Design and Modeling of a Large Amplitude Compliant Revolute Joint: The Helical Shape Compliant Joint

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Arnaud Bruyas ◽  
Francois Geiskopf ◽  
Pierre Renaud
Keyword(s):  
Numerical Simulation ◽  
Large Amplitude ◽  
Compliant Mechanisms ◽  
Large Range ◽  
Compliant Mechanism ◽  
Rotational Stiffness ◽  
Revolute Joint ◽  
Stiffness Model ◽  
Compliant Joint ◽  
Compliant Mechanism Design

In this paper, the design and modeling of a large amplitude compliant revolute joint are introduced. Based on the implementation of multimaterial additive manufacturing (MM-AM), the joint is of interest for robotic contexts where the design of compact and accurate compliant mechanisms is required. The joint design is first experimentally proven to offer a large range of motion and satisfying kinetostatic properties. A parametric study is then conducted using numerical simulation to define the most interesting geometries. An experimental study is in a third step presented to estimate the rotational stiffness, including the manufacturing impact. A stiffness model is provided for relevant geometries, and their use is finally discussed in the context of compliant mechanism design.

Design of a Generic Zero Stiffness Compliant Joint

2010 ◽  
Author(s):  
Femke M. Morsch ◽  
Just L. Herder
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Great Promise ◽  
Optimized Design ◽  
Analytic Model ◽  
Total Potential ◽  
Fea Model ◽  
Compliant Joint ◽  
Joint Element ◽  
Cross Axis

The objective of this paper is to design a generic zero stiffness compliant joint. This compliant joint could be used as a generic construction element in a compliant mechanism. To avoid the spring-back behavior of conventional compliant joints, the principle of static balancing is applied, implying that for each position of the joint the total potential energy should be constant. To this end, a conventional balanced mechanism, consisting of two pivoted bodies which are balanced with two zero-free-length springs, is taken as an initial concept. The joint is replaced by a compliant cross-axis flexural pivot and each spring is replaced by a pair of compliant leaf springs. For both parts an analytic model was implemented and a configuration with the lowest energy fluctuation was found through optimization. A FEA model was used to verify the analytic model of the optimized design. A prototype was manufactured and tested. Both the FEA model and the experiment confirm the reduction of the needed moment to rotate the compliant joint. The experiment shows the balanced compliant joint is not completely balanced but the moment required to rotate the joint is reduced by 70%. Thus, a statically balanced compliant generic joint element was designed which bears great promise in designing statically balanced compliant mechanisms and making this accessible to any designer.

Piezoelectric Actuator Performance Metrics and Relation to Compliant Mechanism Design

2001 ◽  
Author(s):  
Hima Maddisetty ◽  
Mary Frecker
Keyword(s):  
Topology Optimization ◽  
Performance Metrics ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Mechanical Efficiency ◽  
High Energy ◽  
High Energy Density ◽  
High Bandwidth ◽  
Compliant Mechanism Design ◽  
Actuator Performance

Abstract Piezoceramic actuators have gained widespread use due to their desirable qualities of high force, high bandwidth, and high energy density. Compliant mechanisms can be designed for maximum stroke amplification of piezoceramic actuators using topology optimization. In this paper, the mechanical efficiency and other performance metrics of such compliant mechanism/actuator systems are studied. Various definitions of efficiency and other performance metrics of actuators with amplification mechanisms from the literature are reviewed. These metrics are then applied to two compliant mechanism example problems and the effect of the stiffness of the external load is investigated.

A Well-Behaved Revolute Flexure Joint for Compliant Mechanism Design

1999 ◽  
Vol 121 (3) ◽  
pp. 424-429 ◽  
Author(s):  
M. Goldfarb ◽  
J. E. Speich
Keyword(s):  
Mechanism Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Bending Properties ◽  
Thin Beam ◽  
Primary Mechanism ◽  
Joint Characteristics ◽  
Flexure Joints ◽  
Compliant Mechanism Design ◽  
Torsional Properties

This paper describes the design of a unique revolute flexure joint, called a split-tube flexure, that enables (lumped compliance) compliant mechanism design with a considerably larger range-of-motion than a conventional thin beam flexure, and additionally provides significantly better multi-axis revolute joint characteristics. Conventional flexure joints utilize bending as the primary mechanism of deformation. In contrast, the split-tube flexure joint incorporates torsion as the primary mode of deformation, and contrasts the torsional properties of a thin-walled open-section member with the bending properties of that member to obtain desirable joint behavior. The development of this joint enables the development of compliant mechanisms that are quite compliant along kinematic axes, extremely stiff along structural axes, and are capable of kinematically well-behaved large motions.

