A Force Based Approach to Error Analysis of Parallel Kinematic Mechanisms

Error analysis is an important issue in parallel kinematic synthesis because manufacturing and assembly errors have a significant impact on the mechanical precision of the manipulator. In this paper we propose a method to describe the displacements of the tool center point (TCP) in terms of error amplifications for uncertainties in all kinematic parameters. This is done by using the differential geometric properties of kinetostatic transmission. The computational effort of this method only depends on the number of rigid bodies and the topological complexity of the mechanism while the number of parameters does not affect computing time. The performance of this method is demonstrated with an example of the six degree-of-freedom parallel kinematic machine Linapod that is currently investigated in order to optimize the machine’s accuracy.