Rotary Magnetorheological Damper Research Articles

Performance enhancement of a rotary magnetorheological damper induced by needle roller structure

In order to improve the mechanical performances of magnetorheological (MR) damper, a rotary MR damper with needle rollers was proposed based on squeeze mode. The MR fluid was induced to work in a special mode by inserting the needle roller structure, thus the output damping torque of the damper was significantly improved. The experimental results show that the damping torque shows a trend from stable to increased when the angular velocity of the damper is low, and the maximum damping torque increases with the increase of the excitation current due to the insertion of the needle roller structure, which is exactly consistent with “Stribeck effect”. Finally, this interesting phenomenon was analyzed and summarized.

A rotary self-sensing magnetorheological damper based on triboelectric nanogenerator

A rotary self-sensing magnetorheological (MR) damper(RSMRD) based on a triboelectric nanogenerator is proposed in this study, which can provide variable torque and state self-sensing without a power supply. Compared with traditional self-sensing devices, the sensing part of RSMRD has the advantages of small size, no external power supply, and good low-frequency response. The feasibility of the angular velocity self-sensing (AVS) function is verified through theoretical derivation and experimental verification. The experimental results demonstrate a linear relationship between the output voltage generated by the AVS component and the rotational speed of the rotating shaft. Additionally, the torque characteristics of the rotary self-sensing MR damper are tested, revealing a torque generation of approximately 9.26 N ⋅ m at a current of 1.6 A. Furthermore, a fuzzy control algorithm for vehicle braking is proposed, based on the model parameters of RSMRD. The simulink software is used to establish a dynamic model of 1/4 car braking, with an initial braking speed of 15 m s−1. The results indicate that the vehicle comes to a complete stop after 1.64 s, with a braking distance of 10.93 m. Throughout the braking process, the vehicle slip rate remains close to the optimal slip rate of 0.2.

A New Rotary Magnetorheological Damper for a Semi-Active Suspension System of Low-Floor Vehicles

A New Rotary Magnetorheological Damper for a Semi-Active Suspension System of Low-Floor Vehicles

Limited Angle Rotary Magneto-Rheological Damper Design and Geometry Optimization

Manyeto-Reolojik (MR) sıvı uygun bir manyetik alan ile uyarıldığında, görünür viskozitelerinde çok hızlı ve tersinebilen değişimler elde edilen, akıllı malzemelerin bir türüdür. Manyetik alanın kontrolünün kolay olması, bu sıvıları özellikle sönümleyici olarak kullanılabilmelerine olanak sağlamaktadır. Günümüzde doğrusal çalışan damper (sönümleyici, amortisör) ile, dönel olarak çalışan damper (kavrama, fren gibi) tasarımları mevcuttur. Kısıtlı Açılı Dönel MR (KAD-MR) damper ise, açısal olarak sınırlandırılmış dönme hareketiyle MR sıvıyı bir bölmeden diğer bölmeye aktarırken, belirlenen akış bölgesinde MR sıvının manyetik alana maruz bırakıldığı cihazdır. Bu çalışmada yeni bir KAD-MR Damperin kavramsal tasarımı yapılmış ve tork performansını etkileyen tasarım parametrelerinin, hesaplamalı akışkanlar dinamiği (HAD) yardımıyla, belirlenen hedef değerler için en uygun tasarım parametreleri belirlenmiştir.

Development of a Rotary Damper Integrated with Magnetorheological Bearings toward Extremely High Torque–Volume Ratio

Magnetorheological (MR) technology has provided effective solutions to many engineering bottleneck problems due to its controllable nature. However, designing a rotary MR damper with a high torque–volume ratio is always challenging, especially for some specific application scenarios with constrained space, such as robot joints. To solve this problem, a rotary damper based on MR bearings was designed and evaluated in this study. In this rotary damper, two MR bearings are utilized to provide controllable damping torques and serve as rotors, which greatly saves space while providing high torque. This feature grants the characteristics of compact design and high torque–volume ratio. Quasistatic testing shows that the damping torque of this rotary damper can reach 2.92 Nm when the applied current is 1.2 A. It achieves a high torque–volume ratio of 190 kN/m2, which is nearly four times higher than that of existing rotary MR dampers. The experimental results show that the proposed MR damper is effective in satisfying the high torque requirement in a limited space.

