On a Solution Procedure to Synthesize Non-Smooth Path Generating Compliant Mechanisms With Self Contact

2010 ◽  
Author(s):  
B. V. S. Nagendra Reddy ◽  
Anupam Saxena
Keyword(s):  
Large Deformation ◽  
Elastic Deformation ◽  
Optimum Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Solution Procedure ◽  
Motion Generation ◽  
Contact Sites ◽  
Smooth Path ◽  
Single Piece

A contact-aided compliant mechanism (CCM) is a single piece flexible continuum that uses the contact interactions between different portions in addition to the elastic deformation. Our work deals with the design of contact aided compliant mechanisms with initially curved frame elements to trace more complex and non smooth paths. We can achieve these kinematic tasks by using partially compliant mechanisms as well. But the presence of hinges is a disadvantage in terms of increased friction, backlash, need for lubrication, noise and vibrations. In this paper, we propose an automated procedure to obtain the optimum design of large deformation CCMs. Through commercial software, we simulate the formation of pseudo hinges at contact sites that get formed dynamically as the mechanism deforms. By appropriately positioning these pseudo hinges, i.e., by designing a suitable CCM, the aim, in general, is to achieve a variety of function, path and motion generation characteristics via single piece continua.

Systematic Synthesis of Large Displacement Contact-Aided Monolithic Compliant Mechanisms

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
B. V. S. Nagendra Reddy ◽  
Sujitkumar V. Naik ◽  
Anupam Saxena
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Large Displacement ◽  
Contact Site ◽  
Design Algorithm ◽  
Contact Sites ◽  
Single Piece ◽  
Synthesis Procedure ◽  
Systematic Synthesis ◽  
The Continuum

A single-piece contact-aided compliant mechanism (CCM) deforms to use one or many contact interactions to deliver the prescribed intricate input–output functionality. We present an automated synthesis procedure to design CCMs to trace large, non-smooth paths. Such paths can be traced by rigid-body or partially compliant mechanisms as well but the complexity, bulkiness and the presence of hinges is a disadvantage in terms of increased friction, backlash, need for lubrication, noise, and vibrations. In designing CCMs, both curved frame and two-dimensional finite elements are employed to represent the continuum and simulate the formation of contact sites. A contact site is one that allows relative rotation/sliding of a deforming member with respect to the neighboring one it is in contact with. The proposed design algorithm uses commercial software for large displacement contact analysis. The overall procedure automatically determines the CCM topology, feature shapes and sizes, and therefore the number (e.g., single or multiple) and nature (e.g., stiction or sliding) of contact sites. It systematically favors the continuum designs with lower function values when the synthesis problem is posed using a minimization objective. Synthesis of CCMs is exemplified for path generation applications though the proposed method can be employed for any generic kinematic task.

Large Deformation Behavior of Compliant Mechanisms

2001 ◽  
Author(s):  
Jinyong Joo ◽  
Sridhar Kota ◽  
Noboru Kikuchi
Keyword(s):  
Shape Optimization ◽  
Large Deformation ◽  
Deformation Behavior ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Linear Formulation ◽  
Scaling Effect ◽  
Beam Elements ◽  
Linear And Nonlinear ◽  
Amplification Mechanism

Abstract This paper presents a non-linear formulation for size and shape optimization of compliant mechanisms using tapered beam elements. Designs based on linear and nonlinear formulations are compared using a stroke amplification mechanism example. Also, the scaling effect of the compliant mechanism is investigated.

scholarly journals Design of compliant mechanism-based variable camber morphing wing with nonlinear large deformation

2019 ◽  
Vol 16 (6) ◽  
pp. 172988141988674 ◽  
Author(s):  
Yaqing Zhang ◽  
Wenjie Ge ◽  
Ziang Zhang ◽  
Xiaojuan Mo ◽  
Yonghong Zhang
Keyword(s):  
Large Deformation ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Morphing Wing ◽  
Structure Topology ◽  
Trailing Edges ◽  
Morphing Wings

The morphing wing with large deformation can benefit its flight performance a lot in different conditions. In this study, a variable camber morphing wing with compliant leading and trailing edges is designed by large-displacement compliant mechanisms. The compliant mechanisms are carried out by a hyperelastic structure topology optimization, based on a nonlinear meshless method. A laminated leading-edge skin is designed to fit the curvature changing phenomenon of the leading edge during deformation. A morphing wing demonstrator was manufactured to testify its deformation capability. Comparing to other variable camber morphing wings, the proposal can realize larger deflection of leading and trailing edges. The designed morphing wing shows great improvement in aerodynamic performance and enough strength to resist aerodynamic and structural loadings.

