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Tenan, South Korea

Kim H.,Smart System Research Group | Kim C.,Smart System Research Group | Choi S.,Inha University | Moon S.,Shock and Vibration Team | Song W.,Structure Dynamic Design Group
19th International Congress on Sound and Vibration 2012, ICSV 2012 | Year: 2012

For the purpose of vibration control and isolation in a clean room, we propose an active device combining pneumatic, electro-magnetic (EM) and magneto-rheological (MR) forces. The mechanism was the integration of the forces in a parallel connection. The MR parts are designed to operate in the air spring which the EM parts border out side. The control logic was organized with classical methods and switching mode for avoiding operational mismatch among the forces. PC-based controller was constructed to execute the non-linear logic and communication with the peripherals. Pneumatics was constantly operating for maintaining a level of the air mount. MR handles transient response and EM control undertook reduction of resonance response, which were switched mutually with a threshold. The vibration was detected by a laser displacement sensor which had sub-micron resolution. Four active devices were constructed and installed under 3 tons of air mount. The impact test results show the possibility that the proposed device can reduce the transient response as well as the resonance in the air mount.

Kim H.-T.,Smart System Research Group | Kim C.-H.,Smart System Research Group | Choi S.-B.,Inha University | Moon S.-J.,Shock and Vibration Team | Song W.-G.,Industrial Technology Group
Smart Materials and Structures | Year: 2014

With the goal of vibration control and isolation in a clean room, we propose a new type of air mount which consists of pneumatic, electromagnetic (EM), and magnetorheological (MR) actuators. The air mount is installed below a semiconductor manufacturing machine to reduce the adverse effects caused by unwanted vibration. The proposed mechanism integrates the forces in a parallel connection of the three actuators. The MR part is designed to operate in an air spring in which the EM part is installed. The control logic is developed with a classical method and a switching mode to avoid operational mismatch among the forces developed. Based on extended microprocessors, a portable, embedded controller is installed to execute both nonlinear logic and digital communication with the peripherals. The pneumatic forces constantly support the heavy weight of an upper structure and maintain the level of the air mount. The MR damper handles the transient response, while the EM controller reduces the resonance response, which is switched mutually with a threshold. Vibration is detected by laser displacement sensors which have submicron resolution. The impact test results of three tons load weight demonstrate practical feasibility by showing that the proposed triple-actuating mechanism can reduce the transient response as well as the resonance in the air mount, resulting in accurate motion of the semiconductor manufacturing machine. © 2014 IOP Publishing Ltd.

Kim H.-T.,Smart System Research Group | Lee K.-W.,Smart System Research Group | Yang H.-J.,Korea Polytechnic University | Kim S.-C.,AmTechnology
International Journal of Precision Engineering and Manufacturing | Year: 2013

We propose a self-learning method for automatic wafer alignment in the semiconductor manufacturing process. A feed forward neural network is trained by and used for wafer alignment. The network determines the movement of kinematic parts from the misalignment inspected by machine vision. However, it is time-consuming and inconvenient to obtain training data in this way. So, we built an automatic learning rule to gather the data and train the network. The network may determine wrong outputs and cause other misalignments at first, but the error can decrease as the training proceeds. The training sets consisted of a variation of misalignment data and the movement of an alignment stage. Five recent sets are used for training and others are dismissed or forgotten. This retrained network tried aligning, measured misalignment, and made new training sets. This sequence makes it possible to acquire alignment skill and automate the process. After learning, automatic alignment accomplished sub-pixel accuracy for several cases of misalignment. The result showed that the proposed method could be applied to the semiconductor manufacturing process. Its performance improved about 6% compared with conventional algorithms. © 2013 Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.

Kim H.T.,Smart System Research Group | Jin K.C.,Smart System Research Group
Applied Mechanics and Materials | Year: 2013

Recent mechatronic systems, such as inspection machines or 3D imaging apparatuses, acquire and compute massive data for final results. A host in the mechatronic system is commonly composed of multiple hardware devices which interface with high-speed external signals. The host and the devices usually have large memory, so efficient data management is important due to data storage and transfer. In our software structure, each device is managed by respective application and large shared memory (LSM) is allocated in the host for the massive data. The shared memory is accessible from the device applications. Actions of the mechatronic system are driven by combining and broadcasting events through and inter-process communication (IPC). The model with LSM and IPC was applied to a 3D RF imaging system. We expect the proposed model can also be applied to machine vision with big image and engineering simulation with hardware accelerators. © (2013) Trans Tech Publications, Switzerland.

Jin K.C.,Smart System Research Group | Kim H.T.,Smart System Research Group
Applied Mechanics and Materials | Year: 2013

Mojette Transform (MOT) is used mainly in imaging implementation of mechatronicbased imaging system to reconstruct a discrete signal from a finite set of projection planes. The MOT uses a specific algorithm, called Corner Based Inversion (CBI), to reconstruct an image from its projections offering high-speed computing properties. Moreover, the MOT ensures a very low complexity in comparison to the reconstruction based on Fast Fourier Transform (FFT). In this paper, Graphic Processing Unit (GPU) based MOT is presented and also CPU and GPU processing are issued from 1283 image pixels. In the result, performance differences between the CPU and GPU architectures are discussed, and an approach of fast improvement in architectural efficiency is recommend. © (2013) Trans Tech Publications, Switzerland.

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