A numerical error analysis method and its application on a 4RRR parallel kinematic machine

<正> To guarantee the accuracy of error analysis and evaluate the manufacturing tolerance s influence,anumerical error analysis method for parallel kinematic machines (PKMs) is presented in this paper.Quasi-Newton method and genetic algorithm are introduced for the forward kinematic solution.Based onthe inverse and forward kinematic solutions,the end-effector s error calculation procedure is developed.To solve the accuracy problem caused by the length and angular parameters' different units,a normalizationmethod is proposed based on the manufacturing tolerance.Comparison between the error analysis resultscalculated by the traditional method and the numerical method for a 4RRR PKM shows that,this numericalerror analysis method is more accurate,simpler,and can evaluate the machine s real error basedon the manufacturing tolerance.     

某尾矿库的渗流与稳定数值计算分析

运用有限元数值分析方法,对某尾矿库的渗流与稳定进行模拟计算,得到在正常水位运行和洪水水位运行两种工况下库区地下渗流的分布规律、浸润线的位置和尾矿坝的安全系数,根据渗流与稳定的计算结果,对该尾矿库的安全稳定性进行了评价。     

A Numerical Error Modeling Method for Parallel Kinematic Machines and Its Applications

<正>Introduction Unlike serial machines, which suffer from the accumulation of joint errors, parallel kinematic machines (PKMs) are considered to have high accuracy[1]. However, recent investigations have shown that the PKM is not necessarily more accurate than a serial machine with the same manufacturing and assembling