Magnetorheological Research Articles

Design, Modeling, and Vibration Control of a Damper Based on Magnetorheological Fluid and Elastomer

Design, Modeling, and Vibration Control of a Damper Based on Magnetorheological Fluid and Elastomer

Adaptive Control for Suspension System of In-Wheel Motor Vehicle with Magnetorheological Damper

This study proposes two adaptive controllers and applies them to the vibration control of an in-wheel motor vehicle’s (electric vehicle) suspension system, in which a semi-active magnetorheological (MR) damper is installed as an actuator. As a suspension model, a nonlinear quarter car is used, providing greater practical feasibility than linear models. In the synthesis of the controller design, the values of the sprung mass, damping coefficient and suspension stiffness are treated as bounded uncertainties. To take into account the uncertainties, both direct and indirect adaptive sliding mode controllers are designed, in which the principal control parameters for the adaptation law are updated using the auto-tune method. To reflect the practical implementation of the proposed controller, only two accelerometers are used, and the rest of the state values are estimated using a Kalman observer. The designed controller is applied to a quarter car suspension model of an in-wheel motor vehicle featuring an MR damper, followed by a performance evaluation considering factors such as ride comfort and road holding. It is demonstrated in this comparative work that the proposed adaptive controllers show superior control performance to the conventional proportional–integral–derivative (PID) controller by reducing the vibration magnitude by 50% and 70% for the first and second modes, respectively. In addition, it is identified that the second mode (wheel mode) of the in-wheel motor vehicle is more sensitive than the first body mode depending on the mass ratio between the sprung and unsprung mass.

Improving Rotational Stability and Enhancing Efficiency with Variable Inertial Flywheels and Magneto-rheological Fluids

Variations in the rotational speed of a flywheel are naturally resisted by the moment of inertia. A high moment of inertia must be maintained to minimize angular velocity variations. Conversely, a significant moment of inertia makes it difficult to start spinning machines. A flywheel with a variable moment of inertia has been suggested to solve this issue. Although fluctuations between the masses' radii across the flywheel's axis may be used to approximate true inertia, the variable inertial flywheel's (VIF) control mechanisms are somewhat complex. Magneto-rheological (MR) Fluids can be utilized to avoid the complexity of the VIF. The applied device parameters determine the design and construction of the VIF system using a relatively simple control technique. To determine the relation between the semi-active VIF control system and the input parameters of a rotating electrical machine to decrease energy losses, adequate data from a VIF coupled with an induction motor (IM) system is gathered in this study. An analysis was done on the system, and the outcome showed a possible improvement in the performance of IM. This study significantly reduces power consumption and smooth speed build-up possibility for the proposed system.

Investigating the Impact of Circular Sector Pole Head Structure on the Performance of a Multipole Magnetorheological Brake

The magnetorheological brake (MRB) epitomized a revolutionary modification in the braking systems because of its extremely efficient and well-controlled performance. To increase the safety and controllability of automotive braking system, researchers have developed a different MRB structures. Although much research on magnetorheological brakes has shown positive results in terms of brake torque, braking time, thermal efficiency, etc., the ability to increase braking force by expanding the disc surface, through which the magnetic field operates in a compact structure, is restricted. To address this issue, a new multipole MRB configuration with a unique pole head design that maintains compactness. Initially, the conceptual design was achieved by leveraging the combined impact of the twin disc-type structure and multipole concept. The model was used in a dynamic simulation to show how the braking torque of a magnetorheological braking system varies with coil current. The effects of circular sector pole head shape on braking performance were investigated using COMSOL Multiphysics software (version 5.5). A three-dimensional electromagnetic model of the proposed MRB was developed to examine the magnetic flux intensity and the impact of magnetic field dispersion on the proposed pole head structure of a magnetorheological brake. Based on simulation results, the circular sector pole head configuration is capable of increasing the active chaining regions for the MR fluid on the rotor surface, allowing for a more effective use of magnetic flux throughout the whole surface of a rotating brake disc, thereby increasing the magnetic field usage rate. The acquired simulation results show an increase in braking torque while keeping a compact and practical design structure.

