Design, analysis and test of a novel cylinder-driven mode applied to microgripper

2021 ◽  
pp. 1-14
Author(s):  
Xiaodong Chen ◽  
ZM Xie ◽  
Huifeng Tan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Research Field ◽  
Driving Pressure ◽  
Maximum Output ◽  
Element Analysis ◽  
Output Displacement ◽  
Micro Parts ◽  
The Relationship

Abstract How to enlarge the output displacement is a key issue in the research field of microgrippers. It is difficult to further enlarge the output displacement for the traditional displacement transmission mechanism (DTM). In this research, a two-stage amplification cylinder-driven DTM based on the compliant mechanisms is designed to realize the displacement output expansion. The opening and closing of the clamping jaws is driven by the air cylinder to enlarge the output displacement of the microgripper. According to the analysis of statics model of the mechanism, the relationship between the output displacement of the microgripper and the driving pressure of the cylinder is established. The magnification of the microgripper is obtained using a dynamic model. Moreover, based on the finite element analysis, the mechanical structure parameters are optimized. The microgripper was fabricated by utilizing wire electro discharge machining (WEDM) technique, and then a series of experiments were carried out to obtain the relationship between the displacement and the driving pressure. It is found that the maximum output displacement measured is 1190.4μm under the pressure of 0-0.6 Mpa, corresponding to the magnification of 47.63. Compared with the results of finite element analysis and theoretical calculation, the test results have a discrepancy of 2.39% and 6.62%, respectively. The microgripper has successfully grasped a variety of micro-parts with irregular shapes, and parallel grasping can be achieved, demonstrating the potential application of this design in the field of micromanipulation.

Research on the Adjustable LAVAL Nozzle during Pneumatic Conveying

2009 ◽  
Vol 87-88 ◽  
pp. 474-480
Author(s):  
Dong Mei Jiao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Saving ◽  
Laval Nozzle ◽  
Pneumatic Conveying ◽  
Element Analysis ◽  
Output Displacement ◽  
Input And Output ◽  
The Relationship

The relationship between the input and output (displacement of adjusting lever and air flow) of adjustable LAVAL nozzle is deduced. In the pneumatic conveying condition, finite element analysis to adjustable LAVAL nozzle is simulated, and its steady-flow effect is proved. Experiments show the adjustable LAVAL nozzle is energy-saving, can improve the quality of conveyed material, and reduce percentage of damage.

Bistable Compliant Four-Bar Mechanisms With a Single Torsional Spring

2006 ◽  
Author(s):  
Adarsh Mavanthoor ◽  
Ashok Midha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanism Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Stored Energy ◽  
Element Analysis ◽  
Bistable Behavior ◽  
Torsional Spring ◽  
Bistable Mechanism

Significant reduction in cost and time of bistable mechanism design can be achieved by understanding their bistable behavior. This paper presents bistable compliant mechanisms whose pseudo-rigid-body models (PRBM) are four-bar mechanisms with a torsional spring. Stable and unstable equilibrium positions are calculated for such four-bar mechanisms, defining their bistable behavior for all possible permutations of torsional spring locations. Finite Element Analysis (FEA) and simulation is used to illustrate the bistable behavior of a compliant mechanism with a straight compliant member, using stored energy plots. These results, along with the four-bar and the compliant mechanism information, can then be used to design a bistable compliant mechanism to meet specified requirements.

Research on Deflection Analysis and Compensation Method of Ram of Boring and Milling Machining Center

2014 ◽  
Vol 633-634 ◽  
pp. 693-698
Author(s):  
Long Xin ◽  
Shi Chao Cui ◽  
Qi Lin Shu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Least Squares Method ◽  
Preliminary Calculation ◽  
Element Analysis ◽  
Object A ◽  
Machining Center ◽  
Deflection Analysis ◽  
Long Stroke ◽  
The Relationship

In this paper, the ram of boring and milling machining center is taken as the research object. A new method that hydraulic pull rods compensation is proposed to solve the problem of deformation compensation of long stroke ram of boring and milling machining center. Firstly, the method of finite element analysis is used to get the laws of ram deformation and the relationship curve between the ram deformation and the stroke of ram. Secondly, the preliminary calculation value of pull rods compensation force is derived based on the theoretical analysis of material mechanics. The relationship curve between compensation force and the stroke of ram is obtained by finite element analysis and polynomial least squares method. Finally, the analyzed results are as follows: the laws of ram deformation distribution is accurately predicted by the used method, the deflection error of the ram is well controlled,and the machining precision is significantly improved.

