Collinear-Type Statically Balanced Compliant Micro Mechanism (SB-CMM): Experimental Comparison Between Pre-Curved and Straight Beams

2011 ◽  
Author(s):  
Nima Tolou ◽  
Pablo Estevez ◽  
Just L. Herder
Keyword(s):  
Experimental Data ◽  
Range Of Motion ◽  
Robust Design ◽  
Positive Constant ◽  
Experimental Comparison ◽  
Constant Force ◽  
Finite Range ◽  
Curved Beams ◽  
Actuation Force ◽  
Fabrication Errors

The feasibility of collinear-type statically balanced compliant micro mechanism (SB-CMM) with pre-curved beams has been studied experimentally and compares to those with initially straight beams. The collinear-type SB-CMM is a near zero stiffness micro mechanism with a near zero actuation force in a finite range of motion. However, from the experimental data, it was found that the collinear-type SB-CMM are sensitive to fabrication errors, as a results negative or positive constant force instead of zero actuation force maybe obtained. For the case of pre-curved beams, the curvature can be tuned for better zero stiffness behavior. Further improvements in the concept are considered towards a robust design and reliable prototypes, such as optimization and accurate dimensioning and fabrication.

Analysis of athletes’ stadium stress source based on improved layered K-means algorithm

2020 ◽  
Vol 39 (4) ◽  
pp. 5905-5914
Author(s):  
Chen Gong
Keyword(s):  
Experimental Data ◽  
Machine Learning Algorithms ◽  
User Preference ◽  
Experimental Comparison ◽  
Actual Situation ◽  
Medical Field ◽  
Pressure Source ◽  
Preference Model ◽  
Related Research ◽  
Analysis System

Most of the research on stressors is in the medical field, and there are few analysis of athletes’ stressors, so it can not provide reference for the analysis of athletes’ stressors. Based on this, this study combines machine learning algorithms to analyze the pressure source of athletes’ stadium. In terms of data collection, it is mainly obtained through questionnaire survey and interview form, and it is used as experimental data after passing the test. In order to improve the performance of the algorithm, this paper combines the known K-Means algorithm with the layering algorithm to form a new improved layered K-Means algorithm. At the same time, this paper analyzes the performance of the improved hierarchical K-Means algorithm through experimental comparison and compares the clustering results. In addition, the analysis system corresponding to the algorithm is constructed based on the actual situation, the algorithm is applied to practice, and the user preference model is constructed. Finally, this article helps athletes find stressors and find ways to reduce stressors through personalized recommendations. The research shows that the algorithm of this study is reliable and has certain practical effects and can provide theoretical reference for subsequent related research.

scholarly journals Experimental Comparison of Radon Domain Approaches for Resident Space Object’s Parameter Estimation

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1298
Author(s):  
Selenia Ghio ◽  
Marco Martorella ◽  
Daniele Staglianò ◽  
Dario Petri ◽  
Stefano Lischi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Rotation Period ◽  
Research Topic ◽  
Experimental Comparison ◽  
Rotational Period ◽  
Space Objects ◽  
Resident Space Objects ◽  
The Moment ◽  
Inverse Radon Transform ◽  
Inverse Radon

The fast and uncontrolled rise of the space objects population is threatening the safety of space assets. At the moment, space awareness solutions are among the most calling research topic. In fact, it is vital to persistently observe and characterize resident space objects. Instrumental highlights for their characterization are doubtlessly their size and rotational period. The Inverse Radon Transform (IRT) has been demonstrated to be an effective method for this task. The analysis presented in this paper has the aim to compare various approaches relying on IRT for the estimation of the object’s rotation period. Specifically, the comparison is made on the basis of simulated and experimental data.

Computational and Experimental Comparison of Different Volute Geometries in a Radial Compressor

2000 ◽  
Author(s):  
Arttu Reunanen ◽  
Harri Pitkänen ◽  
Timo Siikonen ◽  
Harri Heiska ◽  
Jaakko Larjola ◽  
...  
Keyword(s):  
Experimental Data ◽  
Time Dependent ◽  
Experimental Comparison ◽  
Cfd Analysis ◽  
Laboratory Measurements ◽  
Radial Compressor ◽  
Sliding Mesh ◽  
Overall Performance ◽  
Operating Points ◽  
Mesh Technique

Two different volute geometries of a radial compressor at three different operating points have been analyzed using Computational Fluid Dynamics and detailed laboratory measurements. The performance of the volutes were compared using steady-state CFD-analysis, where the volute and the impeller with diffuser were modeled separately. In addition, a time dependent simulation of the complete compressor using the sliding mesh technique was performed for one operation point. Both volutes were manufactured and the overall performance of the compressor, the pressure distribution in the volute and the flow field in the volute inlet were measured with the respective volute geometries. The results obtained from steady, quasi-steady and time-accurate simulations are compared with experimental data.

