Understanding coupled factors that affect the modelling accuracy of typical planar compliant mechanisms

Hao, Guangbo; Li, Haiyang; Kemalcan, Suzen; Chen, Guimin; Yu, Juebang

doi:10.1007/s11465-016-0392-z

Cited by 17 publications

(9 citation statements)

References 12 publications

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“…This assumption is valid because all links are considered coplanar and the efforts are applied in the links plane. If these hypotheses were not verified, other assumptions should have been taken into account [78]. For all optimization rounds, in order to obtain a smoother layout without checkerboards problem, a filtering procedure is used that consists in the modification of the density variables assigned to the elements with the information of its neighborhoods as was proposed in [79].…”

Section: Resultsmentioning

confidence: 99%

Topology optimization of industrial robots: Application to a five-bar mechanism

Briot

Goldsztejn

2018

Mechanism and Machine Theory

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Recent works introduced topology optimization in the design of robots, but the proposed methodologies led to a local optimization of the performance. Moreover, most of performance indices used are not in strong relation with easy-to-understand technological requirements. We propose a methodology that is able to perform a topology optimization for robots, valid globally in the workspace or for a set of given trajectories, and which is based on the use of technology-oriented performance criteria. In order to enforce the chosen performance indices to be valid globally, optimal robot configurations or trajectories for which extreme performance will be attained are computed, and iteratively updated. In order to decrease the computational time associated with these performance indices, we exploit the structure of the elastic models in order to reduce their computational complexity. Finally, we use an optimization algorithm called the Linearization Method which gives results in a computational time equivalent to standard topology optimization algorithms, but its implementation is less complex and makes it quite easy to perform modification or improvement. The methodology is applied for the design of a five-bar mechanism. We show that our approach leaded to a robust optimization of the robot performance over the whole workspace.

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Section: Resultsmentioning

confidence: 99%

Topology optimization of industrial robots: Application to a five-bar mechanism

Briot

Goldsztejn

2018

Mechanism and Machine Theory

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“…In order to accurately perform analytical modeling, the equivalent modulus of the compliant plates is required. 26 The ranges of the parameters of the compliant plates are listed in Table 1 and the optimization of the parameters is presented in the “Parameters optimization” section. The equivalent modulus of the compliant plates depends on the width-to-thickness ( b / t ) ratio.…”

Section: Modelingmentioning

confidence: 99%

“…Furthermore, the plate modulus of the material E'=E/(1-ν2) ( E is the Young’s modulus and ν is the Poisson’s ratio) is used as the equivalent modulus. 26,27 Table 2 lists the parameters, c1n and c2n ( n = 1,2,…,8). 18…”

Section: Modelingmentioning

confidence: 99%

Design and modeling of a compliant tip-tilt-piston micropositioning stage with a large rotation range

Chen

Ding

Zhu

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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In compliant tip-tilt-piston micropositioning stages, it is difficult to achieve a large rotation range using small air–gap voice coil actuators. With a smaller air gap, the voice coil actuators can produce a larger output force; however, the coil of the voice coil actuator touches the stator as the stage rotates. This paper presents the mechanical design, modeling and experimental tests of a novel large-angle tip-tilt-piston stage driven using four small air-gap voice coil actuators. In order to prevent the occurrence of undesired contact between the coil and stator, a compliant decoupling mechanism is introduced to minimize the transverse displacement of the coil of the voice coil actuator. An improved substructure method based on the compliance matrix is applied to calculate the rotational stiffness of the stage and transverse displacement of the coil. Lagrange’s equation is used to obtain the dynamic resonant frequencies. Based on this, an optimization procedure is proposed for determining the design parameters of the stage. The finite element analysis is performed to verify the theoretical calculation. Finally, a prototype of the stage is fabricated, and experiments are conducted to validate the feasibility of the stage. The proposed stage can achieve rotational–motion strokes of 83.18 mrad and 82.26 mrad in the working axes, for which the rotational mode frequencies are 55.45 Hz and 56.09 Hz, respectively. The motion resolution of the stage is ±6.67 μrad. The maximum transverse displacement of the coil of the voice coil actuator is 10.98 µm, which is negligible as compared to the air gap (0.38 mm) of the voice coil actuator. In summary, a tip-tilt-piston stage was designed to achieve a large rotation range using small-air-gap voice coil actuators.

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“…The deviation between the theoretical model and finite element model (FEM) in terms of compliance (the reciprocal of stiffness) may be caused by the improper assumption about the stress-strain state. 32 The theoretical model is based on the planar stress assumption which may be not proper because the leaf springs in the SPLCM are usually under spatial loads. According to Hao's analysis in Hao et al 32 and the specific parameters of the leaf spring, the difference between the forces under no planar assumption and planar stress assumption may be about 6%-8%, which is close to the compliance error between the theoretical model and FEM.…”

Section: Static Analysis Comparisonmentioning

confidence: 99%

Design and modeling of a novel monolithic parallel XY stage with centimeters travel range

Liu

Fan

Xie

et al. 2017

Advances in Mechanical Engineering

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Since most of XY positioning stages with large travel range proposed by former researchers suffer from loose structure and low out-of-plane payload, this article presents a novel monolithic parallel XY stage based on spatial prismaticprismatic joints with centimeters travel range, compact size, and high out-of-plane payload capacity. The novel parallel linear compliant mechanism of the stage is composed of four spatial prismatic-prismatic joints, which is two compound leaf spring parallelograms serially connected in cubical space to obtain large travel, compact size, and high out-of-plane payload capacity simultaneously. The theoretical static stiffness and resonant frequencies are obtained by matrix structural analysis. As a case study, a reified stage is presented and discussed in detail. Finally, theoretical models are comprehensively compared with finite element analysis models. It is shown that the stage in the case study has the following merits: large travel range up to 20 3 20 mm 2 , high-area ratio of workspace to the outer dimension of the stage about 2.26%, well-constrained cross-axis coupling motion less than 1.5 mm at the full primary motion, acceptable resonant frequencies of the two translational axes about 34 Hz, and large out-of-plane payload capacity more than 24 kg.

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Understanding coupled factors that affect the modelling accuracy of typical planar compliant mechanisms

Cited by 17 publications

References 12 publications

Topology optimization of industrial robots: Application to a five-bar mechanism

Topology optimization of industrial robots: Application to a five-bar mechanism

Design and modeling of a compliant tip-tilt-piston micropositioning stage with a large rotation range

Design and modeling of a novel monolithic parallel XY stage with centimeters travel range

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