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Design and Workspace Analysis of a New Endoscopic Parallel Manipulator
Khalil Ibrahim,Ahmed Ramadan,M. Fanni,Yo Kobayashi,A. A. Abo-Ismail,Masakatus G. Fujie 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10
This paper describes the development of a dexterous endoscopic parallel manipulator for laparoscopic surgery using rigid mechanism. Based on the concept of virtual chain and screw theory, previous endoscopic parallel manipulators are deeply investigated to put their synthesis in a systematic rigorous procedure that helps in proposing the new 4-DOF endoscopic parallel manipulator. The inverse and forward kinematics solutions are derived analytically and numerically respectively. The known problem of limited bending angles was solved in the proposed manipulator as it can reach ± 90o in any direction. The proposed manipulator consists of four legs; two legs are 2-PUU (each leg consists of one active prismatic joint and two passive hook joints); the other two legs are 2-PUS (each leg consists of one active prismatic join, one passive hook joint and one passive spherical joint). Four linear motors are used to drive the mechanism. The performance is investigated through simulation by ADAMS software. Dexterous workspace is obtained and this validates the advantageous bending capability of the new proposed manipulator compared to previous ones.
Maximum Power Point Tracking Controller Connecting PV System to Grid
Ahmed G. Abo-Khalil,Dong-Choon Lee,Jong-Woo Choi,Heung-Geun Kim 전력전자학회 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.3
Photovoltaic (PV) generators have nonlinear V-I characteristics and maximum power points which vary with illumination level and temperature. Using a maximum power point tracker (MPPT) with an intermediate converter can increase the system efficiency by matching the PV systems to the load. This paper presents a maximum power point tracker based on fuzzy logic and a control scheme for a single-phase inverter connected to the utility grid. The fuzzy logic controller (FLC) provides an adaptive nature for system performance. Also the FLC provides excellent features such as fast response, good performance and the ability to change the fuzzy parameters to improve the control system. A single-phase AC-DC inverter is used to connect the PV system to the grid utility and local loads. While a control scheme is implemented to inject the PV output power to the utility grid at unity power factor and reduced harmonic level. The simulation results have shown the effectiveness of the proposed scheme.
Maximum Power Point Tracking Controller Connecting PV System to Grid
Ahmed G. Abo-Khalil,Dong-Choon Lee,Jul-Ki Seok,Jong-Woo Choi,Heung-Geun Kim 전력전자학회 2004 ICPE(ISPE)논문집 Vol.- No.-
The photovoltaic generators have a nonlinear V-I characteristics and maximum power points which vary with the illumination level and temperature. Using maximum power point tracker(MPPT) with the intermediate converter can increase the system efficiency by matching the PV systems to the load. This paper presents a maximum power point tracker based on fuzzy logic and a control scheme for a singlephase inverter connected to the utility grid. The fuzzy logic<br/> controller(FLC) provides an adaptive nature for the system performance. Also the FLC provides excellent features such<br/> as fast response, good performance and the ability to change the fuzzy parameters to improve control system. The singlephase dc/ac inverter is used to connect the PV system to the grid utility and local loads, of which control scheme is implemented to inject the PV output power to the utility grid at unity power factor and reduced harmonic level. The simulation results have shown the effectiveness of the proposed scheme.
Output Power Control of Wind Generation System by Machine Loss Minimization
Abo-Khalil, Ahmed,Lee, Dong-Choon 한국신재생에너지학회 2005 한국신재생에너지학회 학술대회논문집 Vol.2005 No.06
Generator efficiency optimization is important for economic saving and environmental pollution reduction. In general, the machine loss can be reduced by the decreasing the flux level, resulting in the significant reduction of the core loss. This paper proposesan model-based controller is used to decrement the excitation current component on the basis of measured stator current and machine parameters and the q-axis current component controls the generator torque, by which the speed of the induction generator iscontrolled according to the variation of the wind speed in order to produce the maximum output power. The generator reference speed is adjusted according to the optimum tip-speed ratio. The generated power flows into the utility grid through the back-to-back PWM converter. The grid-side converter controls the dc link voltage and the line-side power factor by the q-axis and the d-axis current control, respectively. Experimental results are shown to verify the validity of the proposed scheme.
