Control of a four-link lightweight manipulator arm using fast output sampling

A robust multi-model design approach is used to control a four-link lightweight manipulator arm. The nonlinear plant model is linearized in a number of operating points, and recent LMI methods are employed to design a linear state feedback controller that places the closed-loop poles in a desired pole region simultaneously for all models. Only the joint angles are available for feedback, however, and a fast output sampling technique is used to robustly realize the state feedback design by output feedback. The resulting controller has been testet in real-time experiments and compared with an observer-based robust multi-model approach reported earlier.