Abstract
To investigate the effect of working fluid in solenoids on dynamic characteristics of proportional control valves for improving the valve responses, as an example under one of most severe conditions, dynamic characteristics of a proportional control valve with damping chokes are experimentally investigated. Damping chokes are usually used to improve the stability of spool position control, however, the effect on the dynamic characteristics has not yet been sufficiently clarified. For example, it is known that the dynamic characteristics are changed by the tank line back pressure when high water content fluid is used. The phenomena thought to be caused by cavitation bubbles, however, has not yet been clarified.
In this paper, firstly, the dynamic characteristics of a proportional control valve equipped with additional damping chokes are experimentally investigated. Secondly, a mathematical model describing the nonlinear dynamic characteristics is derived and verified by computer simulation. Finally, a robust control method using a disturbance observer is applied to improve the characteristics and the performance is subsequently examined with computer simulations and experiments.