On the Application of Support Vector Method for Predicting the Current Response of MR Dampers Control Circuit

Magnetorheological (MR) dampers are controlled energy-dissipating devices utilizing smart fluids. They operate in a fast and valveless manner by taking advantage of the rheological properties of MR fluids. The magnitude of the response of MR fluids, when subjected to magnetic fields, is of sufficient magnitude to employ them in various applications, namely, vibration damping, energy absorption, exoskeletons, etc. At the same time, predicting their response to arbitrary mechanical and electrical inputs is still a research challenge. Due to the non-linearities involved in material properties or the design of the solenoid used for activating the fluid modeling the relationships between the control circuit and the material’s response is complex. Modeling studies can be classified into two categories. The parametric approach requires the knowledge of the internal material’s properties and takes advantage of physics formulas to infer the I/O relationships present in the damper. For comparison, the non-parametric approach harnesses various data mapping techniques to describe the device’s behavior. While the latter is more suited for design studies, the former seems ideal for control algorithm prototyping and the like. In this study, based on the so-called Support Vector Method (SVM), the authors develop a non-parametric model of the control circuit of an exemplary rotary MR damper. To the best of the author’s knowledge, it is the first attempt at an SVM application for MR dampers’ control circuit modeling. Using the acquired experimental data, the I/O relationships are inferred using the SVM algorithm, and its performance is verified across a wide range of excitation frequencies. The obtained results are satisfactory, and the current response of the MR damper is well-predicted. The model performance shows the potential for incorporating it into model-based prototyping and designing of MR control systems.

Investigation of a seat suspension installed with compact variable stiffness and damping rotary magnetorheological dampers

Long-term vibration poses a threat to drivers’ health and affects their ride performance. Furthermore, large-magnitude vibration and sudden shocks may even result in end-stop impacts, raising the drivers’ injury risk. To reduce the vibration and avoid end-top impacts, this paper presents an innovative seat suspension installed with variable stiffness and variable damping (VSVD) rotary magnetorheological (MR) dampers. At first, a novel compact VSVD rotary MR damper was designed and prototyped for the suspension, making the suspension’s stiffness and damping controllable. Then, with two identical VSVD MR dampers were installed, the prototyped seat suspension was characterised by an MTS test frame to verify its capabilities of variable stiffness and damping. A control strategy consisting of a nonlinear stiffness control and a no-jerk skyhook damping control was also designed. Finally, the vibration attenuation performance of the seat suspension was numerically and experimentally evaluated under three vibration excitations, i.e., harmonic excitation, bump excitation, and random excitation. Both numerical and experimental results indicate that the vibration control performance of the seat suspension can be significantly improved by the VSVD rotary MR dampers.

Development and performance evaluation of rotary magnetorheological damper with T-shape rotor for seat suspension

Development and performance evaluation of rotary magnetorheological damper with T-shape rotor for seat suspension

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

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 novel scissor-type anti-shock seat employing rotary magnetorheological damper

In order to improve the cushioning performance of anti-shock seat in an impact environment and protect the lives of occupant to the greatest extent, the cushioning performance of a new type of anti-shock seat combining a rotary magnetorheological (MR) damper and a scissor seat was studied. Aiming at the “bottoming out” characteristic of scissor seats after the cushioning stroke is exhausted, and the dynamic model of scissor seats with MR damper is established. In order to test the cushioning performance of the new anti-shock seat in an impact environment, a prototype MR damper was processed and assembled, and the cushioning performance of the seat under different impact speeds was tested using a drop impact test platform. The test results show that the new anti-shock seat can adjust the cushion stroke and cushion force value to keep the acceleration limit of the occupant within the tolerance range, thereby effectively reducing the risk of injury.

Design, modeling, and control of a magnetorheological rotary damper for scissor seat suspension

This research investigates the design, modeling, and control of an improved magnetorheological rotary damper for seat suspension. A magnetorheological damper with optimized flux path is developed to improve the distribution of magnetic field. Its dynamic damping characteristics are tested by MTS machine under sinusoidal excitations. To describe the nonlinear damping characteristics of magnetorheological damper, a hysteretic model based on backbone curve is selected by comparing with other models. To verify the feasibility of seat suspension with the proposed magnetorheological damper, the simulated analysis and experimental tests are conducted. A dynamic model of scissor seat suspension with rotary damper is constructed and simplified. The performances of semi-active system show that the seat suspension with the proposed damper can reduce vibration efficiently.

Design optimization and experimental characterization of a rotary magneto-rheological fluid damper to control torsional vibration

This paper aims at optimum design formulation of a rotary disk-type magneto-rheological (MR) fluid damper to increase its torsional vibration control performance. The objective is to maximize the torsional damping torque for a given volume, geometric and inertia constraints. The damping torque has been derived based on Bingham plastic model for a commercial MR fluid provided by Lord corporation. As MR fluid’s yield strength directly depends on the applied magnetic field intensity, an analytical magnetic circuit analysis has been conducted to approximately evaluate the magnetic field intensity in the MR fluid gap. A finite element model of the rotary MR damper has also been developed to evaluate the magnetic field distribution. A formal design optimization problem has then been formulated to maximize the dynamic range for a given volume under geometric, inertia and torque ratio constraints. Genetic algorithm combined with sequential quadratic programming method has been utilized to accurately capture the global optimum solution. Finally, a proof-of-concept of the optimal design has been manufactured and then tested experimentally to investigate the generated damping torque under different current excitation and also to validate the model and optimization strategy.

