中文摘要：

为了研制六足制孔机器人,提出了一种基于（U＋UPS）P＋UPS机构的三自由度并联机械腿,建立了机械腿机构的误差模型与评价方法,并通过误差分析制造出机械腿试验样机,对试验样机进行了误差标定试验研究。首先,采用矢量链法建立了机械腿机构的误差矢量约束方程,得到了机械腿机构的误差传递模型。接着,定义了一组误差敏感性评价指标,并绘制了误差敏感性评价指标在机械腿机构工作空间内的分布曲面。然后,基于误差敏感性评价指标及机构其他机构学性能,采用蒙特卡罗法对机械腿进行了结构参数设计,选取了一组结构参数,制造了机械腿试验样机。最后,采用一套高精度机器人标定系统对机械腿试验样机进行了误差标定。试验表明：机械腿试验样机的位置误差实测值与理论值之间偏差均小于0.003 mm,姿态误差实测值与理论值之间偏差均小于0.05°,误差敏感性评价指标的实测值与理论值的差值均小于0.03。机械腿试验样机的误差均在合理范围之内,基本达到了设计要求。

英文摘要：

In the process of large passenger aircraft manufacturing and assembly, a lot of drilling and milling work needs to be done. Due to the limitation of the structure, the traditional drilling and milling machines can＇t be used in the drilling and milling work of large passenger aircraft. The hexapod robot with motorized spindle on its trunk is very suitable for the drilling and milling work. The hexapod robot can crawl on the aircraft＇s exterior surface through suckers on its foot. So the hexapod robot can do the drilling and milling work by the motorized spindle on its trunk. For the hexapod drilling robot, a new type of 3-DOF（3 degrees of freedom） mechanical leg based on（U＋UPS）P＋UPS parallel mechanism is presented（U,P and S represent universal pair, prismatic pair and spherical joint, respectively）. The decoupling performance of the mechanical leg＇s motions is very good, and its 2 rotational motions are completely decoupled. Its control algorithm is very simple, so it can be real-time controlled very easily. In order to improve the accuracy of the hexapod drilling robot, the error modeling and evaluation method of the mechanical leg is established. The prototype is manufactured by precision design,and the error calibration experiment is done. First, using the vector chain method, the error vector constraint equation is established and the error propagation model is obtained. Using the error model, the mechanical leg＇s output errors with a given set of error sources can be calculated. Also, the mechanical leg＇s tolerance allocation with a given set of output errors can be calculated too. In order to evaluate the error transfer performance of the mechanical leg, a set of error sensitivity evaluation indices are defined, and the distribution of error sensitivity evaluation indices in the mechanical leg＇s workspace is drawn. It reveals that the error transfer characteristics of the mechanical leg are good in the central area of the workspace.Based on the set of indices, the error sensitivit