Compliant Mechanism Reconfiguration Based on Position Space Concept for Reducing Parasitic Motion

2015 ◽  
Author(s):  
Haiyang Li ◽  
Guangbo Hao
Keyword(s):  
Finite Element Analysis ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Compliant Mechanism ◽  
Position Space ◽  
Element Analysis ◽  
Compact Structure ◽  
Parasitic Motion ◽  
Compliant Parallel Mechanism ◽  
Space Concept

This paper introduces a compliant mechanism reconfiguration approach that can be used to minimize the parasitic motions of a compliant mechanism. This reconfiguration approach is based on the position spaces, identified by the screw theory, of independent compliant modules in a compliant mechanism system. The parasitic motions (rotations) of a compliant mechanism are first modelled associated with the variables representing any positions of the compliant modules in the position spaces. The optimal positions of the compliant modules are then obtained where the parasitic motions are reduced to minimal values. A procedure of the compliant mechanism reconfiguration approach is summarized and demonstrated using a decoupled XYZ compliant parallel mechanism as an example. The analytical results show that the parasitic motions of the XYZ compliant parallel mechanism in the example can be dramatically reduced by the position/structure reconfiguration, which is also validated by finite element analysis. The position space of a compliant module contains a number of possible positions, thus a compliant mechanism can also be efficiently reconfigured to a variety of practical patterns such as the configuration with compact structure.

Position-Space-Based Compliant Mechanism Reconfiguration Approach and Its Application in the Reduction of Parasitic Motion

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Haiyang Li ◽  
Guangbo Hao ◽  
Richard C. Kavanagh
Keyword(s):  
Parallel Mechanism ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Geometrical Shape ◽  
Position Space ◽  
Element Analysis ◽  
Parasitic Motion ◽  
Compliant Parallel Mechanism ◽  
Motion Characteristics ◽  
Cross Axis

This paper introduces a position-space-based reconfiguration (PSR) approach to the reconfiguration of compliant mechanisms. The PSR approach can be employed to reconstruct a compliant mechanism into many new compliant mechanisms, without affecting the mobility of the compliant mechanism. Such a compliant mechanism can be decomposed into rigid stages and compliant modules. Each of the compliant modules can be placed at any one permitted position within its position space, which does not change the constraint imposed by the compliant module on the compliant mechanism. Therefore, a compliant mechanism can be reconfigured through selecting different permitted positions of the associated compliant modules from their position spaces. The proposed PSR approach can be used to change the geometrical shape of a compliant mechanism for easy fabrication, or to improve its motion characteristics such as cross-axis coupling, lost motion, and motion range. While this paper focuses on reducing the parasitic motions of a compliant mechanism using this PSR approach, the associated procedure is summarized and demonstrated using a decoupled XYZ compliant parallel mechanism as an example. The parasitic motion of the XYZ compliant parallel mechanism is modeled analytically, with three variables which represent any permitted positions of the associated compliant modules in their position spaces. The optimal positions of the compliant modules in the XYZ compliant parallel mechanism are finally obtained based on the analytical results, where the parasitic motion is reduced by approximately 50%. The reduction of the parasitic motion is verified by finite-element analysis (FEA) results, which differ from the analytically obtained values by less than 7%.

Design of a 3-DOF Compliant Parallel Mechanism for Displacement Amplification

2013 ◽  
Author(s):  
Qiang Zeng ◽  
Kornel F. Ehmann
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heat Balance ◽  
Parallel Mechanism ◽  
Compliant Mechanism ◽  
Element Analysis ◽  
Resonant Frequencies ◽  
Compact Size ◽  
Compliant Parallel Mechanism ◽  
Monolithic Structure

Prevalent general design methods and applications of compliant displacement amplifiers are focused on 1-DOF units composed into serial structures, which are limited by their output motions, stiffness, heat balance, repeatability and resonant frequencies. To improve the output properties of compliant displacement amplifiers, a monolithic structure is presented in the form of a compliant parallel mechanism. In the proposed moving structure, the compliant mechanism of the displacement amplifier is designed with 3-DOF to generate uniformly magnified output properties in all directions. High first resonant frequencies and amplification ratios are achieved in a compact size compared to existing compliant displacement amplifiers. The related kinematics, amplification ratios and resonant frequencies of the amplifier are analytically modeled, and the results are simulated by finite-element analysis. The proposed design is employable for micro/nano positioning stages operating within a prismatic output workspace.