Utilizing a Classification Scheme to Facilitate Rigid-Body Replacement for Compliant Mechanism Design

2010 ◽  
Author(s):  
Brian M. Olsen ◽  
Yanal Issac ◽  
Larry L. Howell ◽  
Spencer P. Magleby
Keyword(s):  
Rigid Body ◽  
Mechanism Design ◽  
Classification Scheme ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
The Other ◽  
Design Approach ◽  
Compliant Mechanism Design

The knowledge related to the synthesis and analysis of compliant mechanisms continues to grow and mature. Building on this growth, a classification scheme has been established to categorize compliant elements and mechanisms in a manner that engineers can incorporate compliance into their designs. This paper demonstrates a design approach engineers can use to convert an existing rigid-body mechanism into a compliant mechanism by using an established classification scheme. This approach proposes two possible techniques that use rigid-body replacement synthesis in conjunction with a compliant mechanism classification scheme. One technique replaces rigid-body elements with a respective compliant element. The other technique replaces a complex rigid-body mechanism by decomposing the mechanism into simpler functions and then replacing a respective rigid-body mechanism with a compliant mechanism that has a similar functionality.

Hybrid Compliant Mechanism Design Using a Mixed Mesh of Flexure Hinge Elements and Beam Elements Through Topology Optimization

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Lin Cao ◽  
Allan T. Dolovich ◽  
Wenjun (Chris) Zhang
Keyword(s):  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Optimization Technique ◽  
Flexure Hinge ◽  
Beam Elements ◽  
Flexure Hinges ◽  
New Type ◽  
Meshing Scheme ◽  
Compliant Mechanism Design

This paper proposes a topology optimization framework to design compliant mechanisms with a mixed mesh of both beams and flexure hinges for the design domain. Further, a new type of finite element, i.e., super flexure hinge element, was developed to model flexure hinges. Then, an investigation into the effects of the location and size of a flexure hinge in a compliant lever explains why the point-flexure problem often occurs in the resulting design via topology optimization. Two design examples were presented to verify the proposed technique. The effects of link widths and hinge radii were also investigated. The results demonstrated that the proposed meshing scheme and topology optimization technique facilitate the rational decision on the locations and sizes of beams and flexure hinges in compliant mechanisms.

Shape Optimization Framework for the Path of the Primary Compliance Vector in Compliant Mechanisms

2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Hylke Kooistra ◽  
Charles J. Kim ◽  
Werner W. P. J. van de Sande ◽  
Just L. Herder
Keyword(s):  
Mechanism Design ◽  
Deformation Mechanism ◽  
General Framework ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Optimization Framework ◽  
Kinematic Behavior ◽  
Curve Representation ◽  
Compliant Mechanism Design ◽  
Load Perturbations

Abstract The primary compliance vector (PCV) captures the dominant kinematic behavior of a compliant mechanism. Its trajectory describes large deformation mechanism behavior and can be integrated in an optimization objective in detailed compliant mechanism design. This paper presents a general framework for the optimization of the PCV path, the mechanism trajectory of lowest energy, using a unified stiffness characterization and piecewise curve representation. We present a meaningful objective formulation for the PCV path that evaluates path shape, location, orientation, and length independently and apply the framework to two design examples. The framework is useful for design of planar and shell compliant mechanisms that traverse a specified mechanism trajectory and that are insensitive to load perturbations.

A Compliant Mechanism Design Methodology for Coupled and Uncoupled Systems, and Governing Free Choice Selection Considerations

2004 ◽  
Author(s):  
Ashok Midha ◽  
Yuvaraj Annamalai ◽  
Sharath K. Kolachalam
Keyword(s):  
Rigid Body ◽  
Design Methodology ◽  
Free Choice ◽  
Compliant Mechanisms ◽  
State Of The Art ◽  
Compliant Mechanism ◽  
Mechanism Synthesis ◽  
Strongly Coupled ◽  
Revolute Joints ◽  
Compliant Mechanism Design

Compliant mechanisms are defined as mechanisms that gain some, or all of their mobility from the flexibility of their members. Suitable use of pseudo-rigid-body models for compliant segments, and relying on the state-of-the-art knowledge of rigid-body mechanism synthesis types, greatly simplifies the design of compliant mechanisms. Assuming a pseudo-rigid-body four-bar mechanism, with one to four torsional springs located at the revolute joints to represent mechanism compliance, a simple, heuristic approach is provided to develop various compliant mechanism types. The synthesis with compliance method is used for three, four and five precision positions, with consideration of one to four torsional springs, to systematically develop design tables for standard mechanism synthesis types. These tables appropriately reflect the mechanism compliance by specification of either energy or torque. Examples are presented to demonstrate the use of weakly or strongly coupled sets of kinematic and energy/torque equations, as well as different compliant mechanism types in obtaining solutions.

