Numerical investigation on multi-degree-freedom nonlinear chaotic vibration isolation

Jiang, Guoping,Tao, Weijun Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.4

A chaotic vibration isolation system is designed according to the chaotic vibration theory in this paper. The strong nonlinearity is generated by the system. Line spectra in the radiated noise maybe easily detected caused by marine vessels. It is Important to reduce the line spectra by improving the acoustic stealth of marine vessels. A multi-degree-freedom (MDF) nonlinear vibration isolation system (NVIS) system is setup by the experiment and finite element method. The model is established with finite element method. The results show that the behavior of the device gradually varies from period bifurcation into chaotic state and the line spectrum is changed from single spectral structure into broadband spectral structure. It is concluded that chaotic vibration isolation is preferable contrasted on line spectra isolation.

Numerical investigation on multi-degree-freedom nonlinear chaotic vibration isolation

Guoping Jiang,Weijun Tao 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.4

A chaotic vibration isolation system is designed according to the chaotic vibration theory in thispaper. The strong nonlinearity is generated by the system. Line spectra in the radiated noise maybe easily detected caused by marine vessels. It is Important to reduce the line spectra by improving the acoustic stealth of marine vessels. A multi-degree-freedom (MDF) nonlinear vibration isolation system (NVIS) system is setup by the experiment and finite element method. The model is established with finite element method. The results show that the behavior of the device gradually varies from period bifurcation into chaotic state and the line spectrum is changed from single spectral structure into broadband spectral structure.It is concluded that chaotic vibration isolation is preferable contrasted on line spectra isolation.

The obstacle-negotiation capability of rod-climbing robots and the improved mechanism design

Fengyu Xu,J. L Hu,Guoping Jiang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.7

To detect internal steel wire fractures in the cylindrical cable of cable-stayed or suspension bridges automatically in hazardous environmentsinstead of workers, a trilateral clamping-wheeled, rod-climbing robot is designed in this study. In line with this objective, thisstudy also introduces the climbing principle and mechanical structure of this robot (Model-1) and analyzes the static dynamic characteristicsof this mechanism. Furthermore, it establishes the mathematical models of the moving wheels during obstacle negotiation. This studyalso analyzes the relationships of main driving force and resistance with obstacle height to determine the obstacle-negotiation capabilityof the robot and the two main parameters that influence its obstacle negotiation performance, namely, wheel radius and positive pressure. The Model-1 structure was updated to a new climbing mechanism (Model-2) based on analysis results. Furthermore, the optimal anglesof the upper and lower supporting arms were obtained by building the static model of the new mechanism. Finally, Model-2 is superiorto Model-1 in terms of obstacle-negotiation capability and satisfies the requirements for suspended cable detection.

Dynamic performance of a cable with an inspection robot – analysis, simulation, and experiments

Fengyu Xu,Lei Wang,Xingsong Wang,Guoping Jiang 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.5

A special cable inspection robot is designed to inspect automatically the cables of a cable-stayed bridge. The free vibration equation of the cable-robot system is derived firstly to study the dynamic characteristics and safety performance of the system. Then, the effect of the robot on the cable natural frequency is discussed, and the dynamic response equation when a robot is climbing at a constant speed is deduced. Furthermore, the effect of the cable vibration on the robot’s climbing ability is studied. The natural frequency characteristics of the robot are analyzed and optimized to avoid the resonance between the cable and the robot, using a finite element model. Additionally,dynamic cable responses are simulated under different conditions wherein the robot mass are 10 and 200 kg, and the speeds are 0.2 and 0.3 m/s, respectively. At last, to demonstrate further the dynamic characteristics of the cable-robot system experimentally, cables are set up on the Junshan highway bridge over the Yangtze river. Similar experimental models of these cables are constructed, and vibration experiments are conducted to validate the theoretical calculation. The results show that a light robot has little effects on the cable vibration amplitude and vibration acceleration; this confirms the safety of the cable.

