Dynamic modelling and intelligent hybrid optimal controller of hybrid manipulator for vibration suppression and tracking control

Flexible links possess numerous advantages over rigid links which impose the research attention towards employing flexible links in robotics. However, flexible links have a tip vibration that has the difficulty of being presented in dynamic models. Furthermore, the tip vibration leads to the control difficulty as a controller must control a system for the position and the tip elastic vibration. This research proposes a dynamic model and an intelligent hybrid optimal controller of a hybrid manipulator, the hybrid manipulator has a rigid link, a flexible link, and a variable payload. The proposed dynamic model is obtained using a combined technique of the finite element method and the Lagrangian method. The proposed dynamic model is compared with a SimMechanics model in terms of their open-loop responses, and both models have close match responses which indicates that the novel dynamic model is accurate. The intelligent hybrid optimal controller is also proposed based on the integration of an optimal linear quadratic regulator and a fuzzy logic controller. The integration of the fuzzy control and the linear quadratic regulator controller achieves 39.5% reduction of the fuzzy rules which assists to solve the explosion of the fuzzy rules problem since the hybrid manipulator is a multi-input system. The proposed intelligent optimal controller demonstrates improved position control, effective tip vibration suppression, better tip trajectory tracking, and better robustness to overcome the impact of the payload uncertainty compared to the linear quadratic regulator controller based on the simulation validation of the Simulink in MATLAB.