scholarly journals An Approach to Computing Multipoint Inversion and Multiray Surface Intersection on Parametric Surface

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Pei Jingyu ◽  
Wang Xiaoping ◽  
Zhang Leen
Keyword(s):  
High Speed ◽  
Initial Point ◽  
Iteration Process ◽  
Newton Iteration ◽  
Research Field ◽  
New Method ◽  
Parametric Surface ◽  
Surface Intersection ◽  
Arbitrary Precision ◽  
Main Ideas

This article presents a method for multipoint inversion and multiray surface intersection problem on the parametric surface. By combining tracing along the surface and classical Newton iteration, it can solve point inversion and ray-surface intersection issues concerning a large number of points or rays in a stable and high-speed way. What is more, the computation result can approximate to exact solutions with arbitrary precision because of the self-correction of Newton-Raphson iteration. The main ideas are adopting a scheme tracing along the surface to obtain a good initial point, which is close to the desired point with any prescribed precision, and conducting Newton iteration process with the point as a start point to compute desired parameters. The new method enhances greatly iterative convergence rate compared with traditional Newton’s iteration related methods. In addition, it has a better performance than traditional methods, especially in dealing with multipoint inversion and multiray surface intersection problems. The result shows that the new method is superior to them in both speed and stability and can be widely applied to industrial and research field related to CAD and CG.

Detecting and Determining the Characteristic Points on the Parametric Surface/Surface Intersection

1995 ◽  
Author(s):  
Xianglin Zeng ◽  
Qifu Wang ◽  
Ji Zhou ◽  
Jun Yu
Keyword(s):  
Characteristic Point ◽  
New Method ◽  
Parametric Surface ◽  
Initial Interval ◽  
Surface Modelling ◽  
Surface Intersection ◽  
Characteristic Points ◽  
Numeric Solution ◽  
Modelling System ◽  
Significant Point

Abstract In this paper we present a new method for detecting and determining characteristic points on the surface/surface intersection while marching along the intersections. The initial interval which contains a potential characteristic point is first determined by certain criteria, then a numeric solution of the significant point is obtained by the binary subdivision method. Based on these ideas, a new marching algorithm is constructed, and it has been implemented in a surface modelling system (SurfCADM V1.0). Examples are also presented for illustrating the capability of our algorithm.

A new method used for high speed pseudo-random code generating

2014 ◽  
Author(s):  
Zhanfeng Zhao ◽  
Dong Zhang ◽  
Zhiquan Zhou
Keyword(s):  
High Speed ◽  
New Method ◽  
Random Code

scholarly journals A New Method to Verify the Measurement Speed and Accuracy of Frequency Modulated Interferometers

2021 ◽  
Vol 11 (13) ◽  
pp. 5787
Author(s):  
Toan-Thang Vu ◽  
Thanh-Tung Vu ◽  
Van-Doanh Tran ◽  
Thanh-Dong Nguyen ◽  
Ngoc-Tam Bui
Keyword(s):  
Phase Change ◽  
High Speed ◽  
Measurement Accuracy ◽  
Slow Motion ◽  
New Method ◽  
Virtual Displacement ◽  
Electro Optic ◽  
Lock In ◽  
Speed And Accuracy ◽  
Electro Optic Modulator

The measurement speed and measurement accuracy of a displacement measuring interferometer are key parameters. To verify these parameters, a fast and high-accuracy motion is required. However, the displacement induced by a mechanical actuator generates disadvantageous features, such as slow motion, hysteresis, distortion, and vibration. This paper proposes a new method for a nonmechanical high-speed motion using an electro-optic modulator (EOM). The method is based on the principle that all displacement measuring interferometers measure the phase change to calculate the displacement. This means that the EOM can be used to accurately generate phase change rather than a mechanical actuator. The proposed method is then validated by placing the EOM into an arm of a frequency modulation interferometer. By using two lock-in amplifiers, the phase change in an EOM and, hence, the corresponding virtual displacement could be measured by the interferometer. The measurement showed that the system could achieve a displacement at 20 kHz, a speed of 6.08 mm/s, and a displacement noise level < 100 pm//√Hz above 2 kHz. The proposed virtual displacement can be applied to determine both the measurement speed and accuracy of displacement measuring interferometers, such as homodyne interferometers, heterodyne interferometers, and frequency modulated interferometers.

