scholarly journals On the design of a novel fully compliant spherical four-bar mechanism

2019 ◽  
Vol 11 (9) ◽  
pp. 168781401987954
Author(s):  
Volkan Parlaktaş ◽  
Engin Tanık ◽  
Çağıl Merve Tanık

In this article, a novel fully compliant spherical four-bar mechanism is introduced and its generalized design methodology is proposed. The original fully compliant mechanism lies on a plane at the free position (undeflected position); therefore, it has the advantages of ease of manufacturing, minimized parts, and no backlash. First, the mobility conditions of the mechanism are obtained. The dimensions of the mechanism are optimally calculated for maximum output rotation, while keeping the deflection of flexural hinges at an acceptable range. Using an optimization method, design tables are prepared to display the relationship between arc lengths and corresponding deflections of flexural hinges. Input–output torque relationship and stresses at compliant segments are obtained analytically. A mechanism dimensioned by this novel design method is analyzed by a finite element analysis method, and the analytical results are verified. Finally, the mechanism is manufactured and it is ensured that the deflections of the compliant segments are consistent with the theoretical results.

2013 ◽  
Vol 465-466 ◽  
pp. 39-43
Author(s):  
Mohd Nizam Ahmad ◽  
Karimah Mat ◽  
Wan Mansor Wan Muhamad

Compliant mechanism is a new design approach on industry, particularly on product development, which reducing cost, development time and introduction of new quality components. This paper is focusing on the application of compliant mechanism concept on car wiper by using shape optimization method to get optimum compliant design of wiper. Reverse engineering has been used to gather dimensional data in order to model the actual wiper as datum. Compliant wiper designs are developed by replacing the joints at datum wiper; hence the components of wiper were reduced to become single part only. The shape of compliant wiper then was optimized by using ASNYS to get the optimal compliant design. Finite Element Analysis (FEA) was done on both datum and compliant wipers to examine the results. Simple physical and functional testing has been conducted to validate the functionality of compliant wiper. Based on the FEA results and simple testing, the compliant mechanism is able to be implemented at car wiper.


2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110349
Author(s):  
Huiqiang Guo ◽  
Mingzhe Li ◽  
Pengfei Sun ◽  
Changfeng Zhao ◽  
Wenjie Zuo ◽  
...  

Rotary-wing unmanned aerial vehicles (UAVs) are widespread in both the military and civilian applications. However, there are still some problems for the UAV design such as the long design period, high manufacturing cost, and difficulty in maintenance. Therefore, this paper proposes a novel design method to obtain a lightweight and maintainable UAV frame from configurable design to detailed design. First, configurable design is implemented to determine the initial design domain of the UAV frame. Second, topology optimization method based on inertia relief theory is used to transform the initial geometric model into the UAV frame structure. Third, process design is considered to improve the manufacturability and maintainability of the UAV frame. Finally, dynamic drop test is used to validate the crashworthiness of the UAV frame. Therefore, a lightweight UAV frame structure composed of thin-walled parts can be obtained and the design period can be greatly reduced via the proposed method.


2021 ◽  
pp. 1-14
Author(s):  
Xiaodong Chen ◽  
ZM Xie ◽  
Huifeng Tan

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.


Author(s):  
Yangzhi Chen ◽  
Xiaoping Xiao ◽  
Daoping Zhang ◽  
Haifei Xiao ◽  
Yueling Lyu

Based on the space curve meshing theory, a novel noncircular line gear mechanism was advanced, namely, this paper presented a design method of the variable speed ratio noncircular line gear with coplanar axes. Firstly, the universal contact curve equations of the constant speed ratio and variable speed ratio line teeth were established. After the constraint equations of the rotating angle of the driving and driven variable speed ratio noncircular line gears were analyzed and established, the relationship between the rotating angle of the driven variable speed ratio noncircular line gear and the parameter t in the VSR area was assumed to be a piecewise fourth-order curve. Then, the contact curve equations of the variable speed ratio noncircular line gears were derived, and the entity models of variable speed ratio noncircular line gears were built. The prototypes of the parallel axis and intersecting axis variable speed ratio noncircular line gears were manufactured by Stereo Lithography Apparatus, and the speed ratios were measured on the kinematic test rig. The kinematic and finite element analysis results demonstrate that the relationship between the rotating angle of the driven variable speed ratio noncircular line gear and the parameter t conforms to the designed function and the noncircular line teeth smoothly achieve the preset VSR transmission. The proposed design method is helpful to design the variable speed ratio noncircular line gears with lower theoretical sliding rate and wider variation range of the speed ratio; consequently, the designed variable speed ratio noncircular line gears have better applicability in specific variable speed ratio applications.


2020 ◽  
Vol 12 (3) ◽  
pp. 168781402091147 ◽  
Author(s):  
Xiaodong Chen ◽  
Zilong Deng ◽  
Siya Hu ◽  
Xingjun Gao ◽  
Jinhai Gao

The microgripper based on the principle of lever amplification is easy to realize; however, the theoretical amplification factor is limited by the space size and the structure is not compact enough. The microgripper based on the triangular amplification principle has a compact structure and high amplification factor, but it is not conducive to miniaturization design. Considering compactness, parallel clamping, high magnification, and miniaturization design, a three-stage amplifier consisting of a semi-rhombic amplifier and lever amplifiers is designed. To begin with, the theoretical amplification ratio and the relationship between input variables and output variables are calculated by energy method. Furthermore, the finite element analysis software is used to optimize the structural parameters and analyze the performance of the model. Lastly, the experimental verification is carried out. At 150 V of driving voltage, the maximum output displacement was 530mm, and the actual magnification was 24 times. Microparts can be gripped in parallel and stably, which confirms the validity of the design.


Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Xiaodong Chen ◽  
Zilong Deng ◽  
Siya Hu ◽  
Jinhai Gao ◽  
Xingjun Gao

The existing symmetrical microgrippers have larger output displacements compared with the asymmetrical counterparts. However, the two jaws of a symmetrical microgripper are less unlikely to offer the same forces on the two sides of a grasped micro-object due to the manufacture and assembly errors. Therefore, this paper proposes a new asymmetric microgripper to obtain stable output force of the gripper. Compared with symmetrical microgrippers, asymmetrical microgrippers usually have smaller output displacements. In order to increase the output displacement, a compliant mechanism with four stage amplification is employed to design the asymmetric microgripper. Consequently, the proposed asymmetrical microgripper possesses the advantages of both the stable output force of the gripper and large displacement amplification. To begin with, the mechanical model of the microgripper is established in this paper. The relationship between the driving force and the output displacement of the microgripper is then derived, followed by the static characteristics’ analysis of the microgripper. Furthermore, finite element analysis (FEA) of the microgripper is also performed, and the mechanical structure of the microgripper is optimized based on the FEA simulations. Lastly, experimental tests are carried out, with a 5.28% difference from the FEA results and an 8.8% difference from the theoretical results. The results from theoretical calculation, FEA simulations, and experimental tests verify that the displacement amplification ratio and the maximum gripping displacement of the microgripper are up to 31.6 and 632 μm, respectively.


Author(s):  
Fanhao Meng ◽  
Dengfeng Lu ◽  
Jingjun Yu

Taking the tire of the lunar rover as the research background, this paper provides two design concepts of non-pneumatic tires (NPTs) with a compliant cellular solid spoke component. In this study, a series of degrees of freedom (DOFs) and stiffness analysis of NPTs with cellular structures are investigated with the same vertical loading conditions using a commercial finite element analysis tool, ANSYS. The research found that the tread relative to the hub only has in-plane translational degree of freedom in the radial direction, without other DOFs. According to this finding, using the improved design method based on the existing cellular structures and the synthetic design method based on the principle of compliant mechanism, two cases of cellular structures are designed: (i) cross arcs cell and (ii) rectangular cell. Analysis of the influence of geometric parameters of the cell on the performance of NPTs is critical to further improve the performance of the NPTs. Finally, by optimizing the geometrical parameters of the cellular structure, the performance of the NPTs with the cross arcs cell and rectangular cell can be enhanced.


Author(s):  
Kazuhiro Izui ◽  
Kiyoshi Yokota ◽  
Takayuki Yamada ◽  
Shinji Nishiwaki ◽  
Masataka Yoshimura

This paper proposes a structural optimization-based method for the design of compliant mechanism scissors in which the proposed design criteria are based on universal design principles. The first design criterion is the distance from the hand-grip to the center of gravity of the scissors, which should be minimized to reduce the physical effort required of the people using the device. The second design criterion is that of failure tolerance, where the effects of traction applied in undesirable directions upon the performance of the compliant mechanism should be minimized. Based on the proposed design criteria, a multiobjective optimization problem for the universal design of a compliant mechanism scissors is formulated. Furthermore, to obtain an optimal configuration, a new type of topology optimization technique using the level set function to represent structural boundaries is employed. This optimization technique enables rapid verification of resulting design configurations since the boundary shapes of the obtained design solution candidates can be easily converted to finite element models which are then used in large deformation analyses. Finally, the proposed design method is applied to design examples. The optimal configurations obtained by the proposed method provide good universal design performance, indicating the effectiveness and usefulness of the proposed method.


2021 ◽  
Vol 6 (3) ◽  
pp. 24-41
Author(s):  
Ubi Stanley E.

Most Finite Element packages provide means to generate meshes automatically. However, the user is usually confronted with the problem of not knowing whether the mesh generated is appropriate for the problem at hand. Since the accuracy of the Finite Element results is mesh dependent, mesh selection forms a very important step in the analysis of isolated and combined footing pad foundation. SAFE is an ultimate tools use in the design of concrete floors and foundation system, hence provide a suitable means for the user. From framing layout all the way through to detail drawing production, SAFE integrate every aspect of engineering design which are in one process easy and intuitive environment. SAFE provides unmatched benefits to the engineer with its truly unique combination of power, comprehensive capabilities, and ease-of-use. In the context of this research, we have plotted graphs showing the relationship between the nodes and displacement with the stress patterns as generated from the software. It is understood from the graph that multiple elements in the process of meshing will make the footing to be at equilibrium. The research also carry the shape deformed diagram which shows the deformation of the footing due to the impose load (stress) on the footing, it also give the bending moment diagram of the footings. The basic structure and analysis of the single and double pad footing foundations have been designed using Finite Element Analysis (FEA) with the failure planes being considered. The results obtained, it is assumed that FEA is an ideal design method that breaks foundation design into basic elements and nodes that shows the action of the loading on the footings.


2021 ◽  
Author(s):  
Hongwei Xu ◽  
Haibo Zhou ◽  
Zhiqiang Li ◽  
Xia Ju

Abstract Stiffness and workspace are crucial performance indexes of a precision mechanism. In this paper, an optimization method is presented, for a compliant parallel platform to achieve desired stiffness and workspace. First, a numerical model is proposed to reveal the relationship between structural parameters, desired stiffness and workspace of the compliant parallel platform. Then, the influence of the various parameters on stiffness and workspace of the platform is analyzed. Based on Gaussian distribution, the multi-objective optimization problem is transformed into a single-objective one, in order to guarantee convergence precision. Furthermore, particle swarm optimization is used to optimize the structural parameters of the platform, which significantly improve its stiffness and workspace. Last, the effectiveness of the proposed numerical model is verified by finite element analysis and experiment.


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