Kinematic Geometry Description of a Line With Four Positions and Its Application in Dimension Synthesis of Spatial Linkage

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Song Lin ◽  
Hanchao Wang ◽  
Yu Zhang ◽  
Jingyu Jiang
Keyword(s):  
Synthesis Method ◽  
Projection System ◽  
Geometric Characteristics ◽  
Geometric Problems ◽  
Kinematic Geometry ◽  
Plane Projection ◽  
Synthesis Procedure ◽  
Spatial Linkages ◽  
Geometric Relationship ◽  
Geometric Elements

Abstract In the dimension synthesis of the spatial linkages, the geometric characteristics of floating links in mechanisms reveal the geometric relationship between the motion task and the dimensions of the mechanisms. In order to establish the kinematic geometry rules corresponding to the motion of the floating link, this paper transforms the kinematic problems of geometric elements on the floating link into geometric problems and uses the geometric procedure to solve the spatial linkages synthesis problem with four given positions. In a previous work, we have extracted the kinematic geometry rules of a line with two and three positions. However, as the number of task positions increases, the kinematic characteristics representing the position transformation become more complicated. The method proposed in this paper extends the previous work to four given positions and builds up the geometric relationships among the kinematic rules for two, three, and four positions. The establishment of this geometric relationship is helpful to unify the synthesis procedure of synthesis problems with different number of positions. After that, the two-plane projection system and the transformation of projection are introduced to establish a procedural graphical synthesis method.

Geometric Method of Spatial Linkages Synthesis for Function Generation With Three Finite Positions

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Song Lin ◽  
Hanchao Wang ◽  
Jingshuai Liu ◽  
Yu Zhang
Keyword(s):  
Geometric Model ◽  
Synthesis Method ◽  
Geometric Method ◽  
Synthesis Process ◽  
Projection System ◽  
Function Generation ◽  
Kinematic Inversion ◽  
Spatial Geometry ◽  
Plane Projection ◽  
Spatial Linkages

This paper presents a geometric method as a unified synthesis process of function generation for spatial linkages. The synthesis method utilizes the mapping relationship between spatial kinematic geometric model and two-plane projection system to transform the problem from spatial geometry to plane geometry. In this way, the synthesis process of mechanisms can be simplified through the corresponding transformation. Afterward, the line-guidance model is built up. Combining the kinematic inversion in two-plane projection system, this model can be used to realize the spatial linkages synthesis for function generation with three finite positions. Finally, revolute–sphere–sphere–revolute (RSSR) and revolute–sphere–sphere–prism (RSSP) mechanisms are offered to illustrate the application of this method.

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

Design of Nonlinear Rotational Stiffness Using a Noncircular Pulley-Spring Mechanism

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Bongsu Kim ◽  
Ashish D. Deshpande
Keyword(s):  
Inverted Pendulum ◽  
Synthesis Method ◽  
Gravity Compensation ◽  
Passive Torque ◽  
Double Exponential ◽  
Torque Generation ◽  
Synthesis Procedure ◽  
Decomposition Experiments ◽  
Spring Mechanism ◽  
The Masses

We present a new methodology for designing a nonlinear rotational spring with a desired passive torque profile by using a noncircular pulley-spring mechanism. A synthesis procedure for the shape of the noncircular pulley is presented. The method is based on an infinitesimal calculus approach that leads to an analytical solution, and the method is extended to address practical design issues related to the cable routing. Based on the synthesis method, an antagonistic spring configuration is designed for bilateral torque generation and is designed such that there is no slack in the routing cables. Two design examples are presented, namely, double exponential torque generation and gravity compensation for an inverted pendulum. Experiments with a mechanism for gravity compensation of an inverted pendulum validate our approach. We extend our approach to generate nonlinear torques at two joints by introducing the concept of torque decomposition. Experiments with a two-link robotic arm show that the gravitational forces from the masses on each link are accurately compensated for with our noncircular pulley-spring mechanisms.

Further Investigation of Multifacet Drills (MFD’s)—Mathematical Models, Methods of Grinding, and Computer Plotting

1984 ◽  
Vol 106 (4) ◽  
pp. 313-324 ◽  
Author(s):  
L. H. Chen ◽  
S. M. Wu
Keyword(s):  
Mathematical Models ◽  
Computer Aided Design ◽  
Coordinate Transformations ◽  
Geometric Characteristics ◽  
Computer Aided ◽  
Aided Design ◽  
Geometric Elements ◽  
Future Work

The geometric characteristics of nine representative Multifacet Drills (MFD’s) are summarized. Mathematical models of the various component surfaces are derived and analyzed using coordinate transformations. The mathematical models of the geometric elements are used to deduce appropriate grinding methods. Computer plots of MFD’s are also presented to check the mathematical models and to lay a foundation for future work on computer-aided design (CAD) of MFD’s.

