Magnetic Pulse Driven Semi Compliant Four Bar Mechanism

2010 ◽  
Author(s):  
Mutlu S¸entu¨rk ◽  
Murat Can Turan ◽  
Aslı Tekin ◽  
U¨mit So¨nmez ◽  
Kerim Kahraman ◽  
...  
Keyword(s):  
Magnetic Force ◽  
Compliant Mechanism ◽  
Original Position ◽  
Voltage Source ◽  
Magnetic Pulse ◽  
Magnetic Actuation ◽  
Flexible Link ◽  
Magnetically Actuated ◽  
Macro Scale ◽  
Limit Position

A partially compliant four-bar mechanism consists of a rigid crank, a rigid coupler and a flexible link (a rocker) is considered and its actuation by a magnetic force drive is investigated. The magnetic force applied to the coupler or the flexible rocker is converted to a rotational motion of the crank arm. This magnetic actuation force is applied in one direction until the rocker tip reaches its limit position, then with the energy stored in the elastic rocker link, the mechanism returns to its original position resulting of a complete revolution of the crank arm. The magnetic actuation is achieved by an external electromagnet driven by a voltage source and a neodymium permanent magnet attached on the mechanism. A prototype mechanism in macro scale is manufactured and it proved the conceptual contribution of the mechanism. The magnetically actuated compliant mechanism may also find applications in micro scales, actuating the rocker with a conventional rotational comb drive.

scholarly journals Springback Reduction of L-Shaped Part Using Magnetic Pulse Forming

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 390 ◽  
Author(s):  
Xiaohui Cui ◽  
Ang Xiao ◽  
Zhihao Du ◽  
Ziqin Yan ◽  
Hailiang Yu
Keyword(s):  
Magnetic Force ◽  
Sheet Thickness ◽  
Elastic Strain Energy ◽  
Simulation Method ◽  
Discharge Voltage ◽  
Magnetic Pulse ◽  
Technological Parameters ◽  
Blank Holder ◽  
Magnetic Pulse Forming ◽  
Production Environments

This study proposes an electromagnetic-assisted stamping (EMAS) method with magnetic-force loading at the sheet end in order to control the springback phenomenon. The new method does not change the structure of the mold and does not generate a magnetic force at the sheet corner compared to traditional EMAS. Thus, the new approach could greatly extend the mold lifespan and could be readily adopted in commercial production environments. The effects of technological parameters, such as the distance between the blank holder and die, discharge voltage, and sheet thickness on the springback phenomenon were analyzed. Our results suggest that tangential stress and elastic strain energy both decrease with the increase of discharge voltage. The simulation method accurately predicted the deformation of the sheet during the quasi-static stamping and dynamic magnetic forming processes. The simulation and experimental results both show that as the discharge voltage increases, the bent angle after springback decreases.

Trapping and Steering a Magnetic Microbead Using 3D Magnetic Tweezers

2010 ◽  
Author(s):  
Zhipeng Zhang ◽  
Chia-Hsiang Menq
Keyword(s):  
Feedback Control ◽  
Feedback Linearization ◽  
Magnetic Force ◽  
Three Dimensional ◽  
Magnetic Bead ◽  
Magnetic Tweezers ◽  
Three Dimensions ◽  
Force Model ◽  
Magnetic Actuation ◽  
Magnetic Microbead

The development of a magnetic micromanipulation system that is capable of trapping and steering a magnetic microbead in three dimensions is presented in this paper. Hexapole magnetic tweezers were designed and implemented to realize three-dimensional (3D) magnetic actuation. Because magnetic actuation is inherently unstable without feedback control, visual measurement based on computer processing of video images was employed to detect the displacement of the microbead, facilitating real-time feedback control. An analytical magnetic force model was developed to characterize the nonlinearity and position dependency of the magnetic force exerted on the magnetic bead by the hexapole magnetic tweezers. Its inverse model was then derived and employed in feedback linearization. A proportionalintegral controller along with feedback linearization was implemented and the motion of the magnetic bead was successfully stabilized. The control results in terms of 100-nanometer stepping and 3D motion steering were experimentally demonstrated.

