On the Design and Control of a Squeeze-Flow Mode Magnetorheological Fluid Mount

2007 ◽  
Author(s):  
Constantin Ciocanel ◽  
The Nguyen ◽  
Christopher Schroeder ◽  
Mohammad Elahinia
Keyword(s):  
Vibration Isolation ◽  
Hybrid Control ◽  
Control Strategies ◽  
Dynamic Stiffness ◽  
Squeeze Flow ◽  
Flow Mode ◽  
Force Transmissibility ◽  
Displacement Force ◽  
Vertical Vibrations ◽  
And Control

The paper presents the design and control of a magnetorheological (MR) fluid based mount that combines the squeeze and flow modes in operation. The proposed design yields a high static stiffness and a low dynamic stiffness in the working frequency range of the mount, enhancing the vibration isolation capabilities of the mount compared to existing hydraulic mounts. Vertical vibrations, namely displacement/force transmissibility, can be isolated or significantly reduced, in real time, by controlling the fluid yield stress through an applied electric current. The mount governing equations have been derived and the effect of system parameters on its performance was analyzed. Preliminary results on the implementation of skyhook, groundhook and hybrid control strategies are also presented.

A Squeeze-Flow Mode Magnetorheological Mount: Design, Modeling, and Experimental Evaluation

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
T. M. Nguyen ◽  
C. Ciocanel ◽  
M. H. Elahinia
Keyword(s):  
Vibration Isolation ◽  
Magnetic Circuit ◽  
Dynamic Stiffness ◽  
Experimental Results ◽  
Squeeze Flow ◽  
Design Parameters ◽  
Flow Mode ◽  
Wide Range ◽  
Isolation Device ◽  
Stiffness And Damping

This paper presents a dual-mode magnetorheological (MR) fluid mount. Combining the fluid’s flow and squeeze modes of operation gives this MR mount a unique possibility for varying dynamic stiffness and damping. Details on the design of the internal structure of the mount and the magnetic circuit are provided. Simulation and experimental results are presented to show the effectiveness of the magnetic circuit. A mathematical model that combines the behavior of the fluid and the elastomeric parts and takes into account the magnetic activation of the fluid is used to gauge the effect of design parameters on the isolation characteristics of the mount. Experimental results show that in the proposed design, the dynamic stiffness of the mount may be varied over a wide range of frequencies making the mount a unique and versatile vibration isolation device for cases where input excitation occurs over a wide range of frequencies.

Performance of an Adaptive Magnetorheological Fluid Mount

2007 ◽  
Author(s):  
Constantin Ciocanel ◽  
The Nguyen ◽  
Christopher Schroeder ◽  
Mohammad H. Elahinia
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Magnetorheological Fluid ◽  
Flow Mode ◽  
Frequency Range ◽  
Governing Equations ◽  
Mr Fluid ◽  
System Parameters ◽  
Force Transmissibility ◽  
Working Frequency

The paper investigates the response of a magnetorheological (MR) fluid based mount that combines the squeeze and flow modes in operation. The mount governing equations are introduced and the effect of system parameters on its performance is analyzed. The proposed design yields a high static and a low dynamic stiffness in the working frequency range of the mount. The overall vibration isolation characteristic of the mount is enhanced if compared to that of existing hydraulic mounts. Displacement and/or force transmissibility can be isolated or significantly reduced, in real time, by controlling the MR fluid yield stress. An embedded electromagnet is used to activate the MR fluid that can work in either squeeze or flow modes, or in both simultaneously. The results indicate that the flow mode is less effective in reducing transmissibility than the squeeze mode. However, when the flow and squeeze modes are both activated, the effect of the flow mode becomes more obvious.