Perpendicular-to-Grain Strength of Douglas-Fir

1975 ◽  
Vol 2 (1) ◽  
pp. 50-57 ◽  
Author(s):  
J. D. Barrett ◽  
R. O. Foschi ◽  
S. P. Fox
Keyword(s):  
Experimental Data ◽  
Brittle Fracture ◽  
Survival Probability ◽  
Douglas Fir ◽  
Curved Beams ◽  
Allowable Stresses ◽  
Laminated Material

Weibull's theory of brittle fracture is applied to the determination of strength of Douglas-fir wood in tension perpendicular to the grain. Results from tests on blocks of glued-laminated material uniformly stressed in tension are used to derive ultimate stresses, at a given survival probability, for pitched-tapered beams, curved beams, and griplam nail connections. The results of the theory are shown to be in agreement with experimental data. Allowable stresses are derived for blocks, pitched-tapered beams, curved beams, and the particular nailed connection studied.

A Primal Treatise of Constant-Force, Compliant Segments and Mechanisms

2020 ◽  
Author(s):  
Ashok Midha ◽  
Vamsi Lodagala ◽  
Pratheek Bagivalu Prasanna ◽  
Jyothi Komatireddy
Keyword(s):  
Energy Storage ◽  
Range Of Motion ◽  
Design Optimization ◽  
Compliant Mechanisms ◽  
Axial Loading ◽  
Constant Force ◽  
Rigid Link ◽  
Torsional Spring ◽  
Natural Energy

Abstract The evolution of constant-force mechanisms is propelled by a growing interest in being able to exert constant or near-constant force in various applications. Compliant mechanisms have recently received much attention in the design of constant-force mechanisms because of their several advantages, e.g. fewer parts, compact construct, natural energy storage, no backlash, among many others. There have been many research efforts in developing various techniques to design these mechanisms for applications in diverse fields. Several of these techniques require design optimization to generate a constant force over a desired range of motion. There is generally a lack of understanding of the mechanics of the generation of constant force. This paper presents the hypothesis that simple arrangements, such as a rigid link with a torsional spring, or compliant segments, under axial loading are capable of producing constant force. Three compliant segment types are considered herein: fixed-free, pinned-pinned, and fixed-guided beams under axial loading, to demonstrate that they can exert near-constant force, without the need for a design optimization. This paper further exemplifies that the proposed theory is the kernel to generating constant force by different mechanism configurations.

Analytical Modelling of Rolamite Mechanism Made of Shape Memory Alloy for Constant Force Actuators

2015 ◽  
Author(s):  
Andrea Spaggiari ◽  
Eugenio Dragoni
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Metal Strip ◽  
Force Generation ◽  
Constant Force ◽  
Low Friction ◽  
Actuation Force ◽  
Long Stroke ◽  
Force Generator ◽  
Roll Back

This paper analyses the Rolamite architecture exploiting shape memory alloys as power element to obtain a solid state actuator. The Rolamite mechanism was discovered in the late sixties, initially as precision and low friction linear bearing. The most common Rolamite configuration consists of a flexible thin metal strip and two rollers mounted between two fixed parallel guide surfaces. The system can roll back and forth without slipping guided by the plates along its so called sensing axis. The system presents another relevant advantage in addition to low friction coefficient, which is the possibility to provide force generation in a quite simple way. In the original literature works the force was provided thanks to cutouts of various shape in the strip, though this method does not allow the Rolamite to be considered a proper actuator, but only a force generator. In this paper we developed the idea of exploiting the shape memory alloy as Rolamite power element and therefore to use the shape memory effect to change the elastic properties of the strip and to provide the actuation force. The mechanical analyses and the equations where the martensite-austenite transition is modelled in a simplified way, show that this application is feasible, mainly thanks to the initial precurvature of the SMA strip. The discussion of the results highlights some important merits of this architecture such as long stroke, constant force and compactness.

