16 research outputs found
Avaliação da resistência do cascudinho (Alphitobius diaperinus) (Panzer) (Coleoptera: Tenebrionidae) a diferentes temperaturas
Characterization of the larval stages of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) using head capsule width
Simulated Annealing for Solving Piecewise Linear Supplier Selection Problem Considering Quantity Discounts
Supplier selection problems are often complicated due to the conflicting objectives and constraints that need to be considered while selection. This problem becomes still more complicated with the inclusion of quantity discounts offered by the suppliers. A multi component multiple supplier selection model considering quantity discounts under incremental quantity discount scenario is proposed in this paper. The combinatorial nature of the supplier selection problem motivates to explore the use meta-heuristic algorithm for solving this complex problem. The proposed model is evaluated using simulated annealing in this article. The results were found to be near optimal along with the generation of alternate set of solutions. Such type of solutions will be very useful to manufacturing firm where the purchase manager would also like to look at options for alternative solutions
Adaptive control of frictional contact models for nonholonomic wheeled mobile robot
Mobility of the robot depends on the vehicle dimensions, locomotion principles and wheel characteristics. The function of the wheel is to carry the load and to produce the traction force. The main factors of wheel terrain interaction are bearing capacity of ground, traction performance of the wheel and geometry of terrain profile. In this paper the system and control concepts of the wheeled robot is discussed in more detail, within the framework provided by the wheel terrain contact model. The dynamic model of the wheeled robot is presented by considering contact forces of the wheel due to their relative motion of the wheel and contact plane. Finally, a dynamic relation is introduced and results are presented in terms of forces, torques and displacements related to wheel terrain interaction. To estimate the forces in the system arising from the interaction between a deformable wheel and rigid terrain using the software package Ansys 10.0. Simulations were performed using Matlab- Simulink program and the results are shown that the proposed controller can overcome the influences the effect of contact forces in order to achieve the desired trajectory
A Time optimal path planning for trajectory tracking of wheeled mobile robots
Avariety of approaches for trajectory tracking control of wheeled mobile robots have been implemented. This paper presents a model for a time optimal motion control based on fuzzy logic algorithm for a three wheeled nonholonomic mobile robot with desired function. Simplified kinematic equations of a differentially driven robot are designed to follow the path with evaluated linear and angular velocities. Here, the proposed kinematic model is based on a simple geometric approach for getting the desired position and orientation. The speeds are varied depending on the variations in the path and on the posture of the robot. The robot is subjected to move in a constrained workspace. The control architecture was developed based on fuzzy logic algorithm to obtain time optimal motion control of robot trajectory tracking. The kinematic model was done on Matlab software environment and profound impact on the ability of the nonholonomic mobile robot to track the path was evaluated
Mechanical and Microstructure Characterization of Coconut Spathe Fibers and Kenaf Bast Fibers Reinforced Epoxy Polymer Matrix Composites
AbstractIn this present study, the natural fibers such as kenaf and coconut spathe are reinforced in polymer matrix by hand layup process. Alkali treated coconut spathe and kenaf bast fibers are uniformly dispersed with epoxy resin and cured using tri-ethylene tetra amine (TETA) at 250C. The weight proportion of the polymer matrix is maintained constantly 10% whereas the proportions of the fibers are altered within the composites. The mechanical properties like tensile, flexural, impact strengths are analyzed. Fracture analysis of fiber reinforced composites and the effect of alkali treatment on fibers are also observed using scanning electron microscope (SEM)