IMMC
![]() | ELSA, an ankle-foot prosthesis to restore amputees locomotion Researcher: François Heremans Supervisor(s): Renaud Ronsse Over the last decade, active lower-limb prostheses demonstrated their ability to restore a physiological gait for lower-limb amputees by supplying the required positive energy balance during daily life locomotion activities. However, the added-value of such devices is significantly impacted by their limited energetic autonomy, excessive weight and cost preventing their full appropriation by the users. There is thus a strong incentive to produce active yet affordable, lightweight and energy efficient devices. To address these issues, we are developing the ELSA (Efficient Lockable Spring Ankle) prosthesis embedding both a lockable parallel spring and a series elastic actuator, tailored to the walking dynamics of a sound ankle. The first contribution concerns the developement of a bio-inspired, lightweight and stiffness adjustable parallel spring, comprising an energy efficient ratchet and pawl mechanism with servo actuation. The second contribution is the addition of a complementary rope-driven series elastic actuator to generate the active push-off. Our new system produces a sound ankle torque pattern during flat ground walking. Up to 50% of the peak torque is generated passively at a negligible energetic cost (0.1 J/stride). By design, the total system is lightweight (1.2 kg) and low cost. |
Locomotion assistance through active motor primitives Researcher: Henri Laloyaux Supervisor(s): Renaud Ronsse This project is about the development and validation of a new method for assisting human locomotion with robotic devices. It will be based on so-called “motor primitives”, i.e. fundamental units of action which have been identified in the human locomotor apparatus. These primitives will be constrained to be mathematical functions with a limited number of open parameters, therefore optimizing the computational efficiency. Next, the assistance will be designed to be adaptive to the user’s particular gait and status. Finally, some primitives will be specifically developed to support the user’s balance, on top of delivering energy for assisting locomotion. These three objectives will require first theoretical developments, and then experimental validation. |
Captive Trajectory System for the handling of wake-impacted flow devices Researcher: Emile Moreau Supervisor(s): Renaud Ronsse, Philippe Chatelain The main objective of the thesis is to develop a Captive Trajectory System (CTS) for the handling of wake-impacted flow devices that are free flying or swimming, such as aircrafts or bio-inspired robots. Which means that there is no other external force applied on those models, barring gravity, than the one applied by the fluid. The envisioned facility will be unique at an international level. At the same time, its scope of applications will be quite wide, covering, but not limited to, applied and fundamental fluid mechanics (fluid-structure interaction problems), biomechanics (biolocomotion), and civil engineering (wind or flow-structure interactions). Additionally, we see this project as a first foray into the emerging field of experimental studies augmented by Artificial Intelligence or co-simulation. Nowadays, this is not experimentally achievable by the use of Lab facilities, because they only allow, at most, horizontal and vertical displacements and do not feature any force or motion control. Hence, the goal of this thesis, of a rather experimental nature, is to design a robotic system – possibly partially immersed – whose precision, sensing and control capabilities will be able to handle free-moving devices, and to validate fluid-structure interaction models developed by various IMMC research teams, also involved in the project. |
Detecting and using locomotion affordances for lower-limb prostheses by active vision Researcher: Ali Hussein Al-Dabbagh Supervisor(s): Renaud Ronsse Healthy lower-limb biomechanics reveals that active prostheses are necessary to provide amputees with human-like dynamics in various locomotion tasks like walking or stair ascending/descending. Ali’s project is about the specific challenges associated to the transition between two of these tasks, where the control parameters of the device has to be smoothly and timely adapted. Active vision is proposed to be used to augment the prosthesis with vision-based detection of possible locomotion affordances, therefore anticipating these transitions as a function of the user’s behavior. |