Daegu Mechatronics and Materials Institute

Dalseo gu, South Korea

Daegu Mechatronics and Materials Institute

Dalseo gu, South Korea

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Oh S.K.,Daegu Mechatronics and Materials Institute | Lee K.K.,Engivice | Na Y.-S.,Korea Institute of Materials Science | Suh C.H.,Daegu Mechatronics and Materials Institute | And 2 more authors.
International Journal of Precision Engineering and Manufacturing | Year: 2015

Mg alloy has a hexagonal close-packed(HCP) lattice crystal structure, which has fewer slip systems than other structures, and plastic deformation is difficult to achieve at room temperature. To improve its workability, the non-basal plane slip must be activated by increasing the deformation temperature. In this study, the hot deformation behavior of the AZ80 Mg alloy was examined within the temperature range of 250–400°C and the strain rate range of 0.001–10/s, based on the dynamic materials model. The hot deformation characteristic value was determined using the dynamic materials model (DMM), and was approximated using Kriging meta-model. Based on the results, deformation processing maps were derived, and the entire strains were examined to present the processing maps considering the strain during forming. In addition, the processing maps were established considering the hardness after forming, and the process window was presented considering both the formability and the strength of the parts. © 2015, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.

Suh C.H.,Daegu Mechatronics and Materials Institute | Jang W.S.,Daegu Mechatronics and Materials Institute | Oh S.K.,Daegu Mechatronics and Materials Institute | Lee R.G.,Daegu Mechatronics and Materials Institute | And 2 more authors.
Metals and Materials International | Year: 2012

Boron steel is widely used throughout the automobile industry due to its high tensile strength and hardenability. When boron steel is used for body parts, only high strength is required for crashworthiness. However, when boron steel is used for chassis parts, a high fatigue life is needed. The microstructure of boron steel is mainly affected by the cooling rate during hot stamping. Therefore, this study investigated the low cyclic fatigue life according to the cooling rate. The fatigue life increased at a low strain amplitude when the cooling rate was fast. However, at a high strain amplitude, the fatigue life decreased, due to the low ductility and fracture toughness of the martensite formed by rapid cooling. Martensite formed by a fast cooling rate shows excellent fatigue life at a low total strain amplitude; however, a multiphase microstructure formed by a slow cooling rate is recommended if the parts experience high and low total strain amplitudes alternately. In addition, the cooling rate has little effect on the distribution of solute boron and boron precipitations, so it is expected that boron rarely affects low cyclic fatigue. © KIM and Springer.

Park K.-J.,Daegu Mechatronics and Materials Institute | Son J.H.,Daegu Mechatronics and Materials Institute | Cho C.-S.,Daegu Mechatronics and Materials Institute | Kim B.-S.,Daegu Mechatronics and Materials Institute | Kim N.-H.,Optimus System Co.
SAE Technical Papers | Year: 2013

The manual mold heat treatment is affected by workers' skills so maintaining consistent quality is limited. To overcome the limitations of such a manual process and to improve and stabilize the quality of heat treatment, in this study, the composition of the efficient heat treatment system will be investigated by adopting the robot automation system with the exclusive robot and heat treatment automation process. In order to overcome limitations of the precise heat treatment adopting a manual type, this study will cover the virtual working process and the dedicated robot system for heat treatment with OLP(Off-Line Programming). Copyright © 2013 SAE International and Copyright © 2013 TSAE.

Yoon J.-C.,Kyungpook National University | Ahn S.-S.,Daegu Mechatronics and Materials Institute | Lee Y.-J.,Kyungpook National University
INES 2011 - 15th International Conference on Intelligent Engineering Systems, Proceedings | Year: 2011

This paper introduces a spherical robot, called KisBot II, with a new type of two-pendulum driving mechanism. A cross-shape frame is located horizontally in the center of the robot. The main axis of the frame is connected to the outer shell, and each pendulum is connected to the end of the other axis of the frame respectively. The main axis and pendulums can rotate 360 degrees inside the sphere orthogonally without interfering with each other, also the two pendulums can rotate identically or independent of each other. Due to this driving mechanism, KisBot II has various motion generation abilities, including a fast steering ability, turning ability in place and during travelling, and four(forward / backward / left / right) directional driving ability on the ground. Experiments for several motions verify the driving efficiency of the proposed spherical robot. © 2011 IEEE.

Seo H.D.,Kyungpook National University | Ahn S.S.,Daegu Mechatronics and Materials Institute | Yoon J.C.,Kyungpook National University | Lee Y.J.,Kyungpook National University
Applied Mechanics and Materials | Year: 2013

This paper introduces a novel spherical robot, KisBot III, with a newly designed wind-driven driving mechanism. The ducted fan for wind propulsion of the robot is installed at the center of the sphere, and according to the direction of the fan, the robot is able to move forwards or backwards. The outer shell is an open framework of spring carbon rods, and also includes two arms that can be folded-out to make the robot stop and partially deform its shape. Plus, for turning and balance control, a pendulum is located under the ducted-fan frame. By adopting wind as the driving mechanism, the robot has enough propulsion to drive over flat and uneven terrain, and negotiate a raised curb and slope. Experiments verify the driving motions and efficiency of the proposed spherical robot. © (2013) Trans Tech Publications, Switzerland.

