“…where M is the mass of the piston-load assembly, y is the acceleration of the piston, f is the friction force, A is the cylinder cross-sectional area, and 1 p and 2 p are the pressures in the two chambers. The friction force is represented by means of a continuous approximation of the LuGre model [8,9], which is largely employed in control applications [2,8,10,11]. The approximation used in this work was developed specifically for systems where the control signal affects the time derivative of the developed mechanical forces, such as hydraulic and pneumatic actuators [1,2,3,5,6,8].…”