Browsing by Author "Yang, Chia-Feng"

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Implementation of a-Si : H TFT AMOLED display with adaptive current scaling pixel circuit
(2007)
Yang, Chia-Feng
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Wang, Jiun-Shiau
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Huang, Jian-Zhi
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Shieh, Han-Ping D.
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光電工程學系
An active matrix organic light emitting diode (AMOLED) display with adaptive current scaling pixel circuit for a-Si: H TFT process has been demonstrated. In contrast to the conventional current-driven pixel circuit, the adaptive current scaling pixel circuit can shorten the response time effectively while displaying low gray level images due to the outstanding current scaling function and avoid data programming error resulted from long charging time. Moreover, it can also compensate for the variations of the TFT threshold voltage.
Motion behavior of triangular waveform excitation input in an operating impact drive mechanism
(2011-03-01)
Yang, Chia-Feng
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Jeng, Shyr-Long
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Chieng, Wei-Hua
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機械工程學系
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Department of Mechanical Engineering
Stable stepping motion from mechanical excitation of a piezoelectric device is generated using the impact drive mechanism (IDM) based on various triangular waveforms exerted by the counter mass speed. However, stick-slip behavior originating from the contact friction between the movable part and the guide surface poses an obstacle for precise modeling. Therefore, this work presents a concise impulse model for mechanism control of stepping motion behavior. The proposed impulse model incorporates the duty ratio and input frequency of the triangular waveform of counter mass relative displacement as the system input and outputs the estimated step size and the behavior of the stepping motion. An enhanced version of the dynamic model and our experimental results validate the efficacy of the proposed model. An adequate design and control of IDM motion is highly promising for use in nano-scale positioning. (C) 2010 Elsevier B.V. All rights reserved.
Outrigger Force Measure for Mobile Crane Safety Based on Linear Programming Optimization#
(2010)
Jeng, Shyr-Long
;
Yang, Chia-Feng
;
Chieng, Wei-Hua
;
機械工程學系
;
Department of Mechanical Engineering
This work presents a linear programming simplex method for evaluating allowable reaction forces of multiple outriggers with stability constraints. Minimum/maximum pruning approach is adopted to increase the computational efficiency of assessing the outrigger forces when a mobile crane is kept level by the supports of four outriggers. Determining the outrigger forces is an effective means of preventing a mobile crane from tipping over or outrigger failures. Two indices, i.e., moment-index and force-index, which quantify the tendency of tip-over behavior of mobile cranes and examine the bearing capacity of outrigger, are introduced to improve the safety measures. The safety hoist criteria of two mobile crane types equipped with different outriggers are analyzed to demonstrate the feasibility of the proposed scheme. An intelligent anti-upset device that utilizes the outrigger-based stability measures and selectively suppresses critical steering commands in real time is implemented to ensure safe crane operations.