Rotary Magnetorheological Damper Research Articles

Integrated semi-active seat suspension for both longitudinal and vertical vibration isolation

“Functional integration” is to integrate two or multiple systems or mechanisms that are independent with each other and to realize the two or multiple functions using only one actuation system. Maximization of engineering applications of actuation systems could be achieved through the use of the “functional integration” concept-based structural design. In this article, an integrated semi-active seat suspension, mainly composed of a switching mechanism, a transmission amplification mechanism, and a damping force- or torque-controllable rotary magnetorheological (MR) damper working in pure shear mode, for both longitudinal and vertical vibration attenuation, is proposed, designed, and fabricated. The switching mechanism employs the parallelogram frames as a motion guide which keeps the seat moving longitudinally and vertically. Both longitudinal and vertical motions are transformed into a reciprocating rotary motion that is transmitted to the rotary MR damper after an amplification by a gear mechanism. The torque generated by the MR damper can be tuned by adapting the applied current in real time, and hence, effective two-dimensional vibration control of the seat could be realized. The mathematical model of the semi-active seat suspension system is established, and vibration isolation performance of the system is simulated and analyzed. Based on the established experimental test rig, the prototype of the semi-active seat suspension system is tested, and the results of the mathematical model and the experimental test are compared.

Prototype and test of a novel rotary magnetorheological damper based on helical flow

To increase the output damping torque of a rotary magnetorheological (MR) damper with limited geometrical space, a novel rotary MR damper based on helical flow is proposed. A new working mode, helical flow mode, is discussed and applied to enlarge the flow path of MR fluids. The helical flow can improve the performance of the rotary damper by enlarging the length of the active region. Based on the idea, a rotary MR damper is designed. The rotary MR damper contains a spiral piston, dual-coil core, a rotating cylinder and a stator cylinder. Based on the Bingham model, the output damping torque of the damper is analytically derived. The finite element method (FEM) is applied to calculate the magnetic field of the active region. The multi-objective optimal design method is adopted to obtain the optimal geometric parameters. A prototype is fabricated based on the optimal results. To validate the proposed rotary MR damper, two types of experiments including the low rotation speed and the high rotation speed are investigated. The results show that the proposed rotary MR damper has high torque density and compact structure. The helical flow mode can increase the output damping torque with limited space.

Development of a new torsional vibration damper incorporating conventional centrifugal pendulum absorber and magnetorheological damper

Excessive torsional vibrations in mechanical systems with rotating mechanical components result in noise, excessive stresses, or even fatigue failure if not suppressed or controlled properly. Accordingly, they should be suppressed or controlled immediately to ensure system’s reliability. In this study, a hybrid torsional vibration damper is proposed incorporating a conventional centrifugal pendulum vibration absorber and a magnetorheological damper. While centrifugal pendulum vibration absorbers are simple and reliable than passive torsional vibration absorbers, their performance is limited to the designed tuning conditions. Magnetorheological dampers have recently received considerable attention due to their inherent fail-safe feature, low power requirement, and capability to attenuate vibration under unpredictable environmental conditions. This research aims at developing a novel hybrid torsional vibration damper combining conventional centrifugal pendulum vibration absorber with the magnetorheological rotary damper in which the centrifugal pendulum vibration absorber has been connected to the cylindrical housing of the magnetorheological damper. The analytical model of the rotor system integrated with proposed hybrid torsional damper has been developed. The superior performance of the proposed torsional damper has been then demonstrated by comparing the results with those of rotor system without any damper, rotor system with only centrifugal pendulum vibration absorber, and finally rotor system with only magnetorheological rotary damper.

Bypass Rotary Magnetorheological Damper for Automotive Applications

A novel concept of bypass rotary Magneto-rheological (MR) damper is studied in the automotive suspension application. The proposed design is developed based on a vane-type damper structure with an MR control valve located outside of the damper. The design is intended to enhance the ease of maintenance and to reduce the thermal effect from the coil to the MR fluid. The valve is the key component of the damper that exploits the advance characteristics of MR fluid in which have sensitive rheological properties to magnetic field. The ability of the valve to modify the strength of magnetic field has given an advantage that the valve can be operated without any moving parts. The elimination of these parts in the throttling mechanism of the valve will provide benefit in terms of product lifetime and responsiveness. The main objective of this paper is to elaborate the advantages of the bypass rotary MR damper and to demonstrate the damper performance through force-velocity characteristics. The analytical model of the damper is developed and used in the determination of the force-velocity curves and the equivalent damping coefficients.

