Design and modeling of constant-force mechanisms: A survey

Wang, Piyu; Xu, Qingsong

doi:10.1016/j.mechmachtheory.2017.08.017

Cited by 131 publications

(50 citation statements)

References 59 publications

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“…Bistable beams exhibit additional advantages, such as their simplicity, passive holding, low actuation energy, small footprint, large stroke with small restoring forces, and negative stiffness zone. These advantages make bistable beams suitable for an increasing number of applications at different scales, such as space applications [1], biomedical [2], energy harvesting [3,4], resonators [5], actuators [6] accelerometers [7], shock sensors [8], gas sensors [9], pressure sensors [10], flow sensors [11], grippers [12], mechanisms with large displacement and small actuation stroke [13], switches [14], relays [15], memory devices [16], logics [17], lamina emergent frustrum [18], statically-balanced mechanisms [19], soft robotics [20], constant force mechanisms [21,22], bistable positioning [23][24][25][26], and multistable devices [27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Analytical Study of the Snap-Through and Bistability of Beams With Arbitrarily Initial Shape

Hussein

Younis

2020

Journal of Mechanisms and Robotics

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We derive the snap-through solution and the governing snapping force equations for an arbitrarily pre-shaped beam deflected under a mid-length lateral point force. The exact solution is obtained based on the classical theory of elastic beams as a superposition of the initial shape and the modes of buckling. Two kinds of solution are identified depending on the axial force level. The two solutions, bifurcation conditions, bistability conditions, and the snapping force equations are derived and discussed. The snap-through and snapping force solutions are then calculated for two common beam initial shapes, the curved (first buckling shape) and the inclined one (V-shape). In both cases, explicit expressions are obtained describing the snap-through behavior. The analytical modeling results show excellent agreement with the finite element simulations. The comparison between the two cases shows a similar snap-through behavior qualitatively, while several differences and similarities are noticed quantitatively.

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Section: Introductionmentioning

confidence: 99%

Analytical Study of the Snap-Through and Bistability of Beams With Arbitrarily Initial Shape

Hussein

Younis

2020

Journal of Mechanisms and Robotics

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“…Flexure-based compliant mechanisms generally refer to mechanical devices gaining some or all of their mobility through elastic deformation of flexible members [1], which by nature possess the benefits of monolithic structure and variable stiffness over their rigid-body counterparts, thereby reducing friction, backlash, wear, no need for lubrication and assembly. Owing to these uniqueness, compliant mechanisms have been widely applied, including constant-force generation [2], multistable switches [3], micro-electro mechanical systems (MEMS) [4], precision positioning stages and grippers [5][6][7], micro/nanomanipulations [8], fast servotools in precision machining [9], servovalves [10], energy harvesting [11], microvibration suppression [12], alignment of optics, robotic actuation [13], and so forth.…”

Section: Introductionmentioning

confidence: 99%

“…With similar conversion formulas, the kinetostatic and dynamic modeling of all kinds of flexure-hingebased compliant mechanisms were carried out based on the finite element method without dealing with the complicated issue of variable cross section in flexure hinges [91,92]. [2,5,51,52] (Reprinted with permission from Wang and Xu [2]. Copyright 2018 by Elsevier; Reprinted with permission from Qin et al [5].…”

Section: Introductionmentioning

confidence: 99%

Kinetostatic and Dynamic Modeling of Flexure-Based Compliant Mechanisms: A Survey

Ling

Howell

Cao

et al. 2020

Applied Mechanics Reviews

163

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Flexure-based compliant mechanisms are becoming increasingly promising in precision engineering, robotics, and other applications due to the excellent advantages of no friction, no backlash, no wear, and minimal requirement of assembly. Because compliant mechanisms have inherent coupling of kinematic-mechanical behaviors with large deflections and/or complex serial-parallel configurations, the kinetostatic and dynamic analyses are challenging in comparison to their rigid-body counterparts. To address these challenges, a variety of techniques have been reported in a growing stream of publications. This paper surveys and compares the conceptual ideas, key advances, and applicable scopes, and open problems of the state-of-the-art kinetostatic and dynamic modeling methods for compliant mechanisms in terms of small and large deflections. Future challenges are discussed and new opportunities for extended study are highlighted as well. The presented review provides a guide on how to select suitable modeling approaches for those engaged in the field of compliant mechanisms.

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“…Using the characteristics of the mechanical structure, the constant force of mechanisms can provide approximately constant force output. Constant force of mechanisms is widely used in overload protection, biomedical applications, and robotic end effectors to provide friendly interaction with the environment, as well as to protect micro-objects from damage to micro-operations [1]. Because of its many advantages, many scholars have carried out a lot of research on it.…”

Section: Introductionmentioning

confidence: 99%

An Output Force Control for Robotic Manipulator by Changing the Spring Stiffness

Wang

Zheng

et al. 2020

Mathematical Problems in Engineering

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This paper presents an output control for a manipulator by changing the spring stiffness. Through the modeling and analysis of the nonlinear stiffness characteristics of the crank-rocker mechanism, and using the zero stiffness domain search method to select the appropriate spring stiffness, using different spring stiffness to establish different mechanism models, the robot can finally control the output of ideal constant force, and at the same time, the analysis results are applied to the improved design of the tire grabbing manipulator. Through this method, the tire grabbing manipulator becomes a constant grabbing force mechanism, and the mechanism is transformed from a rigid-body mechanism to a pseudo-rigid-body mechanism. The accuracy and stability of the whole system are greatly improved. In this study, the method of adding spring to each joint of the linkage mechanism is applied to the improvement design of the linkage mechanism, and the four-bar constant force mechanism is designed for the first time, which expands the application field of the nonlinear stiffness characteristics of the linkage mechanism, and has great application value to the improvement design of the mechanical system with the linkage mechanism and the control of the output force.

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Design and modeling of constant-force mechanisms: A survey

Cited by 131 publications

References 59 publications

Analytical Study of the Snap-Through and Bistability of Beams With Arbitrarily Initial Shape

Analytical Study of the Snap-Through and Bistability of Beams With Arbitrarily Initial Shape

Kinetostatic and Dynamic Modeling of Flexure-Based Compliant Mechanisms: A Survey

An Output Force Control for Robotic Manipulator by Changing the Spring Stiffness

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