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8 results on '"Teruaki Fukuoka"'

1. Development of a 2-DOF Controlled Magnetic Drive Actuator for Laser Beam Cutting

Author

Xiaoyou ZHANG, Tadahiko SHINSHI, Teruaki FUKUOKA, and Takahiro NAKAI

Subjects
laser beam cutting, magnetic drive actuator, adaptive control, Engineering machinery, tools, and implements, TA213-215, Mechanical engineering and machinery, TJ1-1570
Abstract

Laser beam cutting (LBC) is a non-contact machining method that is widely used in industry. In order to improve cutting speed and reduce the consumption of assist gas, it is necessary to employ a machining method that applies a suitable eccentricity between the laser beam axis and the assist gas nozzle axis. This paper describes the development of a high-speed, high-precision, magnetic drive actuator, which can be attached to a conventional LBC machine to control the relative displacement between the laser beam axis and the assist gas nozzle axis in two orthogonal directions. First, a magnetic drive actuator is designed and fabricated. In the actuator, the motions of the lens in the radial directions are controlled by electromagnets, and the motions in the other directions are constrained by elastic hinges. Second, a compensation method for the zero point of the displacement sensors that are used to measure the displacements of the lens in the radial direction and an adaptive control method for the actuator are presented. Finally, the effectiveness of the presented control method is verified, and the positioning performance of the actuator is evaluated through experiments. The experimental results showed that the vibration of the lens was reduced using the presented control method, and the actuator had a positioning resolution of 0.75 µm, a bandwidth greater than 133 Hz, and a positioning stroke of 1 mm.

Published
2013
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3. Adaptive Control of Magnetic Drive Actuator for Laser Cutting

Author

Xiaoyou Zhang, Takahiro Nakai, Tadahiko Shinshi, Teruaki Fukuoka, and De Qiang Chu

Subjects
Nonlinear system, Engineering, Adaptive control, Machining, Laser cutting, business.industry, Control theory, General Engineering, Vibration amplitude, Actuator, business, Air gap (plumbing), Control methods
Abstract

This paper describes an adaptive control method for a magnetic drive actuator that used for the laser cutting to realize high speed and high accuracy machining. Firstly, a zero bias current method and a nonlinear compensator are examined and used for the actuator. Secondly, an adative control method is presented. Finally, the coefficient of the gap-current-force is estimated and the effectiveness of the presented control method is verified by experiments. The experimental results show that the coefficient of the gap-current-force reduces exponentially depending on the increase in the length of the air gap. By using the adaptive control, the peak-to-peak vibration amplitude of the lens holder is reduced from 1.95um to 1.55um.

Published
2012

4. Precision Control of Magnetic Drive Actuator Used for Laser Cutting wirh Compensation of Zero Point of Displacement Sensor

Author

Teruaki Fukuoka, Xiaoyou Zhang, Takahiro Nakai, Tadahiko Shinshi, and De Qiang Chu

Subjects
Engineering, Electromagnet, Laser cutting, business.industry, Bandwidth (signal processing), Hinge, Zero-point energy, General Medicine, law.invention, Machining, Control theory, law, Actuator, business, Control methods
Abstract

This paper describes a precision control method for a magnetic drive actuator used for the laser cutting to realize high speed and high accuracy machining. Firstly, a zero bias current method is applied to drive the electromagnets to achieve a high-precision and long-stroke of the actuator. Secondly, a compensation method of the zero point of the displacement sensors is presented to prevent the generation of the disturbance force produced by the elastic hinges. Finally, the positioning performance of the actuator is evaluated through experiments and the experimental results show that the actuator has a positioning resolution of the order of micrometer, a bandwidth greater than 130Hz, and a positioning stroke of 1mm.

Published
2012

6. Elucidation of Steplike Output Energy Decrease Observed in ArF Excimer Laser for Microlithography

Author

Teruaki Fukuoka, Kiichiro Uchino, Akira Sumitani, and Takanobu Ishihara

Subjects
Physics and Astronomy (miscellaneous), Excimer laser, business.industry, medicine.medical_treatment, General Engineering, General Physics and Astronomy, chemistry.chemical_element, medicine.disease_cause, Laser, Oxygen, law.invention, X-ray laser, Optics, Xenon, chemistry, law, Fluorine, medicine, Optoelectronics, business, Absorption (electromagnetic radiation), Ultraviolet
Abstract

A steplike decrease in the output energy of an ArF excimer laser for microlithography is caused by the laser light absorption in the laser gas. To identify the absorbing gas component, the light absorption characteristics of the laser gas inside the discharge chamber were investigated under various gas conditions using a continuous xenon light source in the ultraviolet region and an ArF excimer laser at 193 nm. As a result, the oxygen–fluorine compound FxOy generated in the laser discharge was identified as the absorbing molecule, because a strong steplike absorption of the 193 nm laser light was only observed when oxygen and fluorine were added together to the discharge gas. The lifetime of this absorbing molecule was examined against gas temperature during the operation of the laser discharge. The data obtained were useful in setting the best operational conditions for the ArF excimer laser for microlithography.

Published
2007

7. Investigation of a Step-Like Output Energy Decrease Observed in an ArF Excimer Laser for Microlithography

Author

Akira Sumitani, Kiichiro Uchino, Teruaki Fukuoka, and Takanobu Ishihara

Subjects
Physics and Astronomy (miscellaneous), Excimer laser, medicine.medical_treatment, General Engineering, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, Laser, Excimer, Oxygen, law.invention, Xenon, chemistry, law, Impurity, medicine, Absorption (electromagnetic radiation), Energy (signal processing)
Abstract

A step-like decrease of the output energy of an ArF excimer laser for microlithography has been observed during high-repetition rate and high-power operation. The reason for the step-like energy decrease was traced to oxygen by adding 50 ppm of various gas impurities to the laser gas. It is supposed that the energy decrease is caused by laser light absorption due to the oxygen or to some kinds of oxygen compounds because no change was observed in ArF and XeF emission intensities which were monitored as measures of excimer formation, Xe content, and discharge states.

Published
2006

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