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Mg Alloy Rod Strengthened by Combined Processes of Deformation-Restricted Forging and Extrusion
(2024-01-01)
Miura, H.
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Oba, Y.
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Watanabe, C.
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Benjanarasuth, T.
A new method for strengthening Mg alloy rod is proposed. AZ80Mg alloy rods were forged along the longitudinal axis (LA) at extremely high pressures beyond fracture stress under a condition where plastic deformation was eliminated in a die, i.e., deformation-restricted forging (DRFing), followed by cold extrusion. Although the ultimate tensile strength (UTS) and hardness were gradually raised with DRFing stress, the yield strength (YS) was lowered by sharp basal texture evolution on the plane normal to the LA and tensile axis. However, the extrusion after DRFing drastically changed the texture to (0001) LA, causing a large increase in YS. Consequently, a superior balance of mechanical properties: YS of 376 MPa, UTS of 417 MPa, and ductility of 10%, could be achieved after the combined processes of DRFing and extrusion.
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CDM-based two degree of freedom PI controller tuning rules for stable and unstable FOPTD processes and pure integrating processes with time delay
(2019-01-01)
Somasundaram, S.
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Benjanarasuth, T.
This work proposes the coefficient diagram method (CDM)-based two degree of freedom proportional integral (CDM-PI) controller tuning rules for stable and unstable first order plus time delay (FOPTD) processes and pure integrating processes with time delay (PIPTD). To derive the tuning rules, a general first order plus time delay (FOPTD) model, the first order Taylor denominator (TD) approximation technique and the pole allocation strategy named CDM is used. The tuning rules derived here are novel and they relate the controller parameters to the process model parameters directly. The performance of the CDM-PI controller utilising the proposed tuning rules is tested with numerical examples of stable, unstable and pure integrating processes with time delay models. The test results indicate that the proposed tuning rules yield promising results over the other PI controllers. Performance measures confirm the effectiveness of the proposed tuning method.
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An approach for room-temperature multi-directional forging of pure titanium for strengthening
(2018-07-25)
Miura, H.
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Kobayashi, M.
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Aoba, T.
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Aoyama, H.
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Benjanarasuth, T.
Commercially pure Ti grade 2 was multi-directionally forged (MDFed) at room temperature. MDFing could be successfully carried out without any cracking to a cumulative strain of ΣΔε = 2.0. Ultrafine-grained (UFGed) structure gradually developed with increasing cumulative strain mainly by mechanical twinning and kinking. An average grain size of approximately 400 nm was attained. The mechanical properties were drastically modified by the grain refinement and a superior balance of tensile strength and ductility, 710 MPa and 21%, was achieved. Additional cold rolling of the UFGed Ti possessed further better mechanical properties of 930 MPa tensile strength and 19% ductility.
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Effects of strain rate during multi-directional forging on grain refinement and mechanical properties of AZ80Mg alloy
(2016-01-01)
Miura, H.
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Kobayashi, M.
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Benjanarasuth, T.
Samples of AZ80Mg alloy were multi-directionally forged (MDFed) at various strain rates in the rage from 3.0× 10-3 s-1 to 3.0× 10-1 s-1 under decreasing temperature conditions. The MDFing pass temperatures employed were 653 K, 605 K and 553 K. These passes, each of 0.5 strain, were applied up to a cumulative strain of ΣΔϵ= 1.5 at maximum. The average grain size decreased with increasing cumulative strain and depended only weakly on the strain rate. Microstructures with average grain sizes of 0.84 μm, 0.88 μm and 1.2 μm were attained when MDFed at strain rates of 3.0× 10-1 s-1, 3.0× 10-2 s-1 and 3.0×10-3 s-1. The microstructure evolved at 3.0× 10-1 s-1 was less homogeneous. This difference is interpreted as being due to the higher stored energy causing static recrystallization in the latter MDFing condition. As a result, the best balance of the mechanical properties was attained by MDFing at 3.0× 10-2 s-1. In this case, ultimate tensile strength (UTS) of 445 MPa was achieved together with a fracture strain of 22%. By comparison, MDFing at 3.0× 10-1 s-1 led to lower UTS and ductility of 410 MPa and 15% while the yield stresses were comparable.
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Internet based crossover robot remote control competition among Asian countries
(2013-01-01)
Xu, C.
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Ming, A.
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Kanamori, C.
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Aoyama, H.
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Li, H.
We introduce an internet based crossover robot remote control competition project that is an international cooperative program based in Japan, China, Thailand, and Taiwan. This competition is an important component of a long-term higher education reform project aiming to develop a practice based innovative educational methodology jointly promoted by the Ministry of Education, Culture, Sports, Science & Technology of Japan and the University of Electro-Communications. The competition project includes two subjects: the competition itself and the communication and cooperation between students in two countries. The basic mode of the competition is a locally controlled robot and a remotely controlled robot cooperate with each other to complete some tasks. As a unique feature of the project, the student-student communication and cooperation are increased through a specially designed team organization structure that each team consists of two groups from different universities in different countries and the team members are required to cooperate through the internet to complete the competition. The competition has been successfully held four times and the results show it greatly benefits the students, and is expected to promote the development of the practice based educational methodology in the near future. © 2013 Elsevier Ltd. All rights reserved.
