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平面两自由度并联机构运动学标定研究 总被引:1,自引:0,他引:1
提出一种平面两自由度并联机构,由运动学分析得出机构的运动学解析解,针对该机构提出了一种运动学标定的新方法。与传统的并联机构运动学标定方法不同,该方法无需测量末端执行装置的全部位置和姿态,只需测量末端执行装置在工作空间内的一系列位移量;通过使用万能工具显微镜作为检测工具,从而无需额外安装位移传感器。建立了使得距离测量误差平方和最小的非线性规划数学模型,并通过MATLAB软件的优化工具箱进行求解。实验证明了该方法的有效性,并得出了机构运动学参数的最优值。实验结果表明,标定后机构精度明显提高,标定方法可靠。 相似文献
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针对平动并联机构标定中的测量,提出一种基于参数辨识性分析的简单测量方案的设计方法.该方法根据误差模型输出和机构自由度,给出工程实际中常用的基本测量方式,然后逐一进行辨识性分析.在兼顾测量成本、辨识完整性和参数辨识性能的条件下,比较、整合各测量方式,从而确定出一种简单测量方案.利用上述方法,对一台2自由度平动并联机构标定进行简单测量方案的设计,标定仿真结果验证了该方法的实用性和有效性.由该方法得到的测量方案简单易行,实施效率高,其思路适用于工程环境下各种平动并联机构的标定. 相似文献
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一个特殊3自由度并联机构的精度分析及标定 总被引:4,自引:0,他引:4
运动学标定是一种提高机器精度的有效方法。一个改进的误差分析和标定方法得到仿真验证,解决一个用做锻压操作机台虎钳的特殊3自由度并联机器的标定问题。通过建立运动学正解和逆解模型,得到机构的运动空间并对机构进行运动学精度分析,得到机构所有误差源对终端位姿误差的影响因子。结合零部件加工工艺性及精度分析的结果,确定需要标定的误差源,并利用直接微分法得到机构的雅可比矩阵。随机选点建立误差辨识矩阵对机构运动学参数进行标定辨识,Matlab仿真结果显示,经过1次运算得到的运动学参数误差的辨识值与真值之间的偏差小于5%,验证了针对这一特殊3自由度并联机器的精度分析和标定方法的有效性。 相似文献
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以太阳能硅片丝网印刷装备为研究平台,采用并联机构与视觉系统实现硅片和丝网的对准,得到并联机构运动学正反解,完成运动学参数补偿与误差分析;提出了一种区别于传统视觉标定的视觉自标定方法,所得优化参数使机械装配上引起的对准误差最小化。 相似文献
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结合65m天线副反射面位姿调整任务要求,研究天线副反射面调整机构的标定问题。制定出副面调整机构标定流程与方案,利用激光跟踪仪测量机构动平台位姿,根据运动参数的实测信息,由并联机构学理论构造误差函数,并以误差函数最小化为目标进行机构运动学参数辨识;开发完成标定算法,对副面调整机构进行运动学标定,求解获得满足预期精度要求的结构参数,并对机构参数进行补偿。面向工程实际任务开展标定研究,研究结果对并联机构真正应用于工程实践具有重要的指导意义。 相似文献
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通过分析Stewart机构各运动副的制造误差和安装误差,以及其对雅可比矩阵的影响,利用雅可比矩阵和一阶静力影响系数之间的对偶关系,提出基于广义力平衡原理的Stewart平台机构标定方法。该方法通过测量平台各缸作用力,避免了测量虎克铰空间坐标难的问题。通过对平台进行广义力加载测量,得到平台平衡状态时互不相关的广义力和各单缸力的实验数据,最后利用最小二乘法拟合得出实际的一阶静力影响系数,从而标定出机构初始状态时的各铰点空间坐标。实验表明,该方法所标定出的Stewart平台机构参数,能使平台的运动学模型更为精确,有效地提高了平台的定位精度。 相似文献
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为提高6-PSS并联机构的运动精度,需对其进行误差分析和标定研究。利用矢量法构建并联6自由度机构的误差模型,根据MATLAB计算得到机构的误差源对动平台末端位姿影响的灵敏度。对机构进行误差综合分析,结合运动学正解和逆解,提出一种新的基于机构坐标轴姿态约束的运动学标定方法。根据测量初始值,利用标定算法解算得到机构的标定值。借助外部检测设备测量得机构标定前和标定后的位移和角度误差,标定后位移误差由10mm减小到1mm,角度误差由0.3°减小到0.1°。以实际测量数据验证了该标定方法的有效性和正确性,并最终提高了并联机构的运动精度。 相似文献
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针对六轴混联机床中因3-RPS并联机构结构参数误差引起的精度问题,分析了影响3-RPS并联机构几何精度的误差因素,给出了并联机构的误差模型;基于影响并联机构定平台运动精度较大的几何误差参数;建立了运动学标定模型.采用阻尼最小二乘法,经多次优化迭代实现了利用一组测量数据完成非线性超越矛盾标定方程组的求解.利用激光干涉仪完成了标定用数据的测量,通过3-RPS并联机构运动学逆解和各铰链的几何标定参数,得到动平台的实际位姿.通过对标定前后的Z轴定位精度的检测及实际零件加工试验,验证了3-RPS并联机构运动学标定模型和方法的正确性和有效性. 相似文献
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Serial robots are used to handle workpieces with large dimensions, and calibrating kinematic parameters is one of the most efficient ways to upgrade their accuracy. Many models are set up to investigate how many kinematic parameters can be identified to meet the minimal principle,but the base frame and the kinematic parameter are indistinctly calibrated in a one-step way. A two-step method of calibrating kinematic parameters is proposed to improve the accuracy of the robot's base frame and kinematic parameters.The forward kinematics described with respect to the measuring coordinate frame are established based on the productof-exponential(POE) formula. In the first step the robot's base coordinate frame is calibrated by the unit quaternion form. The errors of both the robot's reference configuration and the base coordinate frame's pose are equivalently transformed to the zero-position errors of the robot's joints. The simplified model of the robot's positioning error is established in second-power explicit expressions. Then the identification model is finished by the least square method, requiring measuring position coordinates only. The complete subtasks of calibrating the robot's 39 kinematic parameters are finished in the second step. It's proved by a group of calibration experiments that by the proposed two-step calibration method the average absolute accuracy of industrial robots is updated to 0.23 mm. This paper presents that the robot's base frame should be calibrated before its kinematic parameters in order to upgrade its absolute positioning accuracy. 相似文献
