Design and Validation of a High-Level Controller for Automotive Active Systems

Active systems, from active safety to energy management, play a crucial role in the development of new road vehicles. However, the increasing number of controllers creates an important issue regarding complexity and system integration. This article proposes a high-level controller managing the individual active systems - namely, Torque Vectoring (TV), Active Aerodynamics, Active Suspension, and Active Safety (Anti-lock Braking System [ABS], Traction Control, and Electronic Stability Program [ESP]) - through a dynamic state variation. The high-level controller is implemented and validated in a simulation environment, with a series of tests, and evaluate the performance of the original design and the proposed high-level control. Then, a comparison of the Virtual Driver (VD) response and the Driver-in-the-Loop (DiL) behavior is performed to assess the limits between virtual simulation and real-driver response in a lap time condition. The main advantages of the proposed design methodology are its simplicity and overall cooperation of different active systems, where the proposed model was able to improve the vehicle behavior both in terms of safety and performance, giving more confidence to the driver when cornering and under braking. Some differences were discovered between the behavior of the VD and the DiL, especially regarding the sensitivity to external disturbances

Multibody parameter estimation: A comprehensive case-study for an innovative rear suspension

Numerical and virtual simulation of mechanical systems is a standard part of product development in the automotive sector, and multibody techniques are a consolidated tool to describe vehicle dynamics, elasto- kinematic behavior, handling, and comfort. To achieve high precision results as output of simulations, it is essential to provide the system with reliable data as input, and to accurately describe the vehicle and its subsystems. The task of gathering objective parameters to fully describe a vehicle can seem trivial to the stakeholders directly connected to a project, that can access detailed design data and a plethora of schemes and datasheets covering all subsystems of a vehicle. However, whenever this task regards benchmarking, prototyping, research projects or niche/low-volume products, data availability decreases drastically, and alternative forms of data acquisition become essential. This paper proposes a comprehensive overview of data gathering and experimental procedures used to reliably extract parameters of an existing vehicle using quick and accessible strategies. The analysis is based on a case-study project of an A-segment vehicle mounted with an innovative rear suspension scheme, whose behavior should be described by a dedicated elasto- kinematic multibody model as well as a full vehicle model for dynamic validation. The multibody model is based on Adams/Car with the inclusion of flexible elements, which is briefly described, while a closer focus is given to the experimental extraction of key features, such as: total mass, longitudinal and lateral position of the center of gravity, CoG height, wheel travel and wheel rate, shock-absorber damping coefficient, steering ratio, components inertia and flexible elements strain. The results obtained in the static and dynamic experimental validation suggest a good outcome from the methodology, that can be replicated on many kinds of vehicle modelling activities as an approachable and affordable experimental methodology for small projects

Design and Modelling of the Powertrain of a Hybrid Fuel Cell Electric Vehicle

This paper presents a Fuel Cell Electric Vehicle (FCEV) powertrain development and optimization, aiming to minimize hydrogen consumption. The vehicle is a prototype that run at the Shell Eco-marathon race and its powertrain is composed by a PEM fuel cell, supercapacitors and a DC electric motor. The supercapacitors serve as an energy buffer to satisfy the load peaks requested by the electric motor, allowing a smoother (and closer to a stationary application) working condition for the fuel cell. Thus, the fuel cell can achieve higher efficiency rates and the fuel consumption is minimized. Several models of the powertrain were developed using MATLAB-Simulink and then experimentally validated in laboratory and on the track. The proposed models allow to evaluate two main arrangements between fuel cell and supercapacitors: 1) through a DC/DC converter that sets the FC current to a desired value; 2) using a direct parallel connection between fuel cell and supercapacitors. The results obtained with the direct parallel connection (with the appropriate sizing of the overall capacity) have highlighted a significant efficiency advantage, while the DC/DC converter insertion enables an improved control of the fuel cell current and requires a smaller capacitance. Furthermore, a sizing methodology for the supercapacitors capacitance is proposed for both layouts: with the DC/DC converter it mainly depends on the energy range provided by supercapacitors to the electric motor, while in the direct parallel connection the supercapacitors sizing is outlined by concurrently evaluating the circuit's predicted hydrogen consumption and granting the most suitable conditions to increase the fuel cell performance. Finally, the results obtained from the model were validated by comparing them with experimental data obtained in the laboratory and on the track

Comportamento populacional de cupiúba (Goupia glabra Aubl.) em floresta de terra firme na fazenda Rio Capim, Paragominas (PA).

