Control of a robot with two flexible links

Presents experimental results which are obtained by using a nonlinear control law on a two link flexible robot. Using finite element description of the arms, the authors get a nonlinear model of the robot. The nonlinear decoupling control law uses the inverse dynamic model. This control law, which is very efficient for a rigid robot, has been adapted for flexible structures. The elastic vibrations must be damped by adding to the computed torque a complementary feedback term. This term permits one to obtain a satisfactory behaviour of the structure, but reduces the theoretical interest of the decoupling method. It is computed by linearizing the set of equations on a given point of the desired trajectory and by using a classical LOR method. The experimental results demonstrate the interest of the method and shows its sensitivity versus the position of the linearization point. >