Fabrication of Composite and Sheet Metal Laminated Bistable Jumping Mechanism

2015 ◽  
Vol 7 (2) ◽  
Author(s):  
Sun-Pill Jung ◽  
Gwang-Pil Jung ◽  
Je-Sung Koh ◽  
Dae-Young Lee ◽  
Kyu-Jin Cho
Keyword(s):  
Sheet Metal ◽  
Elastic Component ◽  
Small Scale ◽  
Neutral Position ◽  
Fabrication Method ◽  
Stable States ◽  
Manufacturing Method ◽  
Rigid Body Model ◽  
Jumping Robot ◽  
Bistable Mechanism

A layer-based manufacturing method using composite microstructures is widely used for mesoscale robot fabrication. This fabrication method has enabled the development of a lightweight and robust jumping robot, but there are limitations in relation to the embedding of elastic components. In this paper, a fabrication method for embedding an elastic component at an angled position is developed, extending the capability of the composite microstructures. This method is then used to build an axial spring attached to the bistable mechanism of a jumping robot. Sheet metal is used as an elastic component, which is stamped after the layering and curing process, thereby changing the neutral position of the spring. Two linear springs are designed to be in parallel with a joint to impose bistability; thereby delivering two stable states. This bistable mechanism is triggered with a shape memory alloy (SMA) coil spring actuator. A small-scale jumping mechanism is then fabricated using this mechanism; it jumps when the snap-through of the bistable mechanism occurs. A model of the stamped sheet metal spring is built based on a pseudo rigid body model (PRBM) to estimate the spring performance, and a predictive sheet metal bending model is also built to design the die for stamping. The experimental results show that the stamped sheet metal spring stores 12.63 mJ of elastic energy, and that the mechanism can jump to a height of 175 mm with an initial takeoff velocity of 1.93 m/s.

Design of Two-Link, In-Plane, Bistable Compliant Micro-Mechanisms

1999 ◽  
Vol 121 (3) ◽  
pp. 416-423 ◽  
Author(s):  
B. D. Jensen ◽  
L. L. Howell ◽  
L. G. Salmon
Keyword(s):  
Energy Efficiency ◽  
Power Input ◽  
Stable States ◽  
External Disturbances ◽  
Bistable Behavior ◽  
Positioning Accuracy ◽  
Body Model ◽  
Rigid Body Model ◽  
Bistable Mechanism ◽  
Storage Characteristics

A bistable mechanism has two stable states within its range of motion. Its advantages include the ability to stay in two positions without power input and despite small external disturbances. Therefore, bistable micro-mechanisms could allow the creation of MEMS with improved energy efficiency and positioning accuracy. This paper presents bistable micro-mechanisms which function within the plane of fabrication. These bistable mechanisms, called “Young” bistable mechanisms, obtain their energy storage characteristics from the deflection of two compliant members. They have two pin joints connected to the substrate, and can be constructed of two layers of polysilicon. The pseudo-rigid-body model is used to analyze and design these mechanisms. This approach allows greater freedom and flexibility in the design process. The mechanisms were fabricated and tested to demonstrate their bistable behavior and to determine the repeatability of their stable positions.

Introduction of Two-Link, In-Plane, Bistable Compliant MEMS

1998 ◽  
Author(s):  
Brian D. Jensen ◽  
Larry L. Howell ◽  
Linton G. Salmon
Keyword(s):  
Power Input ◽  
Stable States ◽  
External Disturbances ◽  
Bistable Behavior ◽  
Analysis And Design ◽  
Body Model ◽  
Process Testing ◽  
Rigid Body Model ◽  
Bistable Mechanism ◽  
Storage Characteristics

Abstract A bistable mechanism has two stable states within its range of motion. Its advantages include the ability to stay in two positions without power input and despite small external disturbances. Therefore, bistable micro-mechanisms could allow the creation of MEMS with improved energy efficiency and positioning accuracy. This paper presents the first bistable MEMS which function within the plane of fabrication. These bistable mechanisms, known as “Young” bistable mechanisms, obtain their energy storage characteristics from the deflection of two compliant members, have two pin joints connected to the substrate, and can be constructed of two layers of polysilicon. The pseudo-rigid-body model overcomes problems with nonlinearities in the analysis and design of these mechanisms. This approach allows greater freedom and flexibility in the design process. Testing of the mechanisms demonstrated their bistable behavior and the repeatability of the stable positions.

