Improvement of simulation methods and realtime control a physiotherapy leg robot

One of the effective treatments for the rehabilitation of injured motor functions is physiotherapy. The main objective of this method is to strengthen the muscles in the affected area of the human body, usually in major joints such as the knee, ankle, wrist, shoulder, and spine, which are more prone to muscle injuries and strains. Physiotherapy is typically performed manually by applying manual techniques to the injured limb, but sometimes operator errors can cause harm to the patient. Nowadays, a new type of physiotherapy device has been introduced, in which the application of techniques is performed by a robot to the limb, eliminating many human errors by adhering to the proper conditions of physiotherapy. In this article, after providing a general introduction to these robots, two types of robots are selected for modeling and simulating the physiotherapy robot. The modeling includes parameters such as Denavit-Hartenberg, kinematics, and dynamics of the robots, and the desired path for the physiotherapy robot's leg is generated using the Realtime communication capability in MATLAB software. By aligning with a function that resembles the desired path, the robot's motion is simulated using a PD controller. By comparing two types of robots, RRR and RPR, investigated in this article, it can be said that the RRR robot had better controllability in terms of accuracy as 89.3% in contrast with 76.6% of RRR, reduction of steady-state error, and appropriate transient response behavior along the path.