Determining Maximum Load Carrying Capacity of Flexible Link Manipulators


Department of Mechanical Engineering,Iran University of Science and Technology


Abstract. In this paper, an algorithm is proposed to improve the Maximum Load Carrying Capacity
(MLCC) of
exible robot manipulators. The maximum allowable load which can be achieved by a
manipulator along a given trajectory is limited by the joints' actuator capacity and the end e ector
accuracy constraint. In an open-loop approach, the end e ector deviation from the prede ned path is
signi cant and the accuracy constraint restrains the maximum payload before actuators go into saturation
mode. By using a controller, the accuracy of tracking will improve. The actuator constraint is not a major
concern and, therefore, the full power of the actuators, which leads to an increase in the Maximum Load
Carrying Capacity, can be used. In this case, the controller can play an important role in improving the
maximum payload, so a robust controller is designed. However, the control strategy requires measurement
of the elastic variables' velocity, which is not conveniently measurable. So, a nonlinear observer is designed
to estimate these variables. A stability analysis of the proposed controller and state observer is performed
on the basis of the Lyapunov Direct Method. In order to verify the e ectiveness of the presented method,
simulation is done for a two link
exible manipulator. The obtained maximum payload for open and
closed-loop cases is compared, and the superiority of the method is illustrated.