A Low Cost Knowledge Based System Framework for Design of Bending Die

2013 ◽  
Vol 549 ◽  
pp. 284-291 ◽  
Author(s):  
Deepak Panghal ◽  
Shailendra Kumar
Keyword(s):  
Sheet Metal ◽  
Low Cost ◽  
Visual Basic ◽  
Die Design ◽  
Small Scale ◽  
Production Rules ◽  
System Framework ◽  
Knowledge Based System ◽  
Sheet Metal Parts ◽  
Knowledge Based

This paper presents a low cost knowledge based system (KBS) framework for design of bending die. Considerations for development of KBS are discussed at some length. The proposed framework divides the task of development of expert system into different modules for major activities of bending die design. The procedure of development of KBS modules is also described at length. Production rules for each module are recommended to be coded in the AutoLISP language and designed to be loaded into the prompt area of AutoCAD or through user interface created using Visual Basic. Each module of the proposed framework is user interactive. Development of one module of the proposed framework is also described at length. This module is capable to assess manufacturability of bending sheet metal parts. An illustrative example is also included to demonstrate the usefulness of this module. The proposed system framework is flexible enough to accommodate new acquired knowledge. As the proposed system is implementable on a PC having AutoCAD software, therefore its low cost of implementation makes it affordable even by small scale sheet metal industries.

Metal Flow and Die Filling in Coining of Micro Structures with and without Flash

2005 ◽  
Vol 6-8 ◽  
pp. 631-638 ◽  
Author(s):  
M. Thome ◽  
Gerhard Hirt ◽  
B. Rattay
Keyword(s):  
Numerical Simulations ◽  
Sheet Metal ◽  
Metal Forming ◽  
Production Systems ◽  
Metal Flow ◽  
Small Scale ◽  
Die Filling ◽  
Metal Plates ◽  
Micro Structures ◽  
Channel Structures

The continuing miniaturization of production systems and products poses a challenge for metal forming technologies to produce precise small scale products with microscopic geometric details. Thin metal plates with channel structures are considered to be typical examples for microfluidic applications [1,2]. In this study the coining process of sheet metal to produce channel and rib structures is examined in terms of geometrical die parameters and tool design. For this reason extensive experimental series and numerical simulations have been realized and evaluated.

Cryogenic Sheet Metal Forming - An Overview

2018 ◽  
Vol 941 ◽  
pp. 1397-1403 ◽  
Author(s):  
Florian Grabner ◽  
Belinda Gruber ◽  
Carina Schlögl ◽  
Christian Chimani
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Tensile Tests ◽  
Al Alloys ◽  
Small Scale ◽  
Improve Energy Efficiency ◽  
Automotive Parts ◽  
Industrial Level ◽  
6Xxx Series

Despite extensive efforts to improve energy efficiency in the automotive sector, the use of light-weight aluminium alloys for car bodies is impeded by formability limitations. Although it is a known phenomenon that Al alloys increase their strength and ductility at very low temperatures, it has not been attempted to exploit this effect to increase their overall formability at an industrial scale. Over the last four years, the cryogenic sheet metal forming behaviour of Al-alloys was extensively investigated to establish a process robust enough for manufacturing automotive parts at an industrial level. Initial experiments include tensile tests at temperatures down to –196 °C for characterisation of 5xxx and 6xxx series Al alloys, providing the mechanical material data for numerical design simulations of sheet metal forming processes at cryogenic temperatures. Numerical simulations will not be discussed in this publication. Furthermore, the necessary hardware for cryogenic sheet metal forming was developed and finally resulted in a semi-automated small scale industrial production site. The production of a miniaturized B-Pillar was demonstrated for 5xxx and 6xxx alloys. Due to the part’s demanding geometry, defect-free deep drawing process is possible at cryogenic temperature only. These results demonstrate that the use of Al alloys could be extended beyond their current applications in cars components. For example, the overall formability of 5xxx series alloys nearly doubles compared to room temperature. This paper shall give an overview over our work in the field of cryogenic aluminium sheet metal forming within the last couple of years.

