【作者】 洪林；

【导师】 张策；

【作者基本信息】 天津大学 ， 机械设计及理论， 2004， 博士

【摘要】 本文从并联机器人的典型结构Stewart平台出发,对并联机器人的精度分析和综合问题进行了系统的研究。运用并联机器人输入输出微分关系,建立了机器人输出位姿误差正解的数学模型。提出了并联机器人位姿误差正解的分析方法。该正解模型的建模方法亦适用于其他并联机器人及空间机构的误差分析;对于6-SPS Stewart 平台一类机构及其演化构型,给定各结构参数误差,应用此正解模型可直接得出并联机构输出位姿误差,从理论上为定量分析各结构参数误差对输出位姿误差的影响提供前提条件。全面分析了结构参数和位姿参数对输出位姿误差的影响问题,研究了不同参数下奇异位形和机器人位姿正负偏差最大值出现的位置,结合对位姿正负偏差最大值的控制,提出了结构参数合理取值以有效避开误差敏感区的可行方法。根据并联机器人输出位姿误差的特点,提出了影响因子分析法。研究发现:位姿误差影响因子曲线存在极大值区域和相对稳定区间,应用影响因子分析法,可清晰地反映出结构参数几何奇异性的位置及变化趋势。研究发现: 6-3单三角平台和3-3双三角平台的影响因子较接近,且二者均远小于Stewart平台。研究结果可直接用于并联机器人的结构设计建立了并联机器人动平台输出位姿精度综合的数学模型,提出了基于原始误差等效作用原理和影响因子加权法实现机构精度综合的可行方法;揭示了原始误差等效作用原理的合理使用条件,以及影响因子加权法在并联机器人的结构设计中的作用。结果还表明:影响因子加权法对并联机器人的精度设计具有明确的指导意义。实例分析进一步验证了本文所建立的精度综合方法的有效性和必要性。更多还原

【Abstract】 Based on the typical structure—Stewart platform, this dissertation deals systematically with the error analysis and synthesis of parallel manipulators.The forward kinematics error model for the pose error analysis of the end effector has been formulated in terms of the differential relationship of robot and close-loop vectors of a parallel manipulator. For 6-SPS Stewart platform and its relevant configurations, the pose errors of the end effector can be directly obtained when the structural parameters and errors are given. The modeling method can also be used to the accuracy analysis of other parallel manipulators and spatial mechanisms.The effects of structure and pose parameters on the pose errors of the end effector is analyzed. The positions where uncertain configurations and the maxim deviations of the pose occur have been determined. Under the control of the maxim deviations, reasonable structure parameters, which are not sensitive to the pose errors, can be obtained.A new method—influence factor analysis is put forward according to the characteristics of the pose errors of parallel manipulators. Applying the method, the position of geometrical singularity and the changing trend can be uncovered. The influence factors of 6-3 and 3-3 Stewart platform are found to be approximate and both are far from one of the 6-6 Stewart platform. This results will provide a guideline in the design, manufacturing and assembly of the parallel manipulators.The accuracy synthesis model has been formulated by means of the error theory. Based on the principle that primary errors exert the same effects on the driven member and the concept--influence factors of the pose errors, two methods for pose error synthesis of parallel manipulators have been presented. The numerical examples indicate the necessity and effectiveness of the methods.更多还原