Magnetic Actuation of Meso-Scale Mechanisms

2013 ◽  
Author(s):  
P. M. Moore ◽  
F. Modica ◽  
G. J. Wiens ◽  
I. Fassi
Keyword(s):  
End Milling ◽  
Electrostatic Force ◽  
Magnetic Actuation ◽  
Mems Devices ◽  
Magnetic Actuators ◽  
Magnetic Forces ◽  
Macro Scale ◽  
Loop Feedback ◽  
The Stability ◽  
Meso Scale

This paper discusses the applications and development of magnetic actuators for meso-scale mechanisms. Due to their small sizes, meso-scale parts cannot be actuated using techniques typical of macro-scale mechanisms, such as servos or ball screws. Similarly, the techniques used in micro-actuation, such as the use of electrostatic force in MEMS devices, cannot be easily scaled up to the meso-scale. As a result, the use of magnetic forces for actuating meso-scale mechanisms may be capable of filling this void of actuation methods. A case study of a fixturing mechanism meant for meso-scale end-milling was analyzed. This mechanism uses two fixed-fixed beams in order to actively tune the harmonic modes of the machining operation in order to improve the stability of the cutting. It also uses magnetic forces to actuate the fixturing platform in order to provide close-loop feedback of cutting force.

Maximum Energy-Efficiency Compliant Mechanism Design for Piezoelectric Stack Actuators

Aerospace ◽  
2003 ◽  
Author(s):  
Mostafa M. Abdalla ◽  
Mary Frecker ◽  
Zafer Gu¨rdal ◽  
Terrence Johnson ◽  
Douglas K. Lindner
Keyword(s):  
Energy Efficiency ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Compliant Mechanism ◽  
Mechanical Energy ◽  
Electric Energy ◽  
Energy Conversion Efficiency ◽  
Maximum Energy ◽  
System Level ◽  
Voltage Source

Combined optimization of a compliant mechanism and a piezoelectric stack actuator for maximum energy conversion efficiency is considered. The paper presents a system level analysis in which the actuator and the compliant mechanism are mathematically described as linear two-port systems. The combination of stack and compliant mechanism is used to drive a structure, modeled as a mass-spring system. The analysis assumes all components to be free from dissipation, and the piezoelectric stack is driven by an ideal voltage source. Energy conversion efficiency is defined as the ratio of the output mechanical energy to the input electric energy. Theoretical bounds on the system efficiency are obtained. It is shown that the stack actuator can be optimized separately and matched to the specified structure and an optimally designed complaint mechanism. The optimization problem for the compliant mechanism is formulated to maximize a weighted objective function of energy efficiency and stroke amplification. Optimization results are presented for ground structures modeled using frame elements.

The Development of Force-Deflection Relationships for Compliant Mechanisms

1994 ◽  
Author(s):  
Larry L. Howell ◽  
Ashok Midha
Keyword(s):  
Rigid Body ◽  
Compliant Mechanisms ◽  
Virtual Work ◽  
Compliant Mechanism ◽  
Flexible Link ◽  
Model Concept ◽  
Body Model ◽  
Design Flexibility ◽  
Rigid Body Model ◽  
Manufacturing Time

Abstract The advantages of compliant or flexible link mechanisms include increased design flexibility and reduction in manufacturing time and cost. The analysis of such mechanisms may be difficult and time consuming due to the nonlinearities introduced by large deflections. Also, unlike rigid-body mechanisms, the type and form of motion of a compliant mechanism is dependent on the location and magnitude of applied loads. The pseudo-rigid-body model concept has been developed to simplify the analysis of compliant mechanisms by allowing them to be modeled as rigid-link mechanisms with springs. This work uses the principle of virtual work and the pseudo-rigid-body model concept to develop force-deflection relationships for compliant mechanisms. Several examples are presented, and general design equations are derived for pseudo-rigid-body four-bar and slider-crank mechanisms.

Design of a Graphene Nanoribbon Electrostatic Discharge Compliant Mechanism

2018 ◽  
Author(s):  
Talmage H. Jones ◽  
Jimmy Ng ◽  
Ya-Hong Xie ◽  
Jonathan B. Hopkins
Keyword(s):  
Response Time ◽  
Mechanical Response ◽  
Electrostatic Discharge ◽  
Graphene Nanoribbons ◽  
Compliant Mechanism ◽  
Electrical Response ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Original Position ◽  
Euler Beam

This paper investigates the design of an electrostatic discharge protection device made of single-layer graphene nanoribbons. The device is meant to trigger electrostatic discharge at a target voltage of 1.5V. Other design requirements include the minimization of parasitic capacitance, electrical response time and mechanical response time. The device is designed to discharge static electricity by being pulled to ground through electrostatic forces, then making contact with ground before returning to its original position. Previous designs experienced repeatability issues due to a lack of securing the ribbon and mechanical failure due to high stresses at the boundary conditions. New designs are presented and optimized to maintain a high effective spring constant for the device while reducing stress during electrostatic pull-in. A single-degree of freedom model is used in conjunction with the Bernoulli-Euler beam equations and Castigliano’s method to guide the design process. Behavior of each design is validated, and repeatability is assessed using finite-element simulations. The new designs are to be fabricated using a low pressure chemical vapor deposition process.