Stiffness Modeling and Analysis of Passive Four-Bar Parallelogram in Fully Compliant Parallel Positioning Stage

2011 ◽  
Vol 1 (1) ◽  
pp. 61-78 ◽  
Author(s):  
X. Jia ◽  
Y. Tian ◽  
D. Zhang ◽  
J. Liu
Keyword(s):  
Finite Element Analysis ◽  
Parallel Mechanism ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Stiffness Modeling ◽  
Stiffness Model ◽  
The Finite Element Analysis ◽  
Positioning Stage ◽  
Compliant Parallel Mechanism ◽  
Stiffness Variation

In order to investigate the influence of the stiffness of the compliant prismatic pair, a planar four-bar parallelogram, in a fully compliant parallel mechanism, the stiffness model of the passive compliant prismatic pair in a compliant parallel positioning stage is established using the compliant matrix method and matrix transformation. The influences of the constraints and the compliance of the connecting rods on the flexibility characteristics of the prismatic pair are studied based on the developed model. The relative geometric parameters are changed to show the rules of the stiffness variation and to obtain the demands for simplification in the stiffness modeling of the prismatic pair. Furthermore, the finite element analysis has been conducted to validate the analytical model.

Stiffness Modeling and Analysis of Passive Four-Bar Parallelogram in Fully Compliant Parallel Positioning Stage

2013 ◽  
pp. 59-75
Author(s):  
X. Jia ◽  
Y. Tian ◽  
D. Zhang ◽  
J. Liu
Keyword(s):  
Finite Element Analysis ◽  
Parallel Mechanism ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Stiffness Modeling ◽  
Stiffness Model ◽  
The Finite Element Analysis ◽  
Positioning Stage ◽  
Compliant Parallel Mechanism ◽  
Stiffness Variation

In order to investigate the influence of the stiffness of the compliant prismatic pair, a planar four-bar parallelogram, in a fully compliant parallel mechanism, the stiffness model of the passive compliant prismatic pair in a compliant parallel positioning stage is established using the compliant matrix method and matrix transformation. The influences of the constraints and the compliance of the connecting rods on the flexibility characteristics of the prismatic pair are studied based on the developed model. The relative geometric parameters are changed to show the rules of the stiffness variation and to obtain the demands for simplification in the stiffness modeling of the prismatic pair. Furthermore, the finite element analysis has been conducted to validate the analytical model.

Design and Analysis of a Compact Piezo-actuated Microgripper with a Large Amplification Ratio

2021 ◽  
pp. 1-5
Author(s):  
Fangxin Chen ◽  
Qianjun Zhang ◽  
Yongzhuo Gao ◽  
Wei Dong
Keyword(s):  
Finite Element Analysis ◽  
Design Methodology ◽  
Compliant Mechanisms ◽  
Experimental Studies ◽  
Flexure Hinge ◽  
Element Analysis ◽  
Compact Structure ◽  
Amplification Ratio ◽  
Parasitic Motion ◽  
Structure Dimension

Abstract Abstract This paper presents a piezo-actuated microgripper characterized by large amplification ratio and compact structure size. The microgripper is actuated by a piezo-stack actuator that is integrated with a two-stage displacement amplifier to achieve large travel range. A new design methodology “flexure hinge individualized design” (FHID) was proposed to realize large amplification ratio. According to this methodology, each flexure hinge was designed personally based on force condition of the piviot to reconfigure the motion stiffness of the compliant microgripper so that the parasitic motion and displacement loss could be eliminated. Consequently, a 52-amplification-ratio amplifier was obtained. The developed microgripper was modeled via kinematics and Castigliano's displacement theorem, respectively. Finite element analysis and the experimental studies were conducted to evaluate the characteristics of the microgripper. The results show that the motion stroke of the gripper-tip is 917 μm, and the structure dimension is 62 mm × 42 mm ×12 mm. The design methodology FHID is generic and can be extended to other compliant mechanisms.

Design of a Single-Acting Constant-Force Actuator Based on Dielectric Elastomers

2008 ◽  
Author(s):  
Giovanni Berselli ◽  
Rocco Vertechy ◽  
Gabriele Vassura ◽  
Vincenzo Parenti Castelli
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanism ◽  
Structural Parameters ◽  
Dielectric Elastomer ◽  
Constant Force ◽  
Element Analysis ◽  
Body Model ◽  
Rigid Body Model ◽  
Supporting Frame

The interest in actuators based on dielectric elastomer films as a promising technology in robotic and mechatronic applications is increasing. The overall actuator performances are influenced by the design of both the active film and the film supporting frame. This paper presents a single-acting actuator which is capable of supplying a constant force over a given range of motion. The actuator is obtained by coupling a rectangular film of silicone dielectric elastomer with a monolithic frame designed to suitably modify the force generated by the dielectric elastomer film. The frame is a fully compliant mechanism whose main structural parameters are calculated using a pseudo-rigid-body model and then verified by finite element analysis. Simulations show promising performance of the proposed actuator.