EXPERIMENTAL SETUP FOR TESTING ROTARY MR DAMPERS WITH ENERGY HARVESTING CAPABILITY

Abstract The experimental setup has been developed for laboratory testing of electromechanical energy transducers and rotary magnetorheological (MR) dampers. The design objectives are outlined and the parameters of the key elements of the setup are summarised. The structure of the mechanical and measurement and control systems is presented. Results of functional testing of a newly developed transducer and a MR rotary damper are summarised

A nonlinear structural experiment platform with adjustable plastic hinges: analysis and vibration control

The construction of an experimental nonlinear structural model with little cost and unlimited repeatability for vibration control study represents a challenging task, especially for material nonlinearity. This paper reports the design, analysis and vibration control of a nonlinear structural experiment platform with adjustable hinges. In our approach, magnetorheological rotary brakes are substituted for the joints of a frame structure to simulate the nonlinear material behaviors of plastic hinges. For vibration control, a separate magnetorheological damper was employed to provide semi-active damping force to the nonlinear structure. A dynamic neural network was designed as a state observer to enable the feedback based semi-active vibration control. Based on the dynamic neural network observer, an adaptive fuzzy sliding mode based output control was developed for the magnetorheological damper to suppress the vibrations of the structure. The performance of the intelligent control algorithm was studied by subjecting the structure to shake table experiments. Experimental results show that the magnetorheological rotary brake can simulate the nonlinearity of the structural model with good repeatability. Moreover, different nonlinear behaviors can be achieved by controlling the input voltage of magnetorheological rotary damper. Different levels of nonlinearity in the vibration response of the structure can be achieved with the above adaptive fuzzy sliding mode control algorithm using a dynamic neural network observer.

Design and Performance Evaluation of a Rotary Magnetorheological Damper for Unmanned Vehicle Suspension Systems

We designed and validated a rotary magnetorheological (MR) damper with a specified damping torque capacity, an unsaturated magnetic flux density (MFD), and a high magnetic field intensity (MFI) for unmanned vehicle suspension systems. In this study, for the rotary type MR damper to have these satisfactory performances, the roles of the sealing location and the cover case curvature of the MR damper were investigated by using the detailed 3D finite element model to reflect asymmetrical shapes and sealing components. The current study also optimized the damper cover case curvature based on the MFD, the MFI, and the weight of the MR damper components. The damping torques, which were computed using the characteristic equation of the MR fluid and the MFI of the MR damper, were 239.2, 436.95, and 576.78 N·m at currents of 0.5, 1, and 1.5 A, respectively, at a disk rotating speed of 10 RPM. These predicted damping torques satisfied the specified damping torque of 475 N·m at 1.5 A and showed errors of less than 5% when compared to experimental measurements from the MR damper manufactured by the proposed design. The current study could play an important role in improving the performance of rotary type MR dampers.

A Rotary Magnetorheological Damper for a Tracked Vehicle

A rotary magnetorheological (MR) damper for a semi-active suspension was developed, laboratory tested. The working principle and features of the rotary MR damper was outlined and its theoretical model was developed. Full optimization of the magnetic design was accomplished with the help of magnetic finite element software ANSYS in the limited space. The parameters of the MR damper’s theoretical model were identified by a series of harmonic loading tests. It is demonstrated that the damping capacity of this MR damper is a function of strain amplitude and field strength, and it is feasible to use for the life application in terms of force characteristics.

Optimization Design and Mechanic Characteristic Experiment of the Rotary Magnetorheological Damper

Based on the Bingham model of the magnetorheological fluid,a finite element optimization design method of the rotary magnetorheological damper is presented,In this method,the magnetic permeability of magnetic material is brought into full play by optimizing the structure parameters of damper,so that the optimum electric parameters are obtained.The magnetorheological damper and the mechanic performance test system are developed to research the mechanic performance of the magnetorheological damper,and the damper properties: torque vs speed and yield torque vs current are obtained.What’s more,the temperature change is considered as one of influence factors on magnetorheological damper performance,and the properties of the damper yield torque at different temperatures and different speeds are obtained.The influence of the magnetorheological fluid shear thinning and temperature change on magnetorheological damper performance are analyzed.

Research on Fuzzy-PID Control for a Tension System of Rotary Magnetorheological Damper

A rotary MRF (magnetorheological fluids) damper is introduced in tension control systems. An experimental tension control system is designed by using the MRF damper as tension control actuator. Control strategies of the tension control system are studied. A fuzzy-PID feedback controller for the tension control system is constructed and tested, where the variable parameters of the PID were modified by using the fuzzy inference rules. Experimental results indicate that the fuzzy-PID control strategy can be used in the tension control system to get better performance than the conventional PID control strategy.

