Automated modelling of cartridge valve flow mapping

Proportional poppet-type cartridge valves are the key elements of the energy saving programmable valves, which have been shown in our previous studies to be able to achieve excellent motion control performance while significantly saving energy usage. Unlike costly conventional four-way valves, the cartridge valve has simple structure and is easy to manufacture, but its complicated mathematical model makes the controller design and implementation rather difficult Our previous works used either an off-line individually calibrated or manufacturer supplied flow mappings as the model of the cartridge valves. Neither method is ideal for industrial wide applications as the former method is time-consuming and needs trained engineers with additional flow sensors while the later leads to significantly degraded control performance due to the inaccuracy of the manufacturer supplied flow mappings. To solve this practically very significant problem, this paper focuses on the automated modelling of the cartridge valve flow mapping without using any extra sensors and removing the valves from the system. The estimation of the flow mapping is based on the pressure dynamics in the hydraulic cylinder with consideration of some unknown parameters like effective bulk modulus of fluid. Experimental results are obtained to illustrate the effectiveness and practicality of the proposed novel automated modelling method