A Novel Compliant Mechanism for Converting Reciprocating Translation Into Enclosing Curved Paths

2004 ◽  
Vol 126 (4) ◽  
pp. 667-672 ◽  
Author(s):  
Nilesh D. Mankame ◽  
G. K. Ananthasuresh
Keyword(s):  
Large Deformations ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Two Dimensional ◽  
Contact Interactions ◽  
Macro Scale ◽  
Potential Applications ◽  
Curved Paths ◽  
Single Material ◽  
Flexural Joints

This paper introduces a novel contact-aided compliant mechanism that uses intermittent contacts to convert a single translatory reciprocating input into two output curves, which intersect to enclose a two dimensional region. Contact interactions endow contact-aided compliant mechanisms with enhanced kinematic and kinetostatic capabilities. The mechanism described in this paper is designed to undergo large deformations repeatedly, without yielding by avoiding flexural joints and by using contacts to obtain the desired deformation. A single-material, joint-free and planar design makes the mechanism easy and economical to fabricate at the macro or micro scales. The design is validated experimentally by manufacturing and testing macro scale prototypes. Two potential applications that motivated this mechanism are also noted.

scholarly journals Enhanced real-time pose estimation for closed-loop robotic manipulation of magnetically actuated capsule endoscopes

2018 ◽  
Vol 37 (8) ◽  
pp. 890-911 ◽  
Author(s):  
Addisu Z Taddese ◽  
Piotr R Slawinski ◽  
Marco Pirotta ◽  
Elena De Momi ◽  
Keith L Obstein ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Pose Estimation ◽  
Closed Loop ◽  
Estimation Methods ◽  
Closed Loop Control ◽  
Point Dipole ◽  
Magnetic Actuation ◽  
Loop Control ◽  
Magnetically Actuated ◽  
Capsule Endoscopes

Pose estimation methods for robotically guided magnetic actuation of capsule endoscopes have recently enabled trajectory following and automation of repetitive endoscopic maneuvers. However, these methods face significant challenges in their path to clinical adoption including the presence of regions of magnetic field singularity, where the accuracy of the system degrades, and the need for accurate initialization of the capsule’s pose. In particular, the singularity problem exists for any pose estimation method that utilizes a single source of magnetic field if the method does not rely on the motion of the magnet to obtain multiple measurements from different vantage points. We analyze the workspace of such pose estimation methods with the use of the point-dipole magnetic field model and show that singular regions exist in areas where the capsule is nominally located during magnetic actuation. As the dipole model can approximate most magnetic field sources, the problem discussed herein pertains to a wider set of pose estimation techniques. We then propose a novel hybrid approach employing static and time-varying magnetic field sources and show that this system has no regions of singularity. The proposed system was experimentally validated for accuracy, workspace size, update rate, and performance in regions of magnetic singularity. The system performed as well or better than prior pose estimation methods without requiring accurate initialization and was robust to magnetic singularity. Experimental demonstration of closed-loop control of a tethered magnetic device utilizing the developed pose estimation technique is provided to ascertain its suitability for robotically guided capsule endoscopy. Hence, advances in closed-loop control and intelligent automation of magnetically actuated capsule endoscopes can be further pursued toward clinical realization by employing this pose estimation system.

scholarly journals A Statically Balanced Shape Shifting Surface

2012 ◽  
Author(s):  
Joseph E. Pishnery ◽  
Craig P. Lusk
Keyword(s):  
Compliant Mechanism ◽  
Tiling Array ◽  
Variable Stiffness ◽  
Parent Material ◽  
Thin Plates ◽  
Physical Barrier ◽  
Zero Force ◽  
Polygonal Cell ◽  
Wide Range ◽  
Macro Scale

This paper presents a concept for producing a Statically Balanced Shape-Shifting Surface (SB-SSS). In this context, an SB-SSS is a surface that can require near-zero magnitude force changes to accomplish a change in shape while retaining effectiveness as a physical barrier. This paper focuses on how to statically balance a specifically-designed compliant mechanism and how to incorporate this mechanism into a polygonal cell. The mechanism consists of a compliant Peaucellier-Lipkin linkage layered with a pre-stressed link as the balancer. Prior art is presented that can show how a polygonal cell can be incorporated into a surface via a tiling array. Specifically shaped overlapping thin plates are used to retain the physical barrier requirement. The demonstration of a virtually zero-force Shape-Shifting Surface (SSS) suggests that SSS’s can be designed with a wide range of force-displacement properties, i.e. ranging from that of a square of the parent material to the zero-force mechanism presented here. Applications for an SB-SSS may be macro-scale or micro-scale and may include sensors, biomedical applications, defense applications, and variable stiffness materials.

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