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Internet based crossover robot remote control competition among Asian countries - Development of practice based innovative education methodology, Phase V
(2012-10-23)
Xu, C.
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Ming, A.
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Kanamori, C.
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Aoyama, H.
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Li, H.
We introduce 2011's progress and achievements of an internet based crossover robot remote control competition between Japan and China, Thailand, and Taiwan respectively. The competition project has two subjects: the competition itself and the student-student communication and cooperation. The basic competition mode is a remotely controlled robot via the internet cooperates with a locally controlled robot to finish a specified task and, as a unique feature of the project, the studentstudent communication and cooperation is trained through a crossover team organization style that each team is organized by two groups from different universities and the team members required to cooperate with each other via the internet to make robots and deal with competition affairs. Our experience shows the competition benefits not only students' technical skills but also their various no-technical skills and is expected to promote the development of a practice based university education methodology in the future. © 2012 IEEE.
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Internet based crossover robot remote control competition among Asian countries - Development of practice based innovative education methodology, phase IV
(2011-11-17)
Xu, C.
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Ming, A.
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Kanamori, C.
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Aoyama, H.
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Li, H.
We report the up-to-date progress of an internet based crossover robot remote control competition project starting from 2007, which is an international cooperative education program among Japan, China, Thailand, and Taiwan. The project contains two sub-subjects: the robot competition and the student-student cooperation among the participating universities. The competition is designed to be remotely controlling a robot via the internet to cooperate/compete with a locally controlled robot to finish some specified tasks where both robots are made by the students. The unique feature of the project is that everything concerned with the competition, e.g. the competition rules, the detailed technical problems, etc., are discussed and solved by the students themselves via the internet based cooperation. The demonstration of the competition between UEC and each of the partner universities proves the project helps to improve students' practical ability, innovative skills, good teamwork spirit, and communication skills, etc. © 2011 IEEE.
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Internet based crossover robot remote control competition among Asian countries: Development of practice based innovative education methodology, phase III
(2010-11-29)
Xu, C.
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Ming, A.
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Kanamori, C.
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Aoyama, H.
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Li, H.
We report the 3<sup>rd</sup> year's progress of an internet based crossover robot remote control competition which is an international cooperative educational project among Japan, China, Thailand, and Taiwan. In 2009 we proposed a new competition model called "Cargo loading via internet based cooperation" in which a locally controlled humanoid robot and a wheeled mobile robot under remote control cooperate with each other to search for and find some cargos, then load them on the mobile robot or put them into a cargo box. The unique of the project is that everything concerned with the competition, e.g. the competition rules, the detailed technical problems, etc., are discussed and solved by students themselves from different partner universities via the internet based cooperation. The demonstration of the proposed competition between UEC and partner universities proves the project helps to improve students' practical ability, creative thinking, good teamwork spirit, and communication skills in English, etc. © 2010 IEEE.
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Internet based crossover robot remote control competition in Asian countries - Development of practice based innovative education methodology, Phase II
(2009-12-01)
Xu, C.
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Ming, A.
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Kanamori, C.
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Aoyama, H.
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Li, H.
This paper reports the up-to-date progress of an internet based crossover robot remote control competition which is an international cooperation project of VEC of Japan, VESTC of China, KMITL of Thailand, and TKV of Taiwan. We propose a new competition style called "cargo relay transportation by a locally controlled humanoid robot and a remotely controlled robotic vehicle" in which a locally controlled humanoid robot picks up an object from source, walks to a midway area and hands over the object to a robotic vehicle before it moves to destination and put the object into a box under the remote control via the internet. The robots are developed by students via the internet-based collaboration. The demonstration of the proposed competition between UEC and partner universities proves the project has unique benefits to students in term of improving students' practical ability, creative thinking, good teamwork spirit and communication skills in English, etc. ©2009 IEEE.
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Phase-locked loop process control system using LQR approach
(2004-01-01)
Wanchana, S.
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Benjanarasuth, T.
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Isarakorn, D.
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Ngamwiwit, J.
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Komine, N.
This paper presents the phase-locked loop (PLL) process control system designed by using the approach of linear quadratic regulator (LQR). By considering the loop filter (LF) of phase-locked loop is a part of the process to be controlled, an augmented system can be constructed when voltage control oscillators (VCO) is considered as an added integrator. The integral gain of the proposed augmented system obtained by LQR can be used as an optimal value to design the parameter of LF under the known value of natural frequency of the PLL. The experimental results in controlling the second-order lag pressure process using the proposed PLL show that the system response is fast without overshoot and steady-state error, the output disturbance effect can be rejected, the property of tracking can be obtained and the system can be controlled when process parameter is changed. © 2004 IEEE.

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