SIMULATION STUDY ON PARAMETRIC MODELLING OF MAGNETORHEOLOGICAL DAMPER SYSTEM

The Magnetorheological (MR) damper system serves as a semi-active suspension system designed to absorb road disturbances. This research aims to replicate the MR damper system through a parametric modeling approach, specifically employing the Simple Bouc-Wen Model, Spencer Model, and Hyperbolic-Tangent Model. The objective of this paper is to assess the effectiveness of these modeled MR damper systems with the utilization of a Fuzzy-PID controller. The simulation process is conducted within MATLAB Simulink, whereby a block diagram is devised based on equations related to the suspension system and the parametric models. The inputs for the system encompass sinusoidal and bump road profiles. The outcomes from the modeled MR damper systems reveal that the semi-active suspension system outperforms the passive suspension system. The primary simulation metrics under consideration include sprung displacement, sprung acceleration, and unsprung acceleration. Among the three MR damper models, the Hyperbolic-tangent model displays the most favorable performance, with a mean squared error of 51.44%, while the Bouc-Wen model exhibits the least favorable performance, registering a mean squared error of 25.96%. The integration of the Fuzzy-PID controller demonstrates an enhancement in the sprung suspension system, though the sprung acceleration remains relatively unchanged.

Structural design and multi-objective optimization of an MR isolator based on flow valve-cone rubber structure

Due to the distinctive working environment of high precision machining and manufacturing field, it poses challenges in meeting the isolation requirements, including limited installation space, multi-dimensional vibration, and a wide range of vibration frequencies. To tackle these obstacles, this paper introduces a magnetorheological (MR) isolator that offers adjustable vertical damping characteristics while guaranteeing three-axis vibration isolation through an inclined cone structure. First, the structure of the isolator was designed by combining a flow valve damper with a conical rubber structure. Second, in pursuit of lightweight design and enhanced magnetic field strength, collaborative simulations using ANSYS and Maxwell are conducted to subject the critical components of the isolator to multi-objective optimization. The optimization results demonstrate that the mass of the isolator has been reduced by approximately 27.7%, while the magnetic field intensity has increased by around 20%. Finally, the performance of the MR isolator was verified through static testing and dynamic testing, respectively. The experimental results demonstrate that the isolator can generate a maximum damping force of approximately 778[Formula: see text]N when exposed to a current of 1.5[Formula: see text]A. Compared to the initial value of 445.06[Formula: see text]N at 0[Formula: see text]A, there has been an approximate increase of 1.74 times.

Enhancement of Magnetorheological Fluids with Size and Morphology-Optimized Fe3O4 Nanoparticles: Impacts on Rheological Properties and Stability.

In this study, we synthesized Fe3O4 nanoparticles (Fe3O4 NPs) of varying sizes and morphologies using the solvothermal method and incorporated them as additives into carbonyl iron magnetorheological fluids (CI-MRFs). We tested the shear stress, yield stress, viscosity and storage modulus of the MRFs using a magnetorheometer to investigate how the size and morphology of Fe3O4 NPs influence the performance of MRFs. Our results indicate that the size of the additive nanoparticles significantly enhances the MR properties of MRFs more than their morphological attributes. This enhancement results from optimizing and stabilizing the CI magnetic chain structure of the nanoparticles in the presence of a magnetic field. Specifically, MRFs with Fe3O4 NPs averaging 250 nm in size exhibit higher yield stress and storage modulus and show increased resistance to shear strains. Although the nanoparticle morphology has a modest effect on the rheological properties of MRFs, hexahedral and octahedral particles can enhance rheological properties through increased internal friction compared to spherical particles. Additionally, Fe3O4 NPs of different sizes and morphologies improve the sedimentation stability of MRFs, with those around 250 nm being particularly effective at slowing down sedimentation. Both hexahedral and octahedral Fe3O4 NPs slow down sedimentation more effectively than spherical Fe3O4 NPs. This paper investigates the rheological properties of CI-MRFs by controlling the additive particle size and morphological features, providing a research foundation for the design and optimization of MRFs.