Optimum Design of a Compliant Uniaxial Accelerometer

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Simon Desrochers ◽  
Damiano Pasini ◽  
Jorge Angeles
Keyword(s):  
Stress Concentration ◽  
Optimum Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Pareto Frontier ◽  
Cad Model ◽  
Multi Objective Optimization ◽  
Design Objective ◽  
Multi Objective ◽  
Pareto Plot

This work focuses on the multi-objective optimization of a compliant-mechanism accelerometer. The design objective is to maximize the sensitivity of the accelerometer in its sensing direction, while minimizing its sensitivity in all other directions. In addition, this work proposes a novel compliant hinge intended to reduce the stress concentration in compliant mechanisms. The paper starts with a brief description of the new compliant hinge, the Lamé-shaped hinge, followed by the formulation of the aposteriori multi-objective optimization of the compliant accelerometer. By using the normalized constrained method, an even distribution of the Pareto frontier is found. The paper also provides several optimum solutions on a Pareto plot, as well as the CAD model of the selected solution.

On a Generalized Approach for Design of Compliant Mechanisms Using the Pseudo-Rigid-Body Model Concept

2014 ◽  
Author(s):  
Sushrut G. Bapat ◽  
Ashok Midha ◽  
Ashish B. Koli
Keyword(s):  
Rigid Body ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Motion Generation ◽  
Model Concept ◽  
Finite Element Software ◽  
Body Model ◽  
Wide Range ◽  
Rigid Body Model ◽  
Torque Values

This paper provides a generalized approach for the design of compliant mechanisms. The paper discusses the implicit uncoupling, between the kinematic and energy/torque equations, enabled by the pseudo-rigid-body model concept, and utilizes it for designing a variety of compliant mechanism types for a wide-range of user specifications. Pseudo-rigid-body four-bar mechanisms, with one to four torsional springs located at the revolute joints, are considered to demonstrate the design methodology. Mechanisms are designed for conventional tasks, such as function, path and motion generation, and path generation with prescribed timing, with energy/torque specified at the precision-positions. State-of-the-art rigid-body synthesis techniques are applied to the pseudo-rigid-body model to satisfy the kinematic requirements. Energy/torque equations are then used to account for the necessary compliance according to the user specifications. The approach utilizes a conventional, simple yet efficient optimization formulation to solve energy/torque equations that allow a designer to i) achieve realistic solutions, ii) specify appropriate energy/torque values, and iii) reduce the sensitivities associated with the ‘synthesis with compliance’ approach. A variety of examples are presented to demonstrate the applicability and effectiveness of the approach. All of the examples are verified with the finite element software ANSYS®.

Two Stage Design of Compliant Mechanisms With Superelastic Compliant Joints

2017 ◽  
Author(s):  
Jovana Jovanova ◽  
Mary Frecker
Keyword(s):  
Analytical Model ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Functionally Graded ◽  
Two Stage ◽  
Stage Design ◽  
Rigid Link ◽  
Starting Point ◽  
Single Piece ◽  
Two Stage Design

The design of compliant mechanisms made of Nickel Titanium (NiTi) Shape Memory Alloys (SMAs) is considered to exploit the superelastic behavior of the material to achieve tailored high flexibility on demand. This paper focuses on two-stage design optimization of compliant mechanisms, as a systematic method for design of the composition of the functionally graded NiTi material within the compliant mechanism devices. The location, as well as geometric and mechanical properties, of zones of high and low flexibility will be selected to maximize mechanical performance. The proposed two-stage optimization procedure combines the optimization of an analytical model of a single-piece functionally graded unit, with a detailed FEA of a continuous compliant mechanism. In the first stage, a rigid-link model is developed to initially approximate the behavior of the compliant mechanism. In the second stage the solution of the rigid-link problem serves as the starting point for a continuous analytical model where the mechanism consists of zones with different material properties and geometry, followed by a detailed FEA of a compliant mechanism with integrated zones of superelasticity. The two-stage optimization is a systematic approach for compliant mechanism design with functional grading of the material to exploit superelastic response in controlled manner. Direct energy deposition, as an additive manufacturing technology, is foreseen to fabricate assemblies with multiple single piece functional graded components. This method could be applied to bio-inspired structures, flapping wings, flexible adaptive structures and origami inspired compliant mechanisms.

