Robust regulator design for an arm manipulator

We consider the design of a robust regulator for a 3 DOF robot that is affected by poor repeatability. Instead of applying a nonlinear control an Hoo design was superposed on top of the manufacturer's. From previous recommended methods and a good understanding of the plant a set of weights were selected as to guarantee the solution of the optimization problem. A robust system with excellent regulation properties was reach showing also good tracking features.