Ahmed G. Abo-Khalil,Dong-Choon Lee 전력전자학회 2006 전력전자학술대회 논문집 Vol.- No.-
A novel online capacitance estimation method for a DC-link capacitor in a three-phase AC/DC/AC PWM converter is proposed. A controlled AC voltage with a lower frequency than the line frequency is injected into the DC-link voltage, which then causes AC power ripples at the DC output side. By extracting the AC voltage and power components on the DC output side using digital filters, the capacitance can then be calculated using the recursive least squares method. The proposed method can be simply implemented with only software and no additional hardware. Experimental results confirm that the estimation error is less than 0.2%.
Loss Minimization of DFIG for Wind Power Generation
Ahmed G. Abo-Khalil,Hong-Geuk Park,Dong-Choon Lee,Se-Hyun Lee 전력전자학회 2007 전력전자학술대회 논문집 Vol.- No.-
This paper proposes a loss minimization algorithm for doubly-fed induction generator (DFIG) by controlling the stator reactive power. The proposed strategy directly controls the rotor current to achieve the operating point of minimum generator loss and maximum power point tracking. The maximum power is obtained by tracking the q-axis rotor current with generator speed variation and the minimum generator loss is achieved by controlling the d-axis rotor current. Experimental results are shown to verify the validity of the proposed scheme.
Ahmed H. Khalil,Atef S. Abd Al-Galil,Ahmed A. Sabek,Mohamed M. Zeineldin,Seham Y. Abo-Kora 대한수의학회 2019 Journal of Veterinary Science Vol.20 No.5
This study examined the sedative, analgesic, behavioral, and clinical effects of a combination of xylazine (XY) and nalbuphine-xylazine (NA-XY) in camels. A total of five adult camels were used in a prospective randomized cross-over design with a wash out period of two weeks. Camels were allocated randomly to two treatment groups: the XY group (xylazine, 1.1mL/100 kg IV) and the NA-XY group (xylazine, 1.1mL/100 kg IV and nalbuphine, 1 mg/kg IV). The sedative, analgesic, behavioral, and clinical effects of XY and NA-XY combination were evaluated prior to administration (baseline) and at 5, 15, 30, 45, 60, 75, 90, and 120 minutes post-administration. The results showed that the NA-XY combination accelerates the onset of sedation and analgesia and prolongs the durations of both sedation (p < 0.001) and analgesia (p < 0.01). The behavioral parameters showed higher scores with a NA-XY combination than xylazine alone. Although a XY injection resulted in a significant decline in the heart and respiratory rate, the NA-XY combination group revealed a non-significant change in both clinical parameters compared to the baseline. In conclusion, the use of a NA-XY combination in camels improved the sedative and analgesic onset and duration with an improved outcome in the behavioral scores, as well as in both the heart and respiratory rates compared to XY alone.
Synchronization of Wind Power Generation System Using DFIG to Utility Grid
Ahmed G. Abo-Khalil,Dong-Choon Lee 전력전자학회 2005 전력전자학술대회 논문집 Vol.- No.-
This paper presents a grid connection technique of wind power generation system using DFIG(doubly-fed induction generator). The synchronization of output voltage of the DFIG to the grid utility is investigated and the dynamic response at generator starting is studied. Simulation results using PSCAD show smooth synchronization and fast dynamic response.
Ahmed G. Abo-Khalil,Dong-Choon Lee 전력전자학회 2006 전력전자학술대회 논문집 Vol.- No.-
In this paper, a novel method for wind speed estimation in wind power generation systems is presented. The proposed algorithm is based on estimating the wind speed using Support-Vector-Machines for regression (SVR). The wind speed is estimated using the generator power-speed characteristics as a set of training vectors. SVR is trained off-line to predict a continuos-valued function between the system's inputs and wind speed value. The predicted off-line function as well as the instantaneous generator power and speed are then used to determine the unknown winds speed on-line. The simulation results show that SVR can define the corresponding wind speed rapidly and accurately to determine the optimum generator speed reference for maximum power point tracking.