Use of collaborative robots to generate movement trajectories for rehabilitating patients with joint mobility limitations of the upper extremities.
Authors: Rafael Morano-okuno Hector , Caltenco Castillo Rafael , Sandoval Guillermo 
Published: October 2023

In the 2000s, the application of collaborative robots began to be heard more frequently in various sectors, such as the Manufacturing industry and Healthcare. One of its main advantages is the way of interacting with the user; since it allows to share workspaces more closely without any fatal collisions. Currently, the price of these robots varies with the task type; the more transport load they support and the greater precision in their movements, the more expensive they will be. Nowadays, several works mention the use of collaborative robots to assist in the rehabilitation process of patients. These procedures are expensive since, initially, the purchase of the robot is required, and later the application software to generate the patient's rehabilitation movements. This article presents a methodology to generate the trajectory of the rehabilitation movements of patients with limitations in the upper joints. Engineering application software is used for the academic community (Professors and students). The licenses for operating this software application are free for the academy. In university courses, inverse kinematics projects of collaborative robots can be proposed to generate the rehabilitation trajectories of the patients mentioned above. With this methodology, only the collaborative robot would be required, reducing the initial investment of this type of treatment. When using student software applications, it would be possible to use the other tools that this type of computational tool has, such as 3D printing of parts, some ergonomic analysis of components, or the design of parts or fasteners through the finite element method. To test the methodology developed, a case study was used. It was a final project in the Automation of Manufacturing Systems course of the Tecnologico de Monterrey for students of the Mechatronics Engineering career. In this case study, the generated trajectories stimulate patients' motor skills to draw 2D contours. However, an advantage of the described methodology is that it can be used to generate any 2D or 3D trajectory as required by the patient. The methodology consists of the following stages, 1) 3D modeling of the parts of the collaborative robot that intervenes to generate trajectories, 2) consultation of the reference system of the axes of the collaborative robot, 3) definition of the appropriate movements for the rehabilitation of the patient and 4) programming of the robot. At the beginning of the article, different configurations and applications of collaborative robots are mentioned. Subsequently, the characteristics of the collaborative robot used for this work are described. Next, the methodology implemented for generating trajectories for rehabilitating patients with limitations of the movements of the upper limbs is detailed. Then, the developed methodology is implemented through a case study. Finally, the results, conclusions, and future work are presented.