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Global Robust and Adaptive Output Feedback Dynamic Positioning of Surface Ships

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Journal of Marine Science and Application 2011年第3期10卷 325-332页

作者： khac duc do School of Mechanical and Aerospace Engineering Nanyang Technological University

A constructive method was presented to design a global robust and adaptive output feedback controller for dynamic positioning of surface ships under environmental disturbances induced by waves, wind, and ocean currents. The ship's parameters were not required to be known. An adaptive observer was first designed to estimate the ship's velocities and parameters. The ship position measurements were also passed through the adaptive observer to reduce high frequency measurement noise from entering the control system. Using these estimate signals, the control was then designed based on Lyapunov's direct method to force the ship's position and orientation to globally asymptotically converge to desired values. Simulation results illustrate the effectiveness of the proposed control system. In conclusion, the paper presented a new method to design an effective control system for dynamic positioning of surface ships.

关键词： dynamic positioning surface vessel robust and adaptive output feedback nonlinear control

Path-tracking Control of Underactuated Ships Under Tracking Error Constraints

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Journal of Marine Science and Application 2015年第4期14卷 343-354页

作者： khac duc do Department of Mechanical Engineering Curtin University Kent Street Bentley WA 6102 Australia

This paper presents a constructive design of new controllers that force underactuated ships under constant or slow time-varying sea loads to asymptotically track a parameterized reference path, that guarantees the distance from the ship to the reference path always be within a specified value. The control design is based on a global exponential disturbance observer, a transformation of the ship dynamics to an almost spherical form, an interpretation of the tracking errors in an earth-fixed frame, an introduction of dynamic variables to compensate for relaxation of the reference path generation, p-times differentiable step functions, and backstepping and Lyapunov＇s direct methods. The effectiveness of the proposed results is illustrated through simulations.

关键词： underactuated ship path-tracking error constraint Lyapunov method backstepping method

Global Inverse Optimal Tracking Control of Underactuated Omni-directional Intelligent Navigators （ODINs）

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Journal of Marine Science and Application 2015年第1期14卷 1-13页

作者： khac duc do Department of Mechanical Engineering Curtin University Bentley WA 6102 Australia

This paper presents a design of optimal controllers with respect to a meaningful cost function to force an underactuated omni-directional intelligent navigator （ODIN） under unknown constant environmental loads to track a reference trajectory in two-dimensional space. Motivated by the vehicle＇s steering practice, the yaw angle regarded as a virtual control plus the surge thrust force are used to force the position of the vehicle to globally track its reference trajectory. The control design is based on several recent results developed for inverse optimal control and stability analysis of nonlinear systems, a new design of bounded disturbance observers, and backstepping and Lyapunov＇s direct methods. Both state- and output-feedback control designs are addressed. Simulations are included to illustrate the effectiveness of the proposed results.

关键词： inverse optimality optimal controller global tracking underactuated omni-directional intelligent navigator (ODIN) Lyapunov's direct method backstepping method

Control of Nonlinear Systems with Output Tracking Error Constraints

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Journal of Measurement Science and Instrumentation 2010年第3期1卷 217-223页

作者： khac duc do Dang Binh Nguyen Anh duc Nguyen School of Mechanical Engineering University of Western Australia WA 6009 Australia Rectoral Office Thainguyen University of Technology Thainguyen Vietnam Department of Electrical Engineering Thainguyen University of Technology Thainguyen Vietnam

A oanstructive method is presented to design controllers that force the output of nonlinear systems in a strict feedback form to track a bounded and sufficient smooth reference trajectory asymptotically. Under suitable condition with the initial output tracking error, the proposed controllers guarantee the output tracking error within a symmtric or an asymmetric pre-specified limit range, and boundedness of all signals of the closed loop system. A transformation is inmxuced to take care of the output tracking error constraint. Smooth and/or p -times differentiable step functions are propsed and incor- porated in the output tracking error transformation to overcome difficulties due to the asynxnetric limit range on the output tracking error. As a result, there are no switchings in the proposed controllers despite of the asymmnetric limit range.

关键词： nonlinear system output constraint backstepping Lyapunov method

Nonlinear Control of Magnetic Bearings

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Journal of Measurement Science and Instrumentation 2010年第1期1卷 10-16页

作者： khac duc do Dang Hoe Nguyen Thanh Binh Nguyen School of Mechanical Engineering University of Western Australia WA 6009 Australia Vice-Rectoral Office Thainguyen University of Technology Thainguyen Vietnam Dept. of Human Resource University ofThainguyen Thainguyen Vietnam

In this paper, recent results controling nonlinear systems with output tracking error constmints are applied to the design of new tracking controllers for magnetic bearings. The proposed controllers can force the rotor to track a bounded and sufficiently smooth reference trajectory asymptotically and guarantee non-contactedness betweea the rotor and the stator of the magnetic beadngs. Simulation results are included to illustrate the effectiveness of the propsed controllers.