The variable resonance magnetorheological pendulum tuned mass damper: Mathematical modelling and seismic experimental studies

Tuned mass damper technologies are progressively advancing through innovative application of smart materials, facilitating more versatile infrastructure protection. During seismic events, primarily encountered surrounding fault lines, high-rise buildings and other civil structures can suffer catastrophic failures if not adequately protected. Where traditional passive structural protection may mitigate such damage, adaptive systems which provide controllable vibration attenuation across a wide range of excitation frequencies have seen growth in use, overcoming the challenges resulting from unpredictable seismic spectrums. As a robust solution to this problem, this article presents and analyses a variable resonance magnetorheological-fluid-based pendulum tuned mass damper which employs a rotary magnetorheological damper in a controllable differential transmission to add stiffness to a swinging pendulum mass. The device is mathematically modelled based on magnetic field analysis, the Bingham plastic shear-stress model for magnetorheological fluids, and planetary gearbox kinematic and torque relationships, with the model then being validated against experimental data. The passive and semi-active-controlled performance of the device in seismic vibration suppression is then experimentally investigated using a scale five-storey building. In tests conducted with the 1985 Mexico City record, the semi-active device outperformed the (optimal) passive-on tuning, at best reducing peak displacement by 15.47% and acceleration by 28.28%, with similar improvement seen against the passive-off case for the 1940 El Centro record.

Comparison of dynamic models based on backbone curve for rotary magneto-rheological damper

To realize the accurate control of magneto-rheological system, the nonlinear dynamic model as the joint of damper and control strategy is worthy of being investigated. In this study, the modeling methods based on the backbone curve are proposed to portray the dynamic characteristics of magneto-rheological damper. The modeling methods contain the phase lag method and the hysteresis division method. Six novel algebraic models are deduced from the two methods and compared systematically. The parameters identification of models is conducted by the nonlinear least square method. The nonlinear least square optimization problem is solved by the Levenberg–Marquardt algorithm. The evaluation indexes including the root-mean-square error, mean deviation and computation time are calculated to evaluate the accuracy and feasibility of the novel models. Results show that the modeling methods and their models can describe the nonlinear hysteretic characteristics with feasibility and accuracy.

A novel scissor-type magnetorheological seat suspension system with self-sustainability

A novel scissor-type magnetorheological seat suspension with self-sustainability which integrated self-powered, self-sensing, and self-adaptability is proposed in this study. The adaptive rotary damping system consisted of the rotary magnetorheological damper, and rotary permanent magnet direct current generator is designed to realize the self-sustainability. Effects of damping force and isolation object mass are analyzed for further designing and testing based on the dynamic model. The rotary magnetorheological damper and the electrical part are designed and analyzed theoretically. Series of experimental tests are conducted to verify the feasibility and control performances. The experimental results show that the on–off balance control algorithm based on the self-sensing signals can improve the comfort than the directly and supply-with-rectifier control modes.

Magnetorheological damper–based positioning system with power generation

This study investigates a newly developed positioning system based on a rotary magnetorheological damper with power generation capability, comprising an electromagnetic power generator (energy extractor) generating electrical power, an magnetorheological damper which alters the damping characteristics of the system and an electrical interface, connected in between the coil of the generator and the damper control coil, which conditions the voltage output from the generator. Structural configurations of the damper and the generator are outlined, and the results of their testing and the testing done on the entire system are summarised, covering the tests conducted with and without the interface, under the idle run and under load in the assumed velocity range. The objective of the work is to examine the performance of the proposed positioning system through experiments. Results of the system testing in the uncontrolled case (passive system) and in the controlled one (semi-active system) in a purpose-built test rig are compared and discussed. Three design options of the electrical system controlling the damper are explored. In the first option, the damper is assumed to be controlled starting from the initial moment of the motor shaft’s motion, and in the second option, the control action begins at the instant when the motor shaft assumes the present position. The third variant is similar to the first one except that an additional condenser is connected behind the Graetz bridge. The results confirm the adequacy of the developed positioning system and demonstrate an improvement in control of the system’s dynamic behaviour.

