Vibration suppression control of spatial flexible manipulators

In spatial 3D flexible manipulators, some parameters change, depending upon the arm's configuration. The relationship between vibrations and actuators might be configuration-dependent. Therefore, such configuration dependency has to be considered in the control of 3D spatial flexible manipulators. Linear quadratic regulator (LQR) would be one of the solutions. However, state feedback gains must be computed at various configurations and the gain table would be quite large in the case of multi-DOF manipulators. In this paper, a configuration-dependent variable-gain vibration-suppression control strategy for 3D spatial flexible manipulator is discussed. The vibration control scheme computes the link deflection feedback gain depending upon the current configuration during each sampling period. Thus, no large gain table is needed, and the scheme would be effective in the case of multi-DOF 3D spatial manipulators. The control scheme is examined in the case of a 2-link 7-joint type manipulator through experiments. The stability of the control scheme is also discussed.