Experimental study on seismic performance of CFRP bar reinforced concrete columns with magnetorheological damper

Concrete column with Carbon Fiber Reinforced Polymer (CFRP) bars as longitudinal reinforcement have good self-centering performance, but its energy dissipation property is relatively weak. This article proposed a method of adjust the energy dissipation capacity of the column without affecting its self-centering performance by installing magnetorheological (MR) damper outside the column. To verify the feasibility of this method, pseudo-static tests were conducted on a MR damper, one ordinary reinforced concrete column (RCC), and two CFRP bar reinforced concrete columns with MR damper (CFRP80 and CFRP150), and the currents of the MR damper were 80 mA and 150 mA. The experimental results showed that installing MR damper can effectively improve the carrying capacity, energy dissipation property and stiffness of CFRP bar reinforced concrete columns, and the greater the energizing current of the MR damper, the more obvious these effects. Compared with RCC, CFRP bar reinforced concrete columns have better self-centering performance and ultimate deformation. The residual drifts of RCC, CFRP80 and CFRP150 at the 4 % drift level were 2.50 %, 0.62 % and 0.58 %, respectively. The ultimate drifts of RCC, CFRP80 and CFRP150 were 2.79 %, 4.26 % and 4.34 %, respectively. In addition, the use method of the MR damper can ensure that it does not affect the self-centering performance of CFRP bar reinforced concrete columns.

PATENT ANALYSIS OF EXOSKELETON MECHANISMS AND WAY TO IMPROVE THEIR COMFORT

The issue of creating robotic anthropomorphic mechanisms called exoskeletons for humans is relevant. The exoskeleton design became practically possible due to technological developments, creating powerful computers, sensors, and detectors, collecting info about human movements, and advances in control theory. Introduction of available achievements in the domain of exoskeleton engineering and design, as well as exoskeleton parts and their control methods, protected by patents, to a general audience is the objective of the article. The research methods are analysis of patents and scientific publications on the topic of exoskeletons, and graphical processing of research results. The result of the conducted research is the survey of the patented exoskeletons available in the scientific world. It has been found that the available exoskeleton models are still not user-friendly enough. Therefore, the authors of the article developed and patented a model of an exoskeleton with variable-length links. The model of practical implementation of variable-length link based on using magneto-rheological fluid and adjusting the link stiffness by applying an external magnetic field has been proposed. The proposed model augments the exoskeleton user experience. It has been found that intense publication growth in scientific journals on researched topics started after 2011. The number of published exoskeleton patents increased almost tenfold in the past ten years by 2021. All these demonstrate significant interest in exoskeletons design.

Analysis of settlement stability of aqueous magnetorheological fluid for magnetorheological jet polishing

Magnetorheological fluid is widely used in magnetorheological polishing as a smart material. The settlement stability of magnetorheological fluids plays a crucial role in determining the final polishing results. However, balancing viscosity growth with improved settlement stability is a challenge. This paper experimentally investigated the effects of different surfactant combinations on the settlement stability and viscosity of magnetorheological polishing fluids, and the experimental results showed that; using the combination of 0.25 ml Span 80 and 0.25 ml Tween 60, the deposition rate of magnetorheological solution was 68.5 %, and the zero-field viscosity was 2.3 mPa·s. Polishing experiments were carried out using the configured magnetorheological fluid, and the surface roughness of the workpiece was improved considerably with good results. Magnetorheological fluids with high settling stability also help to reduce the deposition of nanoparticles on the surface of the workpiece and improve the cleaning effect on the surface of the workpiece.