Goupia glabra Aublet, popularmente conhecida como cupiúba, é uma espécie arbórea da família Celastraceae. Possui árvores de grande porte, podendo muitas vezes ocupar a posição de dossel superior em florestas primárias. É uma espécie de grande importância econômica para a região onde ocorre e para o país, sendo comercializada, inclusive, no mercado internacional, devido seus diversos usos e características peculiares. O presente estudo cruza conhecimentos de botânica, ecologia e importância comercial da espécie com informações do comportamento estrutural da cupiúba, a fim de facilitar ações de bom manejo silvicultural, inclusive juntamente com outras espécies que compõe a comunidade na área estudada e na região. Em 84 ha de floresta natural densa de terra firme, na Fazenda Rio Capim, de propriedade da Cikel Brasil Verde S. A., no município de Paragominas (PA), Goupia glabra foi uma das espécies mais representativas quanto ao seu grupo na estrutura florestal, sendo de grande importância ecológica naquela área. Considerando as árvores com diâmetro acima de 45 cm, a espécie apresenta abundância de 0,81 árvore/ha, freqüência de 100%, com área basal de 0,41 m2/ha, volume de 2,58 m3/ha, distribuição diamétrica em todas as classes de árvores, de 45 cm até 144 cm, e qualidade de fuste bem representativa para comercialização.Publicado também on-line

City Car Drag Reduction by means of Flow Control Devices

In the past few decades, the automotive industry saw the development of several environment-friendly technologies, as high efficiency engines, lightweight materials, and low-rolling-resistance tires. Car body styling, together with aerodynamics, play an important role in resolving environmental issues by reducing drag force, which results in high fuel efficiency and lower energy requirements. The main objective of this study is the reduction of the aerodynamic resistance of a city-car prototype by means of flow control devices (air blow and air relief) located into the wheel arches. This work starts from the wind tunnel experimental tests of the baseline version of the XAM 2.0 vehicle, then, dedicated ducts are implemented into the model in order to reduce the turbulence of the front wheel well and the air-flow defection at the end of the sides of the car body. A CFD analysis is carried out in order to assess the effects of the introduced modifications: car shape is varied by CAS, for every modification CFD calculations are performed. A correlation between wind tunnel and CFD results is carried out validating the drag optimization, demonstrating the predictive capabilities of CFD analysis and a record-breaking drag coefficient

Composite Control Arm Design: A Comprehensive Workflow

This paper presents a complete overview of the computational design of an advanced suspension control arm constructed of composite material for light weighting purposes. The proposed methodology presented in detail is split into 3 phases. Phase 1 or Vehicle Performance Simulation, in which basic modelling and a sensibility study is performed to better understand the advantages of unsprung mass reduction (compared to sprung mass reduction) with respect to the vehicle's vertical dynamics. It followed by the development and utilization of a multibody approach to evaluate the full-vehicle response to different dynamic maneuvers, such as harsh road imperfections, sine sweep steering, and double lane change tests. The impact of the improved suspension control arm is highlighted in detail, and the loads to which it is subjected are computed to serve as inputs for the successive phases. Phase 2 or Design and Calculation Phase, where a closer look is given to the structural side of the component, understanding the specific behavior of composite materials and performing modelling of the control arm, followed by fine tuning with Finite Element Method optimization techniques. This phase consists of a topology optimization, followed by composite topography free size, size, and shuffle optimizations to arrive upon the ideal part-layup, and guarantee the desired mechanical characteristics of the component. Lastly, Phase 3 or the Production Preparation closes the design process by generating the production processes, steps, constraints, and tooling for the correct realization of the innovative control arm in a real-world application. The tools presented in this paper were created to allow the design to be completed rapidly, thus defining a blueprint for a full workflow, from engineering request to product delivery, which can be applied to different vehicles and customer requests, representing an essential step forward to the consolidation of the use of composite materials for structural suspension components

Validation of a numerical-experimental methodology for structural health monitoring on automotive components

