Search Results

The design methodology have been proved its effectiveness concerned to new products development, and due to the systematic approach it allows great variety of solutions and concepts developed in the early concept design phase. Axiomatic design was use to create collaborative strategies aiming to reduce the number of control strategies tests. Besides only one of required functions was developed and test each time. A wheelchair dynamic model was developed to test the strategies. At the end of the processes a role and complex control strategy was developed and only validation tests were need to apply the solution in wheelchair motorization.

The increasing market of the continuously changeable transmissions demands that its characteristics of performance fully are known and constantly developed. Of the some existing constructive types one initially opted to the modeling of the system of pulleys of changeable diameter and leather strap. Knowing, that the transmissions are part of the train of force of any vehicle, the model will go to include the characteristics of exit of the engine, torque and rotation and all the components of an automatic transmission that uses CVTs. The initial objective is to determine the geometry of functioning and the positioning of the leather strap in the CVT. Saber its behavior, if it is playing its role in the excellent way.

Hybrid Electric Vehicles (HEVs) currently represent an alternative to reducing fossil fuel consumption used by internal combustion engines. This paper analyses, in a platform of computational simulation and also in experimental condition, the vehicle fuel consumption, before and after hybridization. It checks the similarity of behaviors and/or the investigation of possible differences between the developed mathematical model and experiments performed. Computer simulations help, through mathematical models, a better understanding of physical phenomena related to engineering problems. A well elaborated computer model has a high fidelity degree with the real systems, becoming a powerful analysis tool. The experiments besides allowing a proof of results, they contribute to a refinement of the simulated models. The hybrid technology under study is characterized by the coupling of two electric motors directly to the rear vehicle wheels.

The design methodology have been proved its effectiveness concerned to new products development, and due to the systematic approach it allows great variety of solutions and concepts developed in the early concept design phase. This paper shows two efficient methods in concepts generation, they are: the brainstorm and the morphologic chart. Both were successfully used and the result was a new concept of wheelchair motorization which the electric motors are activated only when the force applied over the propulsion ring exceeds a preset value. This new concept was registered at INPI as an invention patent.

The objective of this paper is to study the design characteristics more viable to build an autonomous vehicle for disabled people (AVD). In this paper, some components are examined for available options and how these options effect the performance of the vehicle. Besides, the dynamic model of a tricycle configuration of AVD is shown. The equations of motion governing the behavior of the vehicle are obtained with the Newton and Euler's equations. Through the dynamic equations, the analyses of dynamic stability and dirigibility for the configuration are made and compared with other configurations with different kinds of driving and steering. Considering the results of stability and dirigibility, a fuzzy controller for navigation and obstacle avoidance control is design. The fuzzy controller was simulated and the results indicate that it is better use the velocity control only on final approach to goal position.

This work presents a study on the related basic aspects with the accelerated tests used in the industry to determine or to confirm the reliability of an item and of the methodologies currented to analysis of the accelerated tests of life of the products. Are argued the importance of the models for each distribution and the methodologies applied in the work.It is implemented programs of computation in VISUAL BASIC language that allow the management and the adequacy for the processing of the data proceeding from the accelerated tests with constant stress and simple failure mode, for complete data, and with censorship the right or multiple, using the distribution of Weibull, Log-normal and Normal, combined with the most used models (Arrhenius model and Inverse Power Law), the program allows to the processing of the data of the accelerated tests for two methods, Squared Minimums and Maximum Likelihood Principle.

In this work the main objective is the development of systems for motorization of conventional wheelchairs, and the great mass of wheelchairs now available in Brazil of the simplest type than they don't allow the pure and simple conversion for motorization. In this aspect the problem comes as a challenge because the great variety of models and types of wheelchairs and the lack of a rigorous normalization impose the use of technologies of search of solutions and the application of methodology knowledge and systematic of project. In this way, firstly a study will be accomplished on the object wheelchair, containing: historical, origin, types and characteristics. The following step will be the search of the possibilities of motorizing conventional wheelchairs, limitations and applications.

