E. Olmeda

SIMPERF: SIMULINK‐based educational software for vehicle's performance estimation

This paper presents an educational software called SIMPERF developed to allow the engineering students to learn easily and quickly about the vehicles performance calculations. This software uses the SIMULINK library of MATLAB which has shown to be a good choice to implement and solve the implicated equations. The model allows us to achieve the vehicles performances with enough accuracy and to modify the parameters than influence on these performances quickly and easily in order to understand the physic phenomena involved.

Bump Modeling and Vehicle Vertical Dynamics Prediction

During a journey, motor vehicles are subjected to different types of irregularities in the pavement. Some of these irregularities are introduced for a specific purpose over a stretch of road to slow down the vehicle at certain road points. However, the influence of installed speed bumps reveals certain additional effects which must be deeply analyzed to ensure vehicle and pedestrian safety. In some cases, it has been found that even when driving over transverse bands at a speed below the legal limit, the vehicle is damaged or tires lose grip with the pavement, precluding any kind of braking or turning maneuvers. Such phenomena indicate that either this element is not properly sized or the location is not appropriate, becoming counterproductive for traffic safety. In order to analyze the influence of these irregularities on the different components of the vehicle and its occupants, a simulation program with MatlabTM has been developed. The validated developed tool takes into account several aspects of the vehicle dynamics, bump geometry, and vehicle speed. The proposed tool provides the best possible information to establish a set of guidelines for the proper design and installation of speed bumps in different roads.

Head injury criterion: the best way to evaluate head damage?

During the design and construction of a new car model, there are a lot of important aspects that have to be taken into account. The cars designers look for a beautiful appearance, for a car as light as possible, try to reduce the manufacture costs and times and, of course, want to guarantee that their car is as safe as it can be. There are several criteria that allow to quantify the safety of a car. One of them, the Head Injury Criterion (also known as HIC) gives a measure of the damage that the head can suffer in case of collision. This paper presents a review of some works related to this criterion. It will be proved that the HIC has several limitations that allow to say that this criterion is clearly improvable.

Influence of Speed Bumps Design on Vehicle Safety

During a journey motor vehicles are forced to overcome different types of irregularities in the pavement. Such irregularities can be random or introduced for a specific purpose, such as asphalt protrusions and transversal bands of rubber, which have been installed into all sorts of avenues and roads open to traffic. Generally, these elements are included in a stretch of road to slow down the vehicle velocity at certain sites, such as pedestrian crossings. However, the influence of speed bumps installed shows other additional effects which must be studied to ensure the safety of vehicles and pedestrians. In some cases, it is found that, passing over ridges and transverse bands at a speed below the limit defined by law, the vehicle is damaged or the tires lose grip with the pavement, precluding any kind of braking or turning maneuvers. Such phenomena indicate that this element is not properly sized, or the placement is not appropriate, becoming counterproductive for traffic safety. In spite of the importance of these consecuences derivated from these elements they haven’t been studied deeply enough and there are very few paper about this subject. In order to analyze the actions generated by the overcome of these irregularities on the different components of the vehicle and its occupants, the problem has been studied not only using computer simulation but also by means of experimental testing on a real vehicle where accelerometers were installed in order to check the severity of the bumps. CarSimTM has been the simulation software used to calculate vehicle dynamic forces on the tires and suspension system and the accelerations and displacements that are applied to the vehicle. To characterize the behavior of a vehicle when is driven over one of these obstacles, it is necessary to study several parameters such as: speed, geometry and dimensions of the bump, and the type of vehicle and its suspension. From this information it is possible to establish a set of guidelines for the proper design and installation of speed bumps in different roads.Copyright

Bus mathematical model of acceleration threshold limit estimation in lateral rollover test

Vehicle safety is a major concerns for researchers, governments and vehicle manufacturers, and therefore a special attention is paid to it. Particularly, rollover is one of the types of accidents where researchers have focused due to the gravity of injuries and the social impact it generates. One of the parameters that define bus lateral behaviour is the acceleration threshold limit, which is defined as the lateral acceleration from which the rollover process begins to take place. This parameter can be obtained by means of a lateral rollover platform test or estimated by means of mathematical models. In this paper, the differences between these methods are deeply analysed, and a new mathematical model is proposed to estimate the acceleration threshold limit in the lateral rollover test. The proposed model simulates the lateral rollover test, and, for the first time, it includes the effect of a variable position of the centre of gravity. Finally, the maximum speed at which the bus can travel in a bend without rolling over is computed.

