Robust tracking control for vibration reduction of long reach manipulator with parameter uncertainty

A robust tracking control is presented for the vibration reduction of a long reach manipulator employed in a nuclear power plant by combining the command shaping technique with sliding-mode control. The combined approach appears to be robust in the presence of severe disturbance and an unknown parameter which will be estimated by the least-square method in real time. In a manoeuvre strategy, it is found that a hybrid trajectory with a combination of low-frequency mode and rigid-body mode results in better performance and is more efficient than the traditional rigid-body trajectory alone which many researchers have employed. The feasibility of the tracking control approach is demonstrated by applying it to the simplified model of robot system. For the applications of the proposed technique to realistic systems, several requirements are discussed such as control stability and large system order resulted from finite element modeling