An experimental validation of a nonlinear velocities observer

International audienceHigh precision measurements of the joint displacement are available to control the robot manipulators. However the signals delivered by velocities sensors are often contaminated by noise and not so useful in control laws. To overcome this problem velocities observers are used. In this paper we demonstrate experimentally the applicability of the method. The estimated velocities obtained by the observer are compared to the estimated velocities obtained by numerical derivation of the positions filtered with a FIR filter. The observer used is a nonlinear high gain one based on the notion of uniform observability. As control law we use the linearizing and decoupling computed torque law. The experiences are conducted on a SCARA robot manipulator built at the laboratory