Epicyclic gear trains are important part of automotive transmissions. They are present in automatic transmissions and in differentials of most vehicles. The dynamic behavior of a single epicyclic gear is well known, and this study presents the results obtained based in a model of a complete transmission. Initially the Wilson gearbox is presented. The main principles of the model are described. Following, the results of a simulation using the model are shown. Finally, the influence of the inertias in the model are presented and it is done some discussion about it

Due to the current changes in the automotive industry several new technologies are being developed and the old ones analyzed. The epicyclic gear trains, or planetary gear trains, are important in the automatic transmissions. In this paper a model is presented to describe the behavior of the transmission during the process of gear change. For this the system chose must be fully described, that means the relation among the rotations of the components must established.

It is considerable the number of research around the subject of motorization of conventional manual wheechairs, however the found models don't take care of the real necessities of the wheelchair users. In the manufacture the necessity of an independent vehicle for the load transport exists. With the increasing necessity in Brazil to develop the knowledge in the area of independent vehicles and not being still available a towboat of tests adjusted to approach such problems. The articulated towboat is an intelligent independent vehicle to tow loads. The users of conventional manual wheelchairs will go to use this vehicle when to need motorization, that is in ascent cases, descending of ramps, or long distances. This vehicle possesss practical applications that they can assist systems of support to the rehabilitation of physical and motor deficiencies and also systems automatized of manufacture.

The development of hybrid vehicles has reached in recent years a high technical and commercial importance. In general, varied vehicular settings enable a motorization with several alternatives and conventional energies combined in order to increase the performance while reducing consumption and environmental impact. In the context of hybridization, particular attention has been given to vehicles that consider a secondary driving source of electric nature, mainly in countries where its cost is relatively low when compared with the cost of fossil fuels such as gasoline. This paper aims to achieve an economic and energy analysis of a hybridized vehicle. The last one has a conventional traction front-wheel driven by an internal combustion engine (ICE) and an electric traction rear-wheel propelled by electric motors (EMs) in-wheel.

This paper focus on the analysis of energy management for hybrid electric vehicles. The development of higher efficiency vehicles depends on the analysis of vehicle characteristics and driving conditions. Sizing the energy capacity of the storage system and defining the type of components, batteries or other kinds of electric components has a direct influence over the performance, consumption and autonomy of the vehicle. The forces involved in a vehicle movement such as aerodynamic drag, rolling resistance, grading resistance, are fully dependent on the conditions of the route; most situations should be represented on the driving pattern cycle, used for emissions and consumption tests, which will be presented and discussed. Modeling vehicle dynamic to analyze power and energy requirements of the vehicle during different test cycles provides an indication of the influence of hybrid technology in performance and fuel consumption.

The purpose of this paper is evaluating the amount of kinetic energy available to be regenerated by a hybrid electric vehicle (HEV) undergoing the Brazilian standardized driving cycle. Improvements on energy efficiency of the cars has become an urgent target of the Brazilian industry since Brazil launched a new automotive regulation imposing the reduction of 15.5% on the fuel consumption of the vehicles to be sold in this country in 2017 comparing to 2011. The HEVs are a possible solution for this situation. They are widely known by the high efficiency, mainly the ones capable to make the regenerative breaking, rescuing an already paid energy. Before the launch of HEVs in Brazil, the feasibility of these vehicles has to be accurately studied and one aspect to be evaluated is how much energy is possible to be rescued in the Brazilian standardized driving cycle.

The need for improved fuel economy for road vehicles has increased the interest in hybrid electric vehicle (HEV) and recovering vehicle energy. This paper aims to evaluate the amount of kinetic energy that could be restored through regenerative braking in a HEV. This work will not resort the Brazilian urban driving cycle NBR 6601, for this cycle does not fully represent a pattern of traffic faced regularly in urban areas, which is typically composed of heavy traffic and long periods of idleness. Therefore, a new drive cycle will be developed that better represents the Brazilian traffic. Also, considering the shortage of energy resources, the large amount of energy dissipated as heat during braking a vehicle is a recurring concern. Therefore, measuring the maximum available energy that could be restored through regenerative braking is the first step towards estimating the profit of using this technology and how it would pay off the investment in the long run.

