Creation of a simulated human gait with ELSA Prosthesis Digital Twin

Amputations are mainly due to vascular diseases such as diabetes. According to the Global Burden of Diseases, Injuries, and Risk Factor Study, in 2016, about 131 million people had diabetes-related lower-extremity complications, including 6.8 million amputations and approximately 0.4 million with a need for a prosthesis. This need for prosthesis led a team of UCLouvain searchers to create a bio-inspired, user-friendly, lightweight and energy-sufficient prosthesis for Trans-tibial amputees. This active prosthesis is called ELSA (Efficient Lockable Spring Ankle). The creators of this prosthesis also created its digital twin to emulate the prosthesis in order to allow the prosthesis software to be iterated safely. This Master's thesis focuses on creating a simulated human gait with ELSA Digital Twin. This study focuses on three kinds of gaits; On flat ground, inclined ground and staircase. Firstly, the baseline simulation setup furnished by ELSA's creators consists of a single simulated step. This step is then periodized to obtain a first gait on flat ground. Next, this gait is optimized and improved to get closer to human behaviour by adapting the walking phase's durations and speeds. In parallel, this gait is getting adapted to sloping grounds. The goal is then to obtain a more human-like behaviour of the simulated user by reproducing the knee movement. Finally, the research focuses on obtaining a stable gait on stairs. This study presents the controls and parameters implemented to reproduce the ELSA prosthesis behaviour by creating a simulated user.