磁流变液响应时间检测方法及装置研究

磁流变液的响应时间是一个关键指标,关系到磁流变智能执行器的实时可控性能。 然而,MRF 的动态响应面临从电 流、磁场强度及剪切应力等多参数耦合中解耦的难题。 本文提出基于偏置正弦激励电流的相位检测法,通过施加偏置正弦电流 激励正弦磁通密度,由扭矩与磁场相位差获得 MRF 响应时间,无需面临阶跃响应中的复杂解耦问题。 此外,本文通过关键机械 参数设计,突破商用流变仪的剪切率限制,实现了最高 3 000 s -1 下的响应时间测量。 基于此,本文设计和制作了一套 MRF 响应 时间检测装置,分析了装配偏心和磁场探针位置引起的误差;测得多种样品在 1~ 3 A 振幅电流下的响应时间为 23 ~ 140 ms,并 发现响应时间随 MRF 浓度增大而先减小再延长,且与外部磁场强度呈负相关。

Study on methodology and instrumentation of measurement of response time of magnetorheological fluids

The response time of magnetorheological fluid ( MRF) is a critical parameter that relates to the real-time controllability of magnetorheological smart actuators. However, the dynamic response of MRF involves a complex coupling from the circuit to the mechanical system, which requires addressing the challenge of decoupling from multiple parameters such as current, magnetic field strength, and shear stress. This article proposes a phase difference method based on the biased sine excitation current. By applying the biased sine current to excite sinusoidal magnetic flux density, the response time of MRF is obtained from the phase difference between the torque and the magnetic field, without facing the complex decoupling encountered in step response. In addition, this article breaks through the shear rate limitation of the general commercial rheometers through the design of the key mechanical parameters. It achieves MRF response time measurements at shear rates up to 3 000 s -1 . Based on this, this article designs and fabricates an MRF response time measurement device, and analyzes errors caused by eccentric assembly and magnetic field probe positioning. It is found that the response time of various samples is 23 ~ 140 ms under 1 ~ 3 A amplitude currents. In addition, the response time is first accelerated and then prolonged with the increase of sample concentration, which is negatively correlated with the external magnetic field strength.