BONDSYM: SIMULINK-based educational software for analysis of dynamic system

This article presents an educational software called BONDSYM developed to allow engineering students to learn easily and quickly about the analysis of dynamic systems through the Bond Graph method. This software uses the SIMULINK library of MATLAB, which has proven to be an excellent choice in order to implement and solve the dynamic equations involved. The application allows for the representation of the behavior of a dynamic system analyzed through the Bond Graph theory in order to understand the dynamic equations and the physical phenomena involved. Based on block diagram of SIMULINK, the different “bonds” of Bond Graph can be integrated as SIMULINK blocks in order to generate the dynamic model. A few simple models are analyzed through this application.

Procedure to verify the maximum speed of automatic transmission mopeds in periodic motor vehicle inspections

Abstract Mopeds are very popular vehicles in Europe for teenagers. They have many advantages as they provide mobility, have a low maintenance cost, and are easy and fun to drive. However, they can be dangerous if their performance is modified in order to obtain higher features that do not comply with the legal established limits. One of the features commonly manipulated on a moped is the maximum speed. However, drive safety is seriously affected. For this reason, an important item to verify on periodic motor vehicle inspection (PMVI) is the maximum speed of the moped. The aim of the present paper is to establish a procedure to check the moped maximum speed during PMVI. A rolling test bench, a test procedure, and a speed limit on this rolling test bench that could be correlated with the test track results have been established from a statistical study with a representative population of automatic transmission mopeds.

Clutch Pedal Sensorization and Evaluation of the Main Parameters Related to Driver Posture

An improper decision for the design, selection and adjustment of the components needed to control a vehicle could generate negative effects and discomfort to the driver, where pedals play a very important role. The aim of the study is to provide a first approach to develop an embedded monitoring device in order to evaluate the posture of the driver, the influence of the clutch pedal and to advise about the possible risk. With that purpose in mind, a testbed was designed and two different sets of tests were carried out. The first test collected information about the volunteers who were part of the experiment, like the applied force on the clutch pedal or the body measurements. The second test was carried out to provide new insight into this matter. One of the more significant findings to emerge from this study is that the force applied on the clutch pedal provides enough information to determine correct driver posture. For this reason, a system composed of a pedal force sensor and an acquisition/processing system can fulfil the requirements to create a healthcare system focused on driver posture.

Characterization of the Noise Emissions of a Passenger Vehicle

One of the main sources of noise pollution in cities is vehicle traffic. In this paper a characterization of the noise emission of a passenger vehicle has been carried out. With this aim a representative driving route for noise emission has been defined in order to study the influence of the driver typology and vehicle type. Therefore, this investigation has been developed in three phases: Firstly, usual driving in an urban area like Madrid has been characterized with a specific driving route. In addition, several vehicle models with great presence in the existing fleet of cars have been selected. Several drivers have covered the driving route at different times of the day and previous parameters have been measured in each test in order to determine average values of behavior. Secondly, the type of vehicles and drivers influence in noise emissions has been deeply analyzed. To achieve this aim a sample of vehicles has been instrumented to obtain physical measurements of the variables that can influence the noise emission level. Positions, velocities, accelerations (longitudinal and lateral) and time have been analyzed using a GPS sensor. Parameters such as, engine speed, engine load, throttle position and engine temperature have been studied through the vehicle CAN BUS and a set of microphones has measured the emitted noise in several points of the vehicle. In order to study the ecological and safety impact in urban and interurban roads by means of the measurement of noise emissions the analysis of the driver behaviour is of paramount importance. To conclude, the previous data has been analyzed and noise equivalent levels have been identified with different test configurations.Copyright