Method for control of steering angles for articulated vehicles using virtual rigid axles

Many methods we have been developed to control the rear wheels of a vehicle, but most of them are designed for automobiles with four wheels. The AWS (all wheel steering) control method for articulated vehicles is currently applied only to Phileas vehicles developed by APTS, but the control algorithm for this system has yet to be reported. In the present paper, a new algorithm is proposed after the AWS ECU (electronic control unit) of the Phileas vehicle was tested and analyzed in order to understand the existing steering algorithm. The new algorithm considers the vehicle geometry, stability of handling, and safety, and can be easily applied to multi-axle vehicles. In order to verify the AWS algorithm, the trajectory and steering angles of each algorithm were compared using the commercial software ADAMS. Turning radius, swing-out, and swept path width were also investigated to determine the turning performance of the proposed algorithm.     

Experimental study of the characteristics of idle vibrations that result from axial forces and the spider positions of constant velocity joints

The vibrational characteristics of automotives during idling were studied experimentally by considering the axial forces of the drive shaft and the spider positions in a constant-velocity joint. The generated forces, such as PF (plunging force) and GAF (generated axial force) in the assembly of the drive-shaft module, were measured directly by an experimental apparatus. Measurements of the GAF and PF did not show the same trends as the joint angles. They depended instead on the types of CV joints. In addition, the relationship between the offset values of the shaft and the spider positions in the tulip of the constant-velocity joint were studied. As a result, the idle vibration characteristics were affected by the variation of the spider positions and the vibrational characteristics in the axial direction of the shaft, including the amplitude and the harmonic periods.     

From suspended particles to strata: The fate of terrestrial substances in the Gaoping (Kaoping) submarine canyon

The river–sea system consisting of the Gaoping (new spelling according to the latest government's directive, formerly spelled Kaoping) River (KPR), shelf, and Submarine Canyon (KPRSC) located off southern Taiwan is an ideal natural laboratory to study the source, pathway, transport, and fate of terrestrial substances. In 2004 during the flood season of the KPR, a system-wide comprehensive field experiment was conducted to investigate particle dynamics from a source-to-sink perspective in the KPRSC with the emphasis on the effect of particle size on the transport, settling, and sedimentation along the pathway. This paper reports the findings from (1) two sediment trap moorings each configured with a Technicap PPS 3/3 sediment trap, and an acoustic current meter (Aquadopp); (2) concurrent hydrographic profiling and water sampling was conducted over 8 h next to the sediment trap moorings; and (3) box-coring in the head region of the submarine canyon near the mooring sites. Particle samples from sediment traps were analyzed for mass fluxes, grain-size composition, total organic carbon (TOC) and nitrogen (TN), organic matter (OM), carbonate, biogenic opal, polycyclic aromatic hydrocarbon (PAH), lithogenic silica and aluminum, and foraminiferal abundance. Samples from box cores were analyzed for grain-size distribution, TOC, particulate organic matter (POM), carbonate, biogenic opal, water content, and ²¹⁰Pb_ex. Water samples were filtered through 500, 250, 63, 10 µm sieves and 0.4 µm filter for the suspended sediment concentration of different size-classes.Results show that the river and shelf do not supply all the suspended particles near the canyon floor. The estimated mass flux near the canyon floor exceeds 800 g/m²/day, whose values are 2–7 times higher than those at the upper rim of the canyon. Most of the suspended particles in the canyon are fine-grained (finer than medium silt) lithogenic sediments whose percentages are 90.2% at the upper rim and 93.6% in the deeper part of the canyon.As suspended particles settle through the canyon, their size-composition shows a downward fining trend. The average percentage of clay-to-fine-silt particles (0.4–10 µm) in the water samples increases from 22.7% above the upper rim of the canyon to 56.0% near the bottom of the canyon. Conversely, the average percentage of the sand-sized (> 63 µm) suspended particles decreases downward from 32.0% above the canyon to 12.0% in the deeper part of the canyon. Correspondingly, the substrate of the canyon is composed largely of hemipelagic lithogenic mud. Parallel to this downward fining trend is the downward decrease of concentrations of suspended nonlithogenic substances such as TOC and PAH, despite of their affinity to fine-grained particles.On the surface of the canyon, down-core variables (grain size, ²¹⁰Pb_ex activity, TOC, water content) near the head region of the canyon show post-depositional disturbances such as hyperpycnite and turbiditic deposits. These deposits point to the occurrences of erosion and deposition related to high-density flows such as turbidity currents, which might be an important process in submarine canyon sedimentation.     

Path planning and collision avoidance for autonomous surface vehicles II: a comparative study of algorithms

Journal of Marine Science and Technology - Artificial intelligence is an enabling technology for autonomous surface vehicles, with methods such as evolutionary algorithms, artificial potential...     

