Observers for rigid robots

In virtually all present-day robotic applications, the design approach is based on controllers which utilize measurements of both position and velocity. However, velocity measurements are often contaminated by noise, and cause the controller´s performance to deteriorate. Therefore the function of the observer is essential that of reconstructing the velocity signals. The present study establishes a new systematic procedure that creates the possibility of obtaining an observer for estimating the link´s velocity in a rigid robot. The underlying approach adopts the concept of semiglobal stabilizability, and the resulting observer´s output converges asymptotically to the system´s velocity vector. In particular, the present approach can be implemented to cases where the robot velocity is either not uniformly bounded or its upper bound is unknown