Modelling and Simulation of a Magnetorheological Fluid Damper with Multi-Accumulator during Mode Shifting 2019-01-0856
In continuous controllable damper, there usually exists a compensation chamber with designated initial gas pressure to provide volume compensation while the damper piston is moving up and down. This compensation chamber works as a gas spring to some degree to provide force to the damper rod. In this work, in order to extend the force range of the continuous controllable damper (CCD) and improve the controlling rate, a novel structure of CCD with three additional compensation chambers is proposed. These additional compensation chambers are charged with high, middle and low pressure respectively, with which the damping force range can be rapidly increased or decreased to higher and lower levels through mode shifting. A dynamic model of this novel CCD with coupled effects between the gas and liquid in the damper is developed, and the output force is simulated parametrically in different conditions. According to the measured force and moving speed of the damper rod, a set of control strategy aimed for rapid response and adaptive force tuning is proposed in order to obtain better dynamic performances. Some bench tests are also conducted to investigate the damper’s performances with different control strategies. Some preliminary results show that the rapid mode shifting of the compensation chambers for higher or lower gas pressure can improve the response of the damper a lot compared with the direct control of the original structure damper with a sealed gas chamber. Based on this control strategy, several cases of the damper response with a half vehicle model under different road conditions are further simulated. Results tell that the coupled control of the additional compensation chambers can prevent the pitch motion and ease the body variation of the whole vehicle significantly.