scholarly journals Mechanical design, analysis and testing of a large-range compliant microgripper

2016 ◽  
Vol 7 (1) ◽  
pp. 119-126 ◽  
Author(s):  
Yilin Liu ◽  
Qingsong Xu

Abstract. This paper presents the mechanical design, analysis, fabrication, and testing procedures of a new large-range microgripper which is based on a flexible hinge structure. The uniqueness of the gripper is that the gripper arms not only provide large gripping range but also deliver approximately rectilinear movement as the displacement in nonworking direction is extremely small. The large gripping range is enabled by a mechanism design based on dual-stage flexure amplifier to magnify the stroke of piezoelectric actuator. The first-stage amplifier is a modified version of the Scott Russell (SR) mechanism and the second-stage amplifier contains a parallel mechanism. The displacement amplification ratio of the modified SR mechanism in the gripper has been enlarged to 3.56 times of the conventional design. Analytical static models of the gripper mechanism are developed and validated through finite-element analysis (FEA) simulation. Results show that the gripping range is over 720 µm with a resonant frequency of 70.7 Hz and negligible displacement in nonworking direction. The total amplification ratio of the input displacement is 16.13. Moreover, a prototype of the gripper is developed by using aluminium 7075 for experimental testing. Experimental results validate the analytical model and FEA simulation results. The proposed microgripper can be employed in various microassembly applications such as pick-and-place of optical fibre.

Author(s):  
Shawn Canfield ◽  
Budy D. Notohardjono

This paper reports the mechanical design, structural analysis, and experimental correlation of bracing concepts for high-end computer servers subjected to loads simulating earthquake conditions. The development and evaluation of these stiffening alternatives follows a step-by-step process of finite element analysis coupled with parallel experimental testing. The numerical model is derived from the simplified CAD geometry of an existing server frame. An analysis of this frame model is subjected to a load environment similar to those endured under actual horizontal table vibration tests. The result of this series of analyses is a design study examining how a range of bracing designs affects the global frame rigidity. This design study builds toward the objective of constructing a verified model of the server frame and components that will lead to a guideline for implementing stiffener designs on high-end server systems.


2015 ◽  
Vol 6 (6) ◽  
pp. 759-774
Author(s):  
André F. B. P. Pinto ◽  
S.M.O. Tavares ◽  
José M. A. César de Sá ◽  
P.M.S.T. de Castro

Purpose – The purpose of this paper is to use PAM-CRASH, a finite element analysis solver, to assess the performance of a mass production vehicle cross car beam (CCB) under an overlap frontal crash scenario (crashworthiness). Simulation results were reviewed according to what is plausible to register regarding some critical points displacements and, moreover, to identify its stress concentrations zones. Furthermore, it was also computed the CCB modal analysis (noise, vibration and harshness (NVH) assessment) in order to examine if its natural modes are within with the original equipment manufacturer (OEM) design targets. Design/methodology/approach – The available data at the beginning of the present study consisted of the structure CAD file and performance requirements stated by the OEM for NVH. No technical information was available concerning crashworthiness. Taking into account these limitations, it was decided to adapt the requirements for other mass production cars of the same category, as regards dynamic loading. A dynamic explicit code finite element analysis was performed throughout the CCB structure simulating the 120e−3 s crash event. For the modal analysis, there were some necessary modifications to the explicit finite element model in order to perform the analysis in implicit code. In addition, the car body in white stiffness was assigned at the boundaries. These stiffness values are withdrawn from the points where the CCB is attached to the car body’s sheet metal components. Findings – Although the unavailability of published results for this particular CCB model prevents a comparison of the present results, the trends and order of magnitude of the crash simulation results are within the expectations for this type of product. Concerning modal analysis, the steering column first natural frequency has a percent deviation from the design lower bound value of 5.09 percent when local body stiffness is considered and of 1.94 percent with fixed boundary conditions. The other requirement of the NVH assessment regarding a 5 Hz minimum interval between first vehicle CCB mode and the first mode of the steering column was indeed achieved with both boundary configurations. Originality/value – This study is a further confirmation of the interest of numerical modeling as a first step before actual experimental testing, saving time and money in an automotive industry that has seen an enormous increase of the demand for new car models in the last decade.


2019 ◽  
Vol 10 (1) ◽  
pp. 299-307
Author(s):  
Jinyin Li ◽  
Peng Yan ◽  
Jianming Li

Abstract. This paper presents an improved modeling method for bridge-type mechanism by taking the input displacement loss into consideration, and establishes an amplification ratio model of bridge-type mechanism according to compliance matrix method and elastic beam theory. Moreover, the amplification ratio of the designed bridge-type nano-positioner is obtained by taking the guiding mechanism as the external load of bridge-type mechanism. Comparing with existing methods, the proposed model is more accurate, which is further verified by finite element analysis(FEA) and experimental test. The consistency of the results obtained from theoretical model, FEA and experimental testing indicates that the proposed model can accurately predict the amplification characteristics of nano-positioners, which helps the analysis and design of bridge-type nano-positioners in practical applications.


