The Semi-active Control Study On Engine Mounting System

The vibration of engine is characteristic of wide frequency and multi-actuators. Traditionally passive isolation can bring into effect within the certain scope of frequency, but it can't meet need of isolation under the different condition. In order to reduce timely and effectively the vibration under the condition of different frequency, the paper describes an ER isolator, whose stiffness is invariable and damp is adjustable, prosecutes semi-active control. It includes preparation of ER material and design and simulink of ER isolator.ER material prepared includes dispersed medium that is shock absorber oil, dispersed phase that is TiO2 granule covered with Al2O3 whose content is 35 percent and additive that is oleic acid whose content is 3 percent. By quantities of experiment, its ER performance is predominant. When the electric field is strengthened to 3kV/mm under the condition that ER fluid's cut velocity is 7/s, the shear stress of the ER fluid can reach 800 Pa. It meets basically the need of engine isolation.We make use of performance of ER fluid and design a two-damp-hole ER isolator provided with particular parameter, then judge of effect of isolation by transfer ratio of force. By means of simulink of Matlab, it is known that the method that electric field is strengthened and two damp holes are turned on can lead to transfer ratio of force to be fallen during the phase of low frequency; on the other hand, the method that electric field is weakened and two damp holes are turned off can lead to transfer ratio of force to be fallen during the phase of high frequency.Under ADAMS environment,it establishes 6-DOF powertrain test rig model and studies the characteristic of force entent and frequency on the condition of sympathetic vibration by means of the performance of ER fluid, it is known that the value of force is small when electric field is strengthened at low rotation speed and the value of force is small when electric field is weakeded at high rotation speed.This is equal to the theory analysis.The vibration of engine have 6-DOF,though The vertical rotation and parallel motion of engine is neglected because their extent is so small that they hardly effect our analysis. After the coordinate is decided at the position of the center of mass ,we estabishe 3-DOF mathematics model of engine and list differential equations of vibration and carry out optimization semi-control by means of Matlab software. Thenafter it is compared with the passtive control, we find that the result of semi-active control is good.