A Negative Impedance Approach to the Design Synthesis and Control of Multi-Energy Active Elements

2005 ◽  
Author(s):  
Thomas J. Connolly
Keyword(s):  
Control System ◽  
Synthesis Method ◽  
Design Tool ◽  
Electric Motors ◽  
Active Device ◽  
Design Synthesis ◽  
System Architectures ◽  
Active Devices ◽  
Synthesis Procedure ◽  
And Control

This paper covers the continuing development and experimental validation of our approach to the design synthesis and control of active devices in dynamic mechanical systems. Active devices, such as electric motors and hydraulic actuators, require an external power input. An innovative feature of this synthesis approach is the use of non-physically realizable elements, i.e., elements that have negative impedances, to model the behavior of an active device. The synthesis method also features the use of bond graphs, as they facilitate modeling of multi-energy systems and devices. The procedure applies to the design or retrofit of systems for which a desired frequency response is prescribed. The overarching goal of the synthesis method is to yield options for the general framework of a controllable, stable, and parameterizable system, using simulation-based techniques. Thus the procedure yields a stable “first draft” of the active device and its control system that can be handed off to respective specialists for further refinement. Simulation results indicate that design possibilities can include purely active devices or a hybrid combination of active and passive elements. In addition, atypical control system architectures, that depart from traditional PI, PD, or PID controllers can arise from the synthesis procedure. We describe validation experiments that use electric motors and rack-and-pinion systems to achieve active control of a quarter-vehicle test article. The results will provide insight into: (1) refining the synthesis procedure to include systems that feature continuous elements, (2) partially automating the synthesis procedure to make it a more versatile design tool, and (3) practical limitations of the synthesis method.

scholarly journals PEGylated Gold Nanoparticles with Interesting Plasmonic Properties Synthesized Using an Original, Rapid, and Easy-to-Implement Procedure

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ștefan Nițică ◽  
Alin Iulian Moldovan ◽  
Valentin Toma ◽  
Cristian Silviu Moldovan ◽  
Ioana Berindan-Neagoe ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Synthesis Method ◽  
Average Diameter ◽  
Liquid Droplets ◽  
Sers Substrates ◽  
New Class ◽  
One Step ◽  
Short Synthesis ◽  
Spherical Gold Nanoparticles ◽  
Synthesis Procedure

In this letter, we report a new, one-step, rapid, and easy-to-implement method for the synthesis of PEGylated gold nanoparticles (PEG-AuNPs) having a narrow size distribution and very interesting plasmonic properties. Unmodified polyethylene glycol molecules with a molecular weight of 1000 g/mole (PEG1000) have been employed as reducing and capping agents for the synthesis of spherical gold nanoparticles having an average diameter of 35 nm, within a few minutes. The novelty of the herein proposed synthesis method consists in the fact that the synthesis takes place inside of a sealed bottle flask containing aqueous solutions of PEG1000, tetrachloroauric(III) acid (HAuCl4), and NaOH, placed in the center of a microwave oven, capable to provide a very uniform temperature environment. It turned out that, during the very short synthesis procedure (2 minutes), PEG 1000 suffers an oxidative transformation in such a manner that its terminal alcohol groups (-CH2-OH) are transformed in carboxylate ones (-COO−). The as-synthesized PEG-AuNPs possess very interesting plasmonic properties allowing the detection of different molecules by means of SER spectroscopy performed either in liquid droplets or on solid spots. As a consequence of their unique plasmonic properties, the SER spectra acquired using this new class of nanoparticles on different molecules of interest (methylene blue, rhodamine 6G, doxorubicin, and 5-fluorouracil) are highly reproducible, making them ideal candidates for further use as SERS substrates.

scholarly journals The Influence Of Traffic Control Devices And Road Geometric Characteristics On Traffic Crushes Of Rular Two Lane Road

2021 ◽  
Vol 23 (11) ◽  
pp. 557-565
Author(s):  
Beimnet Hailemichael Lemena ◽  
◽  
Mengistu Mena Kuleno ◽  
Keyword(s):  
Data Collection ◽  
Traffic Control ◽  
Geometric Characteristic ◽  
Black Spot ◽  
Sampling Technique ◽  
Geometric Characteristics ◽  
Control Devices ◽  
Traffic Control Devices ◽  
Geometric Elements ◽  
Road Segments

