This paper presents a robust tracking control concept based on accurate feedforward compensation for hydraulic valve-cylinder drives. The proposed feedforward compensator is obtained utilizing a generalized description of the valve flow that takes into account any asymmetry of valves and/or cylinders, not assuming these asymmetries to be matched, and utilizes pressur measurements. Hence the proposed compensator is generally applicable to any such drive. Simulation results demonstrate that the proposed compensator achieves superior performance and robustness, compared with a conventional constant gain type feedforward compensator, when subjected to strong perturbations in supply pressure and coulomb friction.
Applied Mechanics and Materials, 2012, Vol 233, p. 100-103