关键词： nonlinear system output constraint bockstepping L yapunov method

Stability in Probability and Inverse Optimal Control of Evolution Systems Driven by Levy Processes

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Effectiveness on post-stroke hemiplegia in patients:electroacupuncture plus cycling vs electroacupuncture alone

自动化学报（英文版） 2020年第2期

作者： khac duc do School of Civil and Mechanical Engineering，Curtin University，Bentley，WA 6102，Australia

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Journal of Traditional Chinese Medicine 2023年第2期43卷 352-358页

作者： Minh duc Nguyen Thanh Van Tran Quoc Vinh Nguyen Ninh khac Nguyen Son Truong Vu Luu Trong Nguyen Linh Vu Phuong Dang Senior Specialist Clinic National Hospital of AcupunctureHanoi 1000Vietnam Department of Senior Specialist National Hospital of Acupuncture Hanoi 1000Vietnam Department of Senior Specialist Military Institute of Traditional MedicineHanoi 1000Vietnam Department of Training and Science National Hospital of AcupunctureHanoi 1000Vietnam Department of Senior Specialist National Hospital of AcupunctureHanoi 1000Vietnam Department of Rehabilitation 108 Military Central HospitalHanoi 1000Vietnam Department of Medicine Dai Nam UniversityHanoi 1000Vietnam

OBJECTIVE:To evaluate the effectiveness of cycling in combination with electroacupuncture in treatment of poststroke hemiplegia patients at National Hospital of Acupuncture,***:The study was designed as a single-centre,outcome-assessor-blinded parallel randomised controlled trial with 120 post-stroke hemiplegia patients randomly assigned into two groups:electroacupuncture plus cycling(CT group) and electroacupuncture(AT group).Patients were assessed before and after the treatment(using muscle grading,modified Rankin,Barthel,Orgorozo scores and electromyography).Statistical Man–Whitney U test,and Fisher’s exact tests were used to compare between CT and AT ***:The results reported statistically significant improvement in motor function in patients suffering from hemiplegia following ischemic stroke in both CT and AT *** in CT group experienced a greater improvement compared to those in AT group including better muscle contraction(increased frequency and amplitude of electromyography and increased muscle grading scale);increased recovery(Orgogozo scale),increased independency(Barthel scale) and decreased disability(Modified Rankin scale)(P < 0.01).CONCLUSIONS:Combination with cycling training significantly improves the recovery of post-stroke patients treated with electroacupuncture.

关键词： electroacupuncture cycle training post-stroke hemiplegia

Twin reversed arterial perfusion sequence-a rare and dangerous complication form of monochorionic twins:A case report

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World Journal of Clinical Cases 2022年第28期10卷 10214-10219页

作者： Nguyen Duy Anh Nguyen-Thi Thu Ha Nguyen-Thi Sim Nguyen khac Toan Phan-Thi Huyen Thuong Nguyen Minh duc Fetal Medicine Center Hanoi Obstetrics and Gynecology HospitalHanoi 100000Vietnam Department of Assisted Reproduction Hanoi Obstetrics and Gynecology HospitalHanoi 100000Vietnam Department of Obstetrics and Gynecology Hanoi University of Medicine and PharmacyHanoi 100000Vietnam Department of Radiology Pham Ngoc Thach University of MedicineHo Chi Minh City 700000Vietnam

BACKGROUND Twin reversed arterial perfusion(TRAP) sequence is an extremely rare congenital anomaly in monochorionic(MC) *** condition is characterized by a malformed fetus(acardiac twin) without cardiac activities being perfused by a structurally normal one(pump twin) via an artery-to-artery anastomosis in a reverse *** SUMMARY We described the first case of TRAP to receive laser surgery in *** 26-wk pregnancy was originally misdiagnosed in another hospital as MC twins with single intrauterine fetal *** admission to our center,the diagnosis was amended to a 26-wk TRAP sequence stage *** acardiac twin was 7.5 cm at the longest length,the ratio of the weight of the acardiac twin to the weight of the pump twin was more than 90%,the pump twin showed fetal distress with absent diastolic flow in umbilical artery of pump twin,and the peak systolic velocity in the middle cerebral artery = 1.6 Mo *** performed emergency laser photocoagulation of the acardiac twin’s umbilical *** surgery,we successfully maintained the pregnancy for 8 wk and ended it electively by cesarean section at 34 wk of gestation due to rupture of *** TRAP should be appropriately diagnosed and treated early to avoid complications of the pump *** laser photocoagulation is a new and effective treatment for this condition.

关键词： Twin reversed arterial perfusion Acardiac twin Pump twin Laser Case report