Effective Stripper-Holding on High Speed Precision Blanking of Electronic Machine Parts

2005 ◽  
Vol 6-8 ◽  
pp. 805-808
Author(s):  
F. Sekine
Keyword(s):  
Mechanical Model ◽  
High Speed ◽  
Thin Sheet ◽  
Dimensional Accuracy ◽  
New Method ◽  
Important Process ◽  
Sheet Metals ◽  
Progressive Dies ◽  
Machine Parts

The blanking of thin sheet metals using progressive dies is an important process on production of precision electronic machine parts. As a model of IC leadframe, an I-shaped and an Lshaped models were blanked and influences of blanking conditions on dimensional accuracy of blanked lead were examined. Furthermore, a mechanical model is proposed to explain the affect of the blanking conditions on product accuracy. In these days, more fine leads are required as electronic machines become more precise and accurate. It must be treated that leads are firmly held for blanking leadframes accurately. In this paper, an effective method of stripper holding leads strongly are discussed and a new method using newly designed stripper is proposed. Consequently the effect of it on lead accuracy is proved.

A New Method of Torque Compensation for High Speed Indexing Cam Mechanism

1999 ◽  
Vol 121 (2) ◽  
pp. 319-323 ◽  
Author(s):  
Teng Guilan ◽  
Fu Haibo ◽  
Zhou Weiyi
Keyword(s):  
Kinetic Energy ◽  
High Speed ◽  
Output Shaft ◽  
New Method ◽  
Linkage Mechanism ◽  
Energy Fluctuation ◽  
Positioning Accuracy ◽  
Input Shaft ◽  
Cam Mechanism

Severe vibration and poor positioning accuracy may occur in an indexing cam mechanism operating at a high speed. Torque fluctuation of the input shaft and the resulting fluctuation of kinetic energy of the mechanism may be the major cause of the vibration. In this paper a method is proposed to minimize the fluctuation by using a so-called “speed-varying flywheel” that produces an opposite kinetic energy fluctuation that can counteract the effect of the energy fluctuation. The flywheel is installed on the output shaft of an additional cam-linkage mechanism. The parameter of the cam-linkage mechanism is optimized. An example is given to demonstrate the effectiveness of this method.

A FE Modelling Method for the Thermal Characteristics of High-Speed Motorized Spindle

2016 ◽  
Vol 693 ◽  
pp. 3-10
Author(s):  
Jia Rui Wang ◽  
Ping Fa Feng ◽  
Zhi Jun Wu ◽  
Ding Wen Yu ◽  
Jian Fu Zhang
Keyword(s):  
High Speed ◽  
Thermal Contact ◽  
Convective Heat Transfer Coefficient ◽  
Thermal Characteristics ◽  
Experimental System ◽  
Research Field ◽  
Motorized Spindle ◽  
Fe Modelling ◽  
Simulation Accuracy ◽  
Modelling Method

Finite element simulation is an effective method to study the thermal characteristics of high-speed motorized spindle, how to improve the simulation accuracy has become the key point of this research field. This paper presents a FEA method using ANSYS to precisely predict the thermal characteristics of high-speed spindle. Firstly, the heating and cooling characteristics of high-speed spindle are analyzed, main heating source, convective heat transfer coefficient, and thermal contact resistance are calculated. Secondly, FEA model of the machine center is built, the temperature field and thermal deformation of the spindle system are simulated. Thirdly, an experimental system to test thermal characteristics is designed, simulation results are compared with the experimental results. The result shows that the simulation errors are controlled in a relative low range, the FE modelling method can precisely predict the thermal characteristics of the motorized spindle.

