The BELK system has advanced features over the existing commercially available offer, facing the following technological challenges with respect to the current state of the art:
• First, there is a powered and wearable solution allowing users to perform knee rehabilitation during normal walking, unlike CPM devices. It is a one-joint-exoskeleton with an innovative transmission system (cable transmission – patented) that make possible to produce it at a reduced cost, which implies a final price similar to this one of CPM devices, but offering very advanced functionalities over them.
• Second, it is about providing the patient with "only when you need it" assistance, when currently the existing powered KAFO devices offer assistance based on all or nothing assistance. Current CPM systems are dedicated exclusively to repeat the movements that a physiotherapist would perform in a session, while KAFO devices reproduce a “robotic” movement, with very rigid pattern of movement, due to the lack of real-time adjustment between the force that patient can do and the force applied by the driver. BELK system only helps the movement in the stretch where the patient cannot. This implies intentionality by the patient that allows accelerating the rehabilitation since the effort realized is superior.
• Third, GOGOA has developed an algorithm to integrate Functional Electric Stimulation (FES) capabilities with the BELK robotic device. This intelligent and adaptable control algorithm allows to modulate the mechanical impedance that the exoskeleton exerts on the leg, combining the individual pattern of motion of the patient, the position of the leg and the force of the interaction between the patient and the device. Therefore, inducing variable muscle activation in the leg, which is indicated for optimal rehabilitation. None of the commercial knee rehabilitation devices (CPM, KAFO or exoskeletons) have this possibility.
In addition, the system is designed to be used at home, with no need to go to the rehabilitation centre, saving money and time, as well as the patient's mood. Technologically, this is possible through an optimal sensoring of the new device and the development of novel assistance control techniques that allow this assistance level based on "only when you need it".
The users needs addressed with this project are these ones related with a fast and effective rehabilitation of the knee and a fast and safe recovering of a natural pattern of gait. The rehabilitation process is a laborious work involving many physical therapy sessions over an extended period of time. These sessions mostly comprise repetitions of physical movements under the supervision of a physiotherapist. Because of this, a robotic system that allows these movements to be executed without the need of a therapist (even at the patient's home) greatly simplifies the process and dramatically reduces costs. Unlike existing CPM systems for knee rehabilitation, BELK may be used in the post-acute and functional training phases of the rehabilitation process as a wearable (non-static) system to accompany and assist the patient during the natural walking function.