Stream-of-Variation (SOV) Theory Applied in Geometric Error Modeling for Six-Axis Motion Platform

In order to understand how geometric errors propagate and how deviations accumulate in a six-axis motion platform (SMP), a new geometric error model based on the stream of variation (SOV) theory is presented in this paper. SOV theory is widely used in industrial engineering with several steps or phases. The conventional geometric error model only calculates the initial and final orientation, yet the deviations after each step in the whole process are still unknown, which are critical parameters in measuring the product quality. In this new error modeling method, each step in the alignment and welding process in SMP can be considered as a station. Thus, the deviations can also be derived after each station, which is beneficial for error identification. Based on the new error modeling approach involving SOV theory, the validation of an optimized configuration is developed by a series of calculations results. By observing the deviations after each station, the optimized configuration can improve accuracy and reduce power loss compared to a traditional configuration. The new error modeling approach based on SOV theory is systematic and comprehensive, and can be applied in other similar environments.