Modeling Gait Patterns of a Patient with Orthopedic Injury Using an Exoskeleton

Abstract

Purpose of reseach. The paper describes the EXOLITE-REHAB rehabilitation robotic complex which makes it possible to do rehabilitation exercises of lower limbs of patients by performing leg lifting, verticalization, squats and other types of movement. In many countries, research work is underway to create devices that allow a person to move in space when the musculo-skeletal system is damaged.  Therefore, the purpose of this article is to study and set the basic regularities and algorithms based on mathematical models describing the controlled movement of the lower limbs exoskeleton by the example of modeling the movement of the exoskeleton's ankle joint.Methods. The key feature of the complex is the use of a follower-up control system that allows us to provide a prescribed movement of the human ankle joint with a high degree of accuracy in a wide range of parameters’ changes. Methods of mathematical modeling of the ankle joint movement are applied, taking into account their subsequent possible use in modeling the movement of exoskeleton links.Results. A kinematic setting of the ankle joint movement trajectory  is used in order to simulate the operation of a robotic system. In order to find the vector of generalized coordinates, the inverse kinematics problem is solved using the vector-matrix method with the application of Jacobian matrix. The results of numerical simulation show high convergence and adequacy of the proposed method.Conclusion. The article considers the method of using a follower-up control system that has a sufficient degree of accuracy of copying the trajectory. The results of modeling the follower-up control system of the EXOLITE-REHAB rehabilitation exoskeleton, working according to the developed algorithm, show that it is able to repeat the required trajectory with sufficient accuracy. In the future, we plan to study the system more deeply on a three-dimensional model with electric drives.