Kinematic Synthesis of Fiber Reinforced Soft Actuators in Parallel Combinations

2012 ◽  
Author(s):  
Joshua Bishop-Moser ◽  
Girish Krishnan ◽  
Charles Kim ◽  
Sridhar Kota
Keyword(s):  
Design Space ◽  
Parallel Kinematics ◽  
Fiber Reinforced ◽  
Kinematic Synthesis ◽  
Pick And Place ◽  
Parallel Configuration ◽  
Soft Actuators ◽  
Free Sets

Complex controlled motions, flexible surfaces, and minimal moving mass all drive the need for soft robots using fiber reinforced elastomer enclosures (FREEs) in a parallel configuration. This paper addresses the challenge of synthesizing a design with desired kinematics, as only small portions of the entire design space have been previously investigated. A systematic characterization of the kinematic freedom, constraint, and actuation directions of all circumferentially and longitudinally repeating fiber topologies is determined. The parallel kinematics is mapped for the combinations of actuators by determining the sets of mobilities necessary in the constituent members for all possible output motions. The kinematics of all possible parallel combinations for pairs and triangular triplets of FREEs are mapped. A graphical user interface (GUI) is presented, which allows a user to input a kinematic specification and generate all feasible FREE sets and their respective kinematics. With the entire design space mapped and easily accessible, a range of possible applications across a span of kinematic requirements becomes readily attainable. A case study is performed to verify the ability of the GUI to determine feasible FREE sets for a pick-and-place manipulator task.

Force and Hydraulic Displacement Amplification of Fiber Reinforced Soft Actuators

2013 ◽  
Author(s):  
Joshua Bishop-Moser ◽  
Girish Krishnan ◽  
Sridhar Kota
Keyword(s):  
Design Space ◽  
Virtual Work ◽  
Small Subset ◽  
Graphical Representations ◽  
High Power Density ◽  
Fiber Reinforced ◽  
Fluid Displacement ◽  
Fiber Reinforcements ◽  
Mckibben Actuators ◽  
Soft Actuators

Soft robots allow for complex continuum motions and shapes that conform to their environment. Using a fiber-reinforced elastomeric enclosure (FREE) driven by fluid provides a high power density, soft continuum actuator. While the force generation for a small subset of this structure known as McKibben actuators has been studied extensively, the force and moments generated by a wider set of fiber reinforcements have not been previously investigated. Using virtual work and kinematics derived from fiber inextensibility and fluid incompressibility, the force and moments for the entire design space of FREEs has been determined analytically. Graphical representations have been created, providing easy tools for synthesis and analysis of force and moments in all possible FREEs. The hydraulic displacement amplification, or volumetric transduction, of output motion to fluid displacement has also been determined using kinematics; this transduction gives an indication of stiffness of the structure. Graphical representations have also been created, providing a designer with an intuitive understanding of the behavior all FREE topologies.

TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

1988 ◽  
Vol 46 ◽  
pp. 738-739
Author(s):  
G. Das ◽  
R. E. Omlor
Keyword(s):  
Titanium Alloys ◽  
Reaction Zone ◽  
Carbon Layer ◽  
Fiber Reinforced ◽  
Reaction Products ◽  
Sic Fibers ◽  
Sic Fiber ◽  
The Matrix ◽  
Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

Integrating The Geophysical Characterization Of Seismic Thin Beds With Stochastic Reservoir Modeling: A Case Study From The Kutei Basin (Offshore Kalimantan, Indonesia)

2011 ◽  
Author(s):  
Giorgio Rocco Cavanna ◽  
Ernesto Caselgrandi ◽  
Elisa Corti ◽  
Alessandro Amato del Monte ◽  
Massimo Fervari ◽  
...  
Keyword(s):  
Reservoir Modeling ◽  
Geophysical Characterization

Failure Analysis of CDM-ESD Damage in a GaAs RFIC

2000 ◽  
Author(s):  
Amy Poe ◽  
Steve Brockett ◽  
Tony Rubalcava
Keyword(s):  
Radio Frequency ◽  
Failure Analysis ◽  
Integrated Circuit ◽  
Production Test ◽  
Analysis Techniques ◽  
Device Model ◽  
Charged Device ◽  
Subsequent Failure

Abstract The intent of this work is to demonstrate the importance of charged device model (CDM) ESD testing and characterization by presenting a case study of a situation in which CDM testing proved invaluable in establishing the reliability of a GaAs radio frequency integrated circuit (RFIC). The problem originated when a sample of passing devices was retested to the final production test. Nine of the 200 sampled devices failed the retest, thus placing the reliability of all of the devices in question. The subsequent failure analysis indicated that the devices failed due to a short on one of two capacitors, bringing into question the reliability of the dielectric. Previous ESD characterization of the part had shown that a certain resistor was likely to fail at thresholds well below the level at which any capacitors were damaged. This paper will discuss the failure analysis techniques which were used and the testing performed to verify the failures were actually due to ESD, and not caused by weak capacitors.

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