Integrated active and semi-active control for seat suspension of a heavy duty vehicle

In this article, an integrated active and semi-active seat suspension for heavy duty vehicles is proposed, and its prototype is built; an integrated control algorithm applied measurable variables (suspension relative displacement and seat acceleration) is designed for the proposed seat prototype. In this seat prototype, an active actuator with low maximum force output (70 N), which is insufficient for an active seat suspension to control the resonance vibration, is applied together with a rotary magnetorheological damper. The magnetorheological damper can suppress the high vibration energy in resonance frequency, and then a small active force can further improve the seat suspension performance greatly. The suspension’s dynamic property is tested with a MTS system, and its model is identified based on the testing data. A modified on–off controller is applied for the rotary magnetorheological damper. A [Formula: see text] controller with the compensation of a disturbance observer is used for the active actuator. Considering the energy saving, the control strategy is designed as that only when the magnetorheological damper is in the off state (0 A current), the active actuator will have active force output, or the active actuator is off. Both simulation and experiment are implemented to verify the proposed seat suspension and controller. In the sinusoidal excitations experiment, the acceleration transmissibility of integrated control seat has lowest value in resonance frequency and frequencies above the resonance, when compared with power on (0.7 A current), power off (0 A current) and semi-active control seat. In the random vibration experiment, the root mean square acceleration of integrated control seat suspension has 47.7%, 33.1% and 26.5% reductions when compared with above-mentioned three kinds of seat suspension. The power spectral density comparison indicates that the integrated seat suspension will have good performance in practical application. The integrated active and semi-active seat suspension can fill energy consumption gap between active and semi-active control seat suspension.

Development of an MR seat suspension with self-powered generation capability

This paper proposes a self-powered magnetorheological (MR) seat suspension on the basis of a rotary MR damper and an electromagnetic induction device. By applying the self-powering component to the MR seat suspension, the operation cost of the semi-active seat is much cheaper because no external energy is required to control the MR damper. In this paper, the structure, design and analysis of the seat suspension were presented following the introduction section. The property tests of the self-powered seat suspension were conducted using an MTS machine. A robust control algorithm was developed to control the self-powered MR seat suspension and the vibration attenuation performance of the seat suspension was tested under two different vibration excitations, i.e. harmonic excitation and random excitation. The testing result verifies that the self-powered MR seat suspension under proper control can improve the ride comfort for passengers and drivers.

Intelligent control of an MR prosthesis knee using of a hybrid self-organizing fuzzy controller and multidimensional wavelet NN

A Magneto rheological (MR) rotary brake as a prosthesis knee is addressed here. To the gait of the amputee, the brake, automatically adapts knee damping coefficient using only local sensing of the knee torque and position. It is difficult to design a model-based controller, since the MR knee system has nonlinear and very complicated governing mathematical equations. Hence, a Hybrid self-organizing fuzzy controller and multidimensional wavelet neural network (HSFCMWNN) is proposed here to control the knee damping coefficient using of the inverse dynamics of the MR rotary damper. A Self-organizing fuzzy controller (SOFC) is also proposed and during the control process, the SOFC continually updates fuzzy rules, while at the beginning contains blank fuzzy rules. Therefore the problem of finding appropriate fuzzy rules and consequently membership functions for the design of a fuzzy logic controller is ignored by using of the SOFC. It is, however, difficult to select appropriate parameters (learning rate and weighting distribution) in the SOFC which are crucial for control of MR prosthesis knee. To deal with this drawback, a hybrid self-organizing fuzzy and multidimensional wavelet neural network is employed appropriately. The proposed strategy uses a Multidimensional wavelet neural network (MWNN) to adjust these parameters in real time, to achieve to optimal values. First, the MWNN is trained by Stochastic gradient algorithm (SGA) and then to reduce the learning cycle to be needed and the appropriate error, a learning procedure based on the Levenberg-Marquardt (LM) algorithm is adopted intentionally. Simulation results demonstrate that the HSFCMWNN performs better in control performance than that of the SOFC in improving gait of the amputee.

Axial squeeze strengthen effect on rotary magneto-rheological damper

Pressure is an important factor to influence the performance of an magneto-rheological (MR) apparatus. The effect of the axial squeeze strengthen effect on rotary MR damper is investigated theoretically and experimentally in this study. First, a theoretical analysis in a microscopic view is proposed. It indicates that a concentrated increment of iron particle content in the working gap results in the effect. Then, a pressure-controlled rotary MR damper with the axial squeeze strengthen effect is designed, manufactured and tested. The results show that the axial squeeze strengthen effect on rotary MR damper is remarkable for the damper with lower particle content in MR fluids. In addition, there is an optimal pressure to obtain the maximum axial squeeze strengthen effect on the rotary MR damper.