Design and Experimental Testing of an Ankle Rehabilitation Robot

Abstract

The ankle joint (AJ) is a crucial joint in daily life, responsible for providing stability, mobility, and support to the lower limbs during routine activities such as walking, jumping, and running. Ankle joint injuries can occur due to sudden twists or turns, leading to ligament sprains, strains, fractures, and dislocations that can cause pain, swelling, and limited mobility. When AJ trauma occurs, joint instability happens, causing mobility limitations or even a loss of joint mobility, and rehabilitation therapy is necessary. AJ rehabilitation is critical for those recovering from ankle injuries to regain strength, stability, and function. Common rehabilitation methods include rest, ice, compression, and elevation (RICE), physical therapy, ankle braces, and exercises to strengthen the surrounding muscles. Traditional rehabilitation therapies are limited and require constant presence from a therapist, but technological advancements offer new ways to fully recover from an injury. In recent decades there has been an upswing in research on robotics, specifically regarding rehabilitation. Robotic platforms (RbPs) offer several advantages for AJ rehabilitation assistance, including customized training programs, real-time feedback, improved performance monitoring, and increased patient engagement. These platforms use advanced technologies such as sensors, actuators, and virtual reality to help patients recover quicker and more efficiently. Furthermore, RbPs can provide a safe and controlled environment for patients who need to rebuild their strength and mobility. They can enable patients to focus on specific areas of weakness or instability and provide targeted training for faster recovery and reduced risk of re-injury. Unfortunately, high costs make it difficult to implement these systems in recuperative institutions, and the need for low-cost platforms is apparent. While different systems are currently being used, none of them fully satisfy patient needs or they lack technical problems. This paper addresses the conception, development, and implementation of rehabilitation platforms (RPs) that are adaptable to patients’ needs by presenting different design solutions (DSs) of ankle RPs, mathematical modeling, and simulations of a selected rehabilitation platform (RP) currently under development. In addition, some results from practical tests of the first prototype of this RP are presented. One patient voluntarily agreed to use this platform for more rehabilitation sessions on her AJ (right leg). To counteract some drawbacks of the first prototype, some improvements in the RP design have been proposed. The results on testing the improved prototype will be the subject of future work.

Development of a portable and compact robotic ankle rehabilitation system

“…The use of robotic structures can bring benefits such as cost reduction in active labor for motion-based rehabilitation procedures and an expanded range of exercises, helping patients maintain mobility through continuous therapy [4][5][6][7][8]. The use of rehabilitation robots during post-stroke rehabilitation is limited due to high costs, and they are often considered too expensive for healthy systems.…”

Field oriented control driver development based on BTS7960 for physiotherapy robot implementation

“…Electrical components play a crucial role in the functioning of ankle physiotherapy robots. These robots typically use electric motors, pneumatic actuators, or electro-hydraulic systems as actuators to provide the necessary movement and force for ankle exercises [12]. Among them, electric motors are commonly used in both wearable and platform-based ankle physiotherapy robots due to their compact size, high efficiency, and precise control capabilities [13].…”

“…This information is crucial for the control system to adjust the robot's movements and provide appropriate assistance or resistance during the exercises [18], [19]. Common sensors used in ankle rehabilitation robots include encoders, force sensors, and accelerometers [12], [20]. Power supplies provide the necessary electrical energy to operate the robot's actuators, control systems, and sensors.…”

A Portable Robotic System for Ankle Joint Rehabilitation

“…Examples of more recent works are [22][23][24] for specific designs and experiences regarding ankle rehabilitation robots. In [22], a supine ankle rehabilitation robot is specifically proposed for the early bedridden rehabilitation of stroke patients.…”

“…Reference [24] presents a rehabilitation platform that is based on a parallel architecture mechanism with a bulky fixed frame that is tested with a prototype with interesting results from kinematic viewpoints.…”