Research On Speed Control Technology Of Mineral Oil-based Magnetorheological Fluids Transmission System

Magnetorheological fluid(MRF) is an important branch of new intelligent materials and has significant rheological properties under an applied external magnetic field. MRF typically shows free-flowing liquids and behaves Newtonian fluids in zero magnetic field; the dispersed magnetic particles can build up the chain-like structure aligned in the direction of magnetic field within milliseconds and MRF exhibits solid-like behavior. These transformations are significantly fast, controllable and reversible. Thus, MRF can be widely applied in a wide range of fields. According to the existing problems of MRF and its transmission technique, the following aspects are researched in the paper.(1)Experimental materials and instruments used by preparation of MRF are introduced. By the method of optimizing MRF preparation process, a new simple and efficient preparation process of MRF used for mechanical transmission is explored. Two groups of MRF samples are prepared with optimized preparation process which are used to study the influence of different additives and carrier fluids on transmission characteristics of MRF. Experimental results show that transmission characteristics of mineral oil-based MRF is better than silicone oil-based MRF and MRF-24 with TM-618 3.5% and Organic Bentonite 3% is best for mechanical transmission system.(2)A disc magnetorheological transmission device(MRTD) is designed, of which the magnetic field are analyzed and simulated. Magnetic circuit design of MRTD is verified by magnetic flux density test-bed. MRF transmission characteristics test-bed is established and the transmission characteristics including no-load characteristic without magnetic field, current-torque characteristic, current-speed characteristic, Slip speed characteristic, constant torque characteristic and response characteristic are researched.(3)Speed control theory of MRTD is elaborated, speed control strategies are designed based on conventional PID control and self-adaptive fuzzy PID control. Simulation models of two controllers are set up and an analysis is carried out in MATLAB/Simulink. Simulation results show that the control effect of self-adaptive fuzzy PID control are superior to conventional PID control.(4)Speed control test-bed of MRF transmission system(MRTS) is designed, of which hardware and software design of test-bed are introduced. transmission system experiment is elaborated and experiment results show that DP811 A programmable power supply can be controlled by PC with LabVIEW platform by means of USB interface; conventional PID control and self-adaptive fuzzy PID control are all effective for speed control of MRTD and can meet the requirements of speed regulation starting-up and speed stability; the control effect of self-adaptive fuzzy PID control are superior to conventional PID control.