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Laser tracking system (LTS) is an advanced device for large size 3D coordinates measuring with the advantages of broad range, high speed and high accuracy. However, its measuring accuracy is highly dominated by the geometric errors of the tracking mirror mechanism. Proper calibration of LTS is essential prior to the use of it for metrology. A kinematics model that describes not only the motion but also the geometric variations of LTS is developed. Through error analysis of the proposed model, it is claimed that gimbals axis misalignments and tracking mirror center off-set are the key contributors to measuring errors of LTS. A self-calibration method is presented of calibrating LTS with planar constraints. Various calibration strategies utilizing single-plane and multiple-plane constraints are proposed for different situations. For each calibration strategy, issues about the error parameter estimation of LTS are exploded to find out in which conditions these parameters can be uniquely estimated. Moreover, these conditions reveal the applicability of the planar constraints to LTS self-calibration. Intensive studies have been made to check validity of the theoretical results. The results show that the measuring accuracy of LTS has increased by 5 times since this technique for calibration is used. 相似文献
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多关节测量臂是一种便携式的坐标测量设备,它由一系列的旋转关节组成。为了提高多关节测量臂的测量精度和可重复性水平,必须对其运动学参数进行校准。首先,利用小生境的混沌优化算法提出了一种新的运动学校准方法以及一种混合目标的运动学校准函数,它考虑了诸如单点测量实验、容积性测量实验等多种性能测量实验的实验结果,然后,采用Levenberg Marquardt(L-M)算法和小生境混沌优化算法应用于运动学参数校准。小生境混沌优化算法显示出了优于L-M算法的性能。实验结果表明:使用NCOA算法校准后,测量误差的标准差始终优于LMA算法,并且校准前后多关节测量臂的测量精度提高了40倍。采用L-M算法和小生境混沌优化算法应用于运动学参数校准。小生境混沌优化算法显示出了优于L-M算法的性能。 相似文献
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《Measurement》2003,34(4):347-353
One of the main tasks of Primary Electromagnetic Laboratory (PEL) in Croatia is to ensure a system of international traceability for its standards. PEL has established resistance traceability for the group of resistance standards in the range of 1 mΩ to 100 MΩ. The preferred way of resistance standard calibration at PEL is self-developed method using two digital voltmeters, which are measuring voltage drops on serially connected standard resistors. The method is also used for calibration purposes of all types of resistors, decades, shunts and resistance measuring devices. Another method for calibrating high-ohm resistance standards is currently being developed to extend the resistance measuring capability of PEL to the TΩ range. 相似文献
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用于结构光视觉传感器标定的特征点获取方法 总被引:5,自引:0,他引:5
提出了一种基于共面参照物自由移动来获取结构光视觉传感器标定特征点的新方法。该方法通过以摄像机三维坐标系为中介,将多个局部世界坐标系下的标定特征点统一到全局世界坐标系中,得到位于光平面上的非共线标定特征点的三维世界坐标。该方法降低了标定设备的成本,简化了结构光视觉传感器的标定过程,从而提高了结构光视觉传感器工程化应用的便捷性。实验表明,该方法切实可行 相似文献
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Part II of this study is essentially an experimental development of the previously shown theoretical model. Based on the model for calibrating the “vision subsystem” developed in part I, an example of measuring and calculating uncertainties that ensures the traceability of the measurements is presented here. The Monte Carlo method is used as a tool for estimating uncertainties and the effectiveness of the proposed method is experimentally verified by measuring a calibrated line scale. Finally, the validity of the calibration parameters of the “vision subsystem” is determined. 相似文献