Magnetorheological Fluid Devices Research Articles

Development of a fail-safe magnetorheological fluid device using electro and permanent magnets

Development of a fail-safe magnetorheological fluid device using electro and permanent magnets

Cooperativity of nanoscale magnetic zeolitic imidazolate framework in magnetorheological fluid

Particle sedimentation and magnetorheological (MR) effect are crucial to the stability and performance of magnetorheological fluid (MRF) and are bottlenecks that hinder their broad application in devices such as dampers, clutches, adaptive shock absorbers, etc. In this study, a magnetic zeolitic imidazolate framework (Fe3O4/ZIF-8) nanomaterial is synthesized, which exhibits exceptional potential as a superior reinforcing agent, effectively mitigating sedimentation issues and enhancing the MR effect of MRF. Introducing a steric effect yields improved particle suspension stability, contributing to the long-term stability and resistance to settling in MRF. Furthermore, a bidispersion coupling system between the nanocomposite particle and carbonyl iron powder in MRF demonstrates remarkable magnetism characteristics, particularly in densely packed two-phase flow conditions. In comparison to an MRF lacking Fe3O4/ZIF-8, the suspension stability and magneto-induced dynamic yield stress of an MRF with a 3 wt% nanocomposite particle are enhanced by 24.8% and 21.12%, respectively. Additionally, the suspension with nanocomposite particles demonstrates exceptional performance in terms of magnetic field responsiveness and aggregation resistance. The comprehensive analysis presented in this paper underscores the efficacy of this solution in maintaining the suspension stability of MRF, a breakthrough with the potential to advance the capabilities of MRF devices and extend their operational lifespans.

Design, modeling, and experimental evaluation of a self-sealing component for rotary shafts in magneto-rheological fluid devices

Design, modeling, and experimental evaluation of a self-sealing component for rotary shafts in magneto-rheological fluid devices

Improvement of Haptic Interface for Teleoperation Endoscopic Surgery Simulators Using Magnetorheological Fluid Devices

A magnetorheological (MR) fluid is a composite material comprising ferromagnetic particles, medium oils, and several types of additives. We developed an MR fluid clutch for haptics (H-MRC) and installed it in a haptic interface that simulates teleoperation endoscopic surgery (ES). To enhance its operability, we redesigned the H-MRC to reduce its weight and improve its control system. We reduced the weight of the H-MRC and haptic gripper by 77.0 g and 137.0 g, respectively. To evaluate the influence of the improvement and force feedback functions on remote operation skills, we conducted pick-and-place tests with a remotely controlled system. In the tests, we subjectively evaluated the NASA-TLX and quantitatively evaluated the success rate of the task. The results of the subjective assessment showed significant reductions in mental stress during the teleoperation task. In addition, the results of the quantitative evaluation showed that the force feedback function was effective against the teleoperation skills of the operators.

Experimental and Numerical Studies of a Soft Impact Piezoelectric Energy Harvesting Using an MR Fluid

Numerical and an experimental study of a soft impact-based piezoelectric energy harvesting system employing a thin layer of magnetorheological (MR) fluid as the impact object is presented in this paper. MR fluid devices are mostly used as vibration suppressors in automobiles and other machinery. MR fluids exhibit variable rheological properties in the presence of a magnetic field, which makes them excellent vibration attenuation devices with easily adaptable damping forces. This behavior can be exploited in vibration energy harvesting to aid frequency up-conversion. The study is carried by solving the theoretical equations numerically and then validating the results experimentally. The Heaviside function is used to model the piecewise nonlinear dynamics of the proposed system. In this way, the sticky and inelastic behavior of the fluid, which causes a time-delay in the oscillations of the beam is best described. The results obtained indicated that increasing the magnetic field increases the voltage generated through frequency amplification. The voltage obtained with a load resistance of 200 k $\Omega $ increased from 9.29 V to 9.42 V when the magnetic field increases from 0.04T to 0.08T for the numerical study and 7.71 V to 8.46 V when the field increased from 0.044T to 0.085T in the experimental study. The frequency is amplified from 59.58 Hz at 0.04T to 82.76 Hz at 0.08T for the numerical results and from 61.02 Hz at 0.044T to 83.04 at 0.085T for the experimental results. The MR fluid acts as a soft impact object in this work.

