Seminários e Teses

Próximos- Anteriores-
Esta semana (de 20/05 a 26/05)
Tese de Doutorado
Analysis and experimental validation of control strategies for autonomous motorcycles stabilization and trajectory tracking
Marilia Maurell Assad, Puc-Rio

Data: 21/05/2018 às 15h e 0min
Local: Sala de Aula do IEPUC

Orientador: Marco A. Meggiolaro
Área de Concentração: Mecânica Aplicada


Autonomous vehicles – defined as land vehicles capable of transporting people or cargo without a human driver – are an interesting and recent problem. Though autopilot has been used on planes and ships since 1950, its application in cars and motorcycles is still in its early stages, and has not been fully marketed yet. In addition to the inherent difficulties in making a vehicle move independently, the autonomous motorcycle has to be able to remain stable at any speed and trajectory, which can be achieved by many different solutions and control techniques.
The main objective of this work is to develop an autonomous electric motorcycle with low cost sensing system. For this, a dynamic model of two-wheeled vehicles is analyzed, capable of describing the real dynamic behavior while being simple enough to allow the implementation of real-time linear control strategies. The latter, in turn, has two different objectives: to maintain the motorcycle stable and to follow a desired trajectory, in an autonomous way.
Experiments were carried out with the small scale motorcycle aiming to characterize its elements for the theoretical model; then the proposed control strategies were simulated with the adjusted dynamic model. Finally, the control algorithms are applied to the real system through an actuated platform capable of reproducing the dynamic behavior of single-track vehicles.
At last, the present work is a tool for teaching engineering, involving multilevel students around a very complex, but familiar, problem. The system allows for continuous learning with increasing difficulty, involving multibody dynamics, result analysis via software simulations, electronics and filters present in the embedded instrumentation and many control techniques to keep the system stable in every desired path, culminating in the experimental application of cited concepts.  

Seminário da pós-graduação
Defect Tolerance under Fatigue and Environmentally-Assisted Cracking Conditions
Prof. Jaime T. Castro, Puc-Rio

Data: 23/05/2018 às 16h e 0min
Local: Sala 106L


Semi-empirical notch sensitivity factors have been used for a long time to quantify notch effects in fatigue
design. Recently, this old concept has been mechanically remodeled using sound stress analysis techniques to
calculate values from the basic fatigue properties of the material, its fatigue limit and its fatigue crack
propagation threshold, properly considering the notch tip stress gradient influence on the fatigue behavior of
mechanically short cracks. This model can thus consider all the loading and notch geometry characteristics
without the need for any data fitting parameter. Moreover, its predictions have been validated by proper tests,
and a criterion to accept tolerable short cracks has been proposed based on it. This same mechanics is then
extended to quantify notch sensitivity effects in environmentally assisted cracking problems, and its predictions
are verified by proper tests as well.