Development of novel magnetorheological dampers with low-speed sensitivity for flying car suspensions

As urban traffic environments continue to grow in complexity, there is an urgent need for a versatile mode of transportation that seamlessly transitions between terrestrial and aerial mobility. In conventional magnetorheological damper (CMRD), the magnetorheological fluid flowing through the narrow annular gap between the piston and cylinder in CMRD results in a damping force directly proportional to velocity. As velocity increases, the damping force rises sharply, posing a significant risk to the vehicle’s mechanical structure and passenger safety. This velocity sensitivity restricts their applications primarily to standard commercial vehicle suspension systems. They face significant challenges when it comes to high-speed impact scenarios. To overcome this limitation, enhance the shock-absorbing capacity of flying cars, ensure passenger safety, and improve passenger comfort during the landing phase, this study introduces a novel magnetorheological damper (NMRD) with unique internal channel structure embedded in a circular permanent magnet. In road travel mode, NMRD maintains a wide dynamic range. During high-speed impact landing, when the impact force exceeds the threshold, the pressure relief channel opens, effectively reducing the peak impact force. This feature greatly expands the application range of magnetorheological dampers. The researches included simulations of the electromagnetic induction phenomenon within the piston, The pressure relief damping force inside the NMRD valve was accurately measured by using material testing system, the peak force and peak acceleration experienced by the two dampers during impact were tested using a dedicated drop hammer apparatus. These tests demonstrate that the NMRD exhibits superior impact resistance performance compared to CMRD. This highlights the promising potential for the NMRD’s application within the suspension systems of flying cars.

An optimal design method for magnetorheological fluid sealing structure for beam director using multi-objective optimizer

For beam directors, tight optical path sealing and low rotational friction torque are critical aspects for the tracking and positioning performance. To maximize sealing pressure and minimize rotational friction torque, a magnetorheological fluid sealing (MRFS) structure design method based on multi-objective COOT (MOCOOT) algorithm optimizer was proposed in this work. The MOCOOT integrates archive, grid strategy, chaotic mapping strategy and COOT optimization algorithm. Firstly, the magnetic field strength of the sealing clearance was derived based on the equivalent magnetic circuit model, the sealing pressure formula of MRFS with pole teeth structures was established, and the friction torque model of MRFS based on Bingham equation was also developed. Then, according to the actual requirements of optical path sealing of beam directors, the constraint conditions of structure parameters were determined, and the optimization target model of sealing pressure and friction torque was constructed. As follows, a multi-objective version of COOT optimization algorithm, named MOCOOT, was proposed to optimize the structural parameters of MRFS structure. Finally, the effectiveness of the proposed method was verified via pressure and rotating friction torque tests implemented on an established experimental platform.

Bioinspired flexible gripper for vacuum non-cooperative target capture

With the development of space exploration activities, the proliferation of non-cooperative targets in space, such as defunct satellites and space debris, has made the development of efficient and reliable non-cooperative target capture technologies in space a priority for space exploration. In this paper, a flexible gripper inspired by the dermo-muscular sac found in flatworms is presented to address the challenges of non-cooperative target capture in the vacuum environment of space. The gripper design leverages magnetorheological fluid and a magnetic field to enable adjustable stiffness, facilitating the effective grasping of delicate target objects while ensuring a stable connection post-capture. Extensive tests demonstrate the strong potential of the gripper for space applications, showcasing its ability to adjust pre-grip contact force and increase gripping force by adjusting indentation depth. The simplicity of the design contributes to ease of manufacturing, making it a promising tool for future space missions.

An adaptive backstepping control strategy based on radial basis function neural networks for the magnetorheological semi-active suspension

Owing to nonlinear issues such as external disturbances and uncertain parameters within the semi-active suspension system (SASS), the vibration amplitude of the suspension system tends to increase, and the time required for the suspension system to reach a steady-state response is prolonged. Hence, this paper proposes an adaptive backstepping control strategy based on radial basis function neural networks (RBF-NNs). Firstly, the damping force characteristics of the magnetorheological (MR) damper are tested, and the experimental data are utilized for parameters identification and fitting of the Bouc-Wen model. To establish a connection between the controller and the forward model of the MR damper, the forward model of the MR damper, the inverse model of the MR damper, and the model of the MR-SASS are constructed. Secondly, the backstepping controller and the adaptive backstepping controller based on RBF-NNs are designed. The stability and reliability of the closed-loop suspension system are verified through stability analysis using Lyapunov function. Finally, the dynamic characteristics of the passive control, backstepping control, and adaptive backstepping control strategies based on RBF-NNs applied to MR-SASS are analyzed under B-Class road excitation and speed bump road excitation. The acceleration, suspension dynamic deflection, and tire dynamic load are selected as the evaluation indices. The results demonstrate that the adaptive backstepping controller based on RBF-NNs significantly enhances the ride comfort of the SASS.