A new method for heat measurement during high speed machining

Measurement ◽  
2012 ◽  
Vol 45 (8) ◽  
pp. 2135-2140 ◽  
Author(s):  
B. Davoodi ◽  
H. Hosseinzadeh
Keyword(s):  
High Speed ◽  
New Method ◽  
High Speed Machining ◽  
Heat Measurement

A New Method for Determining the Effects of Structural Flexibility on the Dynamic Behavior of High Speed Mechanisms

1999 ◽  
Author(s):  
L. Yuan ◽  
J. Rastegar
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
New Method ◽  
Structural Flexibility ◽  
Structural Elements ◽  
Dynamics Modeling ◽  
Linkage Mechanism ◽  
Active Materials ◽  
Response Characteristics ◽  
Four Bar Linkage

Abstract A new method for the analysis of the effects of structural flexibility on the dynamic behavior of mechanical systems is presented. The developed method is in most part based on “tracing” the “propagation” of the effects of the high frequency motion requirements on the dynamic response characteristics of machines with structural flexibilities, particularly those with closed-loop kinematic structures. The method considers the “filtering” action of structural elements with flexibility. Such filtering of higher frequency motions is shown to have a predictable effect on the steady state motion of such mechanical system. The main advantage of the developed method is that the effects of such flexibilities can be determined without the need to perform the usual dynamics modeling and computer simulations. The method is shown to be very simple and readily implementable. The method is applied to a four-bar linkage mechanism with a longitudinally flexible coupler link. The obtained results are shown to be highly accurate as compared to those obtained by computer simulation. The application of the method to systematic design of machines with structural flexibility for high speed and precision operation, optimal integration of smart (active) materials into the structure of such machines, and some related issues are discussed.

scholarly journals Exploring the Mechanisms of the Spatiotemporal Invasion of Tuta absoluta in Asia

Agriculture ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 124 ◽  
Author(s):  
Ritter A. Guimapi ◽  
Ramasamy Srinivasan ◽  
Henri E. Tonnang ◽  
Paola Sotelo-Cardona ◽  
Samira A. Mohamed
Keyword(s):  
High Speed ◽  
Real Life ◽  
Initial Point ◽  
The Philippines ◽  
Control Measures ◽  
Tuta Absoluta ◽  
Invasive Pest ◽  
Spread Pattern ◽  
People Movement ◽  
Not At Risk

International crop exchange always brings the risk of introducing pests to countries where they are not yet present. The invasive pest Tuta absoluta (Meyrick 1917), after taking just a decade (2008–2017) to invade the entire Africa continent, is now continuing its expansion in Asia. From its first detection in Turkey (2009), the pest has extended its range of invasion at a very high speed of progression to the southeast part of Asia. This study adopted the cellular automata modelling method used to successfully predict the spatiotemporal invasion of T. absoluta in Africa to find out if the invasive pest is propagating with a similar pattern of spread in Asia. Using land cover vegetation, temperature, relative humidity and the natural flight ability of Tuta absoluta, we simulated the spread pattern considering Turkey as the initial point in Asia. The model revealed that it would take about 20 years for the pest to reach the southeast part of Asia, unlike real life where it took just about 10 years (2009–2018). This can be explained by international crop trade, especially in tomatoes, and movement of people, suggesting that recommendations and advice from the previous invasion in Europe and Africa were not implemented or not seriously taken into account. Moreover, some countries like Taiwan and the Philippines with suitable environmental condition for the establishment of T. absoluta are not at risk of natural invasion by flight, but quarantine measure must be put in place to avoid invasion by crop transportation or people movement. The results can assist policy makers to better understand the different mechanisms of invasion of T. absoluta in Asia, and therefore adjust or adapt control measures that fit well with the dynamic of the invasive pest observed.

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