Influence of the deviations caused by radial and axial runout of couplings on the positioning accuracy of the industrial robots

Abstract

In most of the industrial domains, the workmanship has been replaced by industrial robots, due to their superior technical features and higher productivity. In order to continuously increase the production rates and performance characteristics required by the more and more complex technologies, the research and implementation of new methods to optimize and improve the performances of the industrial robots are necessary. According to such researches, most of the positioning and follow-up errors of the moving elements are caused by various factors belonging to the mechanical structure of the industrial robot. The deviations caused by radial and frontal runout of the bearings/couplings are an important factor that affects the positioning accuracy of the industrial robots, further to the friction and wear of the bearings in the kinematical linkages. This work presents a new method for determining and decreasing the positioning errors generated by the values of the axial and radial runout of the kinematic couplings, as well as a mathematical method based on the matrix of the direct kinematic. This mathematical model will also be used for simulating the positioning errors generated by the radial and frontal runout. The systematic characteristic of the axial and radial runout deviation rates of each coupling reflects on the positioning errors too, so that correction values may be inserted that eventually lead to increasing the positioning accuracy of the industrial robots.