New Variable Stiffness Damper with Magnetorheological-Based Accumulator Control

2018 ◽  
Vol 775 ◽  
pp. 204-209
Author(s):  
Lim Jian Hong ◽  
Fitrian Imaduddin ◽  
Saiful Amri Mazlan ◽  
Muhammad Hafiz Idris ◽  
Irfan Bahiuddin
Keyword(s):  
Direct Effect ◽  
Mr Damper ◽  
Variable Stiffness ◽  
Experimental Results ◽  
Compression Force ◽  
Control Zone ◽  
Hydraulic Oil ◽  
Compensation Control ◽  
Mr Fluids ◽  
Compression Stiffness

This paper introduces a new design of variable stiffness damper using controlled accumulator filled with Magnetorheological (MR) fluids. The originality of the new design is in its capability to offer less consumption of MR fluids than the conventional design of MR damper. The new design does not fill the whole cylinder with MR fluids but only use the accumulator space as the volume compensation control zone with MR fluids. The MR fluids control the compressive movement of the accumulator piston which alter the flow of the hydraulic oil to the accumulator chamber. As a result, the regulated flow of oil to the accumulator chamber will only have a direct effect to the compression stiffness of the damper. The experimental results show that the proposed design is capable to adjust the compression force while maintaining the rebound force of the damper.

EVALUATIONS OF CLUSTER STRUCTURE AND MAGNETO-RHEOLOGY OF MR SUSPENSIONS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1437-1442 ◽  
Author(s):  
HIDEYA NISHIYAMA ◽  
KAZUNARI KATAGIRI ◽  
KATSUHISA HAMADA ◽  
KAZUTO KIKUCHI ◽  
KATSUHIKO HATA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cluster Formation ◽  
Cluster Structure ◽  
Mr Damper ◽  
Magnetic Flux Density ◽  
Equivalent Damping ◽  
Damping Characteristics ◽  
Mr Fluids ◽  
Equivalent Damping Coefficient ◽  
Particle Shapes

In the present study, we sysnthesize two types of MR fluids with different particle shapes and sizes. The magnetic functions are evaluated circulatingly by the analysis of cluster formation, rheological properties in the applied magnetic field and damping characteristics in the MR damper, comparing with those of commercial MR fluids. Final objective is to provide the fundamental data for the development of newly advanced MR fluids. The main topics consist of geographycal cluster formation depending on particle shapes and sizes, relating to the apparent viscosity and yield stress with magnetic flux density and further equivalent damping coefficient of two newly sysnthesised MR fluids comparing with those of LORD MR fluid.

Isolation Application of Controlled and Uncontrolled Magnetorheological Dampers for Random Base Excitaion

2005 ◽  
Author(s):  
A. Narimani ◽  
M. F. Golnaraghi
Keyword(s):  
Base Isolation ◽  
Mr Damper ◽  
Optimization Method ◽  
Experimental Results ◽  
Base Excitation ◽  
Modeling And Control ◽  
Isolation Systems ◽  
Active Damper ◽  
Suspension Model ◽  
And Control

This paper presents experimental investigation of modeling and control of magnetorhological damper for transient base excitation inputs. Force characteristics of a commercially available MR damper (RD-1005-3) for shock and other transient base excitation are analytically obtained and validated using a scaled suspension model. The proposed model characterizes damper behavior more accurately and efficiently for analytical applications. The time and frequency responses of the developed model are compared with the experimental results and show good agreement. Finally, using the RMS optimization method the performance of the system for different types of controllers is compared with the optimal values of linear isolator system. Experimental results show that the performance of base isolation systems for transient and shock inputs significantly improves by utilizing a controlled semi-active damper over uncontrolled MR damper or an optimally designed passive isolator.

