• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2021, Vol. 57 ›› Issue (9): 39-50.doi: 10.3901/JME.2021.09.039

• 机器人及机构学 • 上一篇    下一篇

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空间连杆机构位移分析的共形几何代数方法

黄昔光1, 刘聪聪1, 黄旭1, 李强1, 李端玲2   

  1. 1. 北方工业大学机械与材料工程学院 北京 100144;
    2. 北京邮电大学自动化学院 北京 100876
  • 收稿日期:2020-08-05 修回日期:2020-11-24 出版日期:2021-05-05 发布日期:2021-06-15
  • 通讯作者: 黄昔光(通信作者),男,1979年出生,博士,副教授,硕士研究生导师。主要研究方向为机构学与机器人学。E-mail:marchbupt@126.com
  • 基金资助:
    国家自然科学基金(51105003,51775004,51775052)、北京市自然科学基金(3172010)、国家重点研发计划(2020YFC0811004)、陕西省自然科学基础研究计划(2019JM-181)和北方工业大学毓优人才支持计划资助项目。

Displacement Analysis of Spatial Linkage Mechanisms Based on Conformal Geometric Algebra

HUANG Xiguang1, LIU Congcong1, HUANG Xu1, LI Qiang1, LI Duanling2   

  1. 1. School of Mechanical and Materials Engineering, North China University of Technology, Beijing 100144;
    2. Automation School, Beijing University of Posts and Telecommunications, Beijing 100876
  • Received:2020-08-05 Revised:2020-11-24 Online:2021-05-05 Published:2021-06-15

摘要: 空间连杆机构位移分析是机构运动学和动力学研究的基础,由于空间连杆机构输入输出位移参数多且强非线性,尽管经过多年研究已经有多种位移分析的求解方法,但多维高阶代数方程组求解至今仍然是困扰机构学与机器人学研究的难题。总结了传统空间连杆机构位移分析理论基本求解过程,阐述了空间连杆机构位移分析中三种常见的几何代数系统,归纳了空间连杆机构位移分析所需的共形几何代数(Conformal geometric algebra,CGA)基本理论。以一种空间6R串联机构和空间RRSRR机构为例,将CGA引入到空间连杆机构位移分析中,把空间连杆机构几何模型中的关节特征点映射到五维共形空间中,建立了关节特征点的CGA表达式,基于特征点构造若干直线、平面或球面等几何体,通过几何体的外积计算获得待求关节交点的CGA形式表达方程,再利用CGA理论框架内的内积或幂零性质直接获得空间连杆机构的关节转角余弦表达或无增无漏根的一元高次位移分析输入输出方程,从而获得空间连杆机构位移分析的全部符号形式解析解。方法实现了几何语言直接(脱离坐标)求解空间连杆机构位移分析,避免了经典机构学理论中复杂的旋转坐标变换矩阵运算以及多元高次非线性方程组求解。基于计算机代数计算系统Maple16编程,数字实例计算表明,方法正确有效,具有较好的几何直观性。

关键词: 共形几何代数, 空间连杆机构, 位移分析, 解析解

Abstract: The displacement analysis is the basis of kinematics and dynamics research for spatial mechanisms. Though there exit many methods to solve the displacement analysis, the solution of multi-dimensional high-order algebraic equations is still a difficult problem in the research of mechanism and robotics due to the strong nonlinearity of input and output displacement parameters of spatial mechanisms. The basic process of traditional displacement analysis theory of spatial mechanisms is analyzed, three common geometric algebraic systems and the basic theoretical framework of conformal geometric algebra (CGA) are expounded. CGA is introduced into the displacement analysis of spatial mechanism and new algorithms are proposed for displacement analysis of a spatial 6R spatial mechanism and a spatial RRSRR mechanism. The revolute joints are determined by the description of rigid motion in CGA. The cosine values of all joint rotating angles and the input-output polynomial equation with a single unknown can be derived by the inner product between and all closed-form solutions are obtained. The algorithm is the pure geometric computation in a clear and coordinates-free way and avoids the use of rational angles or matrices, and complex computations for nonlinear and multivariable equations. Finally, two numerical examples are given to demonstrate the efficiency of the algorithm and the results show that this algorithm can simplify the complexity of computation with strong geometrical intuition based on Maple16.

Key words: conformal geometric algebra, spatial linkage mechanism, displacement analysis, closed-form solutions

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