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.

Bistable Configurations of Compliant Mechanisms Modeled Using Four Links and Translational Joints

2004 ◽  
Vol 126 (4) ◽  
pp. 657-666 ◽  
Author(s):  
Brian D. Jensen ◽  
Larry L. Howell
Keyword(s):  
Energy Storage ◽  
Prior Knowledge ◽  
Compliant Mechanisms ◽  
Power Input ◽  
Local Minima ◽  
Stored Energy ◽  
Bistable Behavior ◽  
Micro Electro Mechanical Systems ◽  
Bistable Mechanism ◽  
Mechanical Devices

Bistable mechanical devices remain stable in two distinct positions without power input. They find application in valves, switches, closures, and clasps. Mechanically bistable behavior results from the storage and release of energy, typically in springs, with stable positions occurring at local minima of stored energy. Compliant mechanisms offer an elegant way to achieve this behavior by incorporating both motion and energy storage into the same flexible element. Interest in compliant bistable mechanisms has also recently increased because of the advantages of bistable behavior in many micro-electro-mechanical systems (MEMS). Design of compliant or rigid-body bistable mechanisms typically requires simultaneous consideration of both energy storage and motion requirements. This paper simplifies this process by developing theory that provides prior knowledge of mechanism configurations that guarantee bistable behavior. Configurations which include one or more translational, or slider, joints are studied in this work. Several different mechanism types are analyzed to determine compliant segment placement that will ensure bistable mechanism operation. Examples demonstrate the power of the theory in design.

A Compliant Bistable Mechanism Design Incorporating Elastica Buckling Beam Theory and Pseudo-Rigid-Body Model

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Ümit Sönmez ◽  
Cem C. Tutum
Keyword(s):  
Rigid Body ◽  
Mechanism Design ◽  
Kinematic Analysis ◽  
Compliant Mechanism ◽  
Beam Theory ◽  
Algebraic Equations ◽  
Body Model ◽  
Buckling Beam ◽  
Rigid Body Model ◽  
Bistable Mechanism

In this work, a new compliant bistable mechanism design is introduced. The combined use of pseudo-rigid-body model (PRBM) and the Elastica buckling theory is presented for the first time to analyze the new design. This mechanism consists of the large deflecting straight beams, buckling beams, and a slider. The kinematic analysis of this new mechanism is studied, using nonlinear Elastica buckling beam theory, the PRBM of a large deflecting cantilever beam, the vector loop closure equations, and numerically solving nonlinear algebraic equations. A design method of the bistable mechanism in microdimensions is investigated by changing the relative stiffness of the flexible beams. The actuation force versus displacement characteristics of several cases is explored and the full simulation results of one of the cases are presented. This paper demonstrates the united application of the PRBM and the buckling Elastica solution for an original compliant mechanism kinematic analysis. New compliant mechanism designs are presented to highlight where such combined kinematic analysis is required.

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 a Linear Bi-Stable Compliant Crank-Slider-Mechanism (LBCCSM)

2014 ◽  
Author(s):  
Ahmad Alqasimi ◽  
Craig Lusk ◽  
Jairo Chimento
Keyword(s):  
Material Selection ◽  
Compliant Mechanism ◽  
Design Guidelines ◽  
Design Parameters ◽  
Bistable Behavior ◽  
Body Model ◽  
Buckling Behavior ◽  
Rigid Body Model ◽  
Rectangular Area ◽  
Post Buckling

This paper presents a new model for a linear bistable compliant mechanism and design guidelines for its use. The mechanism is based on the crank-slider mechanism. This model takes into account the first mode of buckling and post-buckling behavior of a compliant segment to describe the mechanism’s bistable behavior. The kinetic and kinematic equations, derived from the Pseudo-Rigid-Body Model, were solved numerically and are represented in plots. This representation allows the generation of step-by-step design guidelines. The design parameters consist of maximum desired deflection, material selection, safety-factor, compliant segments’ widths, maximum force required for actuator selection and maximum footprint (i.e. the maximum rectangular area that the mechanism can fit inside of and move freely without interfering with other components). Because different applications may have different input requirements, this paper describes two different design approaches with different parameters subsets as inputs.

