A continuous extension of the LuGre friction model with application to the control of a pneumatic servo positioner

This work presents a novel continuous approximation of the LuGre model, with the aim of improving its applicability in the control of a class of systems that include fluid-driven servo positioners. The main attractive of the proposed approximation is the preservation of the properties of boundedness and passivity that are inherent to the original LuGre model, a feature that is not guaranteed in the approximate models that are usually encountered in the specialized literature. The most relevant properties of the proposed approximation are demonstrated analytically, and its applicability is illustrated both analytically and experimentally in the case of a pneumatic servo positioner.