System reliability analysis of the robotic manipulator with random joint clearances

The paper presents an innovative method for computing reliability of a robotic manipulator such that the positional error in the entire trajectory remains within acceptable limits. This problem is equivalent to a series system reliability analysis that can be solved using the extreme value distribution of the positional error. The principle of maximum entropy is applied to derive this distribution. A novel feature of the analysis is the use of fractional moments, instead of integer moments commonly used in the entropy literature. The fractional moments are obtained from a small, simulated sample of positional error. Examples are presented to illustrate accuracy and efficiency of the proposed method.