六自由度并联机构误差分析和补偿

发布时间：2018-06-10 00:33

本文选题：6-PSS并联机构 + 弹性动力学分析　；参考：《重庆大学》2012年硕士论文

【摘要】：并联机构以其刚度大、运动精度高、承载能力强以及运动惯量小等优点，在众多工业领域得到广泛应用。并联机构的精度是其性能的重要指标，，要使其精度得到提高，就要对引起机构末端位姿产生误差的各项因素进行分析研究，以达到对其末端位姿误差进行补偿的目的，从而提高其运动精度。本文以一种型式为6-PSS并联机构的风洞实验运动控制装置为研究对象，对其进行了误差分析和补偿的研究，以使机构末端位姿精度能够达到实验要求。其主要工作包括机构的运动学分析、动力学分析、误差分析、误差参数辨识以及误差的补偿。结合6-PSS并联机构的结构特点，应用速度投影法求得了机构的雅克比矩阵，以及二阶影响系数矩阵，从而得到机构各构件的速度及加速度的表达式，并在此基础建立机构的刚体系统动力模型，然后，进一步将连杆看作弹性杆，应用有限元法建立6-PSS并联机构的弹性动力学模型。综合考虑6-PSS并联机构各项运动学误差，应用矩阵微分法建立机构的误差分析模型；根据机构总误差传递矩阵的型式，应用微分叠加原理对机构各单项误差源的特性进行研究，分析各单项误差源对末端位姿误差的影响特性；应用矩阵奇异值分解理论推得机构的误差敏感度的表达式，并对其特性进行分析计算；对机构弹性误差及铰链间隙误差进行了分析和计算。应用激光跟踪测量法测得6-PSS并联机构的末端实际位姿，在考虑所有静态误差的基础上，建立一种可以准确地将杆长误差和铰链间隙误差分离开的误差辨识模型，并应用最小二乘法对误差辨识模型进行求解，从而实现误差参数的辨识。应用软件补偿法对所有静态误差和动态误差进行补偿，在6-PSS并联机构运动过程中，将铰链间隙误差及连杆弹性变形误差等效为上下铰链位置误差来处理，然后对机构运动学参数进行修正，对修正后的运动学逆解模型进行求解，即可实现机构的误差补偿，从而提高机构的运动精度。本文将并联机构看作刚柔耦合系统的基础上，对机构进行误差分析和补偿过程中综合考虑了静、动态误差，很大的提高了机构的运动精度，对此类型的并联机构的理论研究及实际应用具有极大的指导意义，也为此类并联机构应用领域的拓展奠定了基础。
[Abstract]:Parallel mechanism has been widely used in many industrial fields because of its high stiffness, high precision, strong bearing capacity and small inertia. The precision of parallel mechanism is an important index of its performance. In order to improve its precision, it is necessary to analyze and study the factors that cause the error of the end position and pose of the mechanism, in order to compensate the error of the end position and pose. In this paper, a wind tunnel experimental motion control device of 6-PSS parallel mechanism is taken as the research object, and the error analysis and compensation are carried out, so that the precision of the end position and pose of the mechanism can meet the experimental requirements. The main work includes kinematics analysis, dynamics analysis, error parameter identification and error compensation. Combined with the structural characteristics of 6-PSS parallel mechanism, the Jacobian matrix of the mechanism is obtained by using the velocity projection method. And the second order influence coefficient matrix, so as to obtain the expressions of velocity and acceleration of each component of the mechanism, and then establish the dynamic model of the rigid body system of the mechanism on this basis, and further regard the connecting rod as an elastic rod. The elastic dynamics model of 6-PSS parallel mechanism is established by using finite element method. Considering the kinematics errors of 6-PSS parallel mechanism, the error analysis model of the mechanism is established by using matrix differential method. Using the principle of differential superposition, the characteristics of each single error source of the mechanism are studied, and the influence of each single error source on the terminal position error is analyzed, and the expression of error sensitivity of the mechanism is derived by using the matrix singular value decomposition theory. The elastic error and hinge clearance error of the mechanism are analyzed and calculated. The actual position and pose of 6-PSS parallel mechanism are measured by laser tracking method, and all static errors are considered. An error identification model, which can accurately separate rod length error from hinge gap error, is established, and the least square method is used to solve the error identification model. The software compensation method is used to compensate all the static and dynamic errors in the 6-PSS parallel mechanism. The clearance error of hinge and the error of elastic deformation of connecting rod are equivalent to the position error of upper and lower hinges, then the kinematics parameters of the mechanism are corrected, and the modified inverse kinematics solution model is solved, and the error compensation of the mechanism can be realized. In order to improve the kinematic accuracy of the mechanism, the parallel mechanism is regarded as a rigid-flexible coupling system in this paper. In the process of error analysis and compensation of the mechanism, the static and dynamic errors are considered comprehensively, and the kinematic accuracy of the mechanism is greatly improved. The theoretical research and practical application of this type of parallel mechanism are of great significance, and it also lays a foundation for the expansion of the application field of this kind of parallel mechanism.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH112

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