Application of a Nonlinear Hammerstein-Wiener Estimator in the Development and Control of a Magnetorheological Fluid Haptic Device for Robotic Bone Biopsy

A force generator module (FGM) based on magnetorheological fluid (MRF) was developed to provide force-feedback information for applications in tele-robotic bone biopsy procedures. The FGM is capable of rapidly re-producing a wide range of forces that are common in bone biopsy applications. As a result of the nonlinear nature of MRF, developing robust controllers for these mechanisms can be challenging. In this paper, we present a case study motivated by robotic bone biopsy. We use a non-linear Hammerstein-Wiener (H-W) estimator to address this challenge. The case is presented through three studies. First, an experiment to develop design constraints is presented and describes biopsy force measurements for various animal tissues. Required output forces were found to range between <1 N and <50 N. A second study outlines the design of the FGM and presents the experimental characterization of the hysteretic behavior of the MRF. This data is then used as estimators and validators to develop the nonlinear Hammerstein-Wiener (H-W) model of the MRF. Validation experiments found that the H-W model is capable of predicting the behavior of the MRF device with 95% accuracy and can eliminate hysteresis in a closed-loop control system. The third study demonstrates the FGM used in a 1-DOF haptic controller in a simulated robotic bone-biopsy. The H-W control tracked the input signal while compensating for magnetic hysteresis to achieve optimal performance. In conclusion, the MRF-based device can be used in surgical robotic operations that require a high range of force measurements.

Predicting the thermal sensitivity of MR damper performance based on thermo-rheological properties

One factor which needs to be addressed in magnetorheological (MR) fluid device is operational stability under a given environmental condition and/or localized viscous heating within a device. So, one need to study thermal effects on MR fluids and its influence on performance of MR fluid devices. The aim the present paper is to predict the thermal stability of MR fluid device performance, based on the thermo-rheological properties. The MR fluid is synthesized using flake shape iron particles and its rheological study is carried out in the absence and presence of field using a magneto—rheometer. The thermo-rheology was studied and sensitivity was derived. This fluid is tested for its damper performance in the designed and fabricated flow mode damper. The thermo-sensitivity of the damper is studied and compared with rheological properties. It is suggested that one can predict the damper temperature dependent performance based on the thermo-rheological results.

Design optimization of a novel elastomeric baffle magnetorheological fluid device

This article details the design optimization of a novel magnetorheological fluid device, which incorporates a rolling elastomeric baffle to contain the fluid and minimize cost and complexity. The application considered here is an electronic joystick for a drive-by-wire construction machine, although designs for other semi-active applications could be similarly optimized. Performance is evaluated computationally and experimentally. A computationally efficient system model is developed and validated using finite element analysis to accurately predict the device’s magnetic flux characteristics. The design methodology is based on a variant of the firefly algorithm, which identifies promising initial designs, and conjugate gradient methods, which optimize these designs. A unique graphical method for interpreting the results of population-based firefly optimization is demonstrated. An experimental prototype, based on the optimized design, is tested and its data compared to simulation results.

Modeling and experimental evaluation of a rotary peristaltic magnetorheological fluid device with low off-state torque for haptic interfaces

This article presents a novel rotary magnetorheological fluid device with inherently low off-state torque. The working principle of the device is similar to peristaltic pumps except the fluid remains inside the device and circulates continuously. Unlike other continuous rotation magnetorheological fluid devices, which operate in shear mode, the proposed device works in pressure driven flow mode. A proof of concept prototype with arbitrary dimensions is built and experimentally evaluated. Measured off-state torque is as low as 20 N.mm. Analytical model of the resistant torque and finite element simulations of the magnetic circuit are presented and validated with the experimental results. Using these models, an optimal device with similar off-state characteristics can be designed to fulfill specific requirements of size, weight, power and on-state torque. The proposed concept is promising especially for use in high precision haptic interfaces that require stability and transparency at the lower end of force spectrum.

