Global asymptotic velocity observation of nonlinear systems - application to a frictional industrial emulator

Abstract: Development of velocity observers for mechanical systems with friction deserves a special emphasis, because as evidenced in numerical and experimental tests when a state-of-the-art observer is armed, friction can induce high-frequency oscillations in the estimated signal. In this short paper, two new velocity-observation algorithms are designed, based on this previously reported observer, that eliminate the high-frequency oscillations noted. Numerical and experimental performance comparisons are carried through making use of LuGre model and a mechanical PID control system that incorporates the estimated velocity into the feedback loop.