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An investigation into the vibration of harmonic drive systems
M. Masoumi, H. Alimohammadi
《机械工程前沿(英文)》 2013年 第8卷 第4期 页码 409-419 doi: 10.1007/s11465-013-0275-5
Harmonic drive systems are precise and specific transmission gear systems which are beneficial in terms of the high transmission ratio and almost zero backlash. These inherent and spectacular properties result in using this mechanism in robotic and space sciences where the precision and lightwieght play an important role. This paper presents a vibration analysis of harmonic drive systems using the shell theory. Equations of vibration for the flexspline and the circular spline of the system are derived and used to find the natural frequencies for both parts and, moreover, vibration response of the system under the operating condition is calculated. Also, obtained vibration equations are utilized to study the effects of different involved parameters such as the geometry of the flexspline and its gear tooth, eccentricity, and unbalancing on the vibrational behavior of the system.
关键词: harmonic drive system strain wave gearing mechanism vibration analysis natural frequencies
《机械工程前沿(英文)》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0674-6
关键词: harmonic drive meshing flexibility matrix meshing force loading backlash flexspline contact analysis
Evaluation of the harmonic scalpel in open surgery for abdominal aortic aneurysm
null
《医学前沿(英文)》 2012年 第6卷 第1期 页码 85-88 doi: 10.1007/s11684-012-0174-x
The harmonic scalpel is a hemostatic device primarily designed for use in laparoscopic surgery. During the last few years, many surgeons have begun to use the harmonic scalpel in open surgery. Several papers have cited the benefits of the device compared with conventional knot-tying techniques; however, no evidence showing the advantages of using the harmonic scalpel in complicated abdominal aortic aneurysm (AAA) surgery has been presented. The aim of the present study is to determine the value of the harmonic scalpel in open operation for AAA. A total of 153 patients who underwent open surgery for AAA at the Department of Vascular Surgery of Guangdong General Hospital, China between January 2001 and December 2010, were retrospectively analyzed. Open surgery performed with the harmonic scalpel on 105 patients was compared with open operation using conventional knot-tying techniques on 48 patients. The operative time, intraoperative blood loss, total postoperative drainage fluid volumes, hospital stay, and postoperative complications between the two groups were compared. The harmonic scalpel group was associated with a shorter operation time (113.2±23.6 min vs. 232.1±39.2 min, P<0.01) and lower intraoperative blood loss (126.1±96.6 ml vs. 592.1±207.2 ml, P<0.01). Postoperative drainage fluid volumes were greater in the conventional surgery group than in the harmonic scalpel group (702.1±192.8 ml vs. 198.5±97.4 ml, P<0.01). The hospital stay was shorter for the harmonic scalpel group than for the conventional surgery group (10.7±3.3 d vs. 16.5±4.7 d, P<0.05). No differences between the postoperative complications or hospital mortality of the two groups were found. The harmonic scalpel is a safe and minimally invasive tool in open surgery for AAA and is associated with shorter operative time, shorter hospital stay, and lower intraoperative blood loss and postoperative drainage fluid volumes compared with conventional knot-tying techniques.
关键词: abdominal aortic aneurysm harmonic scalpel minimally invasive
Electromagnetic interference modeling and suppression techniques in variable-frequency drive systems
Le YANG, Shuo WANG, Jianghua FENG
《机械工程前沿(英文)》 2018年 第13卷 第3期 页码 329-353 doi: 10.1007/s11465-018-0466-1
Electromagnetic interference (EMI) causes electromechanical damage to the motors and degrades the reliability of variable-frequency drive (VFD) systems. Unlike fundamental frequency components in motor drive systems, high-frequency EMI noise, coupled with the parasitic parameters of the trough system, are difficult to analyze and reduce. In this article, EMI modeling techniques for different function units in a VFD system, including induction motors, motor bearings, and rectifier-inverters, are reviewed and evaluated in terms of applied frequency range, model parameterization, and model accuracy. The EMI models for the motors are categorized based on modeling techniques and model topologies. Motor bearing and shaft models are also reviewed, and techniques that are used to eliminate bearing current are evaluated. Modeling techniques for conventional rectifier-inverter systems are also summarized. EMI noise suppression techniques, including passive filter, Wheatstone bridge balance, active filter, and optimized modulation, are reviewed and compared based on the VFD system models.