An Improved Method for Designing Flexure-Based Nonlinear Springs

2012 ◽  
Author(s):  
Qiaoling Meng ◽  
Giovanni Berselli ◽  
Rocco Vertechy ◽  
Vincenzo Parenti Castelli
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Empirical Equations ◽  
Element Analysis ◽  
Closed Form Solutions ◽  
Nonlinear Springs ◽  
Aspect Ratios ◽  
Analytical Relations ◽  
Flexural Hinges

Monolithic Flexure-based Compliant Mechanisms (MFCM) can functionally act as nonlinear springs by providing a desired load-displacement profile at one point on their structure. Once the MFCM topology is chosen, these particular springs can be conveniently synthesized by resorting to the well-known Pseudo-Rigid-Body approximation, whose accuracy strongly depends on the modeling precision of the flexures’ principal compliance. For various types of flexures, closed-form solutions have been proposed which express the compliance factors as functions of the flexure dimensions. Nonetheless, the reliability of these analytical relations is limited to slender, beam-like, hinges undergoing small deflections. In order to overcome such limitations, this paper provides empirical equations, derived from finite element analysis, that can be used for the optimal design of circular, elliptical, and corner-filleted flexural hinges with general aspect ratios on the basis of both principal compliance and maximum bearable stress. As a case study, a nonlinear spring conceived as a four-bar linkage MFCM is synthesized and simulated by means of finite element analysis. Numerical results confirm that the aforementioned empirical equations outperform their analytical counterparts when modeling thick cross-section hinges undergoing large deflections.

Study on the Reduction Strategy of Machining-Induced Edge Chipping Based on Finite Element Analysis of In-Process Workpiece Structure

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Hu Gong ◽  
F. Z. Fang ◽  
X. F. Zhang ◽  
Juan Du ◽  
X. T. Hu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Principal Stress ◽  
Maximum Principal Stress ◽  
Machining Process ◽  
Element Analysis ◽  
Edge Chipping ◽  
Additional Support ◽  
The Relationship ◽  
Complex Parts

Edge chipping is one of the most serious issues during machining process of brittle materials. To find an effective method to reduce edge chipping, the relationship between the distribution of maximum principal stress and edge chipping is studied comprehensively based on 3D finite element analysis (FEA) model of in-process workpiece structure in this paper. Three-level influencing factors of edge chipping are proposed, which are helpful to understand the relationship between intuitive machining parameters and edge chipping at different levels. Based on the analysis, several experiments are designed and conducted for drilling and slotting to study the strategy of controlling edge chipping. Two methods are adopted: (a) adding additional support, (b) improving tool path. The result show that edge chipping can be reduced effectively by optimizing the distribution of the maximum principal stress during the machining process. Further, adding addtitional support method is extended to more complex parts and also obtain a good result. Finally, how to use adding additional support method, especially for complex parts, will be discussed in detail. Several open questions are raised for future research.

Mechanical Behaviour of Auxetic Microstructures Using Contact Mechanics and Elastoplasticity

2016 ◽  
Vol 681 ◽  
pp. 100-116
Author(s):  
Georgios A. Drosopoulos ◽  
Nikolaos Kaminakis ◽  
Nikoletta Papadogianni ◽  
Georgios E. Stavroulakis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Contact Mechanics ◽  
Compliant Mechanisms ◽  
Nonlinear Finite Element Analysis ◽  
Nonlinear Finite Element ◽  
Numerical Homogenization ◽  
Element Analysis ◽  
Optimization Formulation

The design of novel mechanical microstructures having auxetic behaviour is proposed in this paper using techniques of topology optimization for compliant mechanisms. The resulting microstructure can be modified in order to cover additional needs, not included in the topology optimization formulation. Classical structural optimization, contact mechanics, homogenization and nonlinear finite element analysis are used for this step. Thus, the modified microstructure or composite is studied with numerical homogenization in order to verify that it still has the wished auxetic behaviour. Finally, nonlinear finite element analysis shows how the auxetic behaviour is influenced by unilateral contact between the constituent materials, large displacements and elastoplasticity.

Euler Buckling of Idealised Horizontal Pipeline Imperfections

2010 ◽  
Author(s):  
Gary Cumming ◽  
Andrew Rathbone
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Factor ◽  
Finite Element Models ◽  
Bend Radius ◽  
Element Analysis ◽  
Euler Buckling ◽  
Critical Buckling Force ◽  
The Relationship

Imperfections introduced by pipelay can not be known until installation is complete; therefore a common approach is to perform finite element analysis of idealised horizontal imperfections to determine critical buckling forces. Rundsag et al 2008 [1], showed that the critical buckling force for a snake lay geometry is directly proportional to the pipeline bend radius. Rathbone et al 2008 [2] showed that, with decreasing arch lengths, the pipeline critical buckling force is proportional to the change in the offset angle. This paper looks at the relationship between the minimum critical buckling force and the horizontal offset angle of the pipeline, considering an Euler buckling approach. The resulting relationship that estimates the critical buckle load based on pipeline stiffness and weight, offset angle and friction factor is then compared against idealised finite element models.

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