Chassis dynamometers are important equipment to perform vehicular experiments in the automotive industry. Usually, these equipments are used according to standard procedures for emissions, fuel consumption, and performance analyses. In this paper, an alternative procedure was developed to experimentally determine the dynamometer inertia and losses related to bearings and transmission systems. Furthermore, a study on the tires rolling resistance, considering a double tire-roller contact, was carried out. The experiments were performed in a 4x2 chassis dynamometer with four rollers, equipped with an eddy current brake (coupled to a transmission reducer of 2.5 instrumented with a 3000 Nm torque flange) and with a 30 CV AC electric motor (coupled to a planetary transmission with reduction of 4.43 and instrumented with a 500 Nm torque flange). The dynamometer was also instrumented with an encoder system for speed measurement.

The automotive industry's recent push towards developing electric and hybrid electric vehicles is a direct response to the growing global pressure due to environmental concerns and has resulted in a search for significantly cleaner and more efficient vehicles. Not only, in order to achieve its purpose, has this search highly depended on the development of advanced technologies. Among all systems and subsystem from a vehicle the powertrain system is going to be the focus of this work. The main goal of the present work is to get a complete mapping of all the functions, components and flows of information and energy, through the application of an existing methodology of analysis, known for “function structure technique”, on the described product. Therefore, this mapping will supply a better understanding of the product architecture. First of all, the composed system, for the hybrid vehicle powertrain, is divided hierarchically in subsystems according to the existing assemblies.

One traditional solution to start an internal combustion engine is the starter motor. Since its conception little was changed in its operational dynamics, even after passing by several design optimization processes. This fact elapses from the absence of application of an analysis tool capable to express the existing relations between its subgroups and the functions that these play. The main goal of the present work is to get a complete mapping of all the functions, components and flows of information and energy, through the application of an existing methodology of analysis, known for “function structure technique”, on the described product. Therefore, this mapping will supply a better understanding of the product architecture. First of all, the composed system for the starter motor is divided hierarchically in subsystems according to the existing assemblies. The operation chain is then separated through static and dynamic inspections during its use in the combustion engine.

The aim of this article is to study the dynamic behavior of a system composed by a child and a wheelchair during the propulsion with a servo-assisted motorization controlled with a logic fuzzy algorithm. The model correspond a vehicle with propulsion on the rear wheels, steering is on the front wheels. The wheels were modeled as rigid and a double bicycle model was used. The fuzzy controller will act over the system applying additional forces during the wheelchair propulsion looking for increase the user mobility and will be tested and evaluated bearing on mind the increasing of the system performance.

Had to the development of new projects of vehicles more economic as for example, the hybrid vehicles, have become bigger investments in transmission systems mechanics more adjusted. Thus being the increasing market of the continuously changeable transmissions it demands that its characteristics of performance fully are known and constantly developed. Of the some existing constructive types one initially opted to the modeling of the system of pulleys of changeable diameter and leather strap. To leave of this modeling one became alterations of some components and verified the behavior of this CVT in a simulation of passage of a vehicle. This passage was drawn so that the vehicle more faced daily situations of a vehicle considered in a track accented, that requested of the transmission the reactions boundary lines that supplied to torque and power of enough engine, or, so that the vehicle executed the passage, a not to leave of the limitations of the system and the CVT.

The automated guided vehicles (AVGs) are normally used for the transport of materials, making great part in the manufacturing systems. This work aims at the study of the contact between ground and wheel in the AVG, thus applying the vehicle dynamics relative. For this, models of the contact between road and wheel had been made of AVG, in each model presents his considerations, simplifications and parameters as the cornering stiffness, the normal force and the sideslip. The models of the contact between road and wheel had been implemented in a multibodies program 2D and observed. The results of this work will be used in the construction of independent vehicles, because many AVGs don't take in consideration the dynamic behavior, they have a super dimension of engine so more weight and consumption of energy than they really need.