Traffic accidents worldwide are among the most alarming phenomena because they cost billions of dollars due to death rates and property damage. In Ethiopia, the accident fatality rate is becoming one of the most serious problems. Specifically, in rural highways where in there are problems with traffic control device enforcement and geometric deficiencies. Gedeo zone faces a similar problem that is considered a hot issue on-road crash. This study focused on the influence of traffic control devices and geometric characteristic related to road crashes. The data collection method was a purposive sampling technique considering both primary and secondary data collection system. Direct field observations were conducted, such as field survey and recording of the existing road geometric elements to figure out which geometric element contributory to traffic crashes. The data collected from the police traffic was categorized by clustering the road into different road segments composed of the same geometric characteristics. The severity of the accident analyzed and identified the hazardous road sections (black spot area). The relationships of accident crash established between the influence of traffic control access devices and geometric elements on the crash reduction at the identified accident-prone areas. Further, the study used ANN modeling through engineering software MATLAB to analyze the weight age of crashes on specified road segments concerning geometric road characteristics. Hence, the gradient carriageway width, super-elevation, cross slope, gradient, sight distance number of the horizontal curve, number of vertical curves, and AADT are the major factors for the occurrence of both fatal and injury at the blackspot segment along the rural highway.

Towards the Design of Compliant Continuum Topologies With Geometric Nonlinearity

1999 ◽  
Author(s):  
A. Saxena ◽  
G. K. Ananthasuresh
Keyword(s):  
Finite Element ◽  
Linear Models ◽  
Compliant Mechanisms ◽  
Synthesis Method ◽  
Finite Element Models ◽  
Computationally Efficient ◽  
Mechanics Model ◽  
Nonlinear Design ◽  
Nonlinear Force ◽  
Synthesis Procedure

Abstract Optimal design methods that use continuum mechanics model for the deformation of the elastic body, are capable of generating suitable topology, shape, and dimensions of compliant mechanisms for desired specifications. Elastic analysis with linear finite element models employed in the synthesis procedures to date is not quantitatively accurate for large displacement situations. Also, the design specifications involving nonlinear force-deflection characteristics and generation of a curved path for the output port are difficult to realize with linear models. In this paper, the synthesis of compliant mechanisms is performed using geometrically nonlinear finite element models that appropriately account for large displacements. Frame elements are chosen for developing the synthesis procedure because of ease of implementation of the general approach and their ability to capture bending deformations. A computationally efficient method for computing the nonlinear design sensitivities is described. Examples are included to illustrate the usefulness of the synthesis method.

Kinematic Theory of Spatial Rack Drives

2016 ◽  
Vol 851 ◽  
pp. 265-272
Author(s):  
Emilia Abadjieva
Keyword(s):  
Vector Analysis ◽  
Spatial Motion ◽  
Geometric Characteristics ◽  
Kinematic Theory ◽  
Motion Transformation ◽  
Kinematic Geometry ◽  
Transformation Type ◽  
Analysis And Synthesis

On the basis of performed vector analysis of spatial motion transformation of type rotation into translation is created a kinematic theory of this transformation type. Using the kinematic theory the basic kinematic-geometric characteristics of spatial rack mechanisms, applicable to their analysis and synthesis are initiated. These characteristics: kinematic cylinder of level, kinematic relative helicoids, and kinematic pitch surfaces are elements of kinematic geometry of the spatial rack drives

Mechanical Error Analysis of Spatial Linkages

1978 ◽  
Vol 100 (4) ◽  
pp. 732-738 ◽  
Author(s):  
S. G. Dhande ◽  
J. Chakraborty
Keyword(s):  
Probability Density Function ◽  
Probability Density ◽  
Density Function ◽  
Experimental Information ◽  
Output Error ◽  
Revolute Joints ◽  
Analysis And Synthesis ◽  
Mean And Variance ◽  
Synthesis Procedure ◽  
Spatial Linkages

In this paper the effect on the output error of function-generating spatial linkages due to tolerances on the links and clearances at the hinges is analyzed. Tolerances on link lengths are assumed to be normally distributed. For the clearance error in spherical, prismatic, and revolute joints, uniform probability density function is assumed. However, the models developed and the analysis procedure proposed can be used for any other probability density function including the mean and variance values derived from experimental information. A synthesis procedure to allocate tolerances and clearances on different members of linkages to restrict the output error within specified units is developed. Results of analysis and synthesis are given for two example problems involving RRSS and RSSR mechanisms.

Sign in / Sign up

Export Citation Format

Share Document