Design and testing of a novel 2-DOF compound constant-force parallel gripper

Zhang, Xiaozhi; Xu, Qingsong

doi:10.1016/j.precisioneng.2018.09.004

Cited by 43 publications

(17 citation statements)

References 26 publications

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“…Constant Force Mechanisms (CFMs) are traditionally the ones that deliver constant output forces while undergoing finite deformations [1,2]. Electrical connectors [3,4], automotive clutches [5,6], exercise equipment [7,8], robotic automation involving end-effectors/grippers [9][10][11][12][13], snap fits [14], MEMS [15,16], force regulation/overload protection [17] and precision positioning [18] are some applications they may find use in. As a CFM offers nearly constant output force (thus will be referred to as with frame elements using stochastic search, with two different optimization formulations, namely, (a) neutral stability (using the buckling modes) and (b) continuous equilibrium (using large deformation analysis).…”

Section: Introductionmentioning

confidence: 99%

“…Compliant mechanisms are preferred over rigid-link ones due to inherent advantages of no friction, no backlash or need for lubrication, ease of assembly and miniaturization.Thus, compliant CFMs are desired over conventional ones. Two design approaches can be employed for monolithic CFMs, just as for generic compliant mechanisms -for instance, those in [1] and [9] are designed using the Pseudo-Rigid-Body Model (PRBM) approach whereas Topology Optimization (TO) is adopted in [2].Compliant constant input force mechanisms (CiFMs), e.g., [29] can also find a variety of applications, especially if the actuation force required is ideally zero over a range of input displacement.Design methods for, and realization of the latter class of CiFMs, termed statically balanced compliant mechanisms (or SBCMs), have gained significant attention in recent years [30][31][32][33][34][35][36][37][38][39]. Static balancing is achieved by ensuring that the (potential) energy stored within the deforming continuum is constant [32] so that both, the actuation force 1 and stiffness 2 are zero over a range of input displacement [40].…”

mentioning

confidence: 99%

“…Compliant constant input force mechanisms (CiFMs), e.g., [29] can also find a variety of applications, especially if the actuation force required is ideally zero over a range of input displacement.…”

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confidence: 99%

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Compliant Constant Output/ Input Force Mechanisms- Topology Optimization with Contact

Reddy¹,

Khatik²,

Corves³

et al. 2022

Preprint

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We synthesize monolithic topologies of constant output (CoFM) and input (CiFM) force mechanisms. During synthesis, we capture all possible aspects of member deformation including finite displacements, buckling, interaction between members, their interaction with external surfaces, and importantly, interaction of the mechanism with flexible workpieces to capture force transfer in true sense. Features of constant force characteristics, e.g., magnitude(s) of the desired force(s), range of input displacement over which slope of the force-displacement curve is near zero, and distance between workpiece and the mechanism are controlled individually via novel objectives proposed herein.Two of the constant output and constant input force mechanisms each, are synthesized using stochastic optimization ensuring ready manufacturability. We observe that presence of external surfaces may not be required for singlepiece mechanisms to attain constant force characteristics. However, interesting solutions are possible if mutual contact is permitted. We also note that desired force characteristics may not remain the same with alteration in the workpieces' shape and/or material properties. We finally fabricate and test the synthesized mechanisms and find that the desired constant force characteristics are by-and-large retained.CoFM henceforth), need for force feedback gets reduced/eliminated which makes it cost effective and easy to use, without the requirement of sensors and control systems. Some conventional (rigidlink with springs) and compliant CFMs are described in [19-21] and [22-27] respectively. Wang and Xu [28] provide a detailed survey, highlighting advantages and pitfalls of five types of conventional and compliant CFMs each. Compliant mechanisms are preferred over rigid-link ones due to inherent advantages of no friction, no backlash or need for lubrication, ease of assembly and miniaturization.Thus, compliant CFMs are desired over conventional ones. Two design approaches can be employed for monolithic CFMs, just as for generic compliant mechanisms -for instance, those in [1] and [9] are designed using the Pseudo-Rigid-Body Model (PRBM) approach whereas Topology Optimization (TO) is adopted in [2].Compliant constant input force mechanisms (CiFMs), e.g., [29] can also find a variety of applications, especially if the actuation force required is ideally zero over a range of input displacement.Design methods for, and realization of the latter class of CiFMs, termed statically balanced compliant mechanisms (or SBCMs), have gained significant attention in recent years [30][31][32][33][34][35][36][37][38][39]. Static balancing is achieved by ensuring that the (potential) energy stored within the deforming continuum is constant [32] so that both, the actuation force 1 and stiffness 2 are zero over a range of input displacement [40]. Synthesis approaches for SBCMs employ the Pseudo-Rigid-Body approach, e.g., [1], stiffness compensation using building blocks, e.g., [32] and topology optimization, e.g, [40]. A compliant constant o...

