Kinetostatic Performance Analysis of a Redundantly Driven Parallel Kinematic Manipulator

In general the mechanical handling of objects in space is performed by manipulators, whose number of actuators is consistent with the number of required degrees of freedom. In addition, manipulators can be equipped with redundant drives, providing the manipulator with more actuators than the mobility actually requires. Thus, an active distribution of drive torques is enabled.Accordingly, this research intends to analyze the effects of torque distribution in over-actuated manipulators relating to load-optimized and energy-efficient handling. By developing torque distribution strategies the maximum torque levels can be reduced and the required drive power thus be decreased. This results in an increased drive utilization, which improves the energy-efficiency of the handling system. On this basis, an innovative handling concept is analyzed, which represents an over-determined system given the number of actuators. Hence, it is shown that the drive utilization of manipulators can be significantly improved by means of actuation redundancy. For this purpose different mathematical optimization approaches are analyzed, which solve the over-actuated system with defined optimization targets. Here, the optimal torque distribution is found using an algorithm, which minimizes the maximum torque for each object position. The results demonstrate the efficiency of active torque distribution in terms of over-actuated manipulators. For a further approach it is planned to develop control methods including optimized torque distribution strategies in order to improve the performance and the energy efficiency of the entire manipulator.Copyright © 2014 by ASME