Technology Research Of Magneto-Rheological Fluid Applicable For Linear Motor Damping Control

Linear motor direct drive feeding technology is an advanced feeding technology developed since 1990s. Compared with traditional feeding technology,it has the merit of high feeding speed, acceleration,longstroke, fast dynamic response and etc, while,the absence of intermediate damping segment degrades the anti-disturbance of the system and makes it difficult to improve positioning accuracy. Magneto-Rheological Fluid (MRF) damping technology is an effective semiactive damping control technology. Because of the merit of fast response, large damping force, easy operation, low facility request and etc, MRF damping technology is greatly developed in the last decade.The application of MRF damping device is greatly depended on the stability and mechanical property of MRF, because the historical condition of MRF greatly contributes to the performance of MR damping device, especially the mechanical property of damping device. Hence, research focus of MRF is focused on its stability and mechanical property.In this paper, multi factors orthogonal experiment has been designed to optimize ingredients of MRF according to test result, the ultrasonic wave diffusion process has been developed to improve MRF stability according to ultrasonic wave cavitation principle. The characteristic of ultrasonic wave diffusion process has been studied and the effectivity of the ultrasonic wave diffusion process has also been verified according to the comparison of ultrasonic wave diffusion process with traditional mechanical mixing process.Based On the comparison of various MRF mechanical model, in this paper a mechanical model has been developed to describe how various factors contribute to MRF mechanical property. Meanwhile, the ralationship between MRF null field viscosity and the MRF ingredients has been analyzed based on the two-phase suspending liquid Einstein equation,the analysis indicates that MRF kinematic viscosity is subjected to applied magnetic field and external temperature.In order to verify the effectivity of MRF mechanical and viscosity model, Visual Studio has been adopted as development platform,a MRF measurement device which based on shear mode has been designed according to fluid mechanics,electromagnetic principle and digital electron technology. The device makes full use of PC resource and can realize real-time data acquisition(DAQ) and presents result visually.Based on the MRF measurement device designed, in this paper the influence of the major factors on the mechanical properties and viscosity of MRF has been analyzed and the reason has discovered, providing reference for the preparation of MRF that is applicable for linear motor damping control.