The effect of kinematic model complexity on manipulator accuracy

A pose measurement system consisting of a small coordinate measuring machine, an IBM personal computer, and several fixtures is described. The pose measurement system is used to collect two data sets of 45 poses each. These data are then used to identify the parameters in five manipulator models of increasing complexity. The models consist of a nominal model, a model with six parameters to determine the actual robot location, a 12-parameter model including robot location and joint offsets, a 30-parameter kinematic model, and a 32-parameter model including compliance in two joints. The pose measurement system is used to evaluate the accuracy of each of the five models. The results demonstrate that, in general, increases in model complexity lead to enhanced accuracy, although the degree of improvement at any level is dependent on the particular robot under study