Variable stiffness mechanisms of dual parameters changing magnetorheological fluid devices

Magnetorheological fluid (MRF) dampers are widely used as the variable damping devices in the semi-active vibration control system. In order to further improve the vibration reduction performance, a variable stiffness MRF damper with two chambers and two springs has been proposed recently. According to the test results, both of the damping and stiffness of the device can be controllable by changing the applied current independently. However, the mechanisms of variable stiffness for this device are still not clear. In this paper, the force transmissions of the parts of the variable stiffness MRF damper are analyzed, which reveals the variable stiffness mechanisms of dual parameters changing MRF devices. There are three stages for the variable stiffness MRF damper due to the friction and the yield of MR fluid. These stages can be controlled by the applied current of the different chambers, which changes the equivalent stiffness of the device. The proposed modelling of the device is verified by simulations and tests. In addition, the relationships between the equivalent stiffness and the parameters of the device are derived, which provide the design guidance for the variable stiffness MRF dampers.

Development and control of a magnetorheological haptic device for robot assisted surgery.

A prototype magnetorheological (MR) fluid-based actuator has been designed for tele-robotic surgical applications. This device is capable of generating forces up to 47 N, with input currents ranging from 0 to 1.5 A. We begin by outlining the physical design of the device, and then discuss a novel nonlinear model of the device's behavior. The model was developed using the Hammerstein-Wiener (H-W) nonlinear black-box technique and is intended to accurately capture the hysteresis behavior of the MR-fluid. Several experiments were conducted on the device to collect estimation and validation datasets to construct the model and assess its performance. Different estimating functions were used to construct the model, and their effectiveness is assessed based on goodness-of-fit and final-prediction-error measurements. A sigmoid network was found to have a goodness-of-fit of 95%. The model estimate was then used to tune a PID controller. Two control schemes were proposed to eliminate the hysteresis behavior present in the MR fluid device. One method uses a traditional force feedback control loop and the other is based on measuring the magnetic field using a Hall-effect sensor embedded within the device. The Hall-effect sensor scheme was found to be superior in terms of cost, simplicity and real-time control performance compared to the force control strategy.

Design and Manufacturing Aspects of Magneto-rheological Fluid (MRF) Clutch

This paper describes a research work concerned with design method and manufacturing details of a Magneto-rheological Fluid (MRF) Clutch which has a multi-layered disks and micro-size (1 micro meters) gaps of MR fluid for automotive applications. Magneto-rheological Fluid devices are finding a wide variety of applications to meet the new market demand. An MR fluid will be in a free-flowing liquid state in the absence of magnetic field, but under a strong magnetic field its viscosity can be increased by more than two orders of magnitude in a very short time (milliseconds) and it exhibits solid-like characteristics. Various devices working with MR fluids include Clutches, Brakes, Hydraulic valves, dampers, robotic arms. The micro-size gap works for the reduction of magnetic resistance, amount of power supply and size of the total system. The controllability of MR fluids provides an adjustable torque transmission and slippage for the applications. Three-dimensional solid modelling is performed for clutch design and manufactured. The benefits with using MRF are fast response, simple interface between electrical power input and mechanical power output and of course the excellent controllability of the fluid. MRF clutches are known as good Torque transmitting devices.

摩擦的特性を利用したロボット関節のための磁気粘性流体デバイスの開発

摩擦的特性を利用したロボット関節のための磁気粘性流体デバイスの開発

Research and Development of Functional Fluid Mechatronics, Rehabilitation Systems, and Mechatronics of Flexible Drive Systems

[abstFig src='/00280001/01.jpg' width=""260"" text='PLEMO-P3 Developed by Furusho Lab at Osaka Univ.' ]We conducted many research and development activities on functional fluid mechatronics, rehabilitation systems, and servo drive systems. In this review, studies on the development of magnetorheological fluid devices, electrorheological effects of liquid crystalline polymers on one-sided pattern electrodes, and vibration control using control theory and liquid crystalline polymer are introduced. In addition, applications of rehabilitation systems for upper and lower extremities employing functional fluids for individuals suffering from stroke, cerebellar ataxia, and Guillain-Barre syndrome are also introduced.

