Design of Planar Multi-Degree-of-Freedom Morphing Mechanisms

2014 ◽  
Author(s):  
Lawrence Funke ◽  
James P. Schmiedeler ◽  
Kai Zhao
Keyword(s):  
Shape Matching ◽  
Design Space ◽  
Degree Of Freedom ◽  
Limiting Factor ◽  
Primary Method ◽  
Single Degree Of Freedom ◽  
Extrusion Dies ◽  
Planar Shape ◽  
Synthesis Procedure ◽  
Block Approach

This paper seeks to advance the design of planar shape-changing mechanisms used in a variety of applications, such as morphing extrusion dies and airfoils. The presence of defects is a limiting factor in finding suitable single-degree-of-freedom (DOF) mechanisms, particularly when the number of shapes to achieve is large and/or the changes among those shapes are significant. This paper presents a new method of designing multi-DOF mechanisms to aid in avoiding these defects. The primary method uses a building-block approach similar to the current one-DOF synthesis procedure and is compared to alternative strategies that seek to leverage the use of multiple single-DOF subchains. While more complex in terms of determining the actuation pattern, the primary method offers a larger design space in which to find solutions. In all cases a genetic algorithm is employed to search the design space. Two example problems involving four prescribed shapes demonstrate the benefits of using multi-DOF mechanisms in terms of shape matching and mechanical advantage.

Design of Planar Multi-Degree-of-Freedom Morphing Mechanisms

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Lawrence W. Funke ◽  
James P. Schmiedeler ◽  
Kai Zhao
Keyword(s):  
Shape Matching ◽  
Design Space ◽  
Degree Of Freedom ◽  
Limiting Factor ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Extrusion Dies ◽  
Assur Group ◽  
Synthesis Procedure ◽  
Block Approach

This paper seeks to advance the design of planar multiloop shape-changing mechanisms used in a variety of applications, such as morphing extrusion dies and airfoils. The presence of defects is a limiting factor in finding suitable single-degree-of-freedom (DOF) morphing mechanisms, particularly when the number of shapes to achieve is large and/or the changes among those shapes are significant. This paper presents methods of designing multi-DOF mechanisms to expand the design space in which to find suitable defect-free solutions. The primary method uses a building block approach with Assur group of class II chains, similar to the current 1-DOF synthesis procedure. It is compared to both the 1-DOF procedure and an alternative multi-DOF procedure that generates mechanisms with single-DOF subchains. In all cases, a genetic algorithm is employed to search the design space. Two example problems involving four prescribed shapes demonstrate that mechanisms exhibiting superior shape matching are achieved with the primary multi-DOF procedure, as compared to the other two procedures.

Single Degree-of-Freedom Morphing Wing (Design and Synthesis)

2004 ◽  
Author(s):  
Matthew D. Stubbs ◽  
William B. Whittier ◽  
Charles F. Reinholtz
Keyword(s):  
Shape Change ◽  
Degree Of Freedom ◽  
Morphing Wing ◽  
Single Degree Of Freedom ◽  
Aircraft Wings ◽  
Design And Synthesis ◽  
Single Degree ◽  
Synthesis Procedure ◽  
Langley Research Center ◽  
Novel Design

Recent research in morphing wing technology has focused on complex multiple-degree-of-freedom (MDOF) mechanisms and smart structures to provide a specified shape change; single degree-of-freedom actuation concepts have generally been ignored or overlooked. In this research, the authors propose a novel design for a single degree-of-freedom (SDOF) mechanism for mission morphing of aircraft wings. A general design methodology has been developed, and this has been applied to a Hyper-Elliptic Cambered Span (HECS) wing developed by engineers at NASA Langley Research Center. The design tools developed include a synthesis procedure for determining the dimensions of the single-degree-of-freedom morphing mechanism, and a sensitivity analysis to determine the effects of manufacturing errors.

Generalized Synthesis of Adjustable Mechanisms

1992 ◽  
Author(s):  
Tushchai Chuenchom ◽  
Sridhar Kota
Keyword(s):  
Three Dimensional ◽  
Cost Effective ◽  
Degree Of Freedom ◽  
Multi Objective Optimization ◽  
Middle Ground ◽  
Single Degree Of Freedom ◽  
Single Mechanism ◽  
Task Requirements ◽  
Synthesis Procedure ◽  
Adjustable Mechanisms

Abstract Conventional mechanisms (cams, gears, and linkage-based that are typically single degree of freedom) are being increasingly replaced by multi-degree of freedom multi-actuators integrated with logic controllers. This new trend in sophistication although provides greatly enhanced flexibility, there are many instances where the flexibility needs are exaggerated and the associated complexity is unnecessary. On the other hand, the conventional mechanisms cannot fulfill multi-task requirements due to lack methods to design-in flexibility. Adjustable mechanisms or “programmable” mechanisms provide a cost-effective middle ground between hard automation and overly flexible expensive robots; especially for tasks that demand only limited flexibility. This paper presents a generalized synthesis procedure for designing adjustable robotic mechanisms for path generation. The goal is to develop a methodology to synthesize a single mechanism that can trace a given set of three-dimensional trajectories by simply adjusting one of the mechanism parameters; say the length of a particular link. The synthesis procedure presented in this paper entails coupler curve classification and pattern recognition techniques, eleven precision-point (Burmester theory) synthesis of geared five-bar mechanisms, multi-objective optimization and statistical analysis.

Kinematic comparison of single degree-of-freedom robotic gait trainers

2021 ◽  
Vol 159 ◽  
pp. 104258
Author(s):  
Jeonghwan Lee ◽  
Lailu Li ◽  
Sung Yul Shin ◽  
Ashish D. Deshpande ◽  
James Sulzer
Keyword(s):  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Robotic Gait
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