A Modular Method for Mechanical Error Analysis of Planar Linkages Composed of Class II Assur Group Kinematic Chains

Abstract

This paper presents a modular method for the mechanical error analysis of complex planar linkages. The topology of the linkage under investigation is decomposed into several class II Assur group kinematic chains (AGKCs) combined in a given sequence. Therefore, the mechanical error of the whole linkage can be analyzed by investigating the error propagations of adopted AGKCs in successive order. Because class II AGKCs are first served as modules, the mechanical error equations of these AGKCs in terms of each error in link lengths and joint variables can be pre-formulated and embedded in form of subroutines in any programmable language. Once the AGKCs constituting the linkage topology is identified, the corresponding subroutines are introduced to compute the error propagations in the linkage. Therefore, the presented modular approach can facilitate the analysis by concentrating on the topology decomposition instead of the algebraic derivation. Numerical examples are provided to illustrate the advantage and flexibility of the modular approach.

An innovative device for enlarging the allowable misalignment for screwing tasks

“…In this section, the mechanism is divided into two four-bar loops. Both four-bar loops can be verified by substituting two sets of known dimension factors into the set of equations derived from the method proposed in Hsu and Chung (2021) and Choubey and Rao (1987).…”

“…Lai and Zhu (2016) published an analytical model for a class of remote center compliance (RCC) mechanisms in order to evaluate the compliance properties and rotational precision of the mechanism. Kim et al (2021) proposed a robotic assembly integrated with displacement sensor on a RCC device to detect the three translation and three rotation components generated by external forces and torques applied to the device. Unfortunately, there are no exciting RCC devices that can be used for a screwing task since they can only carry out an inserting motion without rotation.…”