Suh M.-S.,Korea Institute of Energy Research | Suh C.H.,Daegu Mechatronics and Materials Institute | Nahm S.-H.,Korea Research Institute of Standards and Science | Suh C.-M.,Kyungpook National University
Advances in Mechanical Engineering | Year: 2015

Fatigue characteristics of A7075-T651 aluminum material were studied with surface treatment of shot peening. The fatigue life was characterized by two fatigue testing methods, ultrasonic fatigue test (UFT, 20 kHz) and the rotary-bending fatigue test (RFT, 53 Hz). The fatigue life improvement was confirmed by rotary bending fatigue tester. However, the surface modification effects were hardly observed by UFT method. The RFT results validate that the fatigue properties of RFT show a fine congruence regardless of the test machine types. The results of hardness, compressive residual stress, fatigue strength, and mechanical properties of specimen were improved by shot peening. © Min-Soo Suh et al.

Kim B.-S.,Daegu Mechatronics and Materials Institute | Yang S.-H.,Korea University | Kim J.-D.,Daegu Mechatronics and Materials Institute | Cho C.-S.,Daegu Mechatronics and Materials Institute
2013 44th International Symposium on Robotics, ISR 2013 | Year: 2013

A field of the shipbuilding and the construction industry needs a large size robot. But the existing serial robots have disadvantage of deformation occurred by its weight and the vibration occurred in operating at high speed. In this study, we made the parallel robot which two serial robot connected by one link. This robot is controlled to position(x,y) and rotation(θ) by use of four DC servo motors as redundant actuation manipulators. Working space, singular point and Jacobian of this redundant parallel robot is analyzed © 2013 IEEE.

Park S.,Korea Orthopedics and Rehabilitaion Engineering Center | Kim K.,Daegu Mechatronics and Materials Institute | Mun M.,Korea Orthopedics and Rehabilitaion Engineering Center
Proceedings of the 2nd IASTED International Conference on Computational Bioscience, CompBio 2011 | Year: 2011

In this paper, an integrated training system of myoelectric hands for the upper limb amputee is proposed. Many amputees have trouble in isolating the muscle in the residual limb that produces strong myoelectric signals to control myoelectric prosthesis. It is required to match the user's intentions and the muscles such that when the user activates a muscle it provides a signal to move the prosthetic hand in the direction specified by the selected muscle. The training system we developed is different from the conventional myoelectric training system due to its two features. First, it adopted an alternated wireless connection to overcome the space limitation. Second, it maximizes the effect of visual feedback by simultaneously showing successive envelope EMG signals and virtual 3D hand simulation. It consists of two parts, a Zigbee ™ based wireless EMG transmitter and a receiver, and a graphic user interface to display the information about the training status. In this paper, we describe the merits of the developed wireless EMG transmitter compared to the conventional EMG measurement system. Secondly, we describe the detailed functions of the integrated training system such as 3D virtual hand simulator, multi-DOF wrist module activation and training report which is used to adjust the parameters of the training system based on the post training information.

Kim T.H.,Daegu Mechatronics and Materials Institute | Lee S.H.,Daegu Mechatronics and Materials Institute | Lee S.H.,Saeyang. Co. | Kim W.M.,Saeyang. Co.
Proceedings of the IEEE International Conference on Industrial Technology | Year: 2014

This paper presents a design and analysis of 40,000rpm class high speed slotless brushless DC motor for surgical hand-piece. To design the motor, performance characteristic according to stator slot type is compared. Simple analytical equation is applied to consider about slotless motor characteristics as like torque constant and speed constant. Design of prototype motor is proposed by simple analytical equation and simulation which is based on magnetic circuit analysis. Design result is verified by finite element analysis about 2D and 3D and experimental result. © 2014 IEEE.

Lee S.-H.,Daegu Mechatronics and Materials Institute | Kim T.-H.,Daegu Mechatronics and Materials Institute | Ahn J.-W.,Kyungsung University
2013 International Conference on Electrical Machines and Systems, ICEMS 2013 | Year: 2013

This paper presents the development of E-scooter in large urban areas and industrial areas. The proposed prototype is propelled by two BLDC motors placed on the rear wheels and a 48V lead-acid battery for propulsion energy. A control scheme is based on the low-cost processor and provides the cost effective using hall position sensors alternative to traditional encoders and resolvers. Experimental results will show that the proposed E-scooter can improve the drive efficiency as well as the performance of the variable commercial satisfaction. © 2013 IEEE.

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