Valve Transform Fuzzy Tuning Algorithm for Open-centre Electro-hydraulic Systems

A generic fuzzy tuning algorithm provides a systematic approach of tuning valve transforms in a feedforward controller of a linear hydraulic actuator. It can achieve accurate velocity control by realizing closed-centre characteristics from an open-centre hydraulic system. This tuning algorithm was developed on the basis of a common sense model of system calibration, and was capable of tuning valve transforms for different systems without modification. Evaluations of this technique included dynamic simulation of a large scale, single degree of freedom (1-DOF) hydraulic linear actuator, and laboratory test on a laboratory scale 1-DOF actuator. Results indicated that this generic fuzzy tuning algorithm was capable of tuning valve transform promptly and accurately for identified operating conditions, and achieving effective compensation for accurate velocity control on different hydraulic linear actuators without modification.