Vibration control of a flexible robotic arm-experiments and relationship between sensitivity analysis and H∞ control method

Experimental results on the control of a flexible robotic arm and the relationship between the sensitivity analysis and H_∞ control law are discussed. A three-degree-of-freedom flexible arm is used in the experiment. It is shown that vibrations of a flexible arm can be suppressed by using the LQ (linear quadratic) optimal control law. By sensitivity analysis, the admissible domain of parameter uncertainties where the closed-loop system does not become unstable is shown. Inversely, by using a robust control method, a controller can be constructed where the closed-loop system does not become unstable if there are some parameter uncertainties. Therefore, there seems to be some relationship between the sensitivity analysis and the robust control law