Thermo/Mechanical Design, Modeling, and Testing of Shape Memory Actuated Minimal and Micro Invasive Probe Systems

2002 ◽  
Author(s):  
David R. Wulfman ◽  
Arthur G. Erdman ◽  
Paul J. Strykowski
Keyword(s):  
Shape Memory ◽  
Solid Phase ◽  
Mechanical Design ◽  
Phase Changes ◽  
Segment Length ◽  
Great Promise ◽  
Small Scale ◽  
Neutral Position ◽  
Total System ◽  
Physical Scale

Small scale probes implementing shape memory alloy (SMA) actuation show great promise in applications requiring remote and minimally invasive access to small environments. Such environments include physiological spaces like those located in human and animal bodies as well as cavities within mechanical systems. Probes examined here are generally snake like in appearance composed of one or multiple independent segments, which in turn are made up of one or multiple SMA actuators performing work against an elastic spine. As the actuator(s) of a given segment are activated, the spine bends causing the probe to bend in the area of that segment. When the actuator(s) are deactivated, the force generated in the bending of the spine returns the segment to its neutral position. Activation and deactivation of actuators is accomplished by heating and cooling respectively, enacting the solid phase changes that are characteristic to the shape memory effect. The gage of control over probe shape depends on the number of independent segments that are available per unit length and the degree of control an operator has over each of the segments. The work presented here discusses the constraints imposed on the design of SMA actuated probes, and how those constraints become more critical and limiting with reduced physical scale and refinement of motion control. Numerical and finite element models have been developed showing the interrelationship between mechanical design, the thermal and phase states of the SMA actuator(s), and the mechanical performance of the total system. Performance concerns examined include probe shape control and the limits of shape change as a function of physical scale. Comparative data is presented between behavior predicted by the models developed and performance observed during the testing of prototypes. It is concluded that segment length, linked to refinement of probe control, is limited by its thermal boundary conditions.

scholarly journals Small-scale switch in cover–perimeter relationships of patches indicates shift of dominant species during grassland degradation

2020 ◽  
Vol 13 (6) ◽  
pp. 704-712
Author(s):  
Ming-Hua Song ◽  
Johannes H C Cornelissen ◽  
Yi-Kang Li ◽  
Xing-Liang Xu ◽  
Hua-Kun Zhou ◽  
...  
Keyword(s):  
Climate Changes ◽  
Alternative Stable States ◽  
Species Abundance ◽  
Black Soil ◽  
Intersection Point ◽  
State Transitions ◽  
Small Scale ◽  
Stable States ◽  
Large Spatial Scale ◽  
Vegetation Surveys

Abstract Aims Grasslands are globally threatened by climate changes and unsustainable land-use, which often cause transitions among alternative stable states, and even catastrophic transition to desertification. Spatial vegetation patch configurations have been shown to signify such transitions at large spatial scale. Here, we demonstrate how small-scale patch configurations can also indicate state transitions. Methods The whole spatial series of degradation successions were chosen in alpine grasslands characterized as seven typical communities. Patch numbers, and perimeter and cover of each patch were recorded using adjacent quadrats along transects in each type of the communities. Species abundance within each patch was measured. Important Findings Across seven grazing-induced degradation stages in the world’s largest expanse of grassland, from dense ungrazed turf to bare black-soil crust, patch numbers and perimeters first increased as patch cover decreased. Numbers and perimeters then decreased rapidly beyond an intersection point at 68% of initial continuous vegetation cover. Around this point, the vegetation fluctuated back and forth between the sedge-dominated grassland breaking-up phase and the forb-dominated phase, suggesting impending shift of grassland state. This study thus demonstrates how ground-based small-scale vegetation surveys can provide a quantitative, easy-to-use signals for vegetation degradation, with promise for detecting the catastrophic transition to desertification.

Driving – A Flexible Manufacturing Method for Individualized Sheet Metal Products

2010 ◽  
Vol 447-448 ◽  
pp. 795-800
Author(s):  
Daniel Scherer ◽  
Z. Yang ◽  
H. Hoffmann
Keyword(s):  
Production Process ◽  
Sheet Metal ◽  
Flexible Manufacturing ◽  
Incremental Forming ◽  
Industrial Robot ◽  
General Information ◽  
Work Piece ◽  
Forming Process ◽  
Manufacturing Method ◽  
Metal Products

This paper provides general information about the qualification of driving as an on-demand manufacturing concept for the production of individualized sheet metal products. Driving allows the creation of almost any 2D or 3D geometry, but it is a highly interactive, manual production process. Due to the inevitable variations of the incremental forming process (mechanical properties, tribology, wear etc.) and the high number of forming steps, it cannot be automated by traditional approaches. At the Institute of Metal Forming and Casting (Technische Universitaet Muenchen) a kraftformer machine has been equipped with measuring and controlling instrumentation. An optical online measurement system is installed to detect any geometry deformation of the current work piece and to visualize the deviation between the actual and the stored reference geometry during the whole production process. This variance comparison is the first step for planning any following incremental forming actions based on acquired and/or learned knowledge. The second step is the integration of an industrial robot for work piece handling and the automation of the whole manufacturing process. The last step is the integration of neural networks to predict production strategies for any desired unique geometry.

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