Determination of the Instantaneous Initial Contact Point on a Parallel Gripper Using a Multi Input Fuzzy Rules Emulated Network Controller with Feedback from Ultrasonic and Force Sensors

2013 ◽  
pp. 261-272 ◽  
Author(s):  
César Navarro ◽  
Chidentree Treesatayapun ◽  
Arturo Baltazar
Keyword(s):  
Contact Point ◽  
Fuzzy Rules ◽  
Force Sensors ◽  
Initial Contact ◽  
Network Controller

Using Indentation and Intra-Vascular Ultrasound to Measure Arterial Response

2000 ◽  
Vol 662 ◽  
Author(s):  
P.M. Anderson ◽  
E.N. Glaser ◽  
A.I. Veress ◽  
G.M. Pharr ◽  
D.G. Vince ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Contact Point ◽  
Accurate Determination ◽  
Initial Contact ◽  
Vascular Ultrasound ◽  
Internal Dissipation ◽  
Microindentation Technique ◽  
Micro Indentation

AbstractTwo alternatives to standard tensile testing of arteries are discussed. The first involves inflation of arteries and simultaneous measurement of radial displacement with intra-vascular ultrasound (IVUS). The second involves the measurement of load versus displacement during micro-indentation of the intimal surface. The IVUS technique is used to study the nonlinear stiffening of porcine coronaries during inflation and, ultimately, it may provide a method to determine mechanical properties in vivo. Processing of the IVUS data relies on accurate determination of the luminal/intimal and medial/advential boundaries during inflation. The microindentation technique is used to study the effect of loading rate on tissue stiffness, recovery, and internal dissipation. Ultimately, this technique may provide a method to measure local mechanical properties in the vicinity of an atherosclerotic plaque, for example. Accurate determination of the initial contact point between the indenter and intima is required, however. The techniques appear to successfully capture significant, nonlinear, time-dependent properties of arterial tissue.

Spatial Kinematic Analysis of Threaded Fastener Assembly

2005 ◽  
Vol 128 (1) ◽  
pp. 116-127 ◽  
Author(s):  
Stephen Wiedmann ◽  
Bob Sturges
Keyword(s):  
Design Space ◽  
Compliant Mechanisms ◽  
Contact Point ◽  
Three Dimensional ◽  
Vertical Movement ◽  
Initial Contact ◽  
Geometric Problem ◽  
Intelligent Sensor ◽  
Contact State ◽  
Contact Points

Compliant mechanisms for rigid part mating exist for prismatic geometries. A few instances are known of mechanisms to assemble screw threads. A comprehensive solution to this essentially geometric problem comprises at least three parts: parametric equations for nut and bolt contact in the critical starting phase of assembly, the possible space of motions between these parts during this phase, and the design space of compliant devices which accomplish the desired motions in the presence of friction and positional uncertainty. This work concentrates on the second part in which the threaded pair is modeled numerically, and contact tests are automated through software. Tessellated solid models were used during three-dimensional collision analysis to enumerate the approximate location of the initial contact point. The advent of a second contact point presented a more constrained contact state. Thus, the bolt is rotated about a vector defined by the initial two contact points until a third contact location was found. By analyzing the depth of intersection of the bolt into the nut as well as the vertical movement of the origin of the bolt reference frame, we determined that there are three types of contacts states present: unstable two-point, quasi-stable two-point, stable three point. The space of possible motions is bounded by these end conditions which will differ in detail depending upon the starting orientations. We investigated all potential orientations which obtain from a discretization of the roll, pitch, and yaw uncertainties, each of which has its own set of contact points. From this exhaustive examination, a full contact state history was determined, which lays the foundation for the design space of either compliant mechanisms or intelligent sensor-rich controls.

Nanoindentation Method for Determining the Initial Contact and Adhesion Characteristics of Soft Polydimethylsiloxane

2005 ◽  
Vol 20 (8) ◽  
pp. 2004-2011 ◽  
Author(s):  
Yifang Cao ◽  
Dehua Yang ◽  
Wole Soboyejoy
Keyword(s):  
Indentation Depth ◽  
Contact Point ◽  
Nonlinear Least Squares ◽  
Soft Materials ◽  
Work Of Adhesion ◽  
Contact Radius ◽  
Initial Contact ◽  
Combined Use ◽  
Fitting In ◽  
Load Indentation

In this paper, we present a method for determining the initial contact point and nanoindentation load–indentation depth characteristics for soft materials. The method is applied to the prediction of the load–indentation depth characteristics of polydimethylsiloxane. It involves the combined use of Johnson–Kendall–Roberts and Maugis–Dugdale adhesion theories and nonlinear least squares fitting in the determination of the initial contact point, the transition parameter, and the contact radius at zero contact load. The elastic modulus and the work of adhesion are also extracted from the load–indentation depth curves.