Urban driving cycle for performance evaluation of electric vehicles

Nowadays, a number of environmental issues have seriously come to the fore. For this reason, the R & D spending on eco-friendly vehicles that use electric power has been gradually increasing. In general, fuel economy and pollutant emissions of both conventional and eco-friendly vehicles are measured through chassis dynamometer tests that are performed on a variety of driving cycles before an actual driving test. There are a number of driving cycles that have been developed for the for performance evaluation of conventional vehicles. However, there is a lack of research into driving cycle for EV. Because large differences exist between the drive system and driving charateristics of EV and that of CV, a study on driving cycle for EV should be conducted. In this study, the necessity of an urban driving cycle for the performance evaluation of electric vehicles is confirmed by developing the driving cycle. First, the Gwacheon-city Urban Driving Cycle for Electric Vehicles (GUDC-EV) is developed by using driving data obtained through actual driving experiments and statistical analysis. Second, GUDC-EV is verified by constructing EV simulators and performing simulations that use the actual driving data. The simulation results are then compared against existing urban driving cycles, such as FTP-72, NEDC, and Japan 10–15. These results confirm that GUDC-EV can be used as an urban driving cycle to evaluate the performance of electric vehicles and validate the necessity of development of the driving cycle for electric vehicles.     

Characteristics of collision damage mitigation braking system for pedestrian protection

The vehicle travel velocity at pedestrian contact is considered to be an important parameter that affects the crash outcome. To reduce vehicle/pedestrian impact velocity, a collision damage mitigation braking system (CDMBS) using a sensor for pedestrian protection could be an effective countermeasure. The first purpose of this study is to clarify the relation between vehicle travel velocity and pedestrian injury severity due to differences in pedestrians’ ages in actual traffic accidents. The accident analyses were performed using vehicle-pedestrian accident data in 2009 from the database of the Institute for Traffic Accident Research and Data Analysis (ITARDA) in Japan. The result revealed that the fatality risk became higher with the increase in vehicle travel velocity. The second purpose of this study is to determine the safety performance of production vehicles equipped with the CDMBS for pedestrian protection. It was found that the CDMBS was highly effective in reducing the impact velocity from 50 km/h (vehicle travel velocity) to below 17 km/h, that could result in a significant decrease in fatality risk to be 2% or less. Additionally, the authors investigated a detectable zone with respect to a pedestrian’s position in relation to the vehicle. It was shown that the detectable zones for production vehicles tested were limited to be inside the vehicle front width.     

Computer Aided Simulation on Precision Cold Forging of Universal Joint Cross

IntroductionThefiwtee1emenmethod(FEM)playsanextrmelyimPortantroleintheanalysesofengineeringproblems.ForalongtimethismethodhasmainlybeenaPPliedinthelinearfieldandshownitsgreatpower.HoweveealOtofnonlinearengineeringPrOblemsWhichcanneitherbesimPlyreducedtolinearonesnorrCPresentedbylinearlyanalogywhichshallchnsethePfacticalconditionsrelativelymuch,havechallengedfiniteelementmethod(FEM).RecentymuchProgresshasbeenmadebothinthemathematicalandmechanicaltheoryandthecomPulertechnologysothatevent…     

机车车辆的主要发展方向

铁路运输拥有系统上的优势,尤其是能源和生态优势,但是,为了能获得社会的更好评价和吸引更多客运量和货运量,重要的就是要在机车车辆制造时保证不断采用新技术方案,以便提高旅客舒适度,降低噪声和振动,保证整个铁路系统电磁兼容性和功能的可靠性.     

Development and performance analysis of an automotive power seat for disabled persons

As the number of disabled people grows, independence and mobility become a priority for those individuals. To achieve this goal, a ‘Turny-type power seat’ was developed in this study to assist a disabled person rise from a vehicle without trouble. The design and modeling of the power seat were performed using AutoCAD and CATIA software. The major motions of the power seat system are swiveling, sliding, and extending, which are accomplished primarily by DC motors, chains, and gears. Most of the power seat parts were made from mild steel. Welding technology was used throughout the frame fabrication. To ensure the safety and stability of the power seat, various tests were performed, and the results analyzed. The static analysis of the power seat was carried out by ANSYS 11.0. The results showed that the power seat conformed to the Americans with Disabilities Act (ADA) standards. The durability test was performed by repeatedly rotating and sliding the power seat under loading conditions. Dynamic crash simulation was carried out using the LS-DYNA software. The durability test ensured a longer life of the power seat, while the crash analysis showed a small rotational distortion that was not harmful to passengers. However, the front seat had a slightly larger forward displacement, which was not comfortable for passengers. Therefore, further modifications of the power seat should be done to improve the performance, with attention given to the reduction of the forward displacement in the event of a crash.     

An Alternative Method to Determine the Magic Tyre Model Parameters Using Genetic Algorithms

Summary Tyre behavior plays an important role in vehicle dynamics research. Knowledge of tyre properties is necessary to properly design vehicle components and advance control system. For that purpose mathematical models of the tyre are being used in vehicle simulation models. The Magic Formula Tyre Model is a semi-empirical tyre model which describes tyre behavior quite accurately. The Magic Formula Tyre Model needs a set of parameters to describe the tyre properties; the determination of these parameters is dealt with in this paper. A new method based on genetic techniques is used to determine these parameters. The main advantages of the method are its simplicity of implementation and its fast convergence to optimal solution, with no need of deep knowledge of the searching space. So to start the search, it is not necessary to know a set of starting values of the Magic Formula parameters. The comparison between analytical optimization methods and the method proposed is discussed in this paper.