyword(s):  
Load Transfer ◽  
Ride Comfort ◽  
Active Suspension ◽  
Path Tracking ◽  
Roll Angle ◽  
Lateral Acceleration ◽  
Vehicle Speed ◽  
Model Predictive Controller ◽  
Advantages And Disadvantages ◽  
Predictive Controller

To improve the handling stability of automobiles and reduce the odds of rollover, active or semi-active suspension systems are usually used to control the roll of a vehicle. However, these kinds of control systems often take a zero-roll-angle as the control target and have a limited effect on improving the performance of the vehicle when turning. Tilt control, which actively controls the vehicle to tilt inward during a curve, greatly benefits the comprehensive performance of a vehicle when it is cornering. After analyzing the advantages and disadvantages of the tilt control strategies for narrow commuter vehicles by combining the structure and dynamic characteristics of automobiles, a direct tilt control (DTC) strategy was determined to be more suitable for automobiles. A model predictive controller for the DTC strategy was designed based on an active suspension. This allowed the reverse tilt to cause the moment generated by gravity to offset that generated by the centrifugal force, thereby significantly improving the handling stability, ride comfort, vehicle speed, and rollover prevention. The model predictive controller simultaneously tracked the desired tilt angle and yaw rate, achieving path tracking while improving the anti-rollover capability of the vehicle. Simulations of step-steering input and double-lane change maneuvers were performed. The results showed that, compared with traditional zero-roll-angle control, the proposed tilt control greatly reduced the occupant’s perceived lateral acceleration and the lateral load transfer ratio when the vehicle turned and exhibited a good path-tracking performance.

Effect of unsupported sleepers on dynamic behavior of running vehicles and ride comfort index

2021 ◽  
pp. 095440622198937
Author(s):  
Mojtaba Azizi ◽  
Majid Shahravi ◽  
Jabbar-Ali Zakeri
Keyword(s):  
Numerical Model ◽  
Dynamic Behavior ◽  
Multibody Dynamics ◽  
Field Test ◽  
Ride Comfort ◽  
Vehicle Speed ◽  
Comfort Index ◽  
Railway Industry ◽  
Flexible Track ◽  
Train Speed

Nowadays, with various advancements in the railway industry and increasing speed of trains, the design of railway tracks and vehicles has become vitally important. One of the frequent problems of ballasted tracks is the existence of unsupported sleepers. This phenomenon occurs due to the lack of ballast underneath the sleepers. Here, a model is presented, in which a flexible track model in a multibody dynamics program is developed, in order to study the dynamic behavior of a vehicle. By utilizing the model, it is feasible to simulate unsupported sleepers on the flexible track including rail, sleeper, and ballast components. In order to verify the results of numerical model, a field test is performed. Findings indicate that, in the case of a single unsupported sleeper through the track, the ride comfort index increased by 100% after increasing the train speed from 30 to 110 km/h. Moreover, when it is needed to have ride comfort index improvement over the uncomfortable level, the vehicle speed should be less than 70 km/h and 50 km/h for tracks with one unsupported sleeper and two unsupported sleepers, respectively.

PANDORA: Providing Long Term Access to Australia's Online Electronic Publications

1998 ◽  
Vol 10 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Wendy Smith
Keyword(s):  
World Wide Web ◽  
World Wide ◽  
The Internet ◽  
Online Environment ◽  
National Library ◽  
Policies And Procedures ◽  
Electronic Publications ◽  
Set Up ◽  
Printed Materials

The Internet, particularly through the application of World Wide Web (WWW) technology, has proved to be a very attractive medium for publishing. However, the difficulties of finding appropriate information online and then of ensuring its long term accessibility have created problems for libraries. Practices that work for books and other printed materials do not always translate directly to online materials. The National Library of Australia's PANDORA project has been set up to develop policies and procedures for ensuring long term access to significant Australian publications which are accessible only in an online environment, and to establish and maintain a permanent archive ofthat material.

scholarly journals Experimental Study on Different Types of Curves for Ride Comfort in Automated Vehicles

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Naohisa Hashimoto ◽  
Yusuke Takinami ◽  
Makoto Yamamoto
Keyword(s):  
Traffic Accidents ◽  
Field Experiments ◽  
Ride Comfort ◽  
Vehicle Control ◽  
Automated Vehicles ◽  
Significance Level ◽  
Automated Vehicle ◽  
Driving Assistance ◽  
Human Factor Research ◽  
Automated Vehicle Control