Vibration isolation using a magnetorheological damper in the squeeze-flow mode

1999 ◽  
Author(s):  
Neil D. Sims ◽  
Roger Stanway ◽  
Andrew R. Johnson ◽  
J. S. Yang
Keyword(s):  
Vibration Isolation ◽  
Magnetorheological Damper ◽  
Squeeze Flow ◽  
Flow Mode

ER fluids in the squeeze-flow mode: an application to vibration isolation

1992 ◽  
Vol 28 (1) ◽  
pp. 89-94 ◽  
Author(s):  
R. Stanway ◽  
J.L. Sproston ◽  
M.J. Prendergast ◽  
J.R. Case ◽  
C.E. Wilne
Keyword(s):  
Vibration Isolation ◽  
Squeeze Flow ◽  
Flow Mode ◽  
Er Fluids

scholarly journals Characteristic analysis of a new high-static-low-dynamic stiffness vibration isolator based on the buckling circular plate

2020 ◽  
pp. 146134842090486
Author(s):  
Zhirong Yang ◽  
Yan Wang ◽  
Ziming Huang ◽  
Zhushi Rao
Keyword(s):  
Equilibrium Point ◽  
Circular Plate ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Harmonic Balance Method ◽  
Installation Space ◽  
Vibration Isolator ◽  
Characteristic Analysis ◽  
Linear Spring ◽  
Force Transmissibility

The high-static-low-dynamic stiffness vibration isolator has great advantages in vibration isolation because it can decrease the natural frequency of the system while keeping the load capability, but it is usually difficult to implement because of its complex structures and installation space constraints. A high-static-low-dynamic stiffness vibration isolator composed of a buckling circular plate and a traditional linear spring is proposed in this paper. The buckling circular plate works as the negative stiffness corrector paralleled with the linear spring, which can be integrated into the sleeve. If the load is chosen properly, the static equilibrium point will be at the initial quasi-zero stiffness point. However, any changes of the load will lead the equilibrium point deviating from the initial equilibrium point. The nonlinear mathematical model of high-static-low-dynamic stiffness vibration isolator considering load imperfection is developed and its force transmissibility is analyzed with the harmonic balance method and homotopy perturbation method. The influence rule of the system parameters on it is analyzed and the corresponding results show that the force transmissibility will exhibit complicated characteristics, depending on the load imperfection, damper, and excitation force.

Experimental Verification of Controllability of a Mixed Mode MR Fluid Mount

2011 ◽  
Author(s):  
Shuo Wang ◽  
Mohammad Elahinia ◽  
The Nguyen
Keyword(s):  
Mixed Mode ◽  
Alternative Energy ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Hybrid Vehicles ◽  
Flow Mode ◽  
Shear Mode ◽  
Mr Fluid ◽  
Set Up ◽  
Different Levels

With the advent of alternative energy and hybrid vehicles come new vibration problems and challenges that require nontraditional solutions. Semi-active vibration isolation devices are preferred to address the problem due to their effectiveness and affordability. A magnetorheological (MR) fluid mount can provide effective vibration isolation for applications such as hybrid vehicles. The MR fluid can produce different levels of damping when exposed to different levels of magnetic field. The fluid can be working in three modes which are the flow mode, shear mode and squeeze mode. A mixed mode MR fluid mount was designed to operate in a combination of the flow mode and the squeeze mode. Each of the working modes and the combined working mode has been studied. The mount’s performance has been verified in simulation and experiments. Based on the simulation and experimental results, it can be seen that the mount can provide a large range of dynamic stiffness. Given this range of dynamic stiffness, a controller has been designed to achieve certain dynamic stiffness at certain frequencies. The experiments are set up to realize the hardware-in-the-loop tests. Results from the experiments show that the mixed mode MR fluid mount is able to achieve desired dynamic stiffness which is directly related to vibration transmissibility.

scholarly journals Power Flow in a Two-Stage Nonlinear Vibration Isolation System with High-Static-Low-Dynamic Stiffness

