Electromechanical Model of Variable-Length Link for Exoskeleton or Prosthesis

The purpose of this study is creating a 3-D electromechanical model of a variable-length link simulating the dynamics of telescopic manipulators, anthropomorphic robots, exoskeletons and human musculoskeletal system. The proposed link model has two weighty absolutely rigid sections at the ends and a weightless variable-length section in between. The composed system of Lagrange-Maxwell differential equations of the variable-length link motion, and the created electromechanical model of anthropomorphic system in the Matlab Simulink software are the results of the study. Based on these results, the electric motors and the reduction gears are selected to implement the biomechanical link motion in the human musculoskeletal system. In doing so, the geometry and the inertia properties of the variable-length link corresponding to the shin of an average human being are used. The selected motors have sufficient power reserve. The trajectories ensuring the required link motion are calculated in generalized coordinates. The mechanism load diagrams are charted. The motors control system is proposed. The link positioning error is estimated. The novelty includes the newly developed electromechanical model of controlled variable-length link which can be applied to designing anthropomorphic robots and comfortable exoskeletons of new generation. The results of numerical calculations are presented. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.