| dc.description.abstract | The behaviour of a flexible-link robotic manipulator is studied using an experimental
apparatus. The system is modeled based on the physical laws governing system
dynamics. A non-linear rigid body model is developed which includes backlash and
friction. Through comparison of experimental and simulation results, the small backlash
in the system is shown to have little effect on the system behaviour.
Friction is shown to have a considerable effect on the system dynamics. The finite
element method is used to develop a flexible body model for the flexible link.
Experimental results show that the lateral vibration of the manipulator exhibits the
behaviour of a clamped-free beam or a pinned-free beam during different stages of the
motion. A combined dynamic model has been developed. The model is comprised of
both a clamped-free beam model and a pinned-free beam model with the choice of model
being determined by the boundary conditions at the hub that change due to the non-linear
friction term included in the model.
Experimental and simulation results demonstrate that, at low speeds of rotation, the hub
friction causes the pinned frequencies of vibration to approach the clamped frequencies.
Vibration suppression controllers are considered based on the coupling torque from the
clamped beam model. Different vibration-suppressing controllers are found to be
effective in the pinned, high-speed region, the pinned, low-speed region and the clamped
region. The effectiveness o f vibration-suppressing controllers when added to a classical
PD controller is studied. | |
