Vibration Control Of Grinding Wheels And Rotors By Magnetorheological Dampers

The vibration fault of rotor systems is a problem in rotating machineries.To overcome this problem,this paper designed two new kinds of magnetorheological dampers for rotors.The dampers were applied to suppress the vibrations of grinding wheel spindle,gear system and multi-span shafting.The vibration suppression effects of dampers on the systems were studied.The main research contents of this paper are as follows:(1)Two new kinds of magnetorheological dampers for rotors were designed based on the magnetorheological effect of magnetorheological fluids.The magnetic fields of dampers were simulated by ANSYS.(2)A single-span rotor bench was established.A magnetorheological damper was installed at the rotor.The mass ratio of the magnetorheological fluid and the viscosity of the silicone oil were changed under the same current,and the effects of the damper on the critical speed and resonance amplitude of the rotor system were studied.(3)To solve the spindle vibration caused by unbalanced mass of the grinding wheel,a grinding wheel vibration control bench was established to simulate the operating condition of the grinding machine.The spindle of the grinding machine was modeled,and the vibraion characteristic of the spindle was simulated when the grinding wheel had unbalanced mass.A magnetorheological damper was mounted at the spindle.Contrast experiments between the single-plane and the dual-plane vibration suppression method were carried out.(4)To solve the serious vibration and noise of gearbox,a two-shaft gear bench and a three-shaft gear bench were established.The magnetorheological dampers were applied to suppress the vibrations of gear systems.The vibration suppression performce of the dampers under different control currents and installation positions was experimental studied by monitoring the vibrations of bearing blocks and rotors on the two-shaft gear bench.The vibration suppression performce of the dampers on the three-shaft gear bench was experimental studied by monitoring the vibrations of bearing blocks and rotors and the sound pressure levels of the gear system.(5)To solve the problems associated with the serious vibration of rotors at the critical resonance region,three active control programs were designed,namely,conventional PID control,fuzzy PID control and variable universe fuzzy PID control.The control programs provided appropriate control current for the damper by real-time monitoring the amplitude.A single-span rotor bench was established.The vibration suppression capability of the passive control method,conventional PID control method,fuzzy PID control method and variable universe fuzzy PID control method was compared.(6)The designed active control strategies were applied to suppress the vibrations of multi-span shafting.2N and N+1 supported four-span and five-span rotor benches were established.The vibration characteristics of 2N and N+l supported rotor systems were determined.The magnetorheological dampers based on the fuzzy PID control strategy and the variable universe fuzzy PID control strategy were applied to suppress the vibrations of multi-span shafting.The effects of dampers on the rotor systems were evaluated.