Author(s):  
Pierre-Olivier Dubois ◽  
Lionel Birglen

This paper presents a novel mechanical design of a lower mobility remote center compliance linkage. This mechanism consists in three platforms connected by three legs with universal joints. Two of these platforms are attached to the ground while last one is the mobile platform. Using screw theory, it is first demonstrated that this mechanism allows its mobile platform to rotate around a fixed point in space without having a joint directly connected to this point. Indeed, knowing the mobility of the two former platforms, it is possible to define a wrench system for each leg and thus, find the reciprocal twist system of the mobile platform. Then, the results of the optimization of the mechanism’s design through a genetic algorithm is presented using the conditioning of its Jacobian matrix as a criterion. Finally, a compliant version of the mechanism is developed and a finite element analysis (FEA) simulation demonstrates the proper mobility of the system under typical loading scenarios.


Robotica ◽  
2014 ◽  
Vol 33 (4) ◽  
pp. 787-806 ◽  
Author(s):  
Guangbo Hao ◽  
Haiyang Li

SUMMARYThis paper deals with the design of 3-legged distributed-compliance XYZ compliant parallel manipulators (CPMs) with minimised parasitic rotations, based on the kinematically decoupled 3-PPPRR (P: prismatic joint, and R: revolute joint) and 3-PPPR translational parallel mechanisms (TPMs). The designs are firstly proposed using the kinematic substitution approach, with the help of the stiffness center (SC) overlapping based approach. This is done by an appropriate embedded arrangement so that all of the SCs associated with the passive compliant modules overlap at the point where all of the input forces applied at the input stages intersect. Kinematostatic modelling and characteristic analysis are then carried out for the proposed large-range 3-PPPRR XYZ CPM with overlapping SCs. The results from finite element analysis (FEA) are compared to the characteristics found for the developed analytical models, as are experimental testing results (primary motion) from the prototyped 3-PPPRR XYZ CPM with overlapping SCs. Finally, issues on large-range motion and dynamics of such designs are discussed, as are possible improvements of the actuated compliant P joint. It is shown that the potential merits of the designs presented here include a) minimised parasitic rotations by only using three identical compliant legs; b) compact configurations and small size due to the use of embedded designs; c) approximately kinematostatically decoupled designs capable of easy controls; and d) monolithic fabrication for each leg using existing planar manufacturing technologies such as electric discharge machining (EDM).


2014 ◽  
Vol 564 ◽  
pp. 340-345
Author(s):  
Mohd Roshdi Hassan ◽  
Yong Thian Haw ◽  
Mohd Nasrisyam Asri

This paper describes the design analysis of the behavior of a shape memory alloy (SMA) plate embedded into an aerofoil. Experimentation and simulation were done to fulfill this purpose. The aerofoil is made of silicone rubber material. The SMA plate which was embedded into the maximum chamber of aerofoil during the fabrication process was measured at approximately 175mm, 63mm and 3mm in length, width and thickness respectively. Experimentation was conducted to show that the SMA plate is able to produce two-way shape memory effect. Simulation was executed by using Abaqus 6.9-1 (finite element analysis software). The aerofoil profile was changed by the movement of SMA plate, which has subsequently changed the angle of aerofoil’s trailing edge. The result from the experiment shows that the aerofoil’s trailing edge has undergone a certain amount of displacement after heated. Upon cooling, the aerofoil’s trailing edge did not return to its initial position. Based on this analysis, it is clear that the simulation results are in agreement with the findings of experimental results.


2017 ◽  
Vol 28 (17) ◽  
pp. 2388-2402 ◽  
Author(s):  
Yiling Yang ◽  
Yanding Wei ◽  
Junqiang Lou ◽  
Fengran Xie

This article presents the design, modeling, and experimental testing of a novel piezo-driven XY stage with parallel, decoupled, and compact kinematic structure. The structural design of the stage is based on a hybrid compliant mechanism employing the right-circular double-rocker mechanism and the leaf-type parallelogram mechanism. The proposed XY stage is capable of producing a large workspace range, an excellent decoupled motion, and a suitable resonant frequency. By means of the pseudorigid-body-model method, the theoretical models of the XY stage are derived. Using the finite element analysis simulations, the optimal structural parameters are acquired, and the theoretical models are analyzed and validated. A prototype of the proposed stage was finally manufactured, and several experimental investigations were performed to validate its performances. The experimental results show that the XY stage has a large amplification ratio of 7.48 and a large workspace range of 150.3 µm × 147.9 µm. In addition, the parasitic motion along the y-axis ( x-axis) accounts for 0.94% (0.74%) of the x-axis ( y-axis) motion, which indicates that the stage possesses excellent decoupling characteristics.


2013 ◽  
Vol 313-314 ◽  
pp. 20-26 ◽  
Author(s):  
Jian Zhong Zhang ◽  
Chang Hong Cai ◽  
Chuan Guo Wu

This paper proposes a bi-stable permanent magnetic actuator (PMA) for medium voltage vacuum circuit breaker. The structure of the proposed PMA is discussed and the optimization of the structure is carried out. The model of finite element analysis (FEA) is constructed where the flux distributions, electromagnetic force under different structure parameters are analyzed. The feasibility and correctness of the PMA are verified by the FEA simulation results and the optimal size for movable plunger and stationary iron ring is obtained.


2011 ◽  
Vol 314-316 ◽  
pp. 1218-1221
Author(s):  
Hao Min Huang

Conventional methods of design to be completed ordinary hydraulic transmission gear gearbox design, but for such a non-planet-rule entity, and the deformation of the planet-gear contact stress will have a great impact on the planet gear, it will be very difficult According to conventional design. In this paper, ANSYS software to the situation finite element analysis, the planetary gear to simulate modeling study.


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