Digital Control Damp Valve in Semi-active Suspension

It is known that for automotive semi-active suspension the damping of shock absorber shall be continuously adjustable. One approach for damping adjustment is via adjusting flow area of throttle valve of shock absorber using stepping motor. Throttle valve can be realized using electromagnetic valve or any other type of driving valve. In order to be applied on semi-active suspension, the throttle valve is required to have high control precision, fast response speed, strong anti-pollution capability and etc.. In this paper a new type of digital valve is presented to control the flow area of shock absorber. The configuration is developed by the utilization of the two-motions-degree of freedom of a single spool. To solve the contradiction between the response speed and the quantitative accuracy which characterizes the previous valve of the same sort, a specially designed tracking program is adopted to the stepping motor control to smooth displacement output. Experimental results show that both static and dynamic performances of the digital valve can fulfill the requirement of semi-active suspension, which is valuable in the application of system such as semi-active suspension where the liquid flow needs to be controlled rapidly and accurately.