The Development Of Adjustable Damper And The Design Of Semi-active Suspension On NJ2045 Cross-Country Vehicle

The semi -active suspension makes automobile possess good handling stability and ride comfort when it runs along straight line, speeds up, brakes and turns.My automotive control system control two modes of the variable dampers: soft and hard modes. In order to control the damping mode, the control signals from the ECU are applied to four damper actuators. Upon receiving the control signals from the ECU, the solenoid only operates to move an armature which opens and closes. When the damper control valve is open and the damper is operating under low damping force conditions, the associated vehicle experiences a relatively soft ride as a result. When the damper control valve is closed, the damper is operating under high damping force conditions and the associated vehicle experiences a relative firm ride as a result.Basing on the above considerations, firstly, in my paper, I set up a seven degree of freedom vehicle model to establish the state equation according to moving differential equation. With the state equation, in the time domain, I simulate four main working conditions: driving straight, speeding up, braking and steering to obtain their responses. Then considering the results of simulation and the experience, the two damping values of two-modes variable damper are obtained.Secondly, as for modeling for the damping valve, I use large deflection theory of thin elastic annular plate to analyze the deflection of the damping valve plate. Then I compute the velocity characteristic of variable damper by hydromechanic theory. That is to say to obtain the relation curve between damping force and piston velocity of variable damper.Thirdly, dampers of NJ2045 cross-country vehicle is my test coupon. Test result verify the reliability and accuracy of theoretical computation which gives the design of the damper an excellent guide, according to the two damping values obtained above structure parameters of the variable dampers are worked out.At last, I must develop the electrical control unit of semi-active suspension. The control system has a plurality of signal input sensors. The signals from thesignal input members are processed by an ECU in accordance with a preset program. After processing the signals, the ECU determines the desirable damping force for controlling the variable dampers which are fixed to the wheels of a vehicle. The above semi-active suspension thus provide comfortable ride to a driver and passengers and secure steering safety of the vehicle.