Optimal Structural Design of Micro-Motion Stage with Stiffness Constraints Using Topology and Sizing Optimization Method

2016 ◽  
Vol 679 ◽  
pp. 55-58
Author(s):  
You Dun Bai ◽  
Zhi Jun Yang ◽  
Xin Chen ◽  
Meng Wang
Keyword(s):  
Compliant Mechanisms ◽  
Optimization Methods ◽  
Flexure Hinge ◽  
Leaf Spring ◽  
Element Analysis ◽  
Sizing Optimization ◽  
Flexure Hinges ◽  
Spring Type ◽  
Micro Motion ◽  
Motion Stage

Flexure hinge is widely used in the compliant mechanisms for precision engineering. Generally, compliant mechanisms with flexure hinges are designed using the analytical stiffness formulas, which increases the design complexity. As the development of finite element analysis (FEA) and optimization methods, it is likely to design the flexure hinges directly using the FEA based numerical optimization methods. This paper developed a leaf spring type flexure hinge based micro-motion stage with specific stiffness constraints. Both topology and sizing optimization methods are used in the design of motion stage. The proposed methods is apply to optimal design formed the leaf spring type flexure hinge for a micro motion stage which serves as a guidance mechanism. Further numerical result shows the good stiffness stability of the refined stage.

From Shape to Feature - A Novel Structural Design Idea for Dynamic Feature Adjustable Micro Motion Stages Based on Tension Stiffening

2016 ◽  
Vol 679 ◽  
pp. 49-54 ◽  
Author(s):  
Zhi Jun Yang ◽  
Xin Chen ◽  
Su Juan Wang ◽  
Jian Gao ◽  
Xin Du Chen
Keyword(s):  
Structural Design ◽  
Topological Optimization ◽  
Flexure Hinge ◽  
Leaf Spring ◽  
Dynamic Feature ◽  
Tension Stiffening ◽  
Stringed Instruments ◽  
Spring Type ◽  
Micro Motion ◽  
Design Idea

Guidance mechanism such as fast tool servo (FTS) is widely used in precision machining, in the current design method, either the analytic solution or topological optimization, the dynamic feature, namely the stiffness, inertial and frequency, are subjected to the shape and sizing of the designed structure, especially sensitive to the geometric feature of flexure hinge, which caused high machining precision and high cost. In this proceeding, a novel structural design idea for guidance mechanism type micro motion stages based on tension stiffening which allow the dynamic feature adjustable is presented. Firstly, the design of micro motion stages is reviewed on both analytic and topological optimization, and the advantage of the two kinds of commonly used flexure type, the notch type and leaf spring type, are compared, and the latter is chosen as an idea type for guidance mechanism for its uniform deformation and none stress concentration. Secondly, tension stiffening using in the stringed instruments is described, in which the length, tension and linear density is discussed to change the pitch (vibration frequency and amplitude) of the stringed instruments. Finally, a novel structural design idea origin from stringed instruments is discussed, with the assumption that the leaf spring type flexure hinge are symmetrical layout on both sides of the micro motion stage, the stiffness and frequency change rate are also discussed. A numerical method is used to show the efficiency of the presented method.

scholarly journals Multi-objective optimization of a type of ellipse-parabola shaped superelastic flexure hinge

2016 ◽  
Vol 7 (1) ◽  
pp. 127-134 ◽  
Author(s):  
Zhijiang Du ◽  
Miao Yang ◽  
Wei Dong
Keyword(s):  
Compliant Mechanisms ◽  
Pareto Frontier ◽  
Flexure Hinge ◽  
Multi Objective Optimization ◽  
Nsga Ii ◽  
Element Analysis ◽  
Multi Objective ◽  
Flexure Hinges ◽  
Static Responses ◽  
Motion Range

Abstract. Flexure hinges made of superelastic materials is a promising candidate to enhance the movability of compliant mechanisms. In this paper, we focus on the multi-objective optimization of a type of ellipse-parabola shaped superelastic flexure hinge. The objective is to determine a set of optimal geometric parameters that maximizes the motion range and the relative compliance of the flexure hinge and minimizes the relative rotation error during the deformation as well. Firstly, the paper presents a new type of ellipse-parabola shaped flexure hinge which is constructed by an ellipse arc and a parabola curve. Then, the static responses of superelastic flexure hinges are solved via non-prismatic beam elements derived by the co-rotational approach. Finite element analysis (FEA) and experiment tests are performed to verify the modeling method. Finally, a multi-objective optimization is performed and the Pareto frontier is found via the NSGA-II algorithm.

