Dynamic modeling and end position control of a 5-bar flexible robot with 6-dof

Abstract

In this thesis, a new dynamic model for a six-degree-of-freedom (6-DOF) flexible robot and a new control scheme for a three-degree-of-freedom (3-DOF) flexible robot have been designed and implemented. The dynamic model has been designed on the assumption that the entire mass is concentrated at the center of mass of the set wrist-mass, which is the combined mass of the wrist and the spherical mass attached to it, signifying a compliance matrix can be used to model the oscillations of the structure. This therefore makes the dynamics of the robot very simple: a lumped single mass and an inertia tensor model rather than the usual distributed mass model. A two-nested control-loop scheme has been used to control the position of the base of the wrist by employing encoders and gauge measurements as feed-backs. A stability analysis of the control scheme has been carried out, and the robustness of the proposed control scheme under payload changes is also depicted. Lastly, simulation results that prove the effectiveness of the proposed control scheme are shown.