In the recent years, the materials composing the traditional of aircrafts are being progressively replaced with lower density materials, as the Reinforced Plastics. The same trend has been highlighted in the Automotive field to assess the reduction of fuel consumption and CO2 emission. In order to achieve an optimization of maintenance a variety of on-board systems has been applied for on-line SHM based on piezoelectric transducers earned a particularly high interest for continuous monitoring on metallic and composite structures. The application of this system in automotive could enhance passenger safety, through the monitoring of the vehicle composite material structure health status. In this paper, six mathematical models for evaluating the electrical response of piezoelectric sensors have been implemented, with the aim of selecting the most effective model for damage identification. Experimental tests were carried out on three types of simpler specimens of different geometries made of different materials (steel, aluminum and carbon fiber). A correlation study has been carried on in order to support the positioning of sensors. The proposed numerical-experimental methodology is an essential foundation for the introduction of monitoring systems based on piezoelectric transducers in the Automotive sector

Nutritional and mineral variability in 52 accessions of common bean varieties (Phaseolus vulgaris L.) from Madeira Island

The Phaseolus vulgaris L. is one of the traditional and most important leguminous crops in the Island of Madeira. The island’s bioclimatic tiers, agro-ecological environment and traditional farming practices had a great influence on the evolution of regional bean landraces. The variabili ty of the nutritional and mineral seeds composition of 59 accessions of the Madeiran landraces, standard and commercial varieties was evaluated. Wide ranges of variability in biochemical pa rameters were reported among the Madeiran landraces, being the best sources of protein and mineral nutrition, according to the statistical results and literature comparative evaluation. Spe cifically, the content (g per 100 g DW) of ash ranged from 3.64 - 5.67, lipids from 0.57 - 2.86, pro tein from 18.55 - 29.69, starch from 23.40 - 52.65, soluble sugars from 2.97 - 6.84, while content of dry matter was from 83.35 - 93.55. The seeds also contained (per 100 g DW) between 2.55 - 4.83 g N, 0.30 - 7.50 g P, 1.30 - 2.49 g K, 0.10 - 0.18 g Mg, 4.10 - 10.00 mg Fe, 50.0 - 1.40 mg Cu, 2.20 - 5.00 mg Zn, 0.90 - 3.80 µg Mn and 0.20 - 2.40 µg B. This variability implies that the screened germplasm could serve as a source for breeding new varieties with improved biochemical and nutritional traits or could be highly recommended to meet specific dietary requirements. The cultivar Vagin ha Grossa (ISOP 713) revealed low carbohydrate content that could be a good food choice for di abetics, while cultivar Vermelho (ISOP 724) bean should be offered as a valuable alternative source of protein and minerals in the local diet.info:eu-repo/semantics/publishedVersio

Priority areas for water resources conservation: study case Canal Guandu watershed.

The environmental resilience is strictly dependent of water availability. The identification of priority areas is important to conservation aid land-use planning and urban expansion, conservation, and policy strategy. The goal was to identify priority areas aiming water provision and environmental conservation at the "Canal do Rio Guandu" watershed in Rio de Janeiro, Brazil. To address the goal four micro-basins included in the watershed were selected to optimize collect field data and create the criteria to define the priority levels. Based on prior literature, legacy and field data, an assessment method was proposed based on map algebra with support of Geographical Information System, gathering professional tacit knowledge with spatial data to support the selection of strategic areas. The approach based on was successful to select primarily priority areas and can contribute to regulate the local policies, pointing out areas that can connect legally protected areas with forested fragments, which presents great importance to urban and rural supply

Feasibility study on piezoelectric actuated automotive morphing wing

Active aerodynamics is a promising technology to improve vehicle performance and efficiency, but so far in the automotive field the actuation methods suffer with several drawbacks that jeopardize its functioning and broad implementation. Morphing wings represent a technology already studied for aerospace applications that could help overcoming some of those issues. This paper proposes a piezoelectric transducer actuation for a composite material automotive wing and seeks to validate it through virtual models and physical tests. Experimental validation with a 3D-printed simplified wing profile confirms the feasibility of the technology and helps determining the best position for the piezo actuator. Furthermore, a FEM model is presented, where the piezo effect is simulated through a thermal analogy. An optimization of the composite stacking sequence is performed to maximize the trailing edge displacements, and its results are compared with the deflection caused by aerodynamic loads observed in the wing. The displacement of the trailing edge is in the order of tenths of a millimeter, even though further investigations are necessary to improve overall impact of the solution the preliminary results are promising