Shear-mode Magnetorheological Damper Research Articles

A control system for MR damper-based suspension of front-loaded washing machines featuring magnetic induction coils and phase-lead compensator

This paper studies a semi-active control system for magneto-rheological (MR) damper-based suspension of front-loaded washing machines. In this system, a permanent magnet is fastened to the shaft end of a shear-mode MR damper and an induction coil is wound directly on the slots of damper housing. Vibration of the washing machine tube leads to the relative reciprocal movement between the magnet and induction coil, which results in an induction voltage. The induced voltage is then served as an input signal to control the damping force of the MR damper. Because of the MR fluid hysteresis, a phase-lead compensator and an amplifier are employed in the controller of the MR damper. After the controller design, simulations and experiments are performed to evaluate the control system effectiveness. From the experimental results, performance characteristics of the proposed control system are discussed and compared with those of constant current and uncontrolled states.

Shear Mode Damper Testing Using Flake Shape Based Magnetorheological Fluids

Use of anisotropic iron particles in the magnetorheological (MR) fluid having a high yield stress is a challenge as it increases the viscosity of the fluid in off-state. In this clause, a novel flake shaped iron powder based MR fluid with high yield stress is synthesized and used in shear mode MR damper (SMMD). MR damper design is optimized using fluid properties and Bingham model. Damping performance of newly synthesized MR fluid damper is at par with the available friction based damper used in front loaded washing machine. The unique feature of this design is minimal volume of the fluid (1.5 ml) required to achieve damping force of 50N. Effect of different volume percentage of particles in MR fluid is evaluated in terms of damping force. Effect of testing parameters like displacement and frequency of excitation on damping force was evaluated. Effect of settling of particle on damper performance is discussed in this work. It shows that the flakes shaped-based MR fluid show better stability against gravity. The smaller quantity of present flake shaped-based MR fluid will reduce the cost of shear mode damper.

Development of a Magnetorheological Damper with Self-Powered Ability for Washing Machines

Magnetorheological (MR) dampers have been widely investigated and proposed for vibration mitigation systems because they possess continuous variability of damping coefficient in response to different operating conditions. In the conventional design of MR dampers, a separate controller and power supply are required, causing an increment of complexity and cost, which are not suitable for home appliances like washing machines. To solve these issues and to reuse wasted energy from vibration of washing machines, in this study, a self-powered shear-mode MR damper, which integrates MR damping and energy-harvesting technologies into a single device, is proposed. The MR damper is composed of an inner housing, on which magnetic coils are wound directly, and an outer housing for covering and creating a closed magnetic circuit of the damper. The gap between the inner housing and the moving shaft is filled with MR fluid to produce the damping force. The energy-harvesting part consists of permanent magnets fastened together on the shaft and induction coils wound directly on slots of the housing. The induced power from the induction coils is directly applied to the excitation coils of the damping part to generate a corresponding damping force against the vibration. In order to achieve optimal geometry of the self-powered MR damper, an optimization for both the damping part and the energy harvesting part of the proposed dampers are conducted based on ANSYS finite element analysis. From optimal solutions, a prototype of the proposed damper is designed in detail, manufactured, and experimentally validated.

Magnetorheological dampers in shear mode

In this study, three types of shear mode damper using magnetorheological (MR) fluids aretheoretically analyzed: linear, rotary drum, and rotary disk dampers. The dampingperformance of these shear mode MR dampers is characterized in terms of the dampingcoefficient, which is the ratio of the equivalent viscous damping at field-on status to thedamping at field-off status. For these three types of shear mode MR damper, the dampingcoefficient or dynamic range is derived using three different constitutive models: theBingham–plastic, biviscous, and Herschel–Bulkley models. The impact of constitutivebehavior on shear mode MR dampers is theoretically presented and compared.

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.