Study on the Mechanical Characteristics of an Electrode Tab-Clamp for Lithium-Ion Battery Formation

2012 ◽  
Vol 249-250 ◽  
pp. 707-711
Author(s):  
Cai Hong Ding ◽  
Na Feng
Keyword(s):  
Lithium Ion Battery ◽  
Impact Analysis ◽  
Mechanical Performance ◽  
Lithium Ion ◽  
Design Parameters ◽  
Leaf Spring ◽  
Clamping Force ◽  
Element Analysis ◽  
Spring Type ◽  
Micro Motion

In the formation process of lithium-ion battery, the clamping force of the electrode tab-clamp is a very important factor for lithium-ion battery charge-discharge performance. Different from the traditional spring type tab-clamp, this paper proposes a leaf-spring type tab-clamp, that could produce the deformation of leaf-spring by the micro-motion of an actuating cylinder to provide a controllable clamping force of the tab-clamp upon the electrodes of lithium-ion battery. It is verified that the leaf-spring type structure is available and feasible through finite element analysis (FEA). According to the data from FEA, the relational expression between the clamping force and the micro-motion of the actuating cylinder is drawn out, and an impact analysis about design parameters to the clamping force is accomplished and some useful results are got. The study of this paper is helpful to guide mechanical design of the electrode tab-clamp for lithium-ion battery charging and discharging and to improve its mechanical performance.

Fatigue Life Prediction and Optimal Design of a Flexure Based Micro-Motion Stage

2013 ◽  
Author(s):  
Qiliang Wang ◽  
Xianmin Zhang
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Optimal Design ◽  
Life Prediction ◽  
Design Method ◽  
Fatigue Life Prediction ◽  
Flexure Hinge ◽  
Flexure Hinges ◽  
Micro Motion ◽  
Motion Stage

This paper presents a fatigue-based method for optimal design of a flexure based 3-RRR compliant micro-motion stage, which is driven by three piezoelectric actuators (PZT). As this compliant stage obtains motions from the deflection of its flexure hinges, fatigue failure becomes its major failure mode. The aim of this paper is to provide a method to predict the fatigue life of the stage and redesign it by considering fatigue strength. Firstly, the motion transformation matrix, which reveals the relation between output displacement vector of moving platform and three input displacements of PZT actuators, is established by using the finite element method. Then, the force vectors of all the twelve flexure elements in the stage can be derived. Secondly, the fatigue properties of circular flexure hinge are discussed by considering the effects of flexure dimension parameters, non-zero mean stress, surface conditions and et al. Combined with the material stress life curve and the fatigue strength of the flexure hinges, fatigue life prediction of the micro-motion stage can be carried out by utilizing the nominal stress approach. The aforementioned micro-motion stage, which is optimized based on maximum stress constraint, is presented as an example to illustrate the fatigue life prediction procedure. And the predicted results of fatigue lives in specified condition indicate that fatigue lives of all flexure hinges in the stage differ drastically. In this condition, the stage will fail prematurely due to the most vulnerable hinge. So, the design method based on static strength may lead to unsafe or uneconomic design of the stage. Finally, a fatigue based optimal design method is introduced to redesign the flexure based micro-motion stage. The stage dimensions and the flexure hinge geometry are considered as design variables. The maximum motion range is set as the objective function. And the fatigue strength of flexures is taken as constraint, as well as the natural frequency of the stage and the input force capacity of PZT actuators. A micro-motion stage with optimal dimension parameters is obtained at last. Numerical results show that the optimal stage has a good comprehensive properties and can endure a infinite cycles.

An Empirically Determined Design Guideline for Rectangular Cross Section Nitinol Flexure Hinges With the Focus on Flexibility-Strength Trade-Off

2018 ◽  
Author(s):  
S. Coemert ◽  
M. Olmeda ◽  
J. Fuckner ◽  
C. Rehekampff ◽  
S. V. Brecht ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Cross Section ◽  
Electrical Discharge Machining ◽  
Rectangular Cross Section ◽  
Flexure Hinge ◽  
Element Analysis ◽  
Design Guideline ◽  
Trade Off ◽  
Flexure Hinges ◽  
Compliance Modeling

