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Taoyuan City, Taiwan

Chen J.-C.,National Central University | Tung P.-C.,National Central University | Huang S.-F.,Taipei Veterans General Hospital | Huang S.-F.,National Yang Ming University | And 3 more authors.
International Journal of Innovative Computing, Information and Control | Year: 2013

This study presents a method for the extraction and screening of knee joint vibroarthrographic (VAG) signals using an Empirical Mode Decomposition (EMD) technique. The proposed analysis method is based on the Hilbert Huang transform, which is a powerful tool for the analysis of non-stationary and non-linear time series and basically consists of an empirical mode decomposition method and Hilbert spectral analysis. A technique for time-frequency analysis of the extracted vibration signals is proposed with the goal of diagnosing knee joint diseases. The performance of the EMD technique is verified experimentally. The screening accuracy of the statistical pattern classification is 85.3% in Vibroarthrographic signals. The results confirm that the proposed approach is indeed feasible for the noninvasive diagnosis and monitoring of articular cartilage patholoyy. © 2013 ICIC International. Source


Chen J.-C.,National Central University | Tung P.-C.,National Central University | Huang S.-F.,Taipei Veterans General Hospital | Huang S.-F.,National Yang Ming University | And 2 more authors.
International Journal of Innovative Computing, Information and Control | Year: 2012

This study presents a novel method for the extraction and screening of knee joint vibroarthrographic (VAC) signals using an independent component analysis (ICA) technique. A time-frequency analysis technique of the extracted vibration signals is proposed to carry out knee joint diagnosis. The performance of the ICA technique is verified experimentally. Statistical pattern classification screening accuracy is 82.5% in VAC. The results confirm that ICA is a feasible approach for the noninvasive diagnosis and monitoring of articular cartilage pathology. © 2012 ICIC International. Source


Liu J.-J.,China Engine Corporation | Lu P.-H.,China Engine Corporation | Yang Y.-P.,National Taiwan University | Ye D.-H.,National Taiwan University | Cheng Y.-R.,National Taiwan University
2011 International Conference on Electrical Machines and Systems, ICEMS 2011 | Year: 2011

This paper proposes a control strategy involving energy compensation for the soft-landing of an electromagnetic valve actuator in internal combustion engines. This axisymmetric and cylindrical actuator features a hybrid magnetomotive force with permanent magnet and electromagnet, and a secondary air gap to prevent the permanent magnet irreversibly demagnetizing. It is a straightforward theory in which the positive and negative work of an armature stroke is equalized, enabling a zero landing velocity to be achieved. The resultant of positive and negative work is a function of valve landing velocity, which depends on the release current that releases the armature from one seating position, and the landing current that attracts the armature to the opposite seating position. The magnitude and duty cycle of the release and landing currents are investigated for soft-landing via observation of armature displacement and velocity. The experimental results show that the landing velocity can be greatly reduced by adjusting the duty cycle of the landing current, and the actuating power is greatly reduced after the energy compensation control is applied. © 2011 IEEE. Source


Yang Y.-P.,National Taiwan University | Liu J.-J.,National Taiwan University | Liu J.-J.,China Engine Corporation | Ye D.-H.,National Taiwan University | And 2 more authors.
IEEE/ASME Transactions on Mechatronics | Year: 2013

This paper presents a multiobjective optimal design and an energy compensation control for the soft valve landing of an electromagnetic valve actuator in internal combustion engines. This axisymmetric and cylindrical actuator is used to achieve continuous and independent valve timing and lifting without mechanical cams, which features a hybrid magnetomotive force with permanent magnet (PM) and electromagnet, and a secondary air gap to prevent the PM irreversibly demagnetizing. The dynamics of the electromagnetic valve are modeled with an equivalent magnetic circuit, which is used to perform both sensitivity analysis and an optimal design function to satisfy multiple objectives, such as magnetic holding force, release current, and its rising time. The energy compensation control in which the positive and negative work of an armature stroke is equalized enables a zero landing velocity to be achieved. The experimental results from a prototype actuator show that the landing velocity can be greatly reduced by adjusting the duty cycle of the landing current, and the actuating power is greatly reduced after the energy compensation control is applied. © 1996-2012 IEEE. Source


Yang Y.-P.,National Taiwan University | Liu J.-J.,China Engine Corporation | Lu P.-H.,China Engine Corporation | Cheng Y.-R.,National Taiwan University | Ye D.-H.,National Taiwan University
2011 International Conference on Electrical Machines and Systems, ICEMS 2011 | Year: 2011

This paper proposes a novel design of an electromagnetic valve actuation system for internal combustion engines. This electromagnetic valve uses a hybrid magnetomotive force with a permanent magnet and electromagnet to control the variable timing and soft landing of the valve. Under the restriction of engine space and operation, the dynamics of the electromagnetic valve are modeled with an equivalent magnetic circuit, which is used to perform both sensitivity analysis and an optimal design function to satisfy multiple objectives, such as magnetic holding force, release current, and its rising time. The final design is verified and refined by finite element analysis. A prototype is fabricated and the experimental results show that the dynamical performances of the electromagnetic valve are satisfactory and may be improved by advanced feedback controls. © 2011 IEEE. Source

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