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Compliant Constant Output/ Input Force Mechanisms- Topology Optimization with Contact

Reddy¹,

Khatik²,

Corves³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…With the development of the micro-nano field, it is difficult for the single degree of freedom platforms to meet the requirements of current precise operation. Therefore, the research of high-performance multi-degree of freedom precision positioning platforms has become the research focus in these years [22,23].…”

Section: Introductionmentioning

confidence: 99%

Design of a 3DOF XYZ Bi-Directional Motion Platform Based on Z-Shaped Flexure Hinges

Gan

Long

2021

Micromachines

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This paper presents a design of a 3DOF XYZ bi-directional motion platform based on Z-shaped flexure hinges. In the presented platform, bridge-type mechanisms and Z-shaped flexure hinges are adopted to amplify its output displacement. Bi-direction motion along the X-axis and Y-axis follows the famous differential moving principle DMP, and the bi-directional motion along the Z-axis is realized by using the reverse arrangement of the Z-shaped flexure hinges along the X-axis and Y-axis. Statics analysis of the proposed platform is carried out by the energy method, compliance matrix method, and force balance principle. Meanwhile, the Lagrange method is used to analyze the dynamics of the platform. A series of simulations are conducted to demonstrate the effectiveness of the proposed design. The simulation results show that the average displacements of the platform in the XYZ-axis are ±125.58 μm, ±126.37 μm and ±568.45 μm, respectively.

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“…Compliant constant-force mechanisms are deformable members operated by relying on elastic deformation, and can be used in design of precision systems, such as the positioning stages [2]- [4] and the constant-force compliant grippers [5]- [7]. In order to analyze the input and output relationship of the constant-force mechanisms, Boyle et al [8] developed a mathematical model to analyze a constant-force compression mechanism which consists of a slider, two rigid links, and two large-deflection beams; the dynamic equation is derived from a generalized pseudo-rigid-body model [9].…”

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confidence: 99%

Topology Optimization for Design of a 3D-Printed Constant-Force Compliant Finger

Liu

Chung

2021

IEEE/ASME Trans. Mechatron.

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A compliant constant-force mechanism is a passive force regulation device that can generate a nearly constant output force over a range of input or output displacements while without the use of sensors and feedback control. In topology synthesis of a compliant constantforce mechanism for a given input displacement range, the constant output force can be achieved by maintaining the output displacement to be nearly a same value while the input displacement increases. In order to further control the desired output displacement for the compliant constantforce mechanism before contacting the object, this article introduces a new composite objective function that can consider both the output force (with contact) and the output displacement (without contact) of the synthesized compliant mechanism. The sensitivity for the proposed objective function with respect to the element density is derived while considering the effect of nonlinearity in the large deformation condition. The proposed topology optimization method is used to design an innovative constant-force compliant finger, and its prototype is manufactured by 3-D printing using a flexible thermoplastic elastomer. The experimental results show the developed constant-force compliant finger can provide a nearly constant output force of 41.9 N over the input displacement ranging from 15 to 30 mm while the maximum and average force variations within the constant-force range are 2.2% and 0.9%, respectively. In addition, the developed constant-force compliant finger is used to design a three-fingered constant-force compliant gripper that can be used in robotic grasping of fragile objects.

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Design and testing of a novel 2-DOF compound constant-force parallel gripper

Cited by 43 publications

References 26 publications

Compliant Constant Output/ Input Force Mechanisms- Topology Optimization with Contact

Compliant Constant Output/ Input Force Mechanisms- Topology Optimization with Contact

Design of a 3DOF XYZ Bi-Directional Motion Platform Based on Z-Shaped Flexure Hinges

Topology Optimization for Design of a 3D-Printed Constant-Force Compliant Finger

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