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Seminar khoa hoc

9.00 AM - 10.00 AM: Mr. Ho Nhat Linh (Koei Vietnam Company Limited, Ho Chi Minh City, Vietnam) presents the topic: "Analytical model and computing optimization of a compliant gripper for the assembly system of mini direct-current motor "

Abstract: This study proposes a combination of the kinematics-based design method, statistic method and TLBO algorithm to solve a multi-criteria computing optimization for a compliant gripper. The optimal process of the gripper is employed for grasping and positioning a micro shaft in an assembly system of mini direct current motor. The compliant gripper is designed to handle objects larger than 600 µm. First, the kinematic models of the compliant gripper are developed that accounts for the mechanics of motion and yield relative velocity of joints and links. The static model is paid attention to model the stiffness, displacement, stress, a relation of force and displacement, and the amplification ratio. Next, the dynamic model is established based on Lagrange's principle to determine the first resonant frequency. Then, based on the established mathematical models, a multi-criteria optimization for the compliant gripper is conducted by Taguchi method integrated with TLBO algorithm. Finally, the FEA and experiments are implemented to verify the optimal results and evaluate the performances of the compliant gripper. The results indicated that theoretical models are in good accord with the results from simulations and experiments. Additionally, the performance of the present method is superior to PSO algorithm. The results revealed that the compliant gripper allows a displacement up to 3000 µm and the amplification ratio of 12 times. The compliant gripper is a potential application for the mini direct-current motor assembly system.

10.00 AM – 11.00 AM: Dr. Le Thi Cam Tu (AIMaS, TDTU ) presents the topic: "Detailed Study of Continuum Harmonic Generation by Using Near-Infrared Chirped Pulses" 

Abstract: It has been known that the broadband of continuum harmonics, where occurs a regular periodicity or a wide smooth harmonics, can be obtained by using chirped pulse with frequency is time-dependent. In this work, we present the effect of up-chirped pulse, whose frequency increases in time, on high-order harmonic generation of asymmetric molecules such as CO subjected to a near-infrared laser. Our analyses are based on the results from solving numerically the time-dependent Schrödinger equation within the framework of the single-active electron approximation. Together with the time-frequency analysis and the kinetic energy maps obtained from the equation of motion of an electron moving in the laser electric field, the dynamics of harmonic process especially the effect of chirped pulse on the manifestation of continuum harmonics can be uncovered. Based on this, we release the notice when choosing appropriate parameters to obtain the optimal continuum range.