Rationalized approach to the determination of contact point in force-distance curves: Application to polymer brushes in salt solutions and in water

2010 ◽  
pp. NA-NA ◽  
Author(s):  
Kathryn A. Melzak ◽  
Susana Moreno-Flores ◽  
Kai Yu ◽  
Jayachandran Kizhakkedathu ◽  
José L. Toca-Herrera
Keyword(s):  
Polymer Brushes ◽  
Contact Point ◽  
Salt Solutions

A novel operation approach to determine initial contact point for tooth contact analysis with errors of spiral bevel and hypoid gears

2017 ◽  
Vol 109 ◽  
pp. 155-170 ◽  
Author(s):  
Han Ding ◽  
Yuansheng Zhou ◽  
Jinyuan Tang ◽  
Jue Zhong ◽  
Zhenyu Zhou ◽  
...  
Keyword(s):  
Contact Point ◽  
Contact Analysis ◽  
Initial Contact ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Hypoid Gears ◽  
Spiral Bevel

Determination of the Instantaneous Radius of Curvature of a Cam at the Contact Point with a Flat Follower Moving Orthogonally

1994 ◽  
Vol 208 (2) ◽  
pp. 147-149 ◽  
Author(s):  
R Stone ◽  
H J Leonard
Keyword(s):  
Contact Point ◽  
Radius Of Curvature ◽  
Approximate Analysis

A means of calculating the exact radius of curvature is derived for a cam in contact with a flat follower. A comparison is then made with a widely used approximate analysis.

Design and Manufacture of Spiral Bevel Gears With Reduced Transmission Errors

2008 ◽  
Author(s):  
V. Simon
Keyword(s):  
Contact Point ◽  
Tooth Surface ◽  
Initial Contact ◽  
Generation Process ◽  
Polynomial Functions ◽  
Spiral Bevel Gears ◽  
Transmission Errors ◽  
Bevel Gears ◽  
Spiral Bevel ◽  
Two Sides

A method for the determination of the optimal polynomial functions for the conduction of machine-tool setting variations in pinion teeth finishing in order to reduce the transmission errors in spiral bevel gears is presented. Polynomial functions of order up to five are applied to conduct the variation of the cradle radial setting and of the cutting ratio in the process for pinion teeth generation. Two cases were investigated: in the first case the coefficients of the polynomial functions are constant throughout the whole generation process of one pinion tooth-surface, in the second case the coefficients are different for the generation of the pinion tooth-surface on the two sides of the initial contact point. The obtained results have shown that by the use of two different fifth-order polynomial functions for the variation of the cradle radial setting for the generation of the pinion tooth-surface on the two sides of the initial contact point, the maximum transmission error can be reduced by 81%. By the use of the optimal modified roll, this reduction is 61%. The obtained results have also shown that by the optimal variation of the cradle radial setting, the influence of misalignments inherent in the spiral bevel gear pair and of the transmitted torque on the increase of transmission errors can be considerably reduced.

Application of the Theory of Envelope to the Determination of Camoid Profiles With Translating Followers

1992 ◽  
Author(s):  
Der Min Tsay ◽  
Guan Shyong Hwang
Keyword(s):  
Simple Procedure ◽  
Contact Point ◽  
Machining Process ◽  
Analytical Expression ◽  
Numerical Example ◽  
Pressure Angle ◽  
Independent Parameters

Abstract A new, simple procedure employing the theory of envelope for a family of surfaces with two independent parameters to determine the profiles of camoids with translating spherical followers is presented. Given the follower motion program, the method enables the camoid surface coordinates to be easily generated in an analytical expression. The results are then compared to those obtained by utilizing the principle of contact point between the camoid and the follower surfaces. The pressure angle is analyzed, and the cutter paths required in the machining process are also produced. A numerical example is given to illustrate the application of the approach.

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