关键词: variable-frequency drive (VFD) electromagnetic interference (EMI) motor drive modeling EMI noise suppression
Multi-harmonic forced vibration and resonance of simple beams to moving vehicles
《结构与土木工程前沿(英文)》 页码 981-993 doi: 10.1007/s11709-023-0979-5
关键词: forced vibration linear Euler beam moving load harmonic structure frequency modulation end restraints
Power control of dual-motor electric drive for tracked vehicles
Yuan ZOU, Chengning ZHANG, Fengchun SUN, Jingbo WU,
《机械工程前沿(英文)》 2010年 第5卷 第1期 页码 67-72 doi: 10.1007/s11465-009-0059-0
SCRaMbLE drive application of synthetic yeast genome
Jin Jin, Yuan Ma, Duo Liu
《化学科学与工程前沿(英文)》 2018年 第12卷 第4期 页码 832-834 doi: 10.1007/s11705-018-1749-0
Effects of elastic support on the dynamic behaviors of the wind turbine drive train
Shuaishuai WANG, Caichao ZHU, Chaosheng SONG, Huali HAN
《机械工程前沿(英文)》 2017年 第12卷 第3期 页码 348-356 doi: 10.1007/s11465-017-0420-7
The reliability and service life of wind turbines are influenced by the complex loading applied on the hub, especially amidst a poor external wind environment. A three-point elastic support, which includes the main bearing and two torque arms, was considered in this study. Based on the flexibilities of the planet carrier and the housing, a coupled dynamic model was developed for a wind turbine drive train. Then, the dynamic behaviors of the drive train for different elastic support parameters were computed and analyzed. Frequency response functions were used to examine how different elastic support parameters influence the dynamic behaviors of the drive train. Results showed that the elastic support parameters considerably influenced the dynamic behaviors of the wind turbine drive train. A large support stiffness of the torque arms decreased the dynamic response of the planet carrier and the main bearing, whereas a large support stiffness of the main bearing decreased the dynamic response of planet carrier while increasing that of the main bearing. The findings of this study provide the foundation for optimizing the elastic support stiffness of the wind turbine drive train.
关键词: wind turbine drive train elastic support dynamic behavior frequency response function
Design and analysis of a new high frequency double-servo direct drive rotary valve
Muzhi ZHU,Shengdun ZHAO,Jingxiang LI
《机械工程前沿(英文)》 2016年 第11卷 第4期 页码 344-350 doi: 10.1007/s11465-016-0406-x
Researchers have investigated direct drive valve for many years to solve problems, such as fluid force imbalance and switching frequency. The structure of the rotary valve has received considerable research interest because of its favorable dynamic properties and simple structure. This paper studied the high frequency double-servo direct drive rotary valve (DDRV), and proposed a novel structure and drive method satisfying high reversing frequency and adequate quantity of flow. Servo motors are integrated into the valve by the innovative structure, which is designed to equilibrate the unbalanced radial fluid force with the symmetric distributed oil ports. Aside from the fast reversing function of the valve, the DDRV presented high performance in linearity of the flow quantity and valve opening as a result of the fan-shaped flow ports. In addition, a computational fluid dynamics (CFD) method based on Fluent was conducted to verify the flux regulation effect of the height change of the adjustable boss.
关键词: direct drive rotary valve computational fluid dynamics (CFD) flow regulation
Mohammad Javad REZVANIL, Mohammad Hossein KARGARNOVIN, Davood YOUNESIAN
《机械工程前沿(英文)》 2011年 第6卷 第4期 页码 409-418 doi: 10.1007/s11465-011-0245-8
The response of an infinite Timoshenko beam subjected to a harmonic moving load based on the third-order shear deformation theory (TSDT) is studied. The beam is made of laminated composite, and located on a Pasternak viscoelastic foundation. By using the principle of total minimum potential energy, the governing partial differential equations of motion are obtained. The solution is directed to compute the deflection and bending moment distribution along the length of the beam. Also, the effects of two types of composite materials, stiffness and shear layer viscosity coefficients of foundation, velocity and frequency of the moving load over the beam response are studied. In order to demonstrate the accuracy of the present method, the results TSDT are compared with the previously obtained results based on first-order shear deformation theory, with which good agreements are observed.
关键词: timoshenko composite beam pasternak viscoelastic foundation third-order shear deformation theory (TSDT) harmonic moving load
Hierarchical parameter estimation of DFIG and drive train system in a wind turbine generator
Xueping PAN, Ping JU, Feng WU, Yuqing JIN
《机械工程前沿(英文)》 2017年 第12卷 第3期 页码 367-376 doi: 10.1007/s11465-017-0429-y
A new hierarchical parameter estimation method for doubly fed induction generator (DFIG) and drive train system in a wind turbine generator (WTG) is proposed in this paper. Firstly, the parameters of the DFIG and the drive train are estimated locally under different types of disturbances. Secondly, a coordination estimation method is further applied to identify the parameters of the DFIG and the drive train simultaneously with the purpose of attaining the global optimal estimation results. The main benefit of the proposed scheme is the improved estimation accuracy. Estimation results confirm the applicability of the proposed estimation technique.