Magnetorheological Energy Absorbers Employing a Valve Filled With Porous Media

2008 ◽  
Author(s):  
Ryan Robinson ◽  
Wei Hu ◽  
Norman M. Wereley
Keyword(s):  
Porous Media ◽  
Flow Analysis ◽  
Mr Damper ◽  
Area Ratio ◽  
Experimental Results ◽  
Equivalent Damping ◽  
Piston Valve ◽  
Energy Absorbers ◽  
The Relationship ◽  
Valve Area

The effects of porous media selection on the performance of a porous-valve-based magnetorheological (MR) damper are evaluated. Important media parameters affecting the damper performance, i.e. porosity and morphology (shape), are identified using flow analysis. The relationship between the controllable force of the damper and the porous valve characteristics is studied for three types of porous media. Equivalent damping is determined, and damping performance is compared. Effects of piston-valve area ratio on damper performance are also evaluated. A nonlinear hysteretic biviscous model is applied to the damper and the experimental results are compared with predicted results.

Designs for an adaptive tuned vibration absorber with variable shape stiffness element

2005 ◽  
Vol 461 (2064) ◽  
pp. 3955-3976 ◽  
Author(s):  
Philip Bonello ◽  
Michael J Brennan ◽  
Stephen J Elliott ◽  
Julian F.V Vincent ◽  
George Jeronimidis
Keyword(s):  
Vibration Control ◽  
Shape Change ◽  
Excitation Frequency ◽  
Variable Stiffness ◽  
Experimental Results ◽  
Vibration Absorber ◽  
Time Varying ◽  
Variable Geometry ◽  
Curved Beams ◽  
Tuned Vibration Absorber

An adaptive tuned vibration absorber (ATVA) with a smart variable stiffness element is capable of retuning itself in response to a time-varying excitation frequency, enabling effective vibration control over a range of frequencies. This paper discusses novel methods of achieving variable stiffness in an ATVA by changing shape, as inspired by biological paradigms. It is shown that considerable variation in the tuned frequency can be achieved by actuating a shape change, provided that this is within the limits of the actuator. A feasible design for such an ATVA is one in which the device offers low resistance to the required shape change actuation while not being restricted to low values of the effective stiffness of the vibration absorber. Three such original designs are identified: (i) A pinned–pinned arch beam with fixed profile of slight curvature and variable preload through an adjustable natural curvature; (ii) a vibration absorber with a stiffness element formed from parallel curved beams of adjustable curvature vibrating longitudinally; (iii) a vibration absorber with a variable geometry linkage as stiffness element. The experimental results from demonstrators based on two of these designs show good correlation with the theory.

Development of a Variable Stiffness Over Tube Based on Low-Melting-Point-Alloy for Endoscopic Surgery

2016 ◽  
Vol 10 (2) ◽  
Author(s):  
Ruzhen Zhao ◽  
Yao Yao ◽  
Yun Luo
Keyword(s):  
Melting Point ◽  
Endoscopic Surgery ◽  
Heat Insulation ◽  
Variable Stiffness ◽  
Outer Wall ◽  
Hot Water ◽  
Experimental Results ◽  
Insulation Layer ◽  
Molding Method ◽  
Response Characteristics

Instruments used in endoscopic surgery (colonoscopy surgery or natural orifice transluminal endoscopic surgery (NOTES)) are flexible to be advanced in human body. However, when the end of the instrument reaches the target, the instrument should be rigid enough to hold its shape against external forces for better surgical accuracy. In order to obtain these two properties, a variable stiffness over tube based on low-melting-point-alloy (LMPA) is proposed in this paper. The structure exploits the phase transformation property of the LMPA which enables the stiffness change of the over tube by heating and cooling. A prototype was fabricated using a special molding method, and experiments were carried out to evaluate its variable stiffness property and response characteristics. According to experimental results, it costs 17 s to make the over tube transform from rigid state to flexible state and 18 s to make the over tube transform from flexible state to rigid state. The experimental results also indicated that the over tube is very rigid in rigid state and flexible in compliant state. A heat insulation layer was assembled to prevent human tissue from thermal damage. The temperature of the outer wall of the over tube was 42.5 °C when hot water of 80 °C was pumped into the over tube continually with the help of the heat insulation layer.