Comments on “Extracting the plastic properties of metal materials from microindentation tests: Experimental comparison of recently published methods” by B. Guelorget, et al. [J. Mater. Res. 22, 1512 (2007)]: The correct methods of analyzing experimental data and reverse analysis of indentation tests

2008 ◽  
Vol 23 (3) ◽  
pp. 598-608 ◽  
Author(s):  
Nagahisa Ogasawara ◽  
Manhong Zhao ◽  
Norimasa Chiba ◽  
Xi Chen
Keyword(s):  
Experimental Data ◽  
Experimental Comparison ◽  
Experiment Data ◽  
Plastic Properties ◽  
Acta Mater ◽  
Indentation Tests ◽  
Scripta Mater ◽  
Reverse Analysis ◽  
Metal Materials ◽  
Indentation Methods

Based on microindentation experiments of three different metals, Guelorget et al. [J. Mater. Res. 22, 1512 (2007)] have compared the performance of five different indentation methods on extracting material plastic properties—among them, three papers were proposed by Cao and Lu [Acta Mater.52, 4023 (2004); J. Mater. Res.20, 1194 (2005); J. Mech. Phys. Solids53, 49 (2005)] and two papers were published by our group [Ogasawara et al., Scripta Mater.54, 65 (2006); Zhao et al. Acta Mater.54, 23 (2006)]. They argued that the performances of our techniques in [Ogasawara et al., Scripta Mater.54, 65 (2006); Zhao et al. Acta Mater.54, 23 (2006)] were quite poor. Here we show that Guelorget et al. [J. Mater. Res. 22, 1512 (2007)] have made quite a few mistakes and problematic steps when they handled the experiment data and performed reverse analysis. Indeed, the material plastic properties extracted from the correct procedures based on our papers [Ogasawara et al., Scripta Mater.54, 65 (2006); Zhao et al. Acta Mater.54, 23 (2006)] are much better and more stable than that reported in Guelorget et al. [J. Mater. Res. 22, 1512 (2007)]. Several general issues related to interpreting microindentation data and reverse analysis are also discussed, which may serve as important guidelines for similar studies in the future.

Analytical modelling of Rolamite mechanism made of shape-memory alloy for constant force actuators

2016 ◽  
Vol 28 (16) ◽  
pp. 2208-2221 ◽  
Author(s):  
Andrea Spaggiari ◽  
Eugenio Dragoni
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Mechanical Analysis ◽  
Metal Strip ◽  
Constant Force ◽  
Low Friction ◽  
Actuation Force ◽  
Long Stroke ◽  
Force Generator ◽  
Roll Back

This article analyses the Rolamite architecture exploiting shape-memory alloys as power element to obtain a solid-state actuator. The Rolamite mechanism was discovered in the late 1960s, initially as precision and low friction linear bearing. The most common Rolamite configuration consists of a flexible thin metal strip and two rollers mounted between two fixed parallel guide surfaces. The system can roll back and forth without slipping guided by the plates along its so-called sensing axis. The system presents another relevant advantage in addition to low friction coefficient, which is the possibility to provide force generation in a quite simple way. In the original literature works, the force was provided, thanks to cut-outs of various shapes in the strip, although this method does not allow the Rolamite to be considered a proper actuator, but only a force generator. In this article, we developed the idea of exploiting the shape-memory alloy as Rolamite power element, and therefore, to use the shape-memory effect to change the elastic properties of the strip and to provide the actuation force. The mechanical analysis, where the martensite–austenite transition is modelled in a simplified way, shows that this application is feasible, mainly thanks to the initial precurvature of the shape-memory alloy strip. The discussion of the results highlights some important merits of this architecture such as long stroke, constant force and compactness.

scholarly journals Minimization of excess torque in multi-time deployment-folding hinge joints

2021 ◽  
Vol 5 (1) ◽  
pp. 35-43
Author(s):  
S. A. Zommer ◽  
S. I. Nemchaninov ◽  
A. P. Kravchunovsky ◽  
A. V. Ivanov ◽  
M. S. Rudenko
Keyword(s):  
Experimental Data ◽  
Computational Analysis ◽  
Mechanical Characteristics ◽  
Solar Array ◽  
Constant Force ◽  
Calculation Algorithm ◽  
Drive Force ◽  
Design Algorithms ◽  
Mechanical Devices ◽  
Angle Of Rotation

The paper presents a method for minimizing the torque value of the multi-time deploymentfolding hinges. The objects of research were the hinges assembly of multi-time deployment-folding mechanical devices of solar array, which are used as part of the platforms of spacecraft. A computational analysis of the forces and moments that act in the hinges in the process of their opening and folding is carried out. The minimization of the excessive torque value without changing the design and layout of the hinge is possible by changing the shape of the dependence of the spring drive force on the angle of rotation of the hinge. The possibility of using constant force springs as part of the hinge is considered, the existing design algorithms are improved and a program for calculating the geometric and mechanical characteristics of constant force springs is developed. Experimental data were obtained for measuring the forces of springs of various configurations, showing the dependence of the magnitude of the force on the magnitude of the spring deformation and confirming the efficiency of the proposed calculation algorithm. A prototype of a hinge assembly with a constant force spring drive was developed and manufactured. The possibility of minimizing the excess torque without the need to change the design of the hinge while maintaining its technical characteristics was experimentally confirmed.

Sign in / Sign up

Export Citation Format

Share Document