Tolerance design of manipulator parameters using design of experiment approach

Abstract

A robotic arm must manipulate objects with high accuracy and repeatability to perform precise tasks. There are many factors that cause variations in performance and they referred as noise factors. A probabilistic approach has been used to model the effects of noise factors and an experimental design technique has been adopted to select optimal tolerance of kinematic and dynamic parameters for minimal performance variations. The control and noise factor arrays are employed to identify statistically significant parameters and their interactions. The performance measures like signal to noise ratio and reliability have been utilized and results are validated by Monte Carlo simulations. The proposed design of experiment methodology requires minimal computations. The tolerance design methodology of manipulator is illustrated by 2-DOF revolute–revolute planar manipulator following cubic and quintic trajectory to perform a task. The statistical analysis of simulated performances is carried out using analysis of variance technique, which showed that statistically significant parameters are independent of trajectory. The individual parameter tolerance sensitivity has also been carried out.