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.

scholarly journals Refrigeration of COVID-19 Vaccines: Ideal Storage Characteristics, Energy Efficiency and Environmental Impacts of Various Vaccine Options

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1849
Author(s):  
Alexandre F. Santos ◽  
Pedro D. Gaspar ◽  
Heraldo J. L. de Souza
Keyword(s):  
Energy Efficiency ◽  
Environmental Impacts ◽  
Thermal Load ◽  
Storage Condition ◽  
Storage Conditions ◽  
Energy Simulation ◽  
Energy Usage ◽  
Impact Simulation ◽  
Storage Characteristics ◽  
The Ideal

This article considers the ideal storage conditions for multiple vaccine brands, such as Pfizer, Moderna, CoronaVac, Oxford–AstraZeneca, Janssen COVID-19 and Sputnik V. Refrigerant fluid options for each storage condition, thermal load to cool each type of vaccine and environmental impacts of refrigerants are compared. An energy simulation using the EUED (energy usage effectiveness design) index was developed. The Oxford–AstraZeneca, Janssen COVID-19 and CoronaVac vaccines show 9.34-times higher energy efficiency than Pfizer. In addition, a TEWI (total equivalent warming impact) simulation was developed that prioritizes direct environmental impacts and indirect in refrigeration. From this analysis, it is concluded that the cold storage of Oxford–AstraZeneca, Janssen COVID-19 and CoronaVac vaccines in Brazil generates 35-times less environmental impact than the Pfizer vaccine.

scholarly journals Control of an IPMC Soft Actuator Using Adaptive Full-Order Recursive Terminal Sliding Mode

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 33
Author(s):  
Romina Zarrabi Ekbatani ◽  
Ke Shao ◽  
Jasim Khawwaf ◽  
Hai Wang ◽  
Jinchuan Zheng ◽  
...  
Keyword(s):  
Sliding Mode ◽  
External Disturbance ◽  
Tracking Error ◽  
Working Environment ◽  
Parametric Uncertainties ◽  
Metal Composite ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Positioning Accuracy ◽  
Soft Actuator

The ionic polymer metal composite (IPMC) actuator is a kind of soft actuator that can work for underwater applications. However, IPMC actuator control suffers from high nonlinearity due to the existence of inherent creep and hysteresis phenomena. Furthermore, for underwater applications, they are highly exposed to parametric uncertainties and external disturbances due to the inherent characteristics and working environment. Those factors significantly affect the positioning accuracy and reliability of IPMC actuators. Hence, feedback control techniques are vital in the control of IPMC actuators for suppressing the system uncertainty and external disturbance. In this paper, for the first time an adaptive full-order recursive terminal sliding-mode (AFORTSM) controller is proposed for the IPMC actuator to enhance the positioning accuracy and robustness against parametric uncertainties and external disturbances. The proposed controller incorporates an adaptive algorithm with terminal sliding mode method to release the need for any prerequisite bound of the disturbance. In addition, stability analysis proves that it can guarantee the tracking error to converge to zero in finite time in the presence of uncertainty and disturbance. Experiments are carried out on the IPMC actuator to verify the practical effectiveness of the AFORTSM controller in comparison with a conventional nonsingular terminal sliding mode (NTSM) controller in terms of smaller tracking error and faster disturbance rejection.

Achieving Multistability Through Use of a Single Bistable Compliant Mechanism

2010 ◽  
Author(s):  
Guimin Chen ◽  
Yanjie Gou ◽  
Aimei Zhang
Keyword(s):  
Stable Equilibrium ◽  
Compliant Mechanism ◽  
Power Input ◽  
Successful Operation ◽  
New Approaches ◽  
Reconfigurable Robots ◽  
Bistable Mechanism

A compliant multistable mechanism is capable of steadily staying at multiple distinct positions without power input. Many applications including switches, valves, relays, positioners, and reconfigurable robots may benefit from multistability. In this paper, two new approaches for synthesizing compliant multistable mechanisms are proposed, which enable designers to achieve multistability through the use of a single bistable mechanism. The synthesis approaches are described and illustrated by several design examples. Compound use of both approaches is also discussed. The design potential of the synthesis approaches is demonstrated by the successful operation of several instantiations of designs that exhibit three, four, five, and nine stable equilibrium positions, respectively. The synthesis approaches enable us to design a compliant mechanism with a desired number of stable positions.

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