Innovative AF VCM Actuator for Smart Phone Camera Module

2015 ◽  
Author(s):  
Chien-Sheng Liu ◽  
Hong-Fei Li ◽  
Min-Kai Lee
Keyword(s):  
Permanent Magnet ◽  
Simulation Analysis ◽  
Smart Phone ◽  
Voice Coil Motor ◽  
Industrial Applications ◽  
Experimental Results ◽  
Compression Force ◽  
Commercial Software ◽  
Electromagnetic Structure ◽  
Promising Solution

In the present study, we propose an innovative autofocusing (AF) voice coil motor (VCM) actuator to replace the traditional AF VCM actuators with springs for smart phone camera modules. In the proposed electromagnetic structure, the magnetic pre-compression force between the two guide rods and permanent magnet is used to replace the restoring resilience force of the two springs in the traditional AF VCM actuators. The proposed AF VCM actuator is characterized numerically using the simulation analysis of commercial software Infolytica MagNet and then verified experimentally using a laboratory-built prototype. The experimental results presented in this study show compared to traditional AF VCM actuator, the proposed AF VCM actuator has excellent AF performance to be able to replace the traditional AF VCM actuators. As a result, the proposed device provides a promising solution for smart phone camera modules or industrial applications.

scholarly journals Experimental Study of a Variable Stiffness Seat Suspension Installed With a Compact Rotary MR Damper

2021 ◽  
Vol 8 ◽  
Author(s):  
Shuaishuai Sun ◽  
Jian Yang ◽  
Penghui Wang ◽  
Masami Nakano ◽  
Longjiang Shen ◽  
...  
Keyword(s):  
Ride Comfort ◽  
Excitation Frequency ◽  
Mr Damper ◽  
Variable Stiffness ◽  
Excitation Amplitude ◽  
Harmonic Excitation ◽  
Random Excitation ◽  
Shaking Table ◽  
Seat Suspension ◽  
Vibration Attenuation Performance

Traditional MR seat suspension without stiffness control is not able to avoid the resonance between the excitation and the seat, though it can dampen the vibration energy. To solve this problem, this paper proposed a variable stiffness (VS) magnetorheological (MR) damper to implement an advanced seat suspension. Its natural frequency can be shifted away from the excitation frequency through the variations of stiffness, thereby realizing the non-resonance control. The new seat suspension is designed and prototyped first, and then its dynamic property under different energizing current, excitation amplitude, and excitation frequency was tested using an MTS machine. The testing results verified its stiffness controllability. The vibration attenuation performance of the seat suspension was also evaluated on a vibration shaking table. The vibration reduction performance of the seat suspension was evaluated under two kinds of excitations, i.e., harmonic excitation and random excitation; the experimental results indicate that the new seat suspension outperforms passive seat suspensions regarding their ride comfort.

A New Non-Parametric Model Based on Neural Network for a MR Damper

2008 ◽  
Author(s):  
Mari´a Jesu´s L. Boada ◽  
Jose´ Antonio Calvo ◽  
Beatriz L. Boada ◽  
Vicente Di´az
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Mr Damper ◽  
Parametric Model ◽  
Time Response ◽  
Suitable Model ◽  
Lazy Learning ◽  
Mr Dampers ◽  
Mr Fluids ◽  
Non Parametric

Currently dampers based on magnetorheological (MR) fluids are being used in many applications such as construction, biomechanical and semi-active suspension to improve their behaviour. The main advantage of MR dampers is its very low time response (≈ 10 ms). In many cases, it is necessary to establish a suitable model of MR damper which characterizes its behaviour so that this model can be used in the simulation stage. In this paper, a new non-parametric model is proposed based on neural networks using a recursive lazy learning to model the MR damper behaviour. The proposed method is validated by comparison with experimental obtained responses. Results show that the estimated model correlates very well with the data obtained experimentally and learns quickly.

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