Research On Magnetorheological Fluid Transmission Technology In Microgravity Environment

As people gradually turn their horizons to space,the topic of "Space Mining" has been actively responded by various countries.China,the United States,Luxembourg,Russia,Japan and the European Union have continuously carried out and conducted indepth research on space science,and microgravity environment is one of the inevitable difficulties and key points in the development and utilization of space resources.Facing the complex and changeable space environment,it is necessary to control the transmission device accurately and quickly,and at the same time,it is also required that the transmission device can respond to the control signal actively and quickly.As a new type of intelligent material,magnetorheological fluid has good rheological properties.Its fast response speed and continuous controllability make magnetorheological fluid have a wide application prospect,but the properties of magnetorheological fluid in microgravity environment are rarely studied.Therefore,according to the requirements that the transmission device can achieve fast and accurate response in microgravity environment and the characteristics of magnetorheological fluid transmission device,this paper has carried out the following research:(1)The microstructure and main components of magnetorheological fluid were studied,the role of each component was analyzed,the principle of magnetic domain theory was explored,and the magnetization mechanism of magnetic particles in magnetorheological fluid was explained,thus the rheological process and principle of magnetorheological fluid were explained.In addition,several typical constitutive models of magnetorheological fluid were introduced,and the influencing factors of performance and service life of magnetorheological fluid were analyzed.(2)On the basis of analyzing the factors affecting the performance and service life of magnetorheological fluid,the effects of gravity acceleration,particle size and volume fractions of magnetic particles in magnetorheological fluid on the rheological properties of magnetorheological fluid,such as sedimentation stability,zero-field viscosity and shear yield stress,were studied by COMSOL Multiphysics.The sedimentation stability experiment of magnetorheological fluid in microgravity environment was carried out by using the method of magnetic force compensation gravity.(3)The design theory of magnetorheological fluid transmission device was studied.The working mode and coil arrangement of the transmission device were analyzed and determined.The material type,coil turns and excitation current of the transmission device were determined.The magnetic field of the device was simulated.The power transfer model of the transmission system with magnetorheological fluid in microgravity environment and the transfer function between the system speed and current were derived.(4)The design theory of PID controller as well as the principle and parameter optimization method of grey wolf algorithm were studied,and an improved grey wolf algorithm was proposed;Self-tuning PID controller,grey wolf algorithm optimized PID controller and improved grey wolf algorithm optimized PID controller were designed,and the control performance of the three controllers was simulated by using unit step signal as excitation source.(5)In order to verify the performance of magnetorheological fluid in different gravity environments,a speed control experiment platform for compensating the gravity of magnetorheological fluid was designed and the PC software program was compiled.The speed control experiment under the action of compensation force was carried out.The results showed that the change of gravity acceleration has little effect on the power transmission of the transmission device,and the magnetorheological fluid transmission device can adapt to the complex gravity environment in space.To sum up,the sedimentation stability of magnetorheological fluid in microgravity environment has been improved,which increases the service life of magnetorheological fluid transmission device.At the same time,magnetorheological fluid transmission device can maintain good speed stability under different gravity and can adapt to complex space environment.There are 73 figures,9 tables and 93 references in this paper.