Session: MR-02-01 Theoretical & Computational Kinematics

Paper Number: 66869

Start Time: August 18, 10:00 AM

66869 - A Geometric Approach for Error Space Estimation of Planar Linkage 

This article develops a geometric method to estimate the clearances-induced error space of any planar linkage. The error space  discussed here represents the unconstrained mobility of the end-effector when actuator of the mechanism is locked, and is expressed by a connected geometric body in 3-dimensional Euclidean frame $\{x,y,\theta\}$. First,  error space of the planar mechanism is modeled and closed-form expressions are derived. Then, levels of joints in error propagation analysis are defined and illustrated with an example of a eight-bar linkage, following which error propagation path among closed-loop structures is given. The  modeling of error propagation and accumulation is introduced in detail. Moreover, simplification technique is discussed for simple expression of the error space propagated from previous joints. This study provides a way to have a deep insight into the accuracy performance of any planar linkage and the proposed error space evaluation method is validated by case study of error space estimation of a four-bar linkage and a six-bar linkage. For the four-bar linkage, the structure with optimal accuracy is obtained. And for the six-bar linkage, the error space of the end-effector is expressed in closed form and visualized in the 3-dimensional frame.  Finally, this work is concluded and advances of the proposed method is outlined. 

Presenting Author: Jianzhong Ding Beihang University

Authors:

Jianzhong Ding Beihang University
Chunjie Wang Beihang University