Robotic assistance for rehabilitation of injured ankles

Robotics has gradually entered all walks of life. A variety of models, sizes and technologies are taking center stage in complex operations with high levels of accuracy. In the fields of physical rehabilitation and biomedical engineering, significant developments are taking place in the design and manufacture of innovative devices to improve recovery from muscle injuries. In particular, there are new options for ankle injuries that improve patients’ functionality and mobility.

Based on the concept of the Stewart Platform, Francisco Zebert, an electronic engineering student at the National University of Northeast in Argentina, received the Scholarship for the Encouragement of Scientific Occupations (EVC-CIN), for which he has developed a robot prototype for rehabilitation. Injured ankle. The title of the proposal was “Design and Fabrication of a Prototype of Robotic Platform for Ankle Rehabilitation.” The project is directed by Dr. Maria Ines Pisarello from the Biomedical Engineering Research Group of the Faculty of Exact and Natural Sciences and Surveying of the National University of the North-East.

This project opens new directions of research, in addition to making a promising contribution to the recovery of patients.

The prototype developed by Zebert is of a parallel robot, based on the Stewart platform. These platforms – derived from the Gough-Stewart platform but with rotational actuators – have a number of industrial applications, including flight simulators, teaching, and research. Its high stiffness, load capacity and accuracy in its positioning focused the interest of the scientific community as an alternative to traditional robots.

Francisco Zebert and Maria Ines Pisarello. (Photo: National University of the Northeast/Argentina Investiga)

The proposed prototype designed for ankle rehabilitation has precise and multidirectional control of the motion of the affected joint. “By simulating different types of joint movements and applying controlled loads in different directions, it will provide information about the range of movements of each particular ankle and thus design a specific therapy for each patient,” said Zebert of Argentina Investiga. Explained.

Referring to the impact of the prototype he said, “It is an important contribution to scientific knowledge, especially in the practice of physical rehabilitation.”

The development of the prototype also combines design and 3D printing technology. Control over the speed of ankle healing is achieved through programming with integrated development software implemented in microcontrollers.

Based on the analysis of inverse kinematics, the set allows you to choose six basic movements for the ankle rehabilitation process: dorsiflexion, plantarflexion, inversion, inversion, abduction and adduction.

Inverse kinematics is a technique for determining the configuration that a robot should adopt for final position and orientation. It involves solving a set of mathematical equations that make it possible to capture certain rotation angles depending on the desired translation and rotation. Thus, if we place the ankle on the end effector, it is possible to rotate it accurately.

The prototype is composed of standardized elements: rigid link (CNC machined aluminum alloy steering rod); ball joints; M3 screw and nut; Rotational actuators (servomotors); and elements made from PLA (polylactic acid) material through additive 3D printing with FDM (fused deposition modeling) technology. The latter consists of both the mobile platform and the supports consisting of servomotors, the mobile platform, and the ankle. Its design is made using CAD (Computer-Aided Design) software “SolidWorks”.

Another contribution of the project is the research directions it is open to venture into in the search for new knowledge. some of them are:

– Detailed study of the biomechanics of the ankle: The Stewart platform will allow the ankle to be subjected to a variety of movements in different planes and directions with precision and control. This can provide a deeper understanding of how different types of activities and loads affect the joints and surrounding tissues.

– Optimization of rehabilitation protocols: The platform can be used to study how the ankle heals after specific injuries such as sprains. This will lead to a deeper understanding of the treatment processes and allow the development of more effective and individualized rehabilitation approaches.

– Studying the effect of loading on chronic conditions: Investigating how loading and movement affect the ankle can provide valuable information about chronic conditions such as osteoarthritis. This may lead to new management and treatment strategies optimizing therapeutic approaches.

– Development of simulation models: With detailed data on the response of the ankle to various loads and movements, it is possible to develop more accurate computer simulation models. These models can be used to predict how the ankle will respond to different conditions with the goal of designing more effective treatment and prevention strategies. (Source: Juan Monzón Gramajo / National University of the Northeast / Argentina Investiga)