Design and actuation of a state transformable amorphous soft robot

Traditional solid-state magnetic robots have limited deformability due to their fixed structures, while liquid robots sacrifice stiffness and stability for deformability. To overcome these limitations, a novel state transformable amorphous soft robot, referred to as the AMS-Robot, has been developed utilizing magnetorheological fluid (MRF). This robot can swiftly transition from a Newtonian fluid state (in a weak magnetic field) to a solid Bingham plastic state (in a strong magnetic field) in response to varying magnetic fields. The locomotion of our AMS-Robot, steered by a gradient magnetic field acting on magnetic droplets, converts magnetic energy into kinetic energy and viscous dissipation, enabling functions like deformation, navigation, split-merger, and gradient crawling. Remarkably, the robot exhibits the ability to transport objects weighing approximately 150 times its own weight under a strong magnetic field. Through simulations of its movement within blood vessels, the potential of the AMS-Robot in medical applications is highlighted, showcasing its proficiency in tasks like precision drug delivery and thrombus removal. This groundbreaking approach holds significant promise for advancements in the field of medical applications.

Experimental and theoretical investigation on magnetorheological elastomers containing carbonyl iron particles coated with silane coupling agent

Magnetorheological (MR) elastomer composites, comprising soft silicone rubber, various additives, and different weight fractions of carbonyl iron particles (CIPs) coated with silane coupling agent, are produced via a novel manufacturing process in an anisotropic state. This study encompasses both experimental and modeling investigations into the dynamic viscoelastic properties of magnetorheological elastomer (MREs) in shear mode under varying magnetic fields, displacement amplitudes, and frequencies. Two MRE vibration mitigation devices are fabricated to experimentally assess the shear storage modulus and the loss factor of MREs. The experimental findings reveal a pronounced MR effect in the MRE devices, where both the shear storage modulus and the loss factor increase with rising magnetic fields, frequencies, and particle weight fractions, yet decrease with higher displacement amplitudes. A modified fractional-derivative equivalent parametric model, grounded in a magnetic field- and frequency-dependent shear modulus model along with internal variable theory, is proposed to describe the effects of these key influencing factors on the MREs’ dynamic viscoelastic properties. Comparative analysis of experimental and numerical data demonstrates that this refined mathematical model can accurately represent the dynamic viscoelastic properties of MREs.

Fabrication and property research of a new 3D-Printable magnetorheological elastomer (MRE)

In order to meet the growing design demands for shape and structure of magnetic functional materials, particularly Magnetorheological Elastomers (MREs), additive manufacturing technology has been introduced into MRE production. Reported works of printable MRE (p-MRE) have successfully obtained high relative magnetorheological (MR) performance comparable to traditional MRE. However, there are still few studies on p-MRE with both high relative and absolute MR effects that is required for some applications such as intelligent dampers in automotive industry. In this study, polyurethane (TPU) and carbonyl iron powder (CIP) were utilized as raw materials to formulate p-MRE with high printability and high comprehensive MR performance. Based on the fused deposition modeling (FDM) process, a printing strategy suitable for this p-MRE material was determined through experimental design (DOE). The test result showed that the comprehensive MR performance of the p-MRE sheet samples obtained through linear printing path exceeded the majority of previously reported p-MRE materials. In addition, based on the analysis of the correlation between magnetic hysteresis like effect and MR effects, a circular printing path that may be beneficial for improving MR performance was proposed and corresponding p-MRE sheet sample was printed. The test results showed that compared with the linear printing path, the circular printing path further increases the comprehensive MR effect of the sheet sample to a maximum absolute MR effect of 4.2 MPa and a maximum relative MR effect of 620 %, which is comparable to most conventional MRE materials. Additionally, a theoretical framework associating magnetic field strength and filling density was proposed to explain peculiar phenomena observed in the experiments. On the basis of previous research on MREs and filler modified elastomers, a hypothesis was proposed to link magnetic field intensity with filler density, allowing the existing theory of filler modified elastomers to be used to explain the special phenomena observed in our experiments.