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Ze-Qi Lu ◽  
Dong Shao ◽  
Hu Ding ◽  
Li-Qun Chen
Keyword(s):  
Nonlinear Vibration ◽  
Power Flow ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Harmonic Balance Method ◽  
Harmonic Excitation ◽  
Resonant Peak ◽  
Nonlinear Stiffness ◽  
Two Stage ◽  
Force Transmissibility

The manuscript concerns the power flow characterization in a two-stage nonlinear vibration isolator comprising three springs, which are configured so that each stage of the system has a high-static-low-dynamic stiffness. To demonstrate the distinction of evaluation for vibration isolation using power flow, force transmissibility is used for comparison. The dynamic behavior of the isolator subject to harmonic excitation, however, is of interest here. The harmonic balance method (HBM) could be used to analyze the frequency response curve (FRC) of the strong nonlinear vibration system. A suggested stability analysis to distinguish the stable and the unstable HBM solutions is described. Increasing both upper and lower nonlinear stiffness could bend the first resonant peak to the left. The isolation range in the power and the force transmissibility plot could be extended to the lower frequencies when the nonlinear stiffness is increased, but the rate of roll-off for the power transmissibility is twice the rate for the force transmissibility at each horizontal stiffness setting. An explanation for this phenomenon is given in the paper.

Improving the performance of parallel robots by applying distinct hybrid control techniques

Robotica ◽  
2021 ◽  
pp. 1-25
Author(s):  
André G. Coutinho ◽  
Tarcisio A. Hess-Coelho
Keyword(s):  
Sliding Mode Control ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Control Laws ◽  
Control Techniques ◽  
Mode Control ◽  
And Control

Abstract During the last two decades, parallel robots have become more ubiquitous, employed in a great variety of sectors, from food to aerospace industries. In fact, they are much more efficient than their serial counterparts in terms of performing fast motions and consuming less energy. However, due to their mechanical complexity, they present a highly complex non-linear dynamics, which makes the modelling and control tasks difficult. Aiming to improve the performance and robustness of the control laws already used to control this type of mechanisms, this paper proposes two hybrid control techniques. The first hybrid control is derived from the combination of a pure PD control with a modified Sliding Mode control. The second hybrid control, in its turn, combines a pure Computed Torque with the altered Sliding Mode control. The proposed modifications in the Sliding Mode control aim to achieve a considerable reduction of the tracking errors and chattering. A stability analysis of the proposed control techniques and an experimental validation are carried out, comparing the performance of the pure and hybrid control laws in a 5R parallel mechanism. Moreover, simulations are also conducted to evaluate the behaviour of a 3-dof spatial parallel robot, when performing a 3D-path. Analysing the simulations and the experimental results, it is possible to observe a significant reduction of the path tracking and steady-state errors in both hybrid control strategies.

Design and Analysis of a High-Static-Low-Dynamic Stiffness Isolator Using the Cam-Roller-Spring Mechanism

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Yuhui Yao ◽  
Xiaojian Wang ◽  
Hongguang Li
Keyword(s):  
Harmonic Balance ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Harmonic Balance Method ◽  
Interaction Force ◽  
Linear Spring ◽  
Cam Profile ◽  
Force Transmissibility ◽  
Spring Mechanism

Abstract This paper presents a new design of a high-static-low-dynamic stiffness (HSLDS) isolator with an adjustable cam profile. The interaction force between the cam and roller provides the negative stiffness force and the linear spring provides the positive stiffness force in the HSLDS isolator. Unlike previous studies, the cam profile in this paper can be individually designed to meet different working conditions. Firstly, the harmonic balance method is used to acquire the dynamic response of the HSLDS isolator. Then, the effects of the damping ratio, stiffness ratio, and external force amplitude on the frequency response amplitude and force transmissibility are discussed. Finally, the frequency responses of four designed nonlinear HSLDS isolators and a linear isolator are acquired by the numerical method. The results show that the nonlinear isolator begins to achieve vibration isolation at 0.11 Hz and the linear one is 8.9 Hz. The proposed HSLDS isolator realizes lower vibration isolation frequency than the linear isolator.

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