Modeling Of Hydraulically Interconnected Suspension With Control Analysis

Modern vehicle suspensions are required to achieve a number of oftenconflicting objectives, such as the well-known trade-off between handling stabilityand ride comfort. A vehicle with a relatively stiff suspension is likely to possess goodhandling stability but poor ride comfort. It has been recognised that interconnectedsuspension is able to provide a favorable solution to achieve a desired vehicledynamic performance on a particular body-wheel motion-mode because the forcegenerated by the motion of one wheel station can be transmitted to the other wheelstations through either mechanical or fluid means in an interconnected suspensionsystem.A passive anti-pitch anti-roll hydraulically interconnected suspension isproposed for compromising the control between the pitch and roll mode of the sprungmass. It has the advantage in improving the directional stability and handling qualityof vehicles during steering and braking manoeuvres. Frequency domain analysis of a7-DOF full-car model with the proposed system is presented, then the modal analysismethod is employed to perform the vibration analysis between the vehicle with theconventional suspension and the proposed HIS. The present result offer confirmationthat the effectiveness of the anti-pitch anti-roll HIS system in increasing the pitchstiffness and roll stiffness, and thus improve handling stability.The modeling of the7-DOF vehicle suspension dynamics system is developed,and then the linear active suspension system is developed based on the passivesuspension. Using the dominant vehicle motion-mode energy as a control objective inreal time is considered as an effective strategy to balance the energy consumptionwith the control performance. Simulations validation are conducted when the vehicleis running on bumpy, The results obtained show the motion-mode energy method cananalyze vehicle dynamic characteristics in the terms of total energy and energy ratio,which lay the foundation for real-time control of active suspension.In this paper, a motion-mode detection method and the switching control strategy,where three fuzzy controllers are designed for the vehicle body bounce, pitch and rollmotion-modes, respectively, are developed. Simulations validation are conductedwhen the vehicle is running with J-turn, fishhook, and experimental setup with a4-post test rig for validating the performance of the proposed active suspension system are introduced. The obtained results indicate that the designed controllers caneffectively reduce the pitch motion and prevent rollover, and simultaneously achievegood suspension performance.