Controlling 3-d model of two exoskeleton links with variable length

Abstract

3-D models of one-link and two-link exoskeletons with variable-length links are considered. The construction of a multi-link model is done from a simple one to a complex one. The 3-D analysis of the one-link model with one fixed point is done at first. After that, the two-link model with variable-length links is considered. It has been found that increasing the number of links leads to difficulties in composing the system of differential equations of motion relating to a longer time required for building it, even if the modern systems of computer mathematics are used. The proposed link model can be used for designing the working exoskeleton or anthropomorphic robot. The exoskeleton link consists of two absolutely rigid weighty sections at the link ends and of a weightless section between them. The analytically synthesised trajectories of the exoskeleton motion are given. The problem of finding controlling torques and forces is solved numerically and the solution results are presented graphically. The application of the proposed variable-length link model to an exoskeleton will reduce the load on the User’s joints, increase the User’s comfort and the force applied by the exoskeleton operator, as well as the period of its uninterrupted operation.