Bistable Compliant Four-Bar Mechanisms With a Single Torsional Spring

2006 ◽  
Author(s):  
Adarsh Mavanthoor ◽  
Ashok Midha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanism Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Stored Energy ◽  
Element Analysis ◽  
Bistable Behavior ◽  
Torsional Spring ◽  
Bistable Mechanism

Significant reduction in cost and time of bistable mechanism design can be achieved by understanding their bistable behavior. This paper presents bistable compliant mechanisms whose pseudo-rigid-body models (PRBM) are four-bar mechanisms with a torsional spring. Stable and unstable equilibrium positions are calculated for such four-bar mechanisms, defining their bistable behavior for all possible permutations of torsional spring locations. Finite Element Analysis (FEA) and simulation is used to illustrate the bistable behavior of a compliant mechanism with a straight compliant member, using stored energy plots. These results, along with the four-bar and the compliant mechanism information, can then be used to design a bistable compliant mechanism to meet specified requirements.

Analysis of Parasitic Motion in Compliant Mechanisms Using Eigenwrenches and Eigentwists

2018 ◽  
Author(s):  
Werner W. P. J. van de Sande ◽  
Just L. Herder
Keyword(s):  
Compliant Mechanisms ◽  
Screw Theory ◽  
Compliant Mechanism ◽  
Degree Of Freedom ◽  
Compliance Matrix ◽  
Parasitic Motion ◽  
Actual Degree ◽  
Motion Metrics ◽  
Mechanism Kinematic ◽  
Kinematic Information

Parasitic motion is undesired in precision mechanisms, it causes unwanted kinematics. These erroneous motions are especially apparent in compliant mechanisms. Usually an analysis of parasitic motion is only valid for one type of mechanism. Kinematic information is imbedded in the compliance matrix of any mechanism; an eigenscrew decomposition expresses this kinematic information as screws. It uses screw theory to identify the lines along which a force yields a parallel translation and a rotation yields a parallel moment. These lines are called eigenwrenches and eigentwists. Any other load on the compliant mechanism will lead to parasitic motion. This article introduces two parasitic motion metrics using eigenscrew decomposition: the parasitic resultant from an applied screw and the deviation of an actual degree of freedom from a desired degree of freedom. These metrics are applicable to all compliant mechanism and allow comparison between two compliant mechanisms. These metrics are applied to some common compliant mechanisms as an example.

Experimental Validation of the Kinematics of a 3PRS Compliant Mechanism for Micromilling

2015 ◽  
Author(s):  
Antonio Ruiz ◽  
Francisco Campa Gomez ◽  
Constantino Roldan-Paraponiaris ◽  
Oscar Altuzarra
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Experimental Validation ◽  
Compliant Mechanism ◽  
Motion Controller ◽  
End Effector ◽  
Compliant Joints ◽  
Hybrid Manipulator ◽  
Compliant Parallel Mechanism ◽  
Actuated Joints

The present work deals with the development of a hybrid manipulator of 5 degrees of freedom for milling moulds for microlenses. The manipulator is based on a XY stage under a 3PRS compliant parallel mechanism. The mechanism takes advantage of the compliant joints to achieve higher repetitiveness, smoother motion and a higher bandwidth, due to the high precision demanded from the process, under 0.1 micrometers. This work is focused on the kinematics of the compliant stage of the hybrid manipulator. First, an analysis of the workspace required for the milling of a single mould has been performed, calculating the displacements required in X, Y, Z axis as well as two relative rotations between the tool and the workpiece from a programmed toolpath. Then, the 3PRS compliant parallel mechanism has been designed using FEM with the objective of being stiff enough to support the cutting forces from the micromilling, but flexible enough in the revolution and spherical compliant joints to provide the displacements needed. Finally, a prototype of the 3PRS compliant mechanism has been built, implementing a motion controller to perform translations in Z direction and two rotations. The resulting displacements in the end effector and the actuated joints have been measured and compared with the FEM calculations and with the rigid body kinematics of the 3PRS.

scholarly journals Research on three-stage amplified compliant mechanism-based piezo-driven microgripper

2020 ◽  
Vol 12 (3) ◽  
pp. 168781402091147 ◽  
Author(s):  
Xiaodong Chen ◽  
Zilong Deng ◽  
Siya Hu ◽  
Xingjun Gao ◽  
Jinhai Gao
Keyword(s):  
Amplification Factor ◽  
Compliant Mechanism ◽  
Structural Parameters ◽  
Maximum Output ◽  
Driving Voltage ◽  
Element Analysis ◽  
Compact Structure ◽  
Output Displacement ◽  
Amplification Ratio ◽  
Input Variables

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.

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