Design of magnetorheological valve using serpentine flux path method

Magnetorheological (MR) valve is widely applied in a lot of applications that utilizes the flow mode, which is one of the working modes available for MR fluid devices. This paper introduces the serpentine flux path method in an MR valve, whereby using this method it can help to increase the effective region of the valve. The magnetic flux is guided into the annular gap of the valve, as the magnetic flux can be weaved by alternating the magnetic and non-magnetic materials. The method is simulated using Finite Element Method Magnetics to see the effects of weaving steps and thicknesses of non-magnetic materials to the magnetic flux distribution and pressure drop change in the valve. The results show that MR effective region can be increased with the serpentine flux path method, and the additional steps and thicknesses of non-magnetic materials help to further increase the pressure drops within the valve.

Magnetorheological fluid devices: An advanced solution for active control of the wood manufacturing process

Magnetorheological fluid devices: An advanced solution for active control of the wood manufacturing process

Scaling temperature dependent rheology of magnetorheological fluids

Magnetorheological (MR) fluids are suspensions of micron-scale magnetizable particles suspended in a carrier fluid. When field is applied, MR fluids develop a field controllable yield stress and a field independent post-yield viscosity. However, this viscosity has substantial temperature dependence, varying by up to an order of magnitude over the operating temperature range of MR fluid devices. We apply non-Brownian suspension theory to explain this result and find that the majority of this effect should be caused by the temperature dependent behavior of the carrier fluid. Thus, if two fluids share the same carrier fluid, then their fluid properties should scale in temperature similarly. This result is first validated by measuring viscosity across temperature for custom model fluids designed to conform to theory, showing temperature scaling within 5% for both the MR fluids and their carrier fluid. Then, on a series of related commercially available fluids with unknown additive content, we show that the MR fluids exhibit common scaling to within 4%. We also investigate the effects of magnetic hysteresis and find that it induces a negligible increase in yield stress and no measurable change in viscosity. We conclude that our non-dimensional analysis enables the temperature dependence of novel MR fluids to be characterized with fewer experiments.

Understanding the super-strong behavior of magnetorheological fluid in simultaneous squeeze-shear with the Péclet number

Under squeezing flow, magnetorheological fluid can undergo a strengthening phenomenon which results in a drastic increase of its yield stress. This behavior, also known as the super-strong effect, could be used to significantly increase the performance (e.g. torque-to-weight) of rotary magnetorheological fluid devices (e.g. brakes, clutches), but has yet to be exploited due to limited predictability of the phenomenon. To better understand the occurrence of the super-strong effect, a novel test bench capable of small amplitude oscillatory shear is designed to study the behavior of high-concentration magnetorheological fluid submitted to different simultaneous squeeze-shear conditions and magnetic field strengths. Experimental results, obtained up to 5 mm/s compression speed, show that the squeeze-strengthening effect can be correlated to the Péclet number when squeeze flow is dominant, suggesting that the super-strong behavior is governed by solid–liquid phase separation. This super-strong effect, however, is found greatly reduced when the super-imposed shear-rate approaches the squeeze-rate order of magnitude.

Constitutive model for shear yield stress of magnetorheological fluid based on the concept of state transition

Magnetorheological fluid (MRF) is a smart material whose rheological properties can be varied by a magnetic field; it has been applied in the development of semiactive dampers for a variety of applications. The material essentially consists of a suspension of magnetic particles in a nonmagnetic carrier fluid. It is important to understand the magnetic response of MRF and its dependence on several parameters for improving and designing MRF devices. The purpose of this work is to develop a constitutive model that describes the behavior of the shear yield stress of the material as function of the magnetic field and composition. Taking into account that the material changes its rheology and apparent viscosity according to magnetic field, a magnetically induced state transition is proposed; by the use of a state transition equation, a constitutive model for shear yield stress is defined, consisting of an expression that relates composition of the material and the stimulus applied, it also associates the volume fraction of particles, magnetic field and the material that composes the particles.

The soft-landing features of a micro-magnetorheological fluid damper

The authors demonstrate that the micro magneto-rheological fluid device is designed by the method of outer magnetic coil to generate a mechanical loading less than 20 N. The results confirm that the method can obtain miniature device easily and control the magnetic field conveniently. The magnetic field, the channel gap, and the initial position of valve plug were optimized by finite element simulation and experimental test. Additionally, an impact force at the beginning can be eliminated by using a modeled synchronous linear current, which indicates that the micro-magnetorheological fluid damper has good soft-landing performance.