Accuracy Analysis of Stewart Platform Based on Interval Analysis Method

摘要

A Stewart platform is introduced in the 500 m aperture spherical radio telescope（FAST） as an accuracy adjustable mechanism for feed receivers.Accuracy analysis is the basis of accuracy design.However,a rapid and effective accuracy analysis method for parallel manipulator is still needed.In order to enhance solution efficiency,an interval analysis method（IA method） is introduced to solve the terminal error bound of the Stewart platform with detailed solution path.Taking a terminal pose of the Stewart platform in FAST as an example,the terminal error is solved by the Monte Carlo method（MC method） by 4 980 s,the stochastic mathematical method（SM method） by 0.078 s,and the IA method by 2.203 s.Compared with MC method,the terminal error by SM method leads a 20% underestimate while the IA method can envelop the real error bound of the Stewart platform.This indicates that the IA method outperforms the other two methods by providing quick calculations and enveloping the real error bound of the Stewart platform.According to the given structural error of the dimension parameters of the Stewart platform,the IA method gives a maximum position error of 19.91 mm and maximum orientation error of 0.534°,which suggests that the IA method can be used for accuracy design of the Stewart platform in FAST.The IA method presented is a rapid and effective accuracy analysis method for Stewart platform.