POE-Based Parameter Calibration for Industrial Robots Considering Joint Compliance

In order to improve the absolute pose accuracy further for industrial robots, the effect of the joint compliance, in addition to the geometric errors (GE), should be also considered. In this paper, we have modified an actual forward kinematic equation on the basis of the Global Product-of-Exponential (POE) formula, which takes into account the joint compliance errors (JCE) and GE. Then, the POE-based comprehensive error model for the parameter calibration of industrial robots is presented, which simultaneously identifies the kinematic parameters and compliance coefficients by making use of an iterative least-squares optimization algorithm. Finally, simulation studies are implemented to validate the effectiveness of the proposed calibration method. The verification result shows that the JCE and GE of the industrial robot are effectively compensated by the identified compliance coefficients and kinematic parameters.