Thesis Project Form

Bipedal locomotion is fundamental in human walking, covering an average of 6500 steps per day. However, according to the latest data from the World Health Organization (WHO) there are an estimated 40 million amputees worldwide of which 90% of lower limb amputation. Reintegration into activities of daily living is a priority for amputees and requires anatomically and functionally appropriate technical solutions. In particular, transtibial amputees need an artificial foot and a proper socket for the remaining limb, even for partly recovering the previous capabilities. Among the potentially useful technologies to enhance such recovery there is the electromyography (EMG) sensorization of the remaining muscles, a well-known method for the upper limb prostheses to control the devices. In the lower limb prostheses domain, till now EMG sensors did not find a concrete application to directly control the prosthesis, because the remaining muscles are also solicited when patient weight is applied on the amputated leg, and for patient safety the prosthesis control cannot completely rely on EMG signals. In addition, lower limb muscles are usually less prone to be voluntary contracted respect to the upper limb ones. These problems make the lower limb EMG application, although precious from the point of view of the signal information, challenging for the integration between device and user and it deserves in-depth studies.

This works aims to build an EMG usable setup for the Smart Ankle prosthesis, a device designed inside IIT-INAIL Rehab Technologies Lab which is starting a formal clinical evaluation. Through this setup, the candidate will be able to acquire several EMG signals from the potentially interested muscles of a transtibial amputee. These signals will be analyzed and used together with the other signals coming from the device (angular position and speed, force flexion, presence/absence of vertical load, inertial measurements from IMU, current of the motor) to elaborate a strategy for lower limb EMG real applications. Starting from a position control of the device through EMG signals, with the user on a chair and no load applied on the device, additional more challenging scenarios of direct application will be investigated and simulated.

Proposed work plan and expected results:
1. Understand, run and evaluate EMG functional setup for the transtibial lower limb prosthesis Smart Ankle
2. Through the setup, acquiring signals from both healthy subjects (to test the acquisition) and from the amputee (to take all the useful signals)
3. Elaborate and integrate the information into the control of the device.
4. Perform initially a position control of the Ankle through EMG with the patient on a chair.
5. Elaborate more useful and challenging scenarios of EMG use for a transtibial amputee, like tasks change or muscular feedback acquisition.
The thesis may also produce a scientific article to be submitted to an international conference or journal (the students may contribute to the writing of the article, if they want, but this is not mandatory).