Experimental and numerical analysis of magnetorheological valve based on Herschel–Bulkley–Papanastasiou model

As a kind of smart material, magnetorheological (MR) fluids are widely used in various engineering applications. Choosing an appropriate rheological model to describe flow behavior is crucial in the design of MR actuators. In this paper, the Herschel-Bulkley-Papanastasiou (HBP) model was first developed to fit the rheological properties of the MR fluid. The coupling modeling of the flow field and magnetic field of the radial MR valve were established, and the distribution of the magnetic field, velocity field, shear stress, and shear rate of the radial MR valve were also analyzed. The rheological properties of MR fluids and the inlet and outlet pressures of the MR valve were experimental tests. The experimental and numerical results indicate that the HBP model can better fit the rheological characteristics of MR fluids than that of the BP model, and the numerical results can better predict the magnetic field and flow field characteristics of the MR valve.

A Review on Structural Configurations of Magnetorheological Clutch

Abstract:: In recent years, with the development of "smart materials", magnetorheological fluids have been widely used in the fields of mechanical transmission, aerospace, construction, and medical treatment because of the unique rheological properties that can occur under the action of an applied magnetic field. Magnetorheological clutches with magnetorheological fluid as the working medium have the advantages of simple structure, low noise, fast response, and easy control compared with traditional clutches. In order to provide an overview of the issues encountered by magnetorheological clutches in their current applications and to summarize the optimization designs implemented to address these issues, with the aim of promoting the widespread application of magnetorheological clutches. The basic theory of magnetorheological fluid and magnetorheological clutch design method is introduced. The related patents of magnetorheological clutch structure design are reviewed. The characteristics and advantages of magnetorheological clutch in different working modes are summarized. This study introduces the basic theory of magnetorheological fluid. The problems existing in the application of magnetorheological clutch are explained. The characteristics of magnetorheological clutch based on shear mode, shear-extrusion mode and heat dissipation mode are described. The development trend of magnetorheological clutch is discussed. This paper provides an important basis for the design and application of magnetorheological clutch, offers specific guidance for improving the torque transmission capacity and heat dissipation capacity of magnetorheological clutch, and lays a theoretical foundation for the wide application of magnetorheological clutch in the future.

Investigations of Sustainable Biodegradable Oil and Magnetic Particle‐Based Magnetorheological Fluid Dampers for Vibration Attenuation of a Rotor Dynamic System

This article aims to study the physical characterization and performance of a material‐based magnetorheological fluid (MRF) dampers for vibration attenuation of a high‐speed rotor–motor system near resonance. Four samples are synthesized by combining electrolytic iron and carbonyl iron (CI) with Castor and Karanja oil and experimentally investigated for their contribution to vibration attenuation. The results demonstrate effective vibration attenuation of the biodegradable oil‐based MRF damper than the nonbiodegradable oil‐based MRF damper. The best vibration attenuation is observed in the case of moderately viscous MRF. CI‐based samples exhibit a lower sedimentation rate, hence recommended for MRF. The vibration amplitude is maximum for the Castor oil‐based MRF damper, however, is minimum for the Karanja oil‐based MRF damper. The steady and transient results of vibration amplitudes are obtained and analyzed for different currents supplied to the MRF damper. The range of unstable speed near resonance is also obtained. The prepared samples show higher attenuation of 6–25% than Sample 5. The vibration amplitude attenuation of Sample 4 and Sample 5 are 47% and 22%, respectively. The findings of this study carry significant implications for controlling the vibration of the dynamic system using an eco‐friendly damping system.