Vehicle automation is among the best possible solutions for traffic issues, including traffic accidents, traffic jams, and energy consumption. However, the user acceptance of automated vehicles is critical and is affected by riding comfort. In addition, human factors in automated vehicle control should be clear. This study evaluates the effect of different courses on driving comfort in automated vehicles using field experiments with 25 subjects. This study focused on lateral motion, but speed control was not targeted. Further, generating a path for obstacle avoidance and lane keeping, which have several constraining conditions, was also not targeted. Rendering a comfortable path is beneficial for developing an acceptable system as a car developer and for building new curves for automated or driving assistance systems from the perspective of construction. The automated vehicle drove at a speed of 30 km/h on four courses, namely, clothoid, two types of spline curves, and arc, based on the real intersection. Each participant sat on both the driver and passenger seat and answered a questionnaire. The experimental data indicated the clothoid course to be the most comfortable, while the arc was most uncomfortable for a significance level of 1%. These tendencies are applicable to driver and passenger seats, all genders, and experiences and will be beneficial for human factor research in automated vehicle control.

scholarly journals Integrated Passenger Transport System in Rural Areas – A Literature Review

2020 ◽  
Vol 32 (6) ◽  
pp. 863-873
Author(s):  
Branimir Maretić ◽  
Borna Abramović
Keyword(s):  
Literature Review ◽  
Transport System ◽  
Rural Areas ◽  
Urban Areas ◽  
Planning System ◽  
Passenger Transport ◽  
Public Transport System ◽  
Urban And Rural Areas ◽  
Set Up ◽  
The Impact

The planning and organisation of public passenger transport in rural areas is a complex process. The transport demand in rural areas is often low, which makes it hard to establish and run a financially sustainable public transport system. A solution is integrated passenger transport that eliminates deficiencies and provides benefits for all participants in the public passenger transport process. This paper describes the impact of integrated passenger transport on mobility in rural areas and critically evaluates different literature sources. Integration of passenger transport in urban areas has been described in the context of rural areas, and the challenges of integration of public passenger transport specific to rural areas have been analysed. Through the application in urban and rural areas, the planning of integrated and non-integrated passenger transport has been functionally analysed. The analysis found an increase in the degree of mobility in the areas that use integrated passenger transport compared to the non-integrated one. This research of the literature review has identified the rural areas of mobility as under-researched. The mobility research can set up a more efficient passenger transport planning system in rural areas.

scholarly journals Float: Designing for the Rise in Sea Level

2019 ◽  
Author(s):  
Camilo Cerro ◽  
Keyword(s):  
Sea Level ◽  
Urban Areas ◽  
Healthcare Education ◽  
American University ◽  
Real Possibility ◽  
Urban Problem ◽  
Will Force ◽  
Complex Relationships ◽  
Set Up ◽  
Floating Systems

According to the United Nations, presently, about 54% of the world’s population lives in urban areas, with the number expected to increase to 66% by 2050. Urban areas which are ill prepared to deal with their present population needs will have to develop and manage; housing, healthcare, education, transportation, infrastructure and food pro-duction for an additional 2.5 billion people. With three-quarters of the world’s megalopolis by the sea and 80% of people living within 60 miles of the coast, sea level rise will force a new way of thinking about urban development. Managing urban areas has become one of the most important development challenges of the 21st century. In the UAE specifically, there are nearly 1,300 kilometers of coast-line. Approximately 85% of the population and over 90% of the infra-structure are located within several meters of sea level in low-lying coastal areas. This poses a very specific urban problem of relocation. But not all relocation will need to be done inland. The potential for floating architecture is a very real possibility to help solve some of the problems brought on by the rise in sea level. This is why at the American University of Sharjah, we have been studying this issue and other sustainability related opportunities in a series of courses that started in 2014 with a summer studio course set in Cambodia. Students lived with a floating community in the Tong le Sap lake for a month, studying vernacular floatation systems to inform the development of proposals for floating dwelling studies. This semester (Spring 2018), a fifth year architecture studio set up to transfer specific urban functions to the water within protected areas in the UAE. The aim of the studio was to start looking at possible implementation of floating systems within everyday functions to start a discussion of the potential of this technologies and the feasibility of its use at both an industrial and commercial level. The idea was to develop a series systemic interdependent sustainable designs based on the idea of third nature, hybridizing complex relationships between distinct functions in environments above and below water. This paper will cover the methodology implemented to start tackling these subjects in the studio environment with the aim to create awareness for designers and the general public.

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