Electrospun PHBV/collagen composite nanofibrous scaffolds for tissue engineering

Meng, Wan,Kim, Se-Yong,Yuan, Jiang,Kim, Jung Chul,Kwon, Oh Hyeong,Kawazoe, Naoki,Chen, Guoping,Ito, Yoshihiro,Kang, Inn-Kyu Informa UK (TaylorFrancis) 2007 Journal of Biomaterials Science. Polymer Edition Vol.18 No.1

<P>Electrospinning has recently emerged as a leading technique for the formation of nanofibrous structures made of synthetic and natural extracellular matrix components. In this study, nanofibrous scaffolds were obtained by electrospinning a combination of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and type-I collagen in 1,1,1,3,3,3-hexafluoro-2-isopropanol (HIFP). The resulting fibers ranged from 300 to 600 nm in diameter. Their surfaces were characterized by attenuated total reflection Fourier transform infrared spectroscopy, electron spectroscopy for chemical analysis and atomic force microscopy. The PHBV and collagen components of the PHBV/collagen nanofibrous scaffold were biodegraded by PHB depolymerase and a type-I collagenase aqueous solution, respectively. The cell culture experiments indicated that the PHBV/collagen nanofibrous scaffold accelerated the adhesion and growth of NIH3T3 cells more effectively than the PHBV nanofibrous scaffold, thus making the former a good scaffold for tissue engineering.</P>

Active Fault Tolerant Control Scheme for Satellite Attitude Systems: Multiple Actuator Faults Case

Zhi-Feng Gao,Zepeng Zhou,Guoping Jiang,Mo-Shu Qian,Jin-Xing Lin 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

In this paper, an active fault tolerant control (FTC) design approach is proposed for the satellite attitude systems with exogenous disturbance and multiple actuator faults. Firstly, the nonlinear attitude system model of rigid satellite with multiple actuator faults is given. Next, an actuator fault diagnosis scheme, including a fault detection module and a fault estimation module, is given so as to detect the time of unknown actuator faults occurred and obtain their estimation values. Then, a terminal sliding mode-based fault tolerant attitude controller is designed using backstepping control technique, which guarantees that the closed-loop attitude systems of rigid satellite are asymptotically stable in the presence of multiple actuator faults. Numerical simulations illustrate the good performance of active FTC proposed in this study.

Prediction of Prostate Cancer Risk Stratification Based on A Nonlinear Transformation Stacking Learning Strategy

Xinyu Cao,Yin Fang,Chunguang Yang,Zhenghao Liu,Guoping Xu,Yan Jiang,Peiyan Wu,Wenbo Song,Hanshuo Xing,Xinglong Wu 대한배뇨장애요실금학회 2024 International Neurourology Journal Vol.28 No.1

Purpose: Prostate cancer (PCa) is an epithelial malignancy that originates in the prostate gland and is generally categorized into low, intermediate, and high-risk groups. The primary diagnostic indicator for PCa is the measurement of serum prostate-specific antigen (PSA) values. However, reliance on PSA levels can result in false positives, leading to unnecessary biopsies and an increased risk of invasive injuries. Therefore, it is imperative to develop an efficient and accurate method for PCa risk stratification. Many recent studies on PCa risk stratification based on clinical data have employed a binary classification, distinguishing between low to intermediate and high risk. In this paper, we propose a novel machine learning (ML) approach utilizing a stacking learning strategy for predicting the tripartite risk stratification of PCa. Methods: Clinical records, featuring attributes selected using the lasso method, were utilized with 5 ML classifiers. The outputs of these classifiers underwent transformation by various nonlinear transformers and were then concatenated with the lasso-selected features, resulting in a set of new features. A stacking learning strategy, integrating different ML classifiers, was developed based on these new features. Results: Our proposed approach demonstrated superior performance, achieving an accuracy of 0.83 and an area under the receiver operating characteristic curve value of 0.88 in a dataset comprising 197 PCa patients with 42 clinical characteristics. Conclusions: This study aimed to improve clinicians’ ability to rapidly assess PCa risk stratification while reducing the burden on patients. This was achieved by using artificial intelligence-related technologies as an auxiliary method for diagnosing PCa.