Design and Fabrication of Running Cheetah Mechanical Toy Using Four-Bar Linkage

Abstract

Four-bar is the simplest planar 1-DOF closed loop linkage. It has been studied for centuries for its versatility and simplicity. In this paper a novel design method to obtain a four-bar linkage given a path and its endpoints will be presented. This method will then be applied to a case study of making a model that produces a specified movement based on reference animation. The mechanism obtained had an average root-mean-square of position error of roughly 14.3 pixels for front leg and 25.9 pixels for hind leg. This number is quite small compared to the perimeter of the traced path, which are 530 pixels and 617 pixels for front leg and hind leg respectively. A prototype model of the designed mechanism was fabricated to verify its manufacturing viability and to confirm the correctness of the path generated.