다층신경망을 이용한 전단모드 회전형 MR 댐퍼의 모델링

자기변성유체(magnetorheological fluid)에 관한 연구는 MR 장치의 개발, MR 장치의 수학적 모델링 및 시뮬레이션, 그리고 MR 장치를 채용한 시스템의 제어 알고리즘 개발에 관한 연구로 구분된다. 시뮬레이션을 통한 제어 알고리즘 개발을 위해서는 MR 장치의 비선형 응답을 예상하기 위한 신뢰성 높은 수학적 모델이 요구된다. 또한 MR 장치 시스템을 제어하기 위해서는 제어기에서 요구하는 댐핑력을 출력하기 위한 MR 장치의 전류(또는 전압) 입력 값이 필요하며, 이 입력값을 얻기 위해서는 역댐퍼 모델이 필요하다. 이러한 이유로 MR 장치의 모델링 및 역댐퍼 모델링은 MR 장치개발의 중요한 역할을 담당하며 이에 관한 많은 연구가 요구되고 있다. 본 연구에서는 전단모드 회전형 MR 댐퍼의 모델링을 위해 개발된 MR 댐퍼를 이용하여 동특성 시험기를 제작하였으며, 전단모드 회전형 MR 댐퍼의 특성을 연구하기 위한 실험을 수행하였다. 시험기 시험결과를 통해 모델링에 필요한 시험 데이터들을 획득하였으며 다층신경망을 이용하여 전단모드 회전형 MR 댐퍼의 모델 및 역모델을 구하였다. Scientific challenges in the field of MR(magnetorheological) fluids and devices consist in the development of MR devices, the mathematical modeling and simulation of MR devices, and the development of (optimal) control algorithm for MR device systems. To take a maximum advantage of MR fluids in control applications a reliable mathematical model, which predicts their nonlinear characteristics, is needed. A inverse model of the MR device is required to calculate current(or voltage) input of MR damper, which generates required damping force. In this paper, we implemented test a bench for shear mode rotary MR damper and laboratory tests were performed to study the characteristics of the prototype shear-mode rotary MR damper. The direct identification and inverse dynamics modeling for shear mode rotary MR dampers using multi-layer neural networks are studied.

회전형 MR 댐퍼를 이용한 반능동 현가장치의 퍼지 스카이-훅 제어

최근 고층건물의 방진시스템 및 자동차의 현가장치 분야에 MR 유체를 이용한 반능동 진동제어에 관한 연구가 활발히 진행되면서 MR 유체의 밸브모드 특성을 이용한 선형 MR 댐퍼가 널리 사용되고 있다. 그러나 전단모드를 이용한 회전형 MR 댐퍼에 관한 연구는 초기단계에 머물고 있다. 본 연구에서는, 주행로봇의 무한회전형 액츄에이터용 회전형 댐퍼의 진동제어에 관한 연구를 수행하였으며, 퍼지 로직을 기반으로 한 회전형 MR 댐퍼용 진동제어 알고리즘을 제안하였다. 퍼지제어기의 입출력 이득과 멤버쉽 함수의 모양은 유전자 알고리즘을 이용하여 조정하였다. 시뮬레이션 결과는 MR 댐퍼에 충격력이 가해질 때 퍼지 스카이-훅 제어의 제어성능을 보여준다. Recently, a number of researches about linear magnetorheological(MR) damper using valve-mode characteristics of MR fluid have sufficiently undertaken, but researches about rotary MR damper using shear-mode characteristics of MR fluid are not enough. In this paper, we performed vibration control of shear-mode MR damper for unlimited rotating actuator of mobile robot. Also fuzzy logic based vibration control for shear-mode MR damper is suggested. The parameters, like scaling factor of input/output and center of the triangular membership functions associated with the different linguistic variables, are tuned by genetic algorithm. Simulation results demonstrate the effectiveness of the fuzzy-skyhook controller for vibration control of shear-mode MR damper under impact force.

Design and Analysis of Rotary MR Damper Using Permanent Magnet

As a device for vibration suppression or energy dissipation, semi-active systems have both reliability of passive devices and adaptability of active systems. Among the people studying semi-active devices, the interest in the controllable magnetorheological(MR) fluid has been increased dramatically since 1990s. The torque of the damper using MR fluid can be controlled by the magnetic field. In this paper, we propose a valve mode MR damper using permanent magnetic circuit. Because the power consumption at the steady state is reduced, it consumes less power overall. We investigate the characteristics of this damper such as hysteresis and time delay and show the performance by experiments. The experimental results show that the proposed damper has a good tracking performance for step, ramp and sinusoidal trajectories.