\r刘海涛，潘 巧，尹福文，董成林\r
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AuthorsHTML:\r刘海涛，潘 巧，尹福文，董成林\r
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AuthorsListE:\rLiu Haitao，Pan Qiao，Yin Fuwen，Dong Chenglin\r
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AuthorsHTMLE:\rLiu Haitao，Pan Qiao，Yin Fuwen，Dong Chenglin\r
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Unit:\r天津大学机构理论与装备设计教育部重点实验室，天津 300350\r
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Unit_EngLish:\rKey Laboratory of Mechanism Theory and Equipment Design of Ministry of Education，Tianjin University，Tianjin 300350，China\r
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Abstract_Chinese:\r面向高精度铣削加工需求，完成TriMule 混联机器人在公差层面上的精度综合．TriMule 混联机器人中三自由度并联机构的几何误差源是影响机器人末端位姿精度的主要因素，以其为研究对象，基于矢量法和小摄动原理建立并联机构误差模型，并利用驱动雅可比矩阵和约束雅可比矩阵分离出不可补偿几何误差源和可补偿几何误差源．采用小位移旋量方法建立机构的公差模型，将各类公差以6 项自由度(3 平动和3 转动)的形式表征，进而结合误差模型，得到零部件公差与末端位姿误差的传递函数，完成公差层面的精度建模．为减小精度综合的计算量，同时保证精度综合结果的适用性，利用蒙特卡洛法预估末端参考点位置误差在任务空间上、下平面的分布，进而得到几何误差源对末端位姿精度影响最大的机构位形．最后，以制造成本最小化为目标函数，以精度需求为约束条件，利用MATLAB 优化工具箱完成零部件的精度综合．结果表明：垂直度公差t₅和同轴度公差t₆较小，在设计制造时应予以严格控制；位置度公差t₀和尺寸公差t₄较大，设计制造时可予以适当放宽．\r
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Abstract_English:\rTo meet the accuracy requirement of a hybrid robot for the milling operation，accuracy synthesis is investigated in this study at the tolerance design level．Given that the precision of the hybrid robot is mainly affected by geometric errors in the three-degrees-of-freedom parallel mechanism of the robot，the error model of the parallel mechanism is established on the basis of the vector chain method and perturbation principle．Then，the uncompensable and compensable geometric error sources are separated on the basis of the Jacobian of actuations and constraints．Tolerance modeling is conducted using the small displacement torsor method，in which tolerances are expressed in the form of six degrees of freedom(i.e.，three translations and three rotations)．Sequentially，combined with the developed error model，mapping of the relationship between the tolerances of components and the pose error of the mechanism is achieved．To reduce the computational complexity and ensure the applicability of precision synthesis，the Monte Carlo method is employed to estimate the distribution of the pose error of the mechanism in the upper and lower planes of the task workspace．Consequently，the maximal pose error in the task workspce is detected，which is located at the edge of the lower plane．Finally，with the aid of the MATLAB optimization toolbox，accuracy synthesis of the parallel mechanism is solved by minimizing the manufacturing cost and taking the precision requirement as constraint．The results show that the perpendicularity tolerancet₅ and axiality tolerancet₆ ，which should be strictly controlled，are mall，whereas the positional tolerancet₀ and dimensional tolerancet₄ ，which can be relaxed，are relatively large．\r
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Keyword_Chinese:误差建模；公差建模；精度综合\r

Keywords_English:error modeling；tolerance modeling；accuracy synthesis\r


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