Constant Force Compliant Mechanisms Without Preloading

2021 ◽  
Author(s):  
Premkumar Pujali ◽  
Hong Zhou
Keyword(s):  
Compliant Mechanisms ◽  
Large Range ◽  
Compliant Mechanism ◽  
Experimental Results ◽  
Design Parameters ◽  
Constant Force ◽  
Spline Curves ◽  
Output Force

Abstract A constant force compliant mechanism generates an output force that keeps invariant in a large range of input displacement. Because of the constant force feature and the merits of compliant mechanisms, they are utilized in many applications. A problem in the current constant force compliant mechanisms is their preloading range that is a certain starting range of the input displacement. In the preloading displacement, the output force of a constant force compliant mechanism does not have the desired value. It goes up from zero value. The preloading displacement often occupies one quarter or more of the entire input displacement range, which weakens the performance of constant force compliant mechanisms. The preloading issue is eradicated in this research by using prebuckled beams as components for constructing constant force compliant mechanisms. It is difficult to synthesize constant force compliant mechanisms that are composed of prebuckled beams because of the intertwined force, buckling and deflection characteristics. In this research, the undeformed beams are represented by spline curves and controlled by its interpolation points. The synthesis of constant force compliant mechanisms is systemized as optimizing the design parameters of the composed prebuckled beams. Fully compliant constant force compliant mechanisms are synthesized without preloading. The synthesis solutions are validated by experimental results.

Synthesis of Constant Torque Compliant Mechanisms

2016 ◽  
Vol 8 (6) ◽  
Author(s):  
Hari Nair Prakashah ◽  
Hong Zhou
Keyword(s):  
Compliant Mechanisms ◽  
Large Range ◽  
Compliant Mechanism ◽  
Design Domain ◽  
Control Parameters ◽  
Constant Torque ◽  
Fixed Ring ◽  
Output Torque ◽  
Spline Curves ◽  
Medical And Healthcare

Constant torque compliant mechanisms produce an output torque that does not change in a large range of input rotation. They have wide applications in aerospace, automobile, timing, gardening, medical, and healthcare devices. Unlike constant force compliant mechanisms, the synthesis of constant torque compliant mechanisms has not been extensively investigated yet. In this paper, a method is presented for synthesizing constant torque compliant mechanisms that have coaxial input rotation and output torque. The same shaft is employed for both input rotation and output torque. A synthesized constant torque compliant mechanism is modeled as a set of variable width spline curves within an annular design domain formed between a rotation shaft and a fixed ring. Interpolation circles are used to define variable width spline curves. The synthesis of constant torque compliant mechanisms is systematized as optimizing the control parameters of the interpolation circles of the variable width spline curves. The presented method is demonstrated by the synthesis of constant torque compliant mechanisms that have different number of variable width spline curves in this paper.

Characteristic Deflection Domain for Various Compliant Segment Types, and its Importance in Compliant Mechanism Synthesis and Analysis

2014 ◽  
Author(s):  
Ashok Midha ◽  
Sushrut G. Bapat
Keyword(s):  
Boundary Conditions ◽  
Mechanism Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Solution Process ◽  
Displacement Boundary ◽  
Fundamental Understanding ◽  
Rigid Body Model ◽  
Compliant Mechanism Design ◽  
Insight Into

Compliant mechanism design inherently requires certain specified displacement boundary conditions to be satisfied. Obtaining realistic solutions for such problem types often becomes a challenge as the number of displacement boundary condition specifications increases. Typically, related failures are attributed to the numerical nature of the solution process. Little attention has been given to the fundamental understanding of the deformation behavior of flexible continuum with respect to its limits of mobility or reach. This paper strives to provide an insight into this aspect of compliant mechanism design. To assist a designer with the specification of realistic and achievable requirements, the concept of characteristic deflection domain has been proposed in the past. This paper systematically develops the characteristic deflection domain for a variety of compliant segment types. The pseudo-rigid-body model (PRBM) representation is utilized for determining the lower and upper boundaries of the deflection domain. The paper further investigates the mobility characteristics of compliant mechanisms comprised of multiple segment types. Case studies are presented that help exemplify the use of the characteristic deflection domain plots. The results suggest that the number, type, and orientation of the compliant segments have a significant effect on the mobility of compliant mechanisms. Thus, care must be exercised by the designer when specifying free-choices/boundary conditions in compliant mechanisms synthesis and analysis.

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