Large Deformation Analysis and Experiments With Double Parallelogram Compliant Mechanisms

2018 ◽  
Author(s):  
Abhijit A. Tanksale ◽  
Prasanna S. Gandhi
Keyword(s):  
Large Deformation ◽  
High Precision ◽  
Large Deformations ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Vertical Plane ◽  
Coupled Analysis ◽  
Deformation Analysis ◽  
Flexible Beams ◽  
Straight Line

Compliant mechanisms are highly preferred in applications demanding motion with high precision. These mechanisms provide friction-less, backlash-free precise motion obtained through deformation of flexible members. The double parallelogram compliant mechanism (DPCM) is one the most important compliant mechanisms to obtain highly precise straight-line motion. DPCM when operated in horizontal plane yield high precision straight-line motion (even with large deformations) useful in several engineering applications. However, constraints such as space, dead loads, etc. may demand DPCMs to be used in the vertical plane. For DPCMs operating in a vertical plane, the axial load due to gravity causes tension and compression in flexible beams which get coupled to bending under large deformations. This ultimately affects the parasitic error of straight-line motion. This paper presents a coupled analysis, along with experimental validation, of DPCM operating in vertical plane considering gravity effects with large deformation.

scholarly journals Geometric synthesis method of compliant mechanism based on similarity transformation of pole maps

2021 ◽  
Vol 12 (1) ◽  
pp. 375-391
Author(s):  
Song Lin ◽  
Yu Zhang ◽  
Hanchao Wang ◽  
Jingyu Jiang ◽  
Niels Modler
Keyword(s):  
Rigid Body ◽  
Compliant Mechanisms ◽  
Similarity Transformation ◽  
Compliant Mechanism ◽  
Research Work ◽  
Synthesis Method ◽  
Common Mechanism ◽  
Beam Model ◽  
Motion Generation ◽  
Euler Beam

Abstract. This paper presents a geometric synthesis method for compliant mechanisms based on similarity transformation of pole maps. Motion generation is a typical and common mechanism synthesis task, so this study takes it as the design requirement to expound the proposed method. Most of the current research work relies on numerical solution of the nonlinear Bernoulli–Euler beam model, numerical simulations or physical experiments to study the synthesis method of compliant mechanisms. There is a lack of simpler and more efficient methods to achieve motion generation of compliant mechanisms with various topologies. This study is based on pole map which is a geometric tool to describe the motion of rigid-body mechanisms. In this paper, we first demonstrate the feasibility of applying the similarity transformation of pole map to compliant mechanisms. It is proved that the pole map of compliant mechanisms has the same characteristic as rigid-body mechanisms during similarity transformation. Then we present the procedure of synthesis method in detail and expound the establishment method of function module which can avoid the functional defects of the final designed mechanism. At last, we take the compliant geared linkages and compliant four-bar linkage as examples to illustrate the novel synthesis approach. The result is an applicable and effective synthesis method for motion generation of compliant mechanisms.

Modeling of Compliant Mechanisms in MATLAB Simscape

2020 ◽  
Author(s):  
Paul Pena ◽  
Martin Garcia ◽  
Ayse Tekes
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Flexible Systems ◽  
Flexible Links ◽  
Hopping Robot ◽  
Lumped Parameter ◽  
Single Piece ◽  
Modeling Software ◽  
Cad Models ◽  
Tip Position

Abstract This paper presents the informative process of modeling of compliant mechanisms using MATLAB Simscape. Simscape is the modeling environment analyzing both rigid and flexible systems using either the blocks provided in the library or the CAD models imported from modeling software. We present the modeling of four compliant mechanisms: dwell, five bar, translational and hopping mechanisms. Once the cad model of a system is imported into Simscape, the flexible links or flexure segment on each example system is replaced by its equivalent lumped parameter block. Compliant dwell mechanism is comprised of a rail, two pinned-pinned flexible links, slider, rigid crank and a DC motor. The second mechanism is a fully compliant five bar mechanism incorporating large deflecting flexures and actuated by two servo motors. The objective is to control the trajectory of the tip position. Third example models a bio-inspired translational compliant mechanism driven by servo motors and comprised of three sliders connected by single piece designed 2 rigid arm-flexure hinge linkages mimicking the motion of a caterpillar. The last example is the modeling of a compliant hopping robot consisting of two pairs of gears; one pair is attached to the motor and the other pair allows the bottom links to rotate at same angular velocity in opposite directions.

Topological Synthesis of Compliant Mechanisms Using Multi-Criteria Optimization

1997 ◽  
Vol 119 (2) ◽  
pp. 238-245 ◽  
Author(s):  
M. I. Frecker ◽  
G. K. Ananthasuresh ◽  
S. Nishiwaki ◽  
N. Kikuchi ◽  
S. Kota
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Two Dimensional ◽  
Ground Structure ◽  
New Approach ◽  
Input Force ◽  
Single Piece ◽  
Mechanical Devices ◽  
Compliant Mechanism Design ◽  
Topological Synthesis

Compliant mechanisms are mechanical devices that achieve motion via elastic deformation. A new method for topological synthesis of single-piece compliant mechanisms is presented, using a “design for required deflection” approach. A simple beam example is used to illustrate this concept and to provide the motivation for a new multi-criteria approach for compliant mechanism design. This new approach handles motion and loading requirements simultaneously for a given set of input force and output deflection specifications. Both a truss ground structure and a two-dimensional continuum are used in the implementation which is illustrated with design examples.

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