Synthesis of a passive unloading orthosis with mechanical feedback

Abstract

The development of new assistive devices for walking requires a high quality design implementation of the synthesized devices and taking into account additional requirements for a biomechanical system. In this paper, the existing designs of orthoses with passive unloading are analyzed and ways to expand their functionality are considered. It is shown that the presented designs of unloading knee orthoses have linear elastic characteristics, which cannot provide an extension of the functionality of these auxiliary devices. The paper proposes an improvement of the presented structures of passive unloading orthoses by adding mechanical feedback to their design. The study was carried out using the theory of modified kinematic graphs, which determines the analysis and synthesis of passive elastic devices with the possibility of self-management. Based on the kinematic schemes of the considered orthoses, models in the form of structural graphs were obtained and a further possibility of expanding the functionality of the synthesized device by adding an additional mechanical structure was determined. The analysis of synthesized passive orthoses with added controls was carried out, which showed their full performance and expansion of control capabilities. Also, according to the results of the analysis, the optimal variant of the synthesized device was chosen with its subsequent design implementation using Autodesk Inventor Series CAD. Based on the results of the study, it is shown that the use of the proposed theory of modified kinematic graphs is an effective means of synthesizing new self-controlled orthoses.