关键词: wind turbine generator DFIG drive train system hierarchical parameter estimation method trajectory sensitivity technique
Effect of harmonic distortion on electric energy meters of different metrological principles
Illia DIAHOVCHENKO, Vitalii VOLOKHIN, Victoria KUROCHKINA, Michal ŠPES, Michal KOSTEREC
《能源前沿(英文)》 2019年 第13卷 第2期 页码 377-385 doi: 10.1007/s11708-018-0571-1
关键词: current distortion electric energy meter harmonics power quality
《农业科学与工程前沿(英文)》 2023年 第10卷 第4期 页码 541-552 doi: 10.15302/J-FASE-2023518
Agricultural non-point source pollution is increasingly an important issue affecting surface water quality. Currently, the majority of the studies on nitrogen loss have focused on the agricultural field scale, however, the response of surface water quality at the watershed scale into the nitrogen loss at the field scale is poorly understood. The present study systematically reviewed the critical processes and major factors that nitrogen transport from farm fields to surface water bodies. The critical processes of farmland nitrogen entering surface water bodies involve the processes of nitrogen transport from farmland to ditches and the transformation processes of nitrogen during migration in ditches/rivers. Nitrogen transport from farmland to ditches is one of the prerequisites and critical processes for farmland nitrogen transport to surface water bodies. The transformation of nitrogen forms in ditches/rivers is an intermediate process in the migration of nitrogen from farmland to surface water bodies. Nitrogen loss from farmland is related to soil storage and exogenous inputs. Therefore, nitrogen input management should not only consider the current input, but also the contribution of soil storage due to the historical surpluses. Ditches/rivers have a strong retention capacity for nitrogen, which will significantly affect the process of farmland nitrogen entering surface water bodies. The factors affecting nitrogen transformation in river/ditches can be placed in four categories: (1) factors affecting hydraulic retention time, (2) factors affecting contact area, (3) factors affecting biological activity, and (4) forms and amount of nitrogen loading to river/ditches. Ditch systems are more biologically (including plants and microbes) active than rivers with biological factors having a greater influence on nitrogen transformation. When developing pollution prevention and control strategies, ecological ditches can be constructed to increase biological activity and reduce the amount of surplus nitrogen entering the water body. The present research should be valuable for the evaluation of environment impacts of nitrogen loss and the non-point source pollution control.
关键词: nitrogen loss from soil transformation farm field scale watershed scale
System construction of a four-side primary permanent-magnet linear motor drive mechanical press
Jintao LIANG, Zhengfeng MING, Peida LI
《机械工程前沿(英文)》 2020年 第15卷 第4期 页码 600-609 doi: 10.1007/s11465-020-0597-z
关键词: mechanical press direct drive primary permanent-magnet linear motor (PPMLM) servo system active disturbance rejection control (ADRC) prototype experiment
Novel drive mechanism for in-tube micro robots
CHEN Yangzhi, XING Guangquan, PENG Xuefei, LIU Wenguang, YAO Huaping
《机械工程前沿(英文)》 2007年 第2卷 第1期 页码 94-98 doi: 10.1007/s11465-007-0016-8
关键词: limited conventional transmission maximal transmission upright calculation
标题 作者 时间 类型 操作
Meshing stiffness property and meshing status simulation of harmonic drive under transmission loading
期刊论文
Electromagnetic interference modeling and suppression techniques in variable-frequency drive systems
Le YANG, Shuo WANG, Jianghua FENG
期刊论文
Power control of dual-motor electric drive for tracked vehicles
Yuan ZOU, Chengning ZHANG, Fengchun SUN, Jingbo WU,
期刊论文
Effects of elastic support on the dynamic behaviors of the wind turbine drive train
Shuaishuai WANG, Caichao ZHU, Chaosheng SONG, Huali HAN
期刊论文
Design and analysis of a new high frequency double-servo direct drive rotary valve
Muzhi ZHU,Shengdun ZHAO,Jingxiang LI
期刊论文
Dynamic analysis of composite beam subjected to harmonic moving load based on the third-order shear deformation
Mohammad Javad REZVANIL, Mohammad Hossein KARGARNOVIN, Davood YOUNESIAN
期刊论文
Hierarchical parameter estimation of DFIG and drive train system in a wind turbine generator
Xueping PAN, Ping JU, Feng WU, Yuqing JIN
期刊论文
Effect of harmonic distortion on electric energy meters of different metrological principles
Illia DIAHOVCHENKO, Vitalii VOLOKHIN, Victoria KUROCHKINA, Michal ŠPES, Michal KOSTEREC
期刊论文
CRITICAL PROCESSES AND MAJOR FACTORS THAT DRIVE NITROGEN TRANSPORT FROM FARMLAND TO SURFACE WATER BODIES
期刊论文
System construction of a four-side primary permanent-magnet linear motor drive mechanical press
Jintao LIANG, Zhengfeng MING, Peida LI
期刊论文