In our group, we are developing flexure hinge based manipulators made of nitinol for minimally invasive surgery. On the one hand, sufficient flexibility is required from flexure hinges to be able to cover the surgical workspace. On the other hand, the bending amount of the flexure hinges has to be limited below the yielding point to ensure a safe operation. As a result of these considerations, it has to be questioned how much bending angle a nitinol flexure hinge with given geometric dimensions can provide without being subject to plastic deformation. Due to the nonlinearities resulting from large deflections and the material itself, the applicability of the suggested approaches in the literature regarding compliance modeling of flexure hinges is doubtful. Therefore, a series of experiments was conducted in order to characterize the rectangular cross section nitinol flexure hinges regarding the flexibility-strength trade-off. The nitinol flexure hinge samples were fabricated by wire electrical discharge machining in varying thicknesses while keeping the length constant and in varying lengths while keeping the thickness constant. The samples were loaded and unloaded incrementally until deflections beyond visible plastic deformation occured. Each pose in loaded and unloaded states was recorded by means of a digital microscope. The deflection angles yielding to permanent set values corresponding to 0.1% strain were measured and considered as elastic limit. A quasilinear correlation between maximum elastic deflection angle and length-to-thickness ratio was identified. Based on this correlation, a minimal model was determined to be a limit for a secure design. The proposed guideline was verified by additional measurements with additional samples of random dimensions and finite element analysis.

Hybrid Compliant Mechanism Design Using a Mixed Mesh of Flexure Hinge Elements and Beam Elements Through Topology Optimization

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Lin Cao ◽  
Allan T. Dolovich ◽  
Wenjun (Chris) Zhang
Keyword(s):  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Optimization Technique ◽  
Flexure Hinge ◽  
Beam Elements ◽  
Flexure Hinges ◽  
New Type ◽  
Meshing Scheme ◽  
Compliant Mechanism Design

This paper proposes a topology optimization framework to design compliant mechanisms with a mixed mesh of both beams and flexure hinges for the design domain. Further, a new type of finite element, i.e., super flexure hinge element, was developed to model flexure hinges. Then, an investigation into the effects of the location and size of a flexure hinge in a compliant lever explains why the point-flexure problem often occurs in the resulting design via topology optimization. Two design examples were presented to verify the proposed technique. The effects of link widths and hinge radii were also investigated. The results demonstrated that the proposed meshing scheme and topology optimization technique facilitate the rational decision on the locations and sizes of beams and flexure hinges in compliant mechanisms.

scholarly journals Output decoupling property of planar flexure-based compliant mechanisms with symmetric configuration

2016 ◽  
Vol 7 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Y. S. Du ◽  
T. M. Li ◽  
Y. Jiang ◽  
J. L. Zhang
Keyword(s):  
Analytical Model ◽  
Compliant Mechanisms ◽  
Element Analysis ◽  
Modeling Methods ◽  
Stiffness Modeling ◽  
Symmetric Configuration ◽  
Parallel Structures ◽  
The Matrix ◽  
Micro Motion ◽  
Good Agreement

Abstract. This paper presents the output decoupling property of planar flexure-based compliant mechanisms with symmetric configuration. Compliance/stiffness modeling methods for flexure serial structures and flexure parallel structures are first derived according to the matrix method. Analytical model of mechanisms with symmetric configuration is then developed to analyze the output decoupling property. The proposed analytical model shows that mechanisms are output decoupled when they are symmetry about two perpendicular axes or when they are composed of either three or an even number of identical fundamental forms distributed evenly around the center. Finally, output compliances of RRR and 4-RRR compliant micro-motion stages are derived from the analytical model and finite element analysis (FEA). The comparisons indicate that the results obtained from the proposed analytical model are in good agreement with those derived from FEA, which validates the proposed analytical model.

The Compliant A-Arm Suspension

Aerospace ◽  
2003 ◽  
Author(s):  
Timothy Allred ◽  
Larry L. Howell ◽  
Spencer P. Magleby ◽  
Robert H. Todd
Keyword(s):  
Compliant Mechanisms ◽  
Commercial Application ◽  
Leaf Spring ◽  
Large Deflections ◽  
Element Analysis ◽  
Performance Variables ◽  
Body Model ◽  
Small Deflection ◽  
Rigid Body Model ◽  
Depth Study

The use compliant mechanisms in a suspension system has been demonstrated with leaf spring mechanisms. In this research a novel compliant configuration called the Compliant A-Arm (C-A-Arm) suspension is selected for in-depth study. Closed-from equations are derived for linear small-deflection stiffness equations. Large deflections are analyzed using finite element analysis. A pseudo-rigid-body model is developed to approximate mechanism deflections and stiffness for large deflections. The results suggest that the C-A-Arm configuration may be a viable suspension alternative for future commercial application. In addition, this configuration offers a number of performance variables that could be the basis for an active control system. This paper represents a necessary first step in modeling this new configuration.

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