A Method for Analyzing Error Characteristics of Lower-mobility Parallel Mechanisms

Abstract

Abstract: Screw theory was applied to analyze the screw system of both parallel mechanism and each branch. From the controllable and uncontrollable degree of freedom, a general analytical method (freedom analyzing method) was proposed for analyzing the error characteristics of lower-mobility parallel mechanisms by virtual kinematic pairs. The method was unnecessary to establish static error model and might be used independently to analyze the effects of specific errors on the outputs of the moving platform. Then by taking 3-CUR parallel mechanism as an example,error characteristics were analyzed and obtained in this way. Vector method was used to set up the error model of 3-CUR mechanism and proved the regularity by simulation. The prototype was designed and machined in terms of the regularity and the prototype tests validated the correctness of the freedom analyzing method.

Key words: lower-mobility parallel mechanism, virtual kinematic pair, screw theory, error characteristics

摘要： 应用螺旋理论分析机构螺旋系及分支螺旋系，从机构不可控自由度和可控自由度两方面，通过虚设运动副，形成适用于少自由度并联机构的通用性误差特性分析方法(简称自由度法)，该方法无需误差建模，可单独分析特定误差对动平台输出的影响。以3-CUR并联机构为例，应用该方法进行误差分析，得到其误差特性规律。利用矢量法建立3-CUR机构的误差模型，并经仿真分析验证前述规律，根据此规律设计和加工样机，通过样机试验验证自由度法的正确性。

关键词: 少自由度并联机构, 虚设运动副, 螺旋理论, 误差特性

CLC Number:

TH112

ZENG Daxing;FAN Mingzhou;ZHANG Qingwu;WANG Juanjuan;YANG Yandong;HOU Yulei. A Method for Analyzing Error Characteristics of Lower-mobility Parallel Mechanisms[J]. China Mechanical Engineering.

曾达幸;樊明洲;张庆武;王娟娟;杨彦东;侯雨雷. 一种少自由度并联机构误差特性分析方法[J]. 中国机械工程.

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