Kinematic and Dynamic Modeling of a 5-Bar Assistive Device for Knee Rehabilitation

Abstract

Knee injuries are frequent in people of all ages. In all cases, physical therapy is prescribed to recover strength, and range of motion. Robotic assistive devices are gaining the attention of the community and aim to improve the patients’ quality of life. In this paper, we propose a 5-bars-linkage knee rehabilitation device. We are interested in obtaining the complete dynamic model of the proposed rehabilitation system, in order to develop and evaluate adequate control strategies in future work. With this purpose, we present the kinematics formulation of the device and then, we derive the dynamics using two approaches, in order to validate the model; i.e. we obtain the motion equation using Lagrange approach and an algebraic method which simplifies the modeling. These models are simulated and compared with the physical behavior of the system, showing the functionality of the system and the validity of the models when performing a rehabilitation routine.