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Marcelo Becker & Franco Giussepe Dedini
Department of Mechanical Design, Faculty of Mechanical Engineering - UNICAMP
CEP 13083-970 Campinas - SP Brazil - e-mails: becker@fem.unicamp.br, dedini@dpm.fem.unicamp.br
The objective of this work is to study the constructive forms more viable to build an autonomous vehicle for disabled people (AVD) for use indoors. This article presents the dynamic models of two different configurations of tricycle AVDs. The first configuration has rear driving wheels and front steering wheel and the second, front driving and steering wheel. We used these configurations because they have a good psychological impact on people and on user’s self-image. The equations of motion governing the behavior of vehicle are obtained with the Newton and Euler’s equations. Through the dynamic equations, the analyses of dynamic stability and dirigibility for the configurations are made for different kinds of driving and steering. This work shows that with careful design, the tricycle configuration with rear driving and front steering are more stable and dirigible. Considering the results of stability and dirigibility, a fuzzy controller for navigation, obstacle avoidance and velocity 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.
Keywords: Autonomous Vehicle for Disabled, dynamic behavior, fuzzy controller, self-image, comfort.
COB444 DESEMPENHO DE VEÍCULOS PESADOS NA FREAGEM CONSIDERANDO OS REQUISITOS DA REGULAMENTAÇÃO ECE-R13 / PERFORMANCE OF HEAVY VEHICLES DURING BRAKING PROCESS CONSIDERING THE REQUIREMENTS OF ECE-R13 REGULATION
Dirceu Lavoisier Graci Fernandes & Antônio Carlos Canale
Departamento de Engenharia Mecânica, Escola de Engenharia de São Carlos – USP – São Carlos - CEP 13.560-250 São Carlos, Brasil E.mail: canale@sc.usp.br
Camilo A. Adas
Mercedes-Benz do Brasil - CEP 09880-050 São Bernardo do Campo, Brasil
This paper shows some ECE-R13 requirements for heavy vehicles brake systems, specially the requirements related with brake performance, brake forces distribution and compatibility between towing vehicles and semi-trailers during the braking process. Satisfactory comparison between theoretical values ( obtained with mathematical model and computer program utilized for heavy vehicles braking study ) and experimental values, from road tests, of braking performance were reached on an heavy vehicle example application, where was utilized the LS 1941 tractor of Mercedes-Benz of Brazil coupled with FNV - CARGA SECA semi-trailer of FNV of Brazil, and will be shown on this work. This work intend to be a contribution to the study of ECE-R13 regulation application on heavy vehicles braking process and for vehicle safety.
Keywords: braking process, performance, stability, braking regulation, heavy vehicles, vehicular safety / freagem, desempenho, estabilidade, normas de freios, veículos pesados, segurança veicular.
COB454 PLATAFORMA ORBITAL RECUPERÁVEL PARA EXPERIMENTAÇÃO EM AMBIENTE DE MICROGRAVIDADE RECOVERABLE ORBITAL PLATFORM FOR EXPERIMENTS IN MICRO-GRAVITY ENVIRONMENT
Paulo Moraes Jr.
Divisão de Sistemas Espaciais, Instituto de Aeronáutica e Espaço/Centro Técnico Aeroespacial
12228-904 São José dos Campos-SP, Brasil
Hans-Ulrich Pilchowski
Divisão de Mecânica Espacial e Controle, Instituto Nacional de Pesquisas Espaciais
CP 515, 12201-970 São José dos Campos-SP, Brasil
To perform experiments in a microgravity environment, a recoverable orbital system is proposed. The system comprises a capsule shaped orbital platform, which after satelization will remain in orbit until the experiments are carried out, being later returned to Earth and recovered at ground.. The proposed system concerns an affordable alternative when compared with usual systems, which are quiet expensive if experiment duration and capability are considered. The system under study is based on a return-on-request concept, innovative for users of small scientific and technological experiments. It is expected that a such system would offer a better opportunity to scientific and academic laboratories in performing low cost microgravity experiments. It also seems to be realistic for the purposes and technological domain of the participating institutions, CTA/IAE and INPE. The present paper summarizes and discusses the specification, concept and preliminary design of the system.
