Analysing the Kinematic Characteristics of Bennett Mechanisms and Its Networks for Usage in Forming Deployable Structures

Abstract

Two types of bennett mechanism are      encountered in most of the related literatures. This research aims at finding the best type of bennett mechanism out of the two and then using it for suitable application. One type of bennett mechanism is known as equilateral bennett mechanism, which has all the four kinematic links of equal lengths. Next type is a bennett mechanism having their opposite links of equal length. Using the two types of bennett mechanism, two different networks are created. Their working range, minimum foldability and maximum foldability of the networks were identified using MATLAB-SimMechanics toolbox. Thus, the network having better foldability was identified, so that it can be used for making foldable tent application, which is a deployable structure. The results from the analysis prove that equilateral bennett mechanism had better foldability than its counterpart. Then on analyzing the shapes of the networks, it was found that the networks had a saddle shape. The obtained saddle surface provided certain results like, when the twist angles of the bennett links were varied, saddle surfaces with more steepness are obtained. The influence of twist angle on angular displacement, angular velocity, and angular acceleration of the mechanism were also analyzed. Singularity analysis of these networks was done in Matlab-SimMechanics simulation environment. Coupler curves for both types of bennett mechanism were plotted to identify the trajectory of the output links