Research On The Control Technology Of Axial Compression Braking Torque For Magnetorheological Fluid Brake

Magnetorheological fluid brake(MRF brake),using magnetorheological fluid(MRF)as the working medium,is a new type brake developed on the basis of characteristics rheological properties.The brake has the advantages of simple structure,quick response speed,whose braking torque can be controlled continuously by the external magnetic field,therefore,it has wide prospect for engineering application.In view of the present problems of small torque,more complex braking control and so on,the research contents in this paper are as follows:(1)The basic structural design theory of MRF brake are introduced.The working mode,structure and installation mode of excitation coil for MRF brake are determined,and the braking torque calculation model of MRF brake is established.To increase the requirements of braking torque,The mechanical properties of the axial compression for MRF are further analyzed from two sides of the magnetic domain theory and the axial compression-shear mechanical.After that,the materials needed for the main components of the brake are determined.Finally,an axial compression MRF brake with a braking torque of 8N·m has been designed,and its main parameters,the seal mode and the compression mode are analyzed and designed in detail.(2)The basic theory of electromagnetic field is introduced,the MRF brake self-designed for electromagnetic field finite element simulation analysis is carried out,and experimental verification has been carried out.The performance test-bed of MRF brake is built,the experiments of no-load characteristic without magnetic field,the braking torque adjustation characteristic,the braking constant torque characteristic,the dynamic response characteristic and the performance of axial compression are developped.(3)According to the characteristics of axial compression braking torque control for MRF brake,the control strategy based on the conventional PID,fruit fly optimization algorithm(FOA)PID and improved fruit fly optimization algorithm(IFOA)PID control is designed,and then the three controllers are simulated and analyzed.The simulation results show that: compared with the conventional PID and FOA PID controller,the IFOA PID controller has shorter time to reach steady state and there is no overshoot,the whole process is steady without random jump,which reveals better dynamic response characteristics.(4)The experimental platform of axial compression braking torque control for MRF brake is built,the design of hardware and software for experimental platform is introduced in detail;the braking control experiments are carried out;the results show that the conventional PID control,FOA PID control and IFOA control are all effective for axial compression braking torque control of MRF brake,but the IFOA PID control has better control effect,which is superior to the conventional PID and FOA PID control.