Keywords: plataforma orbital, plataforma recuperável, microgravidade / orbital platform, recoverable platform, micro-gravity
COB461 DINÂMICA NÃO LINEAR DE SUSPENSÕES ATIVAS / NON LINEAR DYNAMICS OF ACTIVE SUSPENSIONS
Ilmar Ferreira Santos & Gustavo Campos Padovese
Dep. de Projeto Mecânico, Fac. de Engenharia Mecânica - UNICAMP
CEP 13083-970 Campinas, Brasil - E-mail: ilmar@dpm.fem.unicamp.br
This paper gives a theoretical contribution to the problem of modeling an independent active suspension using the Newton-Euler's Method, taking into account the constraint equations between the vehicle and the road profile, and including the dry friction between the tyre and the road. After the method's aplication, one obtains 33 non linear equations: 29 equations which describe the reaction forces among the multiple bodies that composes a quarter of independent suspension, and 4 movement equations, which describe the motion of the car's main mass, the oil flow passing through the servovalve and the pressions acting on the active damper. These equations are numerically solved and the results discussed for various operation conditions.
Keywords: Multibody dynamics/ Dinâmica de múltiplos corpos, dry friction/ atrito seco, Newton-Euler/ Newton-Euler, hydraulic systems/ sistemas hidráulicos, output control/ controle de saída.
COB476 VARIAÇÃO DO COEFICIENTE DE ATRITO EM SAPATAS FERROVIÁRIAS E SUA INFLUÊNCIA SOBRE O PROCESSO DE FRENAGEM / VARIATION OF THE FRICTION COEFFICIENT IN RAILROAD BRAKE SHOES AND ITS INFLUENCE ON THE BRAKING PROCESS.
Auteliano A.dos Santos Jr., Leopoldo C. Roza & Fausto Rodrigues F O
Laboratório Ferroviário - Departamento de Projeto Mecânico
Faculdade de Engenharia Mecânica - UNICAMP, CEP. 13100-970 - Campinas (SP) - Brasil - E.mail: aute@fem.unicamp.br
The objective of this work is to present the results of the tests in railroads brake shoes realized in the Railroad Laboratory of State University of Campinas, Brazil. The tests show the influence of parameters do not considered in normal operation of brasilians railroads enterprises: velocity, wear, normal aplication force, temperature and diferences in the materials. The tests followed the Association of American Railroad standard M-926, when possible. The influence of these parameter is analysed and the possible influence on the braking process in a real railroad is discussed. Recommendations are done for the new brake shoes bought by the railroads.
Keywords: Railroad brake shoes, railroad braking systems, brake heating
Ricardo M. Picado
UNICAMP - DMC, UNICAMP/DMC/FEM, CP. 6122, Cep 13081-970, Campinas(SP),
Fone (013)237-4829, Fax (013)788-3722, E-Mail: rmpicado@fem.unicamp.br
The development of semi-active controled suspensions is, nowadays, an area of research poorly explored for automotive suspension applications. Only a small number of models, which are very simple, has been manufactured by the automotive industry. The semi-active control principle, analized in this work, is based on the adjustment, by an actuator, of the damping coeficient of the damper. The actuator is responsable for opening or closing the damper´s dissipative valve. An important drawback for the passive suspensions is that they are optimized for a fixed condition, due to the fixed damping coeficient of its dampers . The semi-active system offers different regulations for different excitation conditions. This means that the semi-active suspension may be optimized for different work conditions. Another advantage of the semi-active suspensions lies in its low energy consumption if compared to the active controled suspensions. Finally, if we compare the passive and the active control suspensions to the semi-active controlled suspensions, as we will see in the following sections in this work, good results for the